CN104561602A

CN104561602A - Method for smelting magnesium and co-producing ferrochrome-containing liquid with ferrosilicon bath stair reduction silicothermic method

Info

Publication number: CN104561602A
Application number: CN201510043724.9A
Authority: CN
Inventors: 牛强
Original assignee: 牛强
Current assignee: Hangzhou Jiman iron Hydrogen Energy Technology Co.,Ltd.
Priority date: 2015-01-28
Filing date: 2015-01-28
Publication date: 2015-04-29
Anticipated expiration: 2035-01-28
Also published as: CN104561602B

Abstract

The invention relates to a method for smelting magnesium and co-producing ferrochrome-containing liquid with a ferrosilicon bath stair reduction silicothermic method, belongs to the technical field of nonferrous magnesium metal extraction and also belongs to technical field of chromium-containing stainless steel and ferrochrome smelting of ferrous metallurgy. Ferrosilicon bath much higher in theoretical chemical demand quantity is used as a silicothermic reducing agent and carrier of chemical reaction, reaction interfacial area is increased and convective heat transfer and mass transfer abilities are strengthened to realize reinforcement of reduction process through intense stirring. After reduction is completed, magnesium smelting reduction slag is eliminated, excessive ferrosilicon is mixed with a new batch of magnesium ore to smelt magnesium until the concentration of ferrosilicon liquid is lower than that of lower silicon, and lower ferrosilicon liquid is mixed with chrome ore to carry out chromium reduction to obtain chromium-containing stainless steel mother liquid. The excessive ferrosilicon bath is respectively used for smelting magnesium and ferrochrome at high concentration and low concentration, ferrochrome raw material is completely utilized, the reaction efficiency is high, energy is saved, carbon, phosphorus and sulphur in the ferrochrome liquid are little, and the co-production cost of magnesium and stainless steel liquid is obviously reduced in comparison with sum of the production cost of magnesium and the production cost of stainless steel liquid.

Description

The coproduction of ferrosilicon bath step reduction magnesium-smelting silicothermic process is containing the method for ferrochrome liquid

Technical field

The invention belongs to non-ferrous metal magnesium Extraction metallurgy technical field, also belong to the technical field of chromium stainless steel in ferrous metallurgy, ferrochrome smelting, particularly magnesium-smelting silicothermic process coproduction is containing the method for ferrochrome liquid.

Background technology

Metal Mg-based hydrogen storage is the lightest structural metallic materials, is used in the fields such as the vehicles, electronic product, material of construction, aerospace, brings energy-conservation effect, be described as " the 3rd metal ", " the green metal material of 21st century ".The Mineral resources of the major metal such as iron and steel, aluminium material are progressively being tending towards exhausted, and the Mineral resources of MAGNESIUM METAL are very abundant, moreover contain the magnesium resource of more horn of plenty in seawater, can for mankind's more than one thousand years.

From natural mineral products, the Technology of extraction of metal magnesium divides two large classes: electrolytic process and hot reducing method.Electrolytic process generally adopts magnesium chloride to be raw material, and while electrolysis obtains MAGNESIUM METAL, by-product chlorine, environmental issue is difficult to overcome, and only adopts electrolytic process less than 20% in MAGNESIUM METAL output global at present.

Several magnesium refining method of Fig. 1 system introduction, the main technique of hot reducing method is silicothermic process, namely silicon is adopted to be reductive agent reduction-oxidation magnesium, MAGNESIUM METAL steam is obtained under high temperature and vacuum condition, then condensation obtains the technique of MAGNESIUM METAL, what wherein occupy main flow is so-called " Pidgeon process " technique (Pidgeon Process), and namely external-heat horizontal tank cycle silicothermic process, this method is current leading industry technology.In addition, France once developed semi-continuous electrical conductivity of molten slag silicon reduction technique (Magnetherm Process) and achieved industrialization, but its ferrosilicon consumes higher than theoretical value, has seldom had factory to adopt this technique at present.

The carbothermy that also have Hansgirg that belong to thermal reduction technique same with silicothermic process.Carbothermy refining magnesium adopts carbonaceous reducing agent magnesium oxide exactly, obtains MAGNESIUM METAL steam and CO gas, obtains MAGNESIUM METAL after fast cooling condensation.The mixed gas of the biggest problem of carbothermy refining magnesium to be product be MAGNESIUM METAL gas and CO gas, when cooling down is to obtain MAGNESIUM METAL, magnesium-reduced reversed reaction can be there is, magnesium is caused again to be oxidized by CO gas, too many MgO and carbon is mixed with in product, the recovery rate of magnesium is reduced greatly, therefore how to make the try one's best quench operation of fast cooling of magnesium gas become very crucial.Carbothermic method adopts the method for the reducing gas dilutions such as a large amount of Sweet natural gas, hydrogen to reduce the temperature of mixed gas, and the introducing of a large amount of foreign gas causes cost to increase, and therefore this carbothermic method was abandoned by industry member afterwards.In recent years, the scientist of CSIR of Australia Commonwealth Scientific and Industrial Research Organisation O considers mixed gas to be expanded by contraction-expanding nozzle to obtain supersonic jet, thus make gas temperature rapid drawdown, and by this technique called after MagSonic technique, but be still in the research trial stage.

In short, the industrial magnesium refining method of certain scale output is had to mainly contain the semicontinuous process for smelting magnesium of electrolytic process, carbothermic method, Pidgeon process and Magnetherm in history, wherein the hot process for smelting magnesium of carbon only used in the factory in 1930-1940 age, and mainstream industry method in the world only has electrolytic process and Pidgeon process at present.Nineteen ninety, electrolytic process output accounted for global magnesium output more than 80% for before mid-term, and Pidgeon process and Magnetherm method output only have an appointment 20%.From at the beginning of 21 century, Magnetherm technique stops production substantially, and electrolytic process also atrophy is a lot, the whole world more than 80% of having only had Pidgeon process output to account for.

No matter be Pidgeon process technique or the semicontinuous process for smelting magnesium of the Magnetherm of France, all using ferrosilicon particularly siliceous more than 75% ferrosilicon (being generally #75 ferrosilicon) as reductive agent, ore containing MgO is as refining magnesium raw material, under elevated temperature in vacuo, there is the magnesian following chemical reaction of Si reduction:

2MgO+Si＝SiO ₂+2Mg(gas) (1)

Above formula (1) is basic chemical reaction.Owing to only having Mg at high temperature to become gas in reactant, resultant, extracted out by vacuum-pumping system, thus leave conversion zone, the low-temperature zone condensation in vacuum-lines becomes solid or liquid, thus obtains MAGNESIUM METAL.

Generally, silicon is using the form of ferrosilicon as reaction mass, and be generally adopt the product C aOMgO after dolomite calcination to react containing magnesium raw material, industrial common chemical equation is:

2(CaO·MgO)+Si(+Fe)＝2CaO·SiO ₂(+Fe)+2Mg(gas) (2)

Silicon is good reductive agent in metallurgical industry, but due to magnesium be active metal, very strong with the binding ability of oxygen, so Si reduction magnesium needs high temperature at ambient pressure.By the dividing potential drop adopting vacuum to reduce resultant MAGNESIUM METAL gas, and with CaO in conjunction with SiO ₂generate stable Dicalcium Phosphate (Feed Grade), make above-mentioned reaction (2) if temperature less than 1200 DEG C can carry out industrial production.

So-called Pidgeon process, is that Canadian metallurgist Pi Jiang teaches in the perfect technique of the 1940's early development, and uses till today.Pidgeon process technique is that promote that in horizontal tank, material carries out chemical reaction, material reaction temperature is about 1150 ~ 1250 DEG C, and vacuum tightness is generally less than 13Pa by the ferrosilicon of siliceous 75%, magnesium-containing ore etc. to mix the solid phase ways of contact such as pressure ball, to adopt external flame heating.Existing production of magnesium by pidgeonprocess has following essential defect:

1. reactant ferrosilicon and forge and whitely carry out chemical reaction with the solid phase way of contact, speed of reaction is slow, and in typical technological process, the reduction reaction cycle reaches 10 ~ 12 hours, inefficiency;

2. adopt flame indirect heating, heat is by reactor outside by being transmitted to inside gradually, and the cycle is long, and heat-energy losses is large, and heat utilization rate is low, and specialty analysis thinks that the heat utilization rate of typical process only has about 20%;

3., because the mode of indirect heating limits reactor volume, typical horizontal tank internal diameter is within 400 millimeters, and batch is little, single tank one time 10-12 hours former magnesium of output only has 20 ~ 30 kilograms, floor space is large, and field management difficulty is large, not easily realizes scale operation and mechanized;

4. adopting containing element silicon 75% ferrosilicon is reductive agent, and the consumption of general ton magnesium ferrosilicon is 1.05 ~ 1.20 tons, and namely silicon far exceedes theoretical consumption figures and causes waste, and all ferro elements waste simultaneously;

5. horizontal tank generally adopts the high temperature steel of the costliness containing nickel, chromium, and consume very fast, cost is high;

6. smoke contamination is serious, and work situation is severe, large to ecotope negative impact around;

7. need hand charging, skim, clear up Crystalline Magnesium, labour intensity is large, is difficult to realize automated job.

The semicontinuous process for smelting magnesium of Magnetherm of France's exploitation, than Pidgeon process progress to some extent, is not only embodied in and adopts electric power to carry out inside heating, thus improve energy utilization rate, and production efficiency obtains very large lifting.But this technique still has the deficiency of several respects: it is of prime importance that ferrosilicon is still seriously in excess in theoretical consumption figures, remaining high temperature iron element is caused all to be wasted and the waste of part element silicon.Needed for magnesium metal reduction per ton, silicon amount theoretical value is 576kg, and amounting to #75 ferrosilicon is 768kg, and in actual production, magnesium per ton consumes #75 ~ #80 ferrosilicon of 1050 ~ 1200kg, correspondingly in remaining ferrosilicon siliceous 18 ~ 22%.In addition, Magnetherm process for smelting magnesium is semi-continuous, often produces 1 ton of MAGNESIUM METAL and about produces 5 ~ 6 tons of reducing slags simultaneously, needs in time most of reducing slag to be discharged reaction zone, and this just needs breaking vacuum, stops smelting, and causes the interruption of production.Further, ferrosilicon, to forge the raw materials such as white powder be join in Mg-smelting furnace with solid-state powder or particle, and by heating up, then fusing starts chemical reaction, and spray compared with liquid phase or pressed powder the mode entering molten bath, its speed of response is still lower.Finally, ferrosilicon production process is discharged from mineral hot furnace with high-temperature fusion liquid, joins in Mg-smelting furnace again, caused larger energy dissipation after being cooled to the solid compared with low temperature.

South Africa Mintek mechanism develops MTMP (MintekThermal Magnesium Process) technique on the basis of Magnetherm technique, its outstanding change no longer adopts vacuum operating in stove, but refine magnesium at ambient pressure, such tapping process can carry out under not end-of-life state, become Total continuity technique, cost is that temperature will be promoted to about 1750 DEG C, energy consumption is caused to raise and the fire proof material of furnace lining lost of life, and more multielement volatilizees together enter furnace gas in company with magnesium, causes the purity of magnesium to decline.And the waste of silicon and iron two element is still comparatively serious in its reductive agent, in remaining ferrosilicon siliceous about 20%.

Described by US Patent No. 2971833 is exactly the process for smelting magnesium being called as Magnetherm, adopts the slag resistive heating under vacuum, once achieves stable industrial-scale production in multiple country.But its ferrosilicon consumes higher than theoretical value, and patent specification P3 page right 69 row report remaining ferrosilicon siliceous 35%, have relatively large residue ferrosilicon to utilize.US Patent No. 5090996, on Magnetherm process for smelting magnesium basis, changes into the reduction refining magnesium under atmospheric pressure state.Refine magnesium with metallic reducing under the patent of US Patent No. 5383953 describes normal pressure, assign to realize by the one-tenth controlling slag, also should regard the improvement of Magnetherm technique as.The ferrosilicon consumption of the not mentioned refining magnesium of above-mentioned patent.US Patent No. 3151977 discloses the method for electrothermal reduction refining magnesium, and the ferrosilicon wherein as reductive agent is the ferrosilicon of 70-80%, and finally the ferrosilicon of siliceous 33% is not utilized.US Patent No. 4699653 describes at ambient pressure that plasma body is as the continuous silicone heat refining magnesium of thermal source, and the little experimental data display provided in embodiment, silicon is not by reduction reaction approach exhaustion.Chinese patent CN95100495.6 discloses a kind of technology of interior heat refining magnesium, and its technique and Magnetherm have similarity, and also just after the solid-state furnace charge of loading, along with the rising of temperature, furnace charge can be molten state.But the reactive system that this patent describes, due to condition of high vacuum degree, causes magnesium vapor to be directly condensed into solid state crystallization magnesium, easily blocks vacuum system, cannot realize continuous seepage.Chinese patent CN201010145505.9 proposes a kind of method of melting and reducing silicon heat refining magnesium, by allocating silicon into, aluminum oxide forms multi-unit fused slag system, reactant and product is made to form ferrosilicon liquid and polynary slag, be liquid phase, improve reacting dynamics condition, but cause very large silicon, ferro element to waste because ferrosilicon is excessive in its three embodiments, even reach the ratio of element silicon waste half.

Chinese patent CN201080000976, CN201010255097, CN201010255111 provide the method and apparatus of vacuum circular flow magnesium-smelting, ferrosilicon liquid can fully be mixed with magnesium ore deposit, and realize circulating under vacuum and atmospheric pressure environment by soaking tub, obtain good reacting dynamics condition, simultaneously can also continuous discharging slag, but only the remaining ferrosilicon after refining magnesium provided to supplementary element silicon thus becomes the comprehensive Utilization Ways of different silicon-containing iron alloy, not yet giving full play to the chemical functional of silicon as the metallurgical reductive agent of high-quality.

Pidgeon process technique as the main technique of Present Global MAGNESIUM METAL output more than 80%, the absolute prevailing technology of method for smelting magnesium by hot process especially, before analyzed the deficiency of the aspects such as its energy consumption, material consumption, efficiency, labor condition, environmental protection.And have liquid phase to participate in a collection of technique of reaction, with Magnetherm technique for representative, follow-up have South Africa MTMP technique, Chinese patent CN201010145505.9 etc., in chemical reaction process, major progress is had compared with Pidgeon process, but the economic advantages in production practice are also not obvious, the Ji Jia factory adopting Magnetherm even cannot with Pidgeon process competition among enterprises and being forced to stop production and close the plant.Except above-mentioned ferrosilicon residue is not utilized effectively, slag ratio higher in its technological process is also a large defect, because the quantity of slag causes far above ferrosilicon amount, flow in molten bath, whipping process is difficult to carry out, and have impact on production efficiency.

The main component of metallurgical cinder is many oxide, unreacted mineral aggregate also can be dissolved in slag in various degree or be fused into liquid state, the viscosity of slag is generally at 0.08 ~ 2Pas, and the viscosity of the general molten metal such as molten steel, iron liquid only has 0.002 ~ 0.008Pas, typically melt more than 10 times that slag phase viscosity is molten metal completely.If oxide ester mp is higher in furnace charge, or can not all dissolve, solid phase particles is had to exist, so slag often presents the rheological characteristics of non-Newtonian fluid, apparent viscosity along with temperature, do not dissolve/do not melt solid phase particles character and quantity, stirring operation, foamy slag and air voids etc. and have very large fluctuation, even tens times to hundreds of times in molten metal viscosity, the mobility of mineral aggregate and slag phase is declined greatly, affects chemical reaction, heat transfer, the carrying out smoothly of mass transfer.

As a comparison, in steelmaking process and follow-up external refining, slag phase quality generally only has 10 ~ 20% of molten metal, and molten bath is using molten metal as main flow media, and metallurgical effect is far better.Due to molten metal bath good fluidity, the quantity of slag is little, " process intensification " means such as Bottom Gas Stirring, induction stirring, top-blown gas jet can be adopted, make molten bath that fierce macro-flow occur, reaction interface is long-pending can increase thousands of times, heat transfer, mass transfer carry out with fierce convection type simultaneously, smelt speed and greatly improve.Such as, molten slag in the situations such as violent stirring, 20-40 times when the capacity of heat transmission is static.For another example, oxygen top blown converter steel making has eliminated openhearth steelmaking completely, and exactly because the former forms the emulsification of abundant disperse in the Liquid Flow of fierceness, core smelting procedure only needs 12-15 minutes, and the latter molten bath is " a pool of stagnant water ", core smelting procedure will expend several hours.

No matter be Pidgeon process, or the method for smelting magnesium by hot technology that existing patent discloses, all calculate according to theoretical reduction agent needed for chemical reaction and allocate ferrosilicon into, can be referred to as " chemistry joins silicon ", consider the ratio of free silica in the degree that chemical reaction carries out and ferrosilicon, generally excessive about 30%.Usually forge in white powder at refining magnesium raw material rhombspar, the atomic ratio of calcium and magnesium is close to 1:1 or a little more than 1, magnesium accounts for forges 23 ~ 25% of white powder quality, because the reduction ratio of magnesium is usually about 80%, magnesium ore deposit add-on is generally 6 ~ 6.5 tons, ton magnesium, more than 75% ferrosilicon that ton magnesium is allocated into only has 1.0 ~ 1.1 tons, even if so furnace charge all melts, the quantity of slag is also 600% of metal liquid measure, in molten bath, slag occupies absolute majority mutually, mobility far away from the molten bath based on molten metal, cause the chemical reaction in molten bath, heat transfer, mass transfer efficiency very low.

Given this, be necessary that a kind of " physics joins silicon " technique newly of design solves the problems referred to above.So-called physics joins silicon, be that the several times of oxide compound furnace charge/slag phase quality are to allocate ferrosilicon into according to the quality of ferro-silicon liquid in molten bath exactly, using the carrier of chemical reaction of holding concurrently as silicon reduction agent far above the ferrosilicon bath of theoretical chemistry requirement, pass through high degree of agitation, make containing the mixing of magnesian magnesium ore deposit highly dispersed wherein, formation is similar to emulsion, the dispersed system of emulsion, wherein external phase medium is low viscous ferrosilicon liquid, disperse phase is the slag phase of unreacted/ reacted oxide compound composition, augmenting response interfacial area, strengthen transmission of heat by convection, mass transfer ability, realize the strengthening of reduction process.After reduction, remove magnesium smelting reducing slag, excessive ferrosilicon liquid must reuse, and turns back to Mg-smelting furnace or stays in Mg-smelting furnace always, mixes row again refine magnesium, until the concentration of ferrosilicon liquid is lower than poor silicon concentration with new a collection of magnesium ore deposit.

Silicon is used for when high density refining magnesium, and its poor ferrosilicon liquid mixes with chrome ore, carries out chrome ore reduction after reducing by concentration, obtains ferrochrome liquid or chromium stainless steel mother liquor.Adopt excessive ferrosilicon to bathe and be respectively used to refining magnesium, refining ferrochrome when high density, lower concentration, ferrosilicon starting material are fully used, and reaction efficiency is high, more energy-conservation, in ferrochrome liquid, carbon, phosphorus, sulphur are very low, and the cost of magnesium and molten stainless steel coproduction has obvious reduction than independent sum of the two.

Summary of the invention

The technical problem to be solved in the present invention is: for drawback and the deficiency of public technology scheme in existing industry refining magnesium technology and forefathers' patent, and patent of the present invention discloses the method for a kind of ferrosilicon bath step reduction magnesium-smelting silicothermic process coproduction chrome-bearing alloy steel.

An object of the present invention is to make full use of the element silicon in reductive agent ferrosilicon and ferro element, and after refining magnesium, the high-temperature physics of remaining ferrosilicon is warm.

Object of the present invention also comprises the dynamic conditions thoroughly improving reaction, reactant is made to form ferrosilicon bath with liquid liquid phase reaction or using mineral as disperse phase Dispersed precipitate in ferrosilicon liquid external phase, two kinds of reactants fully mix, with augmenting response interface, transmission of heat by convection, rate of mass transfer are obviously promoted, make production process more rapidly, more efficient.

For achieving the above object, the invention provides following technical scheme: the coproduction of ferrosilicon bath step reduction magnesium-smelting silicothermic process, containing the method for ferrochrome liquid, is characterized in that, comprises following technique:

A. provide at least containing the molten alloy liquid that silicon, iron two kinds of elements and initial siliceous mass percent are 25-70%, described molten alloy liquid is placed in firing magnesium-smelting furnace, in described firing magnesium-smelting furnace, vacuum tightness remains on 350-50000Pa, and temperature remains on 1200-1800 DEG C;

B. described molten alloy liquid and a collection of containing magnesian material is mixed, after keeping described molten alloy liquid quality to be greater than unreacted and reaction all the time multivariant oxide form the quality of slag phase, and keep the siliceous quality of molten alloy liquid be always Si reduction slag mutually in magnesium chemical theory need the 1.5-200 of siliceous amount doubly, Si reduction magnesium oxide, generate magnesium vapor to overflow described molten alloy liquid collections that be condensed, and described firing magnesium-smelting furnace that the slag formed after reacting is separated out;

C. when the silicon concentration in the reacted molten alloy liquid of described a collection of magnesium oxide is greater than a poor silicon concentration, iterative process B; When the silicon concentration in molten alloy liquid is equal to or less than described poor silicon concentration, form poor silicon molten alloy liquid, described poor silicon molten alloy liquid is placed in refining chromium reduction furnace, described poor silicon concentration refers to that siliceous mass percent in molten alloy liquid is less than a concentration of the initial siliceous mass percent of described molten alloy liquid between 15%-50%;

D. be placed in the poor silicon molten alloy liquid of refining chromium reduction furnace and a collection of material containing chromic oxide described in mixing, Si reduction chromic oxide, generate chromium metal and be dissolved in described poor silicon molten alloy liquid, obtain containing ferrochrome liquid.

One or more being subject in firing magnesium-smelting furnace in argon gas stirring, electromagnetic force stirring or mechanical stirring of molten alloy liquid in described technique A stir.

Also containing mass percent in molten alloy liquid in described technique A is the aluminium element of 1-30%.

Also containing mass percent in molten alloy liquid in described technique A is the nickel element of 0.5-20%.

In described technique B containing magnesian material be the rhombspar after calcining, the magnesite after calcining, the waste and old refractory materials of magnesia, containing magnesian metallurgical slag or containing one or more in the magnesian slag melted.

After a collection of magnesium oxide at least 50% in described technique B reacts, just the slag that reaction is formed is separated from described firing magnesium-smelting furnace.

Described technique B also comprises and add ferrosilicon in described molten alloy liquid, after keeping described molten alloy liquid quality to be greater than unreacted and reaction all the time, multivariant oxide institute forms the quality of slag phase, and keep the siliceous quality of molten alloy liquid be always Si reduction slag mutually in magnesium chemical theory need 1.5-200 times of siliceous amount.

Slag reaction formed in described technique B comprises from the mode that described firing magnesium-smelting furnace is separated and recharging molten alloy liquid to described firing magnesium-smelting furnace after discharging described firing magnesium-smelting furnace together with described molten alloy liquid and slag phase again, or is directly separated from described firing magnesium-smelting furnace by slag.

Add in molten alloy liquid in described technique B containing aluminum oxide and/or containing the material of Calcium Fluoride (Fluorspan) as slag former.

In described technique D is smelt the mother liquor of chromium stainless steel containing ferrochrome liquid, and described is 10-50% containing ferrochrome liquid containing chromium mass percent.

Add calcined limestone in described technique D, rhombspar forge white powder, material containing calcium oxide or containing one or more in magnesian material as slag former.

Present invention also offers the method for another kind of ferrosilicon bath step reduction magnesium-smelting silicothermic process coproduction chromium stainless steel liquid, comprise following technique:

A. provide at least containing silicon, iron two kinds of elements and the molten alloy liquid of initial siliceous mass percent 25-70%, described molten alloy liquid is placed in firing magnesium-smelting furnace, and described firing magnesium-smelting furnace keeps the vacuum condition of 350-50000Pa and the temperature condition of 1200-1800 degrees Celsius;

B. described molten alloy liquid and a collection of containing magnesian material is mixed, described reduction slag of discharging for step D containing magnesian material, after keeping described molten alloy liquid quality to be greater than unreacted and reaction all the time multivariant oxide form the quality of slag phase, and keep the siliceous quality of molten alloy liquid be always Si reduction slag mutually in magnesium chemical theory need the 1.5-200 of siliceous amount doubly, Si reduction magnesium oxide, generate magnesium vapor to overflow described molten alloy liquid collections that be condensed, and described firing magnesium-smelting furnace that the slag of reaction formation is separated out;

D. the poor silicon molten alloy liquid of refining chromium reduction furnace and a collection of at least containing chromic oxide, magnesian material is placed in described in mixing, Si reduction chromic oxide, generating chromium metal is dissolved in described poor silicon molten alloy liquid, obtain chromium stainless steel liquid, turn back to step B after being separated with described chromium stainless steel liquid containing magnesian reduction slag as the melting furnace charge refining magnesium.

Present invention also offers another kind of ferrosilicon bath step reduction magnesium-smelting silicothermic process coproduction containing manganese, containing molybdenum, method containing vanadium or tungsten-containing alloy steel liquid, it is characterized in that, comprise following technique:

B. described molten alloy liquid and a collection of containing magnesian material is mixed, after keeping described molten alloy liquid quality to be greater than unreacted and reaction all the time multivariant oxide form the quality of slag phase, and keep the siliceous quality of molten alloy liquid be always Si reduction slag mutually in magnesium chemical theory need the 1.5-200 of siliceous amount doubly, Si reduction magnesium oxide, generate magnesium vapor to overflow described molten alloy liquid collections that be condensed, and described firing magnesium-smelting furnace that the slag of reaction formation is separated out;

C. when the silicon concentration in the reacted molten alloy liquid of described a collection of magnesium oxide is greater than a poor silicon concentration, iterative process B; When the silicon concentration in molten alloy liquid is equal to or less than described poor silicon concentration, form poor silicon molten alloy liquid, described poor silicon molten alloy liquid is placed in refining manganese, refining molybdenum, refining vanadium or refining tungsten reduction furnace, described poor silicon concentration refers to that siliceous mass percent in molten alloy liquid is less than a concentration of the initial siliceous mass percent of described molten alloy liquid between 15%-50%;

D. the poor silicon molten alloy liquid of refining manganese, refining molybdenum, refining vanadium or refining tungsten reduction furnace and a collection of material containing manganese oxide, molybdenum oxide, vanadium oxide or Tungsten oxide 99.999 is placed in described in mixing, Si reduction manganese oxide, molybdenum oxide, vanadium oxide or Tungsten oxide 99.999, generating manganese metal, molybdenum, vanadium or tungsten is dissolved in described poor silicon molten alloy liquid, obtains containing manganese, containing molybdenum, containing vanadium or tungsten-containing alloy steel liquid.

Compared with prior art, the present invention at least has the following advantages:

(1) make reductive agent Silicon in Ferrosilicon can be consumed in refining magnesium link according to theoretical value, excess silicon is all for the reduction of chromium, and ferro element all enters among ferrochrome or chromium stainless steel, and physical sensible heat fully uses;

(2) ferrosilicon obtained from mine heat furnace smelting participates in refining magnesium in liquid hot charging mode, without the need to heat temperature raising remelting, saves the huge heat that ferrosilicon heats up needed for fusing;

(3) the liquid phase mode that refining reactive magnesium is bathed with ferrosilicon is carried out, substitute " chemistry joins silicon " with " physics joins silicon ", under the prerequisite that ferrosilicon liquid is fully excessive, magnesium ore deposit is fully incubated by ferrosilicon liquid with solid phase particles or slag phase drop, adopt " process intensification " means such as argon bottom-blowing, induction stirring, top-blown gas jet again, make interfacial chemical reaction, heat transfer, mass transfer speed promoted significantly under the state that is uniformly mixed of fierceness;

(4) adopt the inventive method to carry out the large-scale commercial production of MAGNESIUM METAL, the element silicon consumption of MAGNESIUM METAL per ton is reduced to 580kg from 825kg, reduces about 30%; The ferro element of MAGNESIUM METAL consumption per ton is reduced to almost nil from 275kg; Magnesium metal smelting process per ton power consumption only has 6500-7500kwh, reduces about 80% than Pidgeon process energy consumption, reduces 20% than techniques such as the semicontinuous electrically heated of Magnetherm;

(5) compare from speed of response, refining reactive magnesium in the present invention can complete being less than in 1 minute, and Pidgeon process generally needs 10-12 hour, and speed improves more than 300 times;

(6) from efficiency, present method single reaction vessel can realize product magnesium 5-20 ton per hour, and single tank production capacity per hour of Pidgeon process only has 2-3 kilogram, improving productivity more than 2000 times;

(7) in the mode of production, be easy to realize mechanize, automatization, information-based operation, substitute hand labor, environmental protection aspect also has more advantages than Pidgeon process;

(8) from coproduction chrome stainless steel, utilize and originally refined the approximate reduction by ferrosilicon agent consumption of magnesium, energy consumption, the raw metal that output MAGNESIUM METAL, molten stainless steel two kinds are important, define two class industries of inherent coupling mutually, its economic benefit is produced separately than two kinds of products and is significantly improved.

Accompanying drawing explanation

Fig. 1 is magnesium refining method overview.

Fig. 2 is the free energy of reaction comparative graph of silicon reduction refining magnesium, refining chromium.

Fig. 3 is different ferrosilicon densograms.

Fig. 4 is the method schematic diagram of ferrosilicon of the present invention bath step reduction magnesium-smelting silicothermic process coproduction containing ferrochrome liquid.

In Fig. 4, each several part sign implication is:

10---vacuum Mg-smelting furnace

11---magnesium vapor condensing chamber

12---fly-ash separator

13---vacuum pump

20---refining chromium stove

100---melting ferrosilicon liquid molten bath in Mg-smelting furnace

101---magnesium ore deposit, refining magnesium flux (magnesium oxide, calcium oxide, aluminum oxide, Calcium Fluoride (Fluorspan) etc.)

102---for refining the high silicon melting ferrosilicon liquid of magnesium

201---chrome ore, refining chromium fusing assistant (chromic oxide, ferric oxide, magnesium oxide, calcium oxide etc.)

202---for refining the poor silicon melting ferrosilicon liquid of chromium

Fig. 5 is the smelting principle of first embodiment of the invention.

Fig. 6 is the smelting principle of second embodiment of the invention.

Fig. 7 is the smelting principle of third embodiment of the invention.

Fig. 8 is ferrosilicon, the magnesium oxide flow direction of material schematic diagram of fourth embodiment of the invention.

Fig. 9 is the solubility curve figure of carbon in ferrosilicon.

Embodiment

Refer to Fig. 1 to Fig. 9, describe square ratio juris and the technology contents of ferrosilicon of the present invention bath step reduction magnesium-smelting silicothermic process coproduction chrome-bearing alloy liquid below in conjunction with accompanying drawing.

Silicon is reductive agent important in metallurgy, except serving as except reductive agent in magnesium-smelting silicothermic process, can also as the reductive agent of a lot of other alloying elements, and from chromated oxide, ferriferous oxide, such as reduce corresponding metal.

All must containing the chromium element of more than 13% in all stainless steels.Containing chromated oxide in chrome ore, chromated oxide wherein, reduction of ferrous oxide can be entered into ferrous alloy liquid by thermal reduction, realize DIRECT ALLOYING, become mother liquor of stainless steel.Except stainless steel, some other high quality steel also needs higher chromium content.In addition, ferriferous oxide also can directly by Si reduction.Some other high quality steel, needs to allocate manganese, molybdenum, vanadium, tungsten etc. into, also can with silicon as reductive agent, and from its oxide ore, DIRECT ALLOYING is to molten metal, thus saves the energy dissipation of J. sigillate link and heat fused repeatedly.

In metallurgical process, the general free energy change of chemical reaction that adopts judges to react the trend of carrying out and the degree of carrying out.Under Fig. 2 shows 0.05 normal atmosphere silicon heat refining magnesium rod part, the absolute value of the free energy negative value of silicon heat refining magnesium is less than the absolute value of the free energy negative value of silicon heat refining chromium, and that is, Si reduction chromium more easily carries out.

The thermodynamic data of reaction formula (1) is utilized to calculate: under 1873K, during Si reduction magnesium, under pressure 0.05atm condition, silicon activity minimum in ferrosilicon liquid is about 0.005.The ferrosilicon of this activity value corresponding, detect from table 1, ferrosilicon concentration is between 11.11 ~ 17.65%, and the amount of unreacted silicon is more considerable, this is because the silicon in ferrosilicon is divided into free silica and FeSi, FeSi ₂deng silicide, along with consumption and the silicon concentration reduction of free silica, silicon activity reduces rapidly.Silicon activity as shown in table 1 and the relation of silicon concentration, when Silicon in Ferrosilicon concentration is reduced to 0.2 from 0.4, density loss is to original half, but activity only has original 1/37th.

Table 1 ferro-silicon activity quotient γ and silicon concentration relation (temperature 1873K)

The reaction formula of Si reduction chromium is as follows

Si + \frac{2}{3} {Cr}_{2} O_{3} + CaO = \frac{4}{3} Cr + 2 CaO \cdot {SiO}_{2}

Utilize the thermodynamic data of reaction formula (3), equally under 1873K, during Si reduction chromium, silicon activity minimum in ferrosilicon liquid is 0.1ppm, namely 10 ^-7, utilize silicon concentration in table 1 close to 0 time activity quotient 0.00132, the molar fraction that can calculate now remaining silicon is 7.6E-5, and mass percent is 0.0038%, and visible silicon utilizes very fully thoroughly.

In fact, in the industrial production, thermodynamic equilibrium state can not be reached completely, and always need higher silicon concentration to terminate reduction process, thus silicon heat refining magnesium usual excess silicon weight of iron per-cent is 18-35%, and use Si reduction chrome ore, the silicon concentration balanced during terminal is usually in 0.5% such level.Can say, realize the order extraction of MAGNESIUM METAL, ferrochrome with the step reduction of silicon, both having met the principle of metallurgical thermodynamics, is also industrially reasonable.

Ferrosilicon bath step reduction magnesium-smelting silicothermic process of the present invention coproduction is the chemical thermodynamic principle based on " the step reduction of silicon " containing ferrochrome liquid, namely during Si reduction magnesium, even if under vacuum, along with silicon concentration reduces, the reducing power of silicon declines, to such an extent as to the ferrosilicon of lower concentration cannot participate in reaction, but due to chromium reduction easier than magnesium, the Si reduction chromium in this ferrosilicon is utilized to be feasible.Silicon in such ferrosilicon is when high density, and as the reductive agent of magnesium, when low concentration, as the reductive agent of chromium, the chromium after reduction and the ferro element in ferrosilicon form ferrochrome liquid, as the mother liquor of stainless steel and other chrome-bearing alloy steel.

Method that the present invention also adopts " physics joins silicon " solves the deficiency of " chemistry joins silicon " of existing silicon heat refining magnesium Technology, namely no longer ferrosilicon is allocated into the silicon amount needed for chemical reaction, but allocate ferrosilicon liquid as main uniform external phase, mineral aggregate and reducing slag as minority disperse phase using ferrosilicon liquid in molten bath, to form ferrosilicon bath reaction molten bath.Physics joins the ferrosilicon amount added needed for silicon joins silicon ferrosilicon add-on considerably beyond chemistry, but the ferrosilicon liquid of surplus is after this batch of magnesium ore deposit reacts completely and be separated with slag, can stay in stove always or again return in stove, the refining reactive magnesium that the ferrosilicon re-starting a new round with new a collection of magnesium ore deposit is bathed, until the silicon concentration of ferrosilicon lower than no longer have after poor silicon concentration reduction magnesium ore deposit ability, move back and with its as refining chromium reductive agent.

" physics joins silicon " method, makes the present invention and prior art significantly different.First, ferrosilicon liquid is fully excessive, its quantity joins the needs of silicon far above chemistry, chemistry joins 1.5 ~ 200 times of silicon amount often, and ferrosilicon liquid quality is greater than the quality of reacting front and being formed slag phase after reaction by multivariant oxide, thus using ferrosilicon bath as external phase, under magnesium vapor generates the foam caused by reduction effect of overflowing and the vigorous stirring effect blasting external source of the gas, the solid particle of slag phase, liquid phase drop are well-dispersed in ferrosilicon bath, form the dispersed system of similar emulsion, emulsion, reaction interface is long-pending, convection action had remarkable enhancing.Second, the silicon concentration of initial ferrosilicon liquid should not be too high, and prior art is generally considered from thermodynamics of reactions angle, all tends to higher silicon concentration, conventional more than 70% ferrosilicon, even adopt 72%, 75%, the 78% even ferrosilicon of 80%, the present invention due to ferrosilicon superfluous, reducing behind a collection of magnesium ore deposit, ferrosilicon liquid is wanted to be separated with slag, again to utilize, so need the density of ferrosilicon liquid and slag density to have larger difference, general slag density 2500-3000kg/m ³, molten metal density needs higher than slag 1500kg/m ³left and right, is conducive to slag and is separated.Consider this two kinds of needs, liquid-tight for initial ferrosilicon degree is determined at 4000kg/m ³as well, with reference to the relation of ferrosilicon density and its silicon concentration in figure 3, ferrosilicon liquid mass ratio should not higher than 65%, and after fusing, density also declines, to some extent generally about 10%.Refining magnesium process adopts argon gas to stir, and slag air voids is higher, also can to a certain degree reduce slag phase density.Commercially available ferrosilicon is generally #75, #72, less less than 70%, in this way be more suitable for liquid ferrosilicon hot charging refining magnesium, upstream provides the ferrosilicon that the mine heat furnace smelting 60% of ferrosilicon is even lower, and operation is very light, and output is also larger, hot charging comes to refine magnesium, save ferrosilicon to heat up a large amount of heat energy of fusing, because the specific heat of silicon, melting heat are all much bigger than iron, so the heat energy that liquid ferrosilicon hot charging is saved is considerably beyond Steel Plant's molten iron, molten steel hot charging.

Excessive ferrosilicon liquid needs recycling, both can stay in Mg-smelting furnace and pull down reducing slag, more optimize be in Mg-smelting furnace flow out after, be promoted to furnace roof again, disposable from furnace roof, continuously or interval recharge in stove, rely on the gravitional force under the swash of wave of top and origin of heat, hot ferrosilicon liquid has certain impact capacity, be conducive to eliminating vacuum suction, blast argon gas, magnesium vapor escapes the excessive foamy slag caused, also can break through the slag blanket scull (skull) that top, molten bath in stove easily occurs, improve the mobility of silicon molten iron bath.

Chrome ore generally have lump ore and fine ore point, lump ore is applicable to ferrous metallurgy technique to refine chrome-bearing alloy, but lump ore is more and more rare, price is higher, and increasing chrome ore is the form of fine ore, it is all particularly fine ore after low-grade Chromium ore beneficiation, generally all want first to make artificial lump ore through oversintering, pelletizing and briquetting could use, although so chromite ore fine supply is higher than lump ore in Iron And Steel Industry, needs are through complicated pre-treatment, often be out of favour, and processing cost is higher.In the present invention, the remaining ferrosilicon of the melting after refining magnesium, directly can enter ferrosilicon molten bath by chromite ore fine, carry out the alloying of chromium, obtain containing ferrochrome or chrome-bearing alloy steel, if adopt the method for injection metallurgy, speed of reaction is very high, and the unfavourable condition of fine ore becomes favourable condition.

In embodiments, with the poor ferrosilicon liquid after refining magnesium, carry out the reduction DIRECT ALLOYING of chrome ore, smelting chrome stainless steel liquid is preferred scheme.

General Implementing process of the present invention is as follows, and composition graphs 4 is explained.

A. furnace charge prepares

A01: after melting high temperature ferrosilicon liquid 102 taps a blast furnace from mineral hot furnace, enter the ferrosilicon bag with insulation cover, be transported to Mg-smelting furnace feed location, such as, adopt the ferrosilicon liquid of 65%, and the amount of ferrosilicon liquid is 2 times of the complete quantity of slag of refining magnesium, roughly in ferrosilicon, silicon content is 10-15 times of theoretical silicon demand;

A02: dolomite becomes after calcining in rotary kiln to be forged white, and namely magnesium ore deposit 101, is transported to Mg-smelting furnace 20 feed location while hot, for energy-conservation, can in tolerance range at equipment, the cooling of magnesium ore deposit is more few better, such as 800-1000 DEG C;

A03: prepare a certain amount of calcined bauxite, fluorite etc. in addition and jointly form as fusing assistant and calcined dolomite and refine magnesium raw material 101, be aluminum oxide according to 15% of the complete 80% magnesium oxide reduction gained slag of refining magnesium, 5% prepare burden for Calcium Fluoride (Fluorspan), be transported to Mg-smelting furnace 20 feed location.

B. furnace charge mixing

B01: push up from Mg-smelting furnace stove 20 and join in stove by a part of magnesium ore deposit, fusing assistant 101, is slowly injected in stove from top by ferrosilicon liquid 102 simultaneously, keeps ferrosilicon liquid to inject from top constantly for a long time;

B02: in smelting process, with the rhythm mated with ferrosilicon liquid phase and quantity, will join in stove containing magnesium furnace charge 101 off and on or constantly, and make ferrosilicon liquid and furnace charge in stove, fall into close position.

C. silicon heat refining magnesium

C01: resistance, electroslag, induction, plasma can be adopted or there is the electric-arc heating mode of stable arc device, molten bath in stove 100 power transmission is heated, maintain bath temperature 1400-1700 DEG C in stove, 800-50000Pa is evacuated to vacuum pump 13 in stove, argon bottom-blowing, the outer magnetic stirrer of startup stove simultaneously, make fully to mix with liquid ferrosilicon liquid 102 containing magnesium furnace charge 101, violent stirring, keeps the lasting furnace charge supply at top simultaneously;

C02: magnesium vapor generates, effusion furnace chamber, enter condenser 11, be condensed collection, and remaining furnace gas, through fly-ash separator 12, is taken away by vacuum pump 13.

D. tap a blast furnace slag tap, slag gold be separated

D01: smelt to a certain extent, when such as magnesium vapor no longer produces or productive rate obviously declines, or according to after the tap to tap time that operating experience is determined, reduce gas stirring and function composite by electromagnetic stirring, change into and be evenly blown into rare gas element from furnace bottom, make ferrosilicon bathe flowing to weaken, progressively separate clear and definite slag blanket and ferrosilicon liquid layer;

D02: regulating stove internal gas pressure, malleation to stove inside and outside air pressure balance or stove, carry out tapping a blast furnace tapping operation, can mix out by slag iron, also first can tap a blast furnace and then slag tap in bottom, also only can slag tap from higher position stays in stove by ferrosilicon, then carry out slag gold in the hot metal ladle in stove or outside stove to be separated, skimming both can have been taked to operate, also can tap a blast furnace bottom, make slag, ferrosilicon liquid is divided in two containers, slag is removed as other purposes.

E. ferrosilicon liquid returns

E01: judge whether ferrosilicon liquid reaches poor silicon concentration, suppose to be defined as 30%, according to ferrosilicon liquid starting point concentration and total amount, in conjunction with the magnesium ore deposit amount added and magnesium content, magnesium reduction rate, roughly can obtain ferrosilicon liquid concentration, also can take more advanced on-line quick detection or carry out automatization identification according to the magnesium output in magnesium condenser, protracted experience and fixing operation also can know silicon concentration.If silicon concentration is greater than poor silicon concentration, then turn back to A01 operation sequence, again enter in stove, a collection of magnesium ore deposit secondary response again with new, until D02 operation, and then judges whether to reach poor silicon concentration;

E02: any moment during this period, certain density ferrosilicon liquid or silicon-iron block can be supplemented, with the consumption of supplementary silicon, supplement ferrosilicon or do not supplement ferrosilicon, all do not affect normal operation, it is too fast that supplementary ferrosilicon can make silicon molten iron bath be unlikely to volume decline, because the enrichment of the continuous consumption of silicon and iron brings the lifting of the liquid-tight degree of ferrosilicon.

F is poor, and ferrosilicon liquid is transported to ferrochrome stove

F01: after repeatedly the recoverable refining magnesium of ferrosilicon liquid operates, ferrosilicon liquid is come out of the stove again, and current ferrosilicon liquid reaches poor silicon concentration 30%, after being separated, no longer turns back to Mg-smelting furnace 10, but be transported to the feed location of ferrochrome stove 20 with slag;

F02: poor silicon ferrosilicon liquid 202 is with the feed way similar with Mg-smelting furnace, forging with chrome ore, lime, rhombspar joins in ferrochrome stove together with the fusing assistant 201 such as white, for maintaining good melting bath stirring, solid charge can add by stages and in groups or continuously, ferrosilicon bath remains unchanged, and tapping operation several times can be divided in centre, and then adds solid charge, also chrome ore and lime etc. can be melt into slag in advance, disposable or add in batches and mix with ferrosilicon liquid;

G smelts ferrochrome

G01: by modes such as bottom blown gas, top-blown gas jet, induction stirring, the overall shakes of ferrochrome stove, enhancing mixed process, make iron in chrome ore, chromium be entered into metal pool 200 by Si reduction, the calcium oxide, magnesium oxide etc. that generate silicon oxide and alkalescence combine slag is middle mutually;

G02: silicon reduction chromium, iron are originally as thermopositive reaction, and generally can not need outside heat supply, also suitably can adopt the mode supplementary heatings such as electrically heated, oxygen, combustion gas, iron scale, other chemical heat sources, can vacuumize also can without the need to vacuum environment;

G03: continue to add or add solid charge or fritting melt cinder is bathed to ferrosilicon in batches, until Silicon in Ferrosilicon approach exhaustion, or close to a lower concentration, such as 0.5 ~ 3%, in order to the chrome ore in furnace charge is comparatively thoroughly reduced, then suitably pass into oxidizing gas or add the oxygenants such as iron scale, allocating suitable lime etc. simultaneously into, the silicon in ferrochrome is thoroughly removed.

The refining of H ferrochrome

H01: ferrochrome liquid directly can be smelted into containing chromium stainless steel mother liquors such as chromium 13%, 20%, 25%, or allocate nickel into and become nickel chromium stainless steel mother liquor, or allocate nickel into, manganese becomes Ni-Cr-Mn system mother liquor of stainless steel, or smelt into the ferrochrome containing chromium 40 ~ 50% and higher chromium content.If smelting product chromium content is told somebody what one's real intentions are, increase in refining ferrochrome link the ratio using iron ore, make the more ferriferous oxides of Si reduction;

H02: according to the content of impurity in furnace charge, can carry out refining, to promote quality further to ferrochrome liquid or mother liquor of stainless steel.

First embodiment:

A, from the ferrosilicon liquid 48 tons of 65% of mine heat furnace smelting, keeps temperature 1600 DEG C, and the rhombspar that to prepare containing MgO be 40% simultaneously forges white 20 tons, keeps 800 DEG C of temperature, gets 3.5 tons, the bauxite of calcining, 1.3 tons, fluorite ready as fusing assistant.

B ferrosilicon liquid is blended in the liquid material container 102 above Mg-smelting furnace, injects Mg-smelting furnace, forge white 101 and also join in stove from intermittent type above furnace roof from liquid material container 102 intermittent type, and makes the ferrosilicon liquid in stove and forge white, fusing assistant and mix.

C solid-state furnace charge ferrosilicon liquid adds half while also adds a half, and start power transmission in stove, be evacuated to 3000Pa simultaneously, pass into argon gas and carry out bottom blowing stirring, start have magnesium vapor to enter into condensing chamber 11, maintenance molten bath and charge-temperature are not less than 1600 DEG C.Start in condensing chamber to cool to magnesium vapor, make magnesium condensation.Synchronously add all residue furnace charges successively, and continue power transmission, vacuumize smelting.After all furnace charges enter stove, continue smelting 10 minutes.

D reduces the flow of argon bottom-blowing, and make molten metal in molten bath, slag layering, be filled with argon gas in stove to pressure-fired, open furnace bottom liquid outlet, ferrosilicon liquid first flows out, and then slag flows out subsequently, covers above ferrosilicon liquid, with artificial or skimmer by slag skim.

Ferrosilicon liquid is delivered to above Mg-smelting furnace by E again, restarts the step of A-D.Repeat 4 times totally 5 times smelt after, measuring ferrosilicon liquid total amount is 36 tons, silicon concentration is 53%, adds 65% ferrosilicon liquid 15 tons, and ferrosilicon liquid total amount is 51 tons, siliceous is 56.8%, continue the step repeating A-D, then carry out 9 smeltings, last 3 adjustment vacuum tightnesss are to 1000Pa, final residual ferrosilicon liquid total amount is 29.7 tons, silicon content 26%.

The ferrosilicon liquid of 29.7 tons siliceous 26% is transported to ferrochrome stove charging opening by F, gets out chromite 35 tons, iron scale 15 tons, 35 tons, lime, rhombspar forges white 2 tons, after mixing, add ferrochrome stove several times, pull down reducing slag before feeding in raw material at every turn, then add mixture charge.

G reducing and smelting is complete, pulls down reducing slag, tapping, obtains Molten Ferroalloys 43 tons, is wherein respectively 0.1%, 0.008%, 0.004% containing chromium 20.1%, C, P, S, can uses as mother liquor of stainless steel.

Amount to and obtain MAGNESIUM METAL 35 tons, power consumption 7200kwh on average per ton.

In first embodiment, the source whereabouts of the smelting principle of Si reduction chromium and chromium, ferro element as shown in Figure 5.

Second embodiment:

Raw material prepares substantially identical with the first embodiment, during the smelting of every stove, add in ferrosilicon liquid containing aluminium 20%, siliceous 40% Alsimin 2 tons, all the other operations are constant.The preferential Si reduction magnesium of aluminium, becomes aluminum oxide and enters in slag.Reductive agent aluminium alloy still can stably manufactured MAGNESIUM METAL, ferrochrome liquid.In second embodiment, the source whereabouts of the smelting principle of aluminium, Si reduction chromium and chromium, ferro element as shown in Figure 6.

3rd embodiment:

Initial feed adopts the ferrosilicon liquid 48 tons containing nickel, and wherein siliceous is still 65%, nickeliferous 7%, and all the other are iron, and ferrosilicon is not added in centre, and other operations are constant.Reductive agent aluminium alloy still can stably manufactured MAGNESIUM METAL, drop to after below 35 tons in ferrosilicon total amount, change every stove calcined dolomite into reduce by half and add, fusing assistant auxiliary material also reduces by half in proportion and adds, siliceous 30% time, aluminium alloy quality is 24 tons, turns and goes to smelt ferrochrome, allocate chrome ore and iron scale into, in refining chromium process, nickel is stayed in aluminium alloy, final obtain containing chromium 20%, nickeliferous 8.6% mother liquor of stainless steel 36 tons.In 3rd embodiment, the source whereabouts of the smelting principle of Si reduction chromium and chromium, nickel, ferro element as shown in Figure 7.

4th embodiment:

The present embodiment adopts " reverse recoverable " will refine chromium slag as refining magnesium raw material containing magnesium oxide melting, namely ferrosilicon 102 is introduced into Mg-smelting furnace 10, refining chromium stove 20 is entered after the complete poor silicon of refining magnesium, but be first enter refining chromium stove 20 as the integral part of refining Cr materials 201 containing magnesian magnesium ore deposit, then the slag-2 refining the rich magnesium of the poor iron of the complete poor chromium afterwards of chromium is re-used as refining magnesium raw material 101 and enters into Mg-smelting furnace 10, ferrosilicon liquid as shown in Figure 8, the technique glide path of magnesium oxide mineral aggregate.

By calcined dolomite and chrome ore, lime and fusing assistant etc. be mixing in advance, form the raw material 201 of refining chromium stove 20, join refining chromium stove 20 several times, and fully mix with the ferrosilicon liquid 202 of 30%, keep ferrosilicon liquid and often criticize the ratio of mineral aggregate far above the silicon amount needed for chemical reaction, often criticize mineral aggregate after completion of the reaction, discharge containing magnesian hot slag, Mg-smelting furnace 10 is entered into as refining magnesium raw material 101 " reverse ", fully mix with the ferrosilicon liquid 102 of siliceous 65%, carry out refining magnesium, the whole reducing slag discharge that refining magnesium is complete, then the magnesian melting furnace charge that contains continued refining chromium stove is newly discharged mixes as 101 with the high silicon ferrosilicon liquid 101 in Mg-smelting furnace, carry out refining magnesium.

In above-mentioned four embodiments, when poor silicon ferrosilicon liquid after refining magnesium smelts chromium stainless steel mother liquor, except the main alloy element chromium shown in Fig. 5, Fig. 6, Fig. 7, nickel, iron source, molten stainless steel also needs the constituent content such as carbon, phosphorus, sulphur, oxygen, hydrogen, nitrogen that control ratio is lower.

Chromium stainless steel liquid carbon containing in the present invention and embodiment is lower, this is because the solubleness of original carbon is less in ferrosilicon, as shown in Figure 9, so can obtain the mother liquor of stainless steel of low-carbon (LC).

Emphasized is dephosphorization once.In stainless steel smelting process, dephosphorization is a vital task.General ferrous metallurgy adopts dephosphorization under oxidizing atmosphereLin Fenpeibi means, but when smelting stainless steel, and due to chromium in stainless steel, to have precedence over phosphorus oxidized and cause the loss of alloying element chromium, so the stainless steel capital is dephosphorization under oxidizing atmosphereLin Fenpeibi in early days, once enter the later stage, dephosphorization just compares and difficult for.But method provided by the invention, makes two large advantages realize the dephosphorization of smelting stainless steel.This two large advantage is vacuum-evaporation dephosphorization, dephosphorization under reducing atmosphere respectively.

Phosphorus is Volatile Elements, and boiling point only has 280 DEG C, completely can by volatilization dephosphorization, and its vapour pressure is even higher than the volatile metal that magnesium is such.But in Iron And Steel Industry, phosphorus is combined into comparatively stable Fe with iron in molten steel ₂p, Fe ₃p, reduces the activity of phosphorus, is thus difficult to slough phosphorus in molten steel by the method for evaporation in Iron And Steel Industry.

But phosphorus is not when not combining with iron, and easily enter gas phase, apply this feature, the Electric Cooker yellow phosphorus of phosphorous chemical industry is able to large-scale production, also utilize in the Physical purification of polysilicon phosphorous vapor pressure higher come deep phosphorous removal.In Electric Cooker yellow phosphorus industry is produced, as long as do not add steel cuttings in furnace charge, the phosphorus major part obtained that just can realize reducing enters into gas phase with phosphorous vapor, condensation is collected and is obtained yellow phosphorus, and the ferrophosphorus of by-product only has the 10-20% of yellow phosphorus, phosphorous rate 18-26%, visible phosphorus is not combined with iron, and the phosphorus obtained 1400-1600 DEG C of reduction has at least 95% evaporation to enter gas phase.If but added steel cuttings in furnace charge, the phosphorus about 80% obtained that so reduces would enter into ferrophosphorus, enters into gas phase within only having 20%, thus to become with ferrophosphorus be major product, and the condensed thick phosphorus of phosphorous vapor is byproduct.

During Physical purification photovoltaic crystal silicon material, also adopt the method for vacuum-evaporation dephosphorization.The pure silicon material of melting is left standstill several hours in a vacuum, phosphorus content can be removed to several ppm magnitude.

In ferrosilicon liquid, because silicon and iron generate stable FeSi etc., phosphorus can not be combined with iron, thus possess the condition of vacuum-evaporation dephosphorization, generally at more than silicone content 20-30%, phosphorus just can adopt vacuum vapor deposition method to remove in a large number.

In ferrosilicon refining magnesium link, vacuum suction, blast that argon gas stirs, magnesium vapor generates and is pumped, these three kinds of vacuum effects are superimposed, and are very beneficial for removing of phosphorus.

Except vacuum-evaporation dephosphorization, dephosphorization under reducing atmosphere is also important dephosphorization means.The calcined dolomite containing CaO, MgO being used for refining magnesium adds also fully mixing in ferrosilicon liquid, and while a large amount of generation magnesium, have a small amount of calcium also to generate, possess strong reductive condition, these two kinds of metals can generate Ca with phosphorus ₃p ₂, Mg ₃p ₂enter slag phase, i.e. so-called dephosphorization under reducing atmosphere, as shown in formula (4), (5).In conventional stainless steel smelting, because the vapour pressure of calcium, magnesium metal is very high, when adding molten stainless steel dephosphorizing, most of calcium, magnesium vaporization losses, only have and be combined with phosphorus on a small quantity, so dephosphorization metal utilizing status is not ideal enough.And the present invention is just to produce magnesium vapor in a large number in one of object, thus there is not the situation of dephosphorization evaporation of metal loss.

3Ca+2[P]＝{Ca ₃P ₂} (4)

3Mg+2[P]＝{Mg ₃P ₂} (5)

Note also that, the phosphorus content of poor silicon ferrosilicon is lower, but in refining ferrochrome link, needs the phosphorus content taken precautions against in the fusing assistant such as chrome ore and lime too not high.

If the phosphorus of Mg-smelting furnace material is very high, so certain Ca can be there is in smelting magnesium slag ₃p ₂, Mg ₃p ₂, the protection against the tide of this slag be noted, directly can not contact with water or water vapour, in case generate the PH of severe toxicity ₃, the health of harm people, should be oxidized to phosphoric acid salt as early as possible under protection against the tide and isolated air conditions.

Desulfurization is also the approach similar to dephosphorization, but more easy.In stainless steel smelting, add the slag charge that alkalescence is higher, can desulfurization be realized.The present invention refines magnesium link, and the magnesium ore deposit added is that alkaline rhombspar is forged white, can effectively desulfurization.In addition, the evaporation sweetening effectiveness similar to evaporation dephosphorization also can be superimposed, and obtains excellent sweetening effectiveness.

Deoxidation effect.Adopt poor silicon ferrosilicon liquid smelting stainless steel, wherein because silicone content is high, oxygen level is very low, reaches good deoxidation effect.

Degasifying effect.In refining magnesium link, vacuum suction, argon gas stir, magnesium vapor is taken away, H, the N etc. in ferrosilicon liquid can be removed to lower level.

In addition to the advantages indicated above, adopt poor silicon ferrosilicon liquid as the DIRECT ALLOYING of carrying out chrome ore, One's name is legion, cheap chromite ore fine can be made full use of.Natural chrome ore about 75% is chromite ore fine, only has 25% for chrome ore block.When adopting the ferrochrome needed for mine heat furnace smelting stainless steel, in order to the ventilation property of mineral hot furnace operation, expensive lump ore must be selected, or by cheap fine ore briquetting in advance, pelletizing or sintering become bulk material, cause complex process, energy consumption improves, cost increases, and in the present invention poor silicon ferrosilicon liquid still according to refining magnesium time mode, using poor silicon ferrosilicon liquid as external phase, chromite ore fine carries out both abundant mixing as disperse phase, the granularity of chromite ore fine is comparatively carefully conducive to refining chromium process on the contrary, good chromium element DIRECT ALLOYING can be obtained, making it possible to low cost utilizes in liberal supply, cheap chromite ore fine.

In 4th embodiment, adopt " recoverable " to refine chromium slag as refining magnesium raw material containing magnesium oxide melting, at least bring three further to optimize.In chrome ore, content of magnesia is very high, usually can reach 10-22%, and after particularly refining chromium, in residue slag, magnesium oxide is higher, and being used for as unfavorable refining magnesium, is the larger wasting of resources.Also have, the heat energy of refining magnesium process need external world's input is larger, and to refine chromium process energy consumption be negative value or remain basically stable, so refining chromium stove will be introduced into after dolomite calcination, be equivalent to magnesium ore deposit to melt in advance in refining chromium stove, reduces the thermal load of refining magnesium link, refine chromium link to fail to reduce in the high silicon iron liquid of the abundant small amounts chromium reduced in Mg-smelting furnace simultaneously, enter into ferrosilicon liquid, finally flowed to again refining chromium stove, therefore the comprehensive recovery rate of chromium obtains and promotes further.

Table 2 technical solution of the present invention is in the advantage in refining magnesium field

Table 3 technical solution of the present invention is smelting the advantage in chrome stainless steel field

In sum, these are only preferred embodiment of the present invention, should not limit the scope of the invention with this, namely every simple equivalence done according to claims of the present invention and description changes and modifies, and all should still remain within the scope of the patent.

Claims

1. the coproduction of ferrosilicon bath step reduction magnesium-smelting silicothermic process is containing the method for ferrochrome liquid, it is characterized in that, comprises following technique:

2. ferrosilicon bath step reduction magnesium-smelting silicothermic process as claimed in claim 1 coproduction is containing the method for ferrochrome liquid, it is characterized in that, one or more being subject in firing magnesium-smelting furnace in argon gas stirring, electromagnetic force stirring or mechanical stirring of the molten alloy liquid in described technique A stir.

3. ferrosilicon bath step reduction magnesium-smelting silicothermic process as claimed in claim 1 coproduction is containing the method for ferrochrome liquid, and it is characterized in that, also containing mass percent in the molten alloy liquid in described technique A is the aluminium element of 1-30%.

4. ferrosilicon bath step reduction magnesium-smelting silicothermic process as claimed in claim 1 coproduction is containing the method for ferrochrome liquid, and it is characterized in that, also containing mass percent in the molten alloy liquid in described technique A is the nickel element of 0.5-20%.

5. ferrosilicon bath step reduction magnesium-smelting silicothermic process as claimed in claim 1 coproduction is containing the method for ferrochrome liquid, it is characterized in that, in described technique B containing magnesian material be the rhombspar after calcining, the magnesite after calcining, the waste and old refractory materials of magnesia, containing magnesian metallurgical slag or containing one or more in the magnesian slag melted.

6. ferrosilicon bath step reduction magnesium-smelting silicothermic process as claimed in claim 1 coproduction is containing the method for ferrochrome liquid, it is characterized in that, after a collection of magnesium oxide at least 50% in described technique B reacts, just the slag that reaction is formed is separated from described firing magnesium-smelting furnace.

7. ferrosilicon bath step reduction magnesium-smelting silicothermic process as claimed in claim 1 coproduction is containing the method for ferrochrome liquid, it is characterized in that, described technique B also comprises and add ferrosilicon in described molten alloy liquid, after keeping described molten alloy liquid quality to be greater than unreacted and reaction all the time, multivariant oxide institute forms the quality of slag phase, and keep the siliceous quality of molten alloy liquid be always Si reduction slag mutually in magnesium chemical theory need 1.5-200 times of siliceous amount.

8. ferrosilicon bath step reduction magnesium-smelting silicothermic process as claimed in claim 1 coproduction is containing the method for ferrochrome liquid, it is characterized in that, slag reaction formed in described technique B comprises from the mode that described firing magnesium-smelting furnace is separated and recharging molten alloy liquid to described firing magnesium-smelting furnace after discharging described firing magnesium-smelting furnace together with described molten alloy liquid and slag phase again, or is directly separated from described firing magnesium-smelting furnace by slag.

9. ferrosilicon bath step reduction magnesium-smelting silicothermic process as claimed in claim 1 coproduction is containing the method for ferrochrome liquid, it is characterized in that, adds containing aluminum oxide and/or the material containing Calcium Fluoride (Fluorspan) as slag former in the molten alloy liquid in described technique B.

10. ferrosilicon bath step reduction magnesium-smelting silicothermic process as claimed in claim 1 coproduction is containing the method for ferrochrome liquid, it is characterized in that, in described technique D is smelt the mother liquor of chromium stainless steel containing ferrochrome liquid, and described is 10-50% containing ferrochrome liquid containing chromium mass percent.

11. ferrosilicon bath step reduction magnesium-smelting silicothermic process as claimed in claim 1 coproduction are containing the method for ferrochrome liquid, it is characterized in that, in described technique D, add calcined limestone, rhombspar forges white powder, material containing calcium oxide or containing one or more in magnesian material as slag former.

The method of 12. ferrosilicon bath step reduction magnesium-smelting silicothermic process coproduction chromium stainless steel liquid, is characterized in that, comprise following technique:

13. ferrosilicon bath steps reduction magnesium-smelting silicothermic process coproduction are containing manganese, containing molybdenum, method containing vanadium or tungsten-containing alloy steel liquid, is characterized in that, comprise following technique: