CN102242262A - Method for treating low-grade zinc oxide ore by using weakly alkaline amino acid salt system - Google Patents

Abstract

The invention discloses a method for treating a low-grade zinc oxide ore by using a weakly alkaline amino acid salt system, which comprises the following steps of: grinding the complex low-grade zinc oxide ore, and performing cooperated leaching in the weakly alkaline amino acid salt system under the certain condition to ensure that zinc, lead, cadmium, copper, nickel and the like are dissolved in leachate and calcium, magnesium, iron, silicon and the like are undissolved and stay in leaching residues; adding CaO or Ca(OH)2 into the leachate to ensure that the zinc is precipitated in the form of zinc oxide and recovered, and valuable metals such as the lead, the cadmium, the copper, the nickel and the like are co-precipitated with the zinc and enriched in crude zinc oxide; and regulating the pH of solution in which the zinc is precipitated to be a certain value by using CO2, regenerating a leaching agent, returning the regenerated leaching agent for recycling, and calcining CaCO3 generated in the process of regenerating the leaching agent for recycling. The method for treating the low-grade zinc oxide ore by using the weakly alkaline amino acid salt system can be used for effectively treating various complex low-grade zinc oxide ores with high calcium, magnesium, iron and silicon content, and the operation system is mild and has small toxic and side effects on human bodies and an environment.

Description

A kind of weakly alkaline amino acid salts system is handled the method for low-grade zinc oxide ore

Technical field

The present invention relates to a kind of treatment process of low-grade zinc oxide ore, particularly relate to the method that a kind of weakly alkaline amino acid salts system is handled low-grade zinc oxide ore.

Background technology

Along with the zinc sulfide ore resource of Yi Xuanye is continually developed and consumed, zinc oxide ore more and more is subjected to the attention of zinc metallurgy industry.Zinc oxide ore is a secondary mineral, be by after the zinc sulfide ore oxygenolysis with country rock in carbonate or silicate reaction form, mainly comprise smithsonite (ZnCO ₃), hydrozincite (2ZnCO ₃3Zn (OH) ₂), willemite (Zn ₂SiO ₄), lapis calaminaris (Zn ₄(H ₂O) Si ₂O ₇(OH) ₂) etc.The zinc oxide ore grade is generally lower, generally is lower than 20%, and impurity calcium, magnesium, iron, silicone content are higher, and complicated component is difficult to sort.

The treatment process of zinc oxide comprises pyrogenic process and wet method two big classes.This type of low-grade zinc oxide ore of pyrogenic attack is because of its energy consumption height, and economic benefit is low, and the development of reasons such as operating environment difference is restricted.Wet processing process is with its investment thermal process that progressively replaced little, simple to operate, and wet method comprises that mainly acidleach, ammonia soak and three kinds of technologies of NaOH leaching.

Acid leaching process is a leaching agent with sulfuric acid mainly, during leaching in the zinc oxide mineral a large amount of impurity such as calcium, magnesium, iron and silicon consume leaching agent, pollute leach liquor with acid-respons, and silicon in the acidic solution system easily formation silica gel make the solid-liquid separation difficulty.Contain a large amount of impurity in the leach liquor of acidleach process output, need to carry out the qualified electric zinc product of electrodeposition output after the purifying treatment.In the ammonia soaking technology mainly with NH ₃Be part, itself and Zn ²⁺Form coordination ion and make that Zn enters solution in the zinc oxide mineral, calcium, magnesium, iron, silicon can not dissolved in a large number in the process, but the ammonia volatilization is arranged in the leaching process, and is bigger to human body, environmental hazard.Now, a lot of researchs are intended to leach with the alternative ammoniacal liquor of part ammonium salt.Zinc content is not high in the leach liquor of ammonia soaking technology processing low-grade zinc oxide ore output, need to leach to improve zinc concentration in the solution through solvent extraction or circulation, but the electricity of the solution electrodeposition output after enrichment zinc, anode is emitted the part NH in the nitrogen consumption solution during ammono-system electrodeposition ₃, so liquid can return leaching after must replenishing ammoniacal liquor behind the ammono-system electrodeposition.The NaOH extract technology is to utilize OH ^-With Zn ²⁺Form coordination ion and make Zn dissolving in the mineral, but the NaOH concentration that adopts in leaching process is higher, belongs to the strong basicity system, alkaline consumption is higher in the technology, and a large amount of dissolvings of silicon formation water glass enter solution in the leaching process.Zinc content is lower in the leach liquor of NaOH extract technology processing low-grade zinc oxide ore output, it is undesirable that directly electrodeposition is produced electric zinc effect, can make zinc sulfide concentrates and zinc oxide concentrate respectively by sulfide precipitation or hydrolytic precipitation, but liquid Returning utilization difficulty behind the heavy zinc.(1. handle theory and the technical study that low-grade zinc oxide ore is produced electric zinc in the auspicious .MACA system of Wang Rui: [D]. Changsha: Central South University, 2009.5:17-24. 2. old love is good, Zhao Zhongwei, Jia Xijun, Deng. zinc oxide ore comprehensive utilization status and prospects [J]. mining metallurgical engineering, 2008. (28) 6:62-66.)

There is following shortcoming in above-mentioned zinc oxide ore treatment process:

(1) the thermal process initial cost is big, and environmental pollution is heavy, and when handling low-grade zinc oxide, zinc recovery is not high, and economic benefit is low.

When (2) acid leaching process was handled the complicated low-grade zinc oxide ore of high calcium-containing, magnesium, iron and silicon, the acid consumption was high, purify numerous and diverse, filtration difficulty.

(3) institute's evaporable ammonia toxic side effect height in the ammonia soaking technology, bigger to human body, environmental hazard, and need constantly add ammoniacal liquor in the technology to keep total ammonia concentration.

(4) the NaOH extract technology should not be handled high silicon low-grade zinc oxide ore to the equipment requirements height, and is difficult to return use after containing zinc lixiviating solution recovery zinc.

Summary of the invention

Technical problem to be solved by this invention provides a kind of method that can effectively handle the high complicated low-grade zinc oxide ore of various calcics, magnesium, iron and silicon and operation system gentleness, human body and the little weakly alkaline amino acid salts system of environment toxic side effect be handled low-grade zinc oxide ore.

In order to solve the problems of the technologies described above, weakly alkaline amino acid salts system provided by the invention is handled the method for low-grade zinc oxide ore, with complicated low-grade zinc oxide ore levigate after, cooperate in the weakly alkaline amino acid salts system under certain condition and leach, dissolvings such as zinc, lead, cadmium, copper and mickel enter leach liquor, and calcium, magnesium, iron and silicon etc. do not dissolve and stays in leached mud; Add CaO or Ca (OH) in the leach liquor ₂Zinc is reclaimed with zinc oxide form precipitation, and valuable metal such as lead, cadmium, copper and mickel and zinc co-precipitation are enriched in the tutty; Solution CO after the depositing zinc ₂Regulator solution pH makes leaching agent regeneration to certain value, and the leaching agent after the regeneration returns recycle, the CaCO of leaching agent regenerative process output ₃Through calcining back Returning utilization, concrete processing step and parameter are as follows:

(1), alkalescence cooperates leaching:

Low-grade zinc oxide ore cooperates leaching in the weakly alkaline amino acid salts aqueous solution, low-grade zinc oxide ore is levigate and 100% to cross the aperture be the sieve of 75～200um, it is 2: 1～7: 1 at liquid-solid ratio L/Kg then, Synergist S-421 95 concentration 0.5～5mol/L, pH value 7～11 (with solid sodium hydroxide regulation system pH), 15～95 ℃ of extraction temperatures, extraction time 0.5～6.0h, leach under the condition of stirring velocity 100～700r/min, leach and finish the back solid-liquid separation; Principal reaction in the alkalescence cooperation leaching process is following, and (amino acid is abbreviated as H _xL, L ^X-Be amino acid radical anion):

${\mathrm{ZnCO}}_3+{\mathrm{iL}}^{x-}={\mathrm{ZnL}}_i^{2-\mathrm{ix}}+{\mathrm{CO}}_3^{2-}---\left(1\right)$

$2\mathrm{Zn}{\mathrm{CO}}_3\·3\mathrm{Zn}{\left(\mathrm{OH}\right)}_2+{5\mathrm{iL}}^{x-}={5\mathrm{ZnL}}_i^{2-\mathrm{ix}}+{2\mathrm{CO}}_3^{2-}+{6\mathrm{OH}}^{-}---\left(2\right)$

${\mathrm{Zn}}_2{\mathrm{SiO}}_4+{2\mathrm{iL}}^{x-}+{2H}_{2}O={2\mathrm{ZnL}}_i^{2-\mathrm{ix}}+{\mathrm{SiO}}_2\↓+{4\mathrm{OH}}^{-}---\left(3\right)$

${\mathrm{Zn}}_4\left(H_{2}O\right){\mathrm{Si}}_2{O}_7{\left(\mathrm{OH}\right)}_2+{4\mathrm{iL}}^{x-}+{2H}_{2}O={4\mathrm{ZnL}}_i^{2-\mathrm{ix}}+2{\mathrm{SiO}}_2\↓+{8\mathrm{OH}}^{-}---\left(4\right)$

$\mathrm{ZnO}+{\mathrm{iL}}^{x-}+H_{2}O={\mathrm{ZnL}}_i^{2-\mathrm{ix}}+{2\mathrm{OH}}^{-}---\left(5\right)$

(2), the recovery of zinc in the leach liquor:

In containing zinc lixiviating solution, add CaO or Ca (OH) ₂Zinc in the precipitation solution, CaO or Ca (OH) ₂Particle diameter requires 75～200um, and the adding mode can directly add or the back adding of sizing mixing for powder, and the adding mode of sizing mixing is water (volume L): CaO or Ca (OH) ₂(quality kg) is 1: 1～5: 1, heavy zinc endpoint pH 9～11.5,15～95 ℃ of temperature, reaction times 0.5～3h, stirring velocity 100～700r/min; Principal reaction is as follows in the process:

${\mathrm{ZnL}}_i^{2-\mathrm{ix}}+\mathrm{Ca}{\left(\mathrm{OH}\right)}_2=\mathrm{ZnO}\↓+{\mathrm{CaL}}_i^{2-\mathrm{ix}}+H_{2}O$

(3), leaching agent regeneration:

Feed CO in the solution after depositing zinc ₂Gas is controlled the flow velocity 0.2～2L/min of carbonic acid gas with the regeneration leaching agent, stirring velocity 100～700r/min, and 15～95 ℃ of temperature, endpoint pH 7～11 can reach leaching agent regenerated purpose.Principal reaction is as follows in the process:

${\mathrm{CaL}}_i^{2-\mathrm{ix}}+{\mathrm{CO}}_2+H_{2}O={\mathrm{CaCO}}_3\↓+{2H}^{+}+{\mathrm{iL}}^{x-}$

Described sodium hydroxide, calcium hydroxide, calcium oxide and carbonic acid gas are technical grade reagent, and Synergist S-421 95 is one or more in Padil, L-glutamic acid, iminodiethanoic acid and the complexon I, can also add by its corresponding sodium-salt form.

The present invention is applicable to and handles calcic, magnesium, iron and the high low-grade zinc oxide ore of silicon that its main component scope is (%): Zn 4～20, CaO 2～50, MgO 0.01～25, Fe 1～20, SiO by weight percentage ₂2～65, Cu 0.0001～1, Ni 0.0001～1, Pb 0.1～15, Cd 0.01～10, Al ₂O ₃0.01～10 and S 0.5～8.

The present invention compared with prior art has following advantage: 1 the present invention can handle the high complicated low-grade zinc oxide ore of various calcics, magnesium, iron and silicon, various oxidation state zinc species in the mineral all there is good leaching effect, calcium, magnesium, iron and silicon etc. do not dissolve during leaching, and can comprehensively reclaim valuable metals such as lead, cadmium, copper and mickel; The used leaching system of 2 the present invention is a weakly alkaline amino acid salts system, and is little to environment, human body toxic side effect; 3 the present invention leach the renewable realization circulation of system and leach, and have reduced production cost, and the circulation leaching process is stable, leaching yield is high, need not to replenish Synergist S-421 95 in the process; Agents useful for same wide material sources among 4 the present invention, and can regeneration, reduced production cost, can realize the target of clean metallurgical.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

Embodiment

The invention will be further described below in conjunction with drawings and Examples.

Embodiment 1:

Referring to Fig. 1, after zinc oxide ore was levigate, it was the 150um screen cloth that the gained mineral dust is crossed the aperture, its main component (wt%): Zn 6.5, Fe 6.5, CaO 25.74, MgO 0.83, Al ₂O ₃2.20, SiO ₂17.53, Cu 0.0049, Pb 0.91 and S 4.60, wherein the zinc content that exists with zink sulphide is 0.97%, all the other are oxidation state zinc; The technical grade Sodium Glutamate, content 〉=95%; Industrial sodium hydroxide, content 〉=96%; The technical grade calcium oxide, content 〉=88%, the levigate aperture 106um screen cloth of crossing.

Getting above-mentioned Sodium Glutamate 133.5g mixes with 500ml water, under 80 ℃, regulate its pH value to 9 with NaOH, making part glutamate total concn is the 1.5mol/L infusion solution, regulate stirring velocity 300r/min, add zinc oxide ore 100g, behind the agitation leach 5h, filtered while hot, store up after the leached mud washing, after merging, wash water and leach liquor get leach liquor 550ml, leach liquor main component (mg/L): Zn 7970, Ca 156.4, Mg 11.0, Fe 1.8, Cu 13.0, Ni 0.27, Pb 98.6, Cd 105.4 and Si 51.8, total zinc leaching rate is 67.44%.

Leach liquor 25 ℃, when stirring velocity is 400r/min, directly adds lime powder and regulate pH value to 11, reaction 1h after-filtration, heavy cadmia washing back oven dry is weighed, tutty 6.5g, liquid 550ml behind the heavy zinc, the zinc rate of sinking is 87%.Tutty main component (wt%): Zn 57.2, Ca 8.5, Mg 0.10, Fe 0.31, Cu 0.0201, Pb 0.51, Cd 0.013,027.0, Al 0.0107 and Mn 0.451.Liquid main component (mg/L): Zn 500, Ca 4210.6, Mg 4.3, Fe 0, Cu 3.1, Ni 0, Pb 53.5, Cd 35.6 and Si153.2 behind the heavy zinc.

Behind the heavy zinc liquid 80 ℃, during stirring velocity 100r/min, logical CO ₂Heavy calcium, pilot-gas flow velocity 0.2L/min, the system pH for the treatment of reduces to 9, closes the source of the gas after-filtration, dry after pulp water is washed lime carbonate slag 5.4g, liquid directly returns and soaks the ore deposit behind the heavy calcium.

Embodiment 2:

Referring to Fig. 1, crossing the aperture after zinc oxide ore is levigate is the 150um screen cloth, its main component (wt%): Zn 7.72, Fe 4.84, CaO 8.02, MgO 0.57, Cd 0.23, SiO ₂46.06, Cu 0.01, Ni 0.0019, Pb 1.86, wherein the zinc content that exists with zink sulphide is 1.35%, all the other are oxidation state zinc.The technical grade iminodiethanoic acid, content 〉=95%; Industrial sodium hydroxide, content 〉=96%; The technical grade calcium oxide, content 〉=88%, the levigate aperture 106um screen cloth of crossing.

Getting above-mentioned imino-diacid 140g mixes with 1000ml water, under 70 ℃, regulate its pH value to 8 with NaOH, making part iminodiacetic acid (salt) acid group total concn is the 1mol/L infusion solution, regulate stirring velocity to 300r/min, add zinc oxide ore 200g, filtered while hot behind the leaching 4h, store up after the leached mud washing, after merging, wash water and leach liquor get leach liquor 1000ml, leach liquor composition (mg/L): Zn 11844, Ca 583.18, Mg 8.88, Fe 64.29, Cu 7.77, Ni 0.11, Pb 1427.08, Cd 141.93 and Si 69.67, total zinc leaching rate is 76.71%.

Leach liquor 85 ℃, during stirring velocity 400r/min, directly add the CaO powder and regulate pH value to 10, reaction 1h after-filtration, heavy cadmia washing back oven dry is weighed, tutty 17.6g, liquid 1000ml behind the heavy zinc sinks zinc rate 93.37%.Tutty main component (wt%): Zn 56.91, Ca 9.583, Mg 0.225, Fe 0.5012, Cu 0.0166, Pb 3.40, Cd 0.032, Si 0.536,028.5, Mn 1.101, Al 0.0107 and S 0.0794.Liquid main component (mg/L): Zn 776, Ca 4893.08, Mg 5.84, Fe 0, Cu 4.84, Ni 0, Pb 482.04, Cd 49.16 and Si 769.44 behind the heavy zinc.

Behind the heavy zinc liquid 70 ℃, during stirring velocity 100r/min, logical CO ₂Heavy calcium, pilot-gas flow velocity 1L/min, the system pH for the treatment of reduces to 8, closes the source of the gas after-filtration, dry after pulp water is washed lime carbonate slag 12g, liquid 1000ml behind the heavy calcium.Lime carbonate slag main component (wt%): Zn 0.0383, Ca 45.46, Mg 0.024, Fe 0.019, Cu 0.006, Pb 0.6607, Cd 0.008, O 43.2, Na 1.07 and S 0.62.Liquid main component (mg/L): Zn 623, Ca 103.76, Mg 0, Fe 0, Cu 4.12, Ni 0, Pb 275.12, Cd 41.36 and Si 100.16 behind the heavy calcium.Liquid directly returns and soaks the ore deposit behind the heavy calcium.

Liquid 1000ml is warming up to 70 ℃ behind the above-mentioned heavy calcium, regulate stirring velocity to 300r/min, add zinc oxide ore 200g, filtered while hot behind the leaching 4h, pulp water is stored up after washing, after merging, wash water and leach liquor get leach liquor 1000ml, leach liquor main component (mg/L): Zn 12670, Ca 0, Mg 0.72, Fe 0, Cu 11.16, Ni 0, Pb 163.56, Cd 104.64 and Si 112.32, and total zinc leaching rate is 78.0%.

Embodiment 3:

Referring to Fig. 1, crossing the aperture after zinc oxide ore is levigate is the 150um screen cloth, its main component (wt%): Zn 7.72, Fe 4.84, CaO 8.02, MgO 0.57, Cd 0.23, SiO2 46.06, Cu 0.01, Ni 0.0019, Pb 1.86, wherein the zinc content that exists with zink sulphide is 1.35%, and all the other are oxidation state zinc.The technical grade Padil, content 〉=98%; Industrial sodium hydroxide, content 〉=96%; The technical grade calcium oxide, content 〉=88%, the levigate aperture 150um screen cloth of crossing.

Getting above-mentioned Padil 92g mixes with 1000ml water, under 75 ℃, regulate its pH value to 8.5 with NaOH, making part Padil root total concn is the 1.2mol/L infusion solution, regulate stirring velocity to 300r/min, add zinc oxide ore 200g, filtered while hot behind the leaching 6h, store up after the leached mud washing, after merging, wash water and leach liquor get leach liquor 1000ml, leach liquor composition (mg/L): Zn 11800, Ca 136.32, Mg 5.75, Fe 20.17, Cu 7.77, Ni 0.11, Pb 1227.64, Cd 101.55 and Si 13.80, total zinc leaching rate is 76.42%.

Leach liquor 90 ℃, during stirring velocity 100r/min, directly add the CaO powder and regulate pH value to 9.6, reaction 0.5h after-filtration, heavy cadmia washing back oven dry is weighed, tutty 17.6g, liquid 1000ml behind the heavy zinc sinks zinc rate 93.5%.Tutty main component (wt%): Zn 56.67, Ca 9.573, Mg 0.225, Fe 0.500, Cu 0.0166, Pb 3.40, Cd 0.032, Si 0.536,0 28.5, Mn 1.101, Al 0.0107 and S 0.0794.Liquid main component (mg/L): Zn 767, Ca 4895.54, Mg 5.84, Fe 0, Cu 4.84, Ni 0, Pb 482.04, Cd 49.16 and Si 673.20 behind the heavy zinc.

Behind the heavy zinc liquid 55 ℃, during stirring velocity 100r/min, the heavy calcium of logical CO2, pilot-gas flow velocity 2L/min, the system pH for the treatment of reduces to 8.2, closes the source of the gas after-filtration, dry after pulp water is washed lime carbonate slag 12g, liquid 1000ml behind the heavy calcium.Lime carbonate slag main component (wt%): Zn0.0383, Ca 45.46, Mg 0.024, Fe 0.019, Cu 0.006, Pb 0.6607, Cd 0.008, O 43.2, Na 1.07 and S 0.62.Liquid main component (mg/L): Zn 623, Ca 103.76, Mg 0, Fe 0, Cu 4.12, Ni 0, Pb 275.12, Cd 41.36 and Si 100.16 behind the heavy calcium.Liquid directly returns and soaks the ore deposit behind the heavy calcium.

Liquid 1000ml is warming up to 75 ℃ behind the above-mentioned heavy calcium, regulate stirring velocity to 300r/min, add zinc oxide ore 200g, filtered while hot behind the leaching 6h, pulp water is stored up after washing, after merging, wash water and leach liquor get leach liquor 1000ml, leach liquor main component (mg/L): Zn 12570, Ca 0, Mg 0.72, Fe 0, Cu 11.16, Ni 0, Pb 163.56, Cd 104.64 and Si 112.32, and total zinc leaching rate is 77.38%.

Embodiment 4:

Referring to Fig. 1, crossing the aperture after zinc oxide ore is levigate is the 150um screen cloth, its main component (wt%): Zn 7.72, Fe 4.84, CaO 8.02, MgO 0.57, Cd 0.23, SiO2 46.06, Cu 0.01, Ni 0.0019, Pb 1.86, wherein the zinc content that exists with zink sulphide is 1.35%, and all the other are oxidation state zinc.The technical grade complexon I, content 〉=98%; Industrial sodium hydroxide, content 〉=96%; The technical grade calcium oxide, content 〉=88%, the levigate aperture 200um screen cloth of crossing.

Getting above-mentioned complexon I 195g mixes with 1000ml water, under 70 ℃, regulate its pH value to 8 with NaOH, making part complexon I root total concn is the 1.0mol/L infusion solution, regulate stirring velocity to 400r/min, add zinc oxide ore 200g, filtered while hot behind the leaching 5h, store up after the leached mud washing, after merging, wash water and leach liquor get leach liquor 1000ml, leach liquor composition (mg/L): Zn 11925, Ca 542.10, Mg 8.88, Fe 64.29, Cu 7.77, Ni 0.11, Pb 1427.08, Cd 141.93 and Si 51.83, total zinc leaching rate is 77.23%.

Leach liquor 80 ℃, during stirring velocity 200r/min, directly add the CaO powder and regulate pH value to 10, reaction 1h after-filtration, heavy cadmia washing back oven dry is weighed, tutty 17.6g, liquid 1000ml behind the heavy zinc sinks zinc rate 93.71%.Tutty main component (wt%): Zn 55.99, Ca 9.583, Mg 0.225, Fe 0.5012, Cu 0.0166, Pb 3.40, Cd 0.032, Si 0.536, O 28.5, Mn 1.101, Al 0.0107 and S 0.0794.Liquid main component (mg/L): Zn 750, Ca 4893.08, Mg 5.84, Fe 0, Cu 4.84, Ni 0, Pb 482.04, Cd 49.16 and Si 769.44 behind the heavy zinc.

Behind the heavy zinc liquid 40 ℃, during stirring velocity 200r/min, logical CO ₂Heavy calcium, pilot-gas flow velocity 0.5L/min, the system pH for the treatment of reduces to 8.5, closes the source of the gas after-filtration, dry after pulp water is washed lime carbonate slag 12g, liquid 1000ml behind the heavy calcium.Lime carbonate slag main component (wt%): Zn0.0383, Ca 45.46, Mg 0.024, Fe 0.019, Cu 0.006, Pb 0.6607, Cd 0.008, O 43.2, Na 1.07 and S 0.62.Liquid main component (mg/L): Zn 623, Ca 103.76, Mg 0, Fe 0, Cu 4.12, Ni 0, Pb 275.12, Cd 41.36 and Si 100.16 behind the heavy calcium.Liquid directly returns and soaks the ore deposit behind the heavy calcium.

Liquid 1000ml is warming up to 70 ℃ behind the above-mentioned heavy calcium, regulate stirring velocity to 400r/min, add zinc oxide ore 200g, filtered while hot behind the leaching 5h, pulp water is stored up after washing, get leach liquor 1000ml after wash water and leach liquor merge, leach liquor main component (m g/L): Zn 12670, Ca 0, Mg 0.72, Fe 0, Cu 11.16, Ni 0, Pb 163.56, Cd 104.64 and Si 112.32, total zinc leaching rate is 78.0%.

Claims (6)

1. a weakly alkaline amino acid salts system is handled the method for low-grade zinc oxide ore, with complicated low-grade zinc oxide ore levigate after, cooperate in the weakly alkaline amino acid salts system under certain condition and leach, zinc, lead, cadmium, copper and mickel dissolving enter leach liquor, and calcium, magnesium, iron and silicon do not dissolve and stays in leached mud; Add CaO or Ca (OH) in the leach liquor ₂Zinc is reclaimed with zinc oxide form precipitation, and lead, cadmium, copper and mickel valuable metal and zinc co-precipitation are enriched in the tutty, it is characterized in that: concrete processing step and parameter are as follows:

(1), alkalescence cooperates leaching:

Low-grade zinc oxide ore cooperates leaching in the weakly alkaline amino acid salts aqueous solution, low-grade zinc oxide ore is levigate and 100% to cross the aperture be the sieve of 75～200um, it is 2: 1～7: 1 at liquid-solid ratio L/Kg then, Synergist S-421 95 concentration 0.5～5mol/L, pH value 7～11,15～95 ℃ of extraction temperatures, extraction time 0.5～6.0h, leach under the condition of stirring velocity 100～700r/min, leach and finish the back solid-liquid separation;

(2), the recovery of zinc in the leach liquor:

In containing zinc lixiviating solution, add CaO or Ca (OH) ₂Zinc in the precipitation solution, CaO or Ca (OH) ₂Particle diameter requires 75～200um, heavy zinc endpoint pH 9～11.5, and 15～95 ℃ of temperature, reaction times 0.5～3h, stirring velocity 100～700r/min, the reaction after-filtration, heavy cadmia washing back oven dry gets final product.

2. weakly alkaline amino acid salts system according to claim 1 is handled the method for low-grade zinc oxide ore, it is characterized in that: use solid sodium hydroxide regulation system pH in the above-mentioned steps (1).

3. weakly alkaline amino acid salts system according to claim 1 and 2 is handled the method for low-grade zinc oxide ore, it is characterized in that: CaO or Ca (OH) in the above-mentioned steps (2) ₂The adding mode be that powder directly adds or the back of sizing mixing adds, the adding mode of sizing mixing is water: CaO or Ca (OH) ₂Be 1: 1～5: 1, unit is: volume L: quality kg.

4. weakly alkaline amino acid salts system according to claim 1 and 2 is handled the method for low-grade zinc oxide ore, and it is characterized in that: described sodium hydroxide, calcium hydroxide, calcium oxide and carbonic acid gas are technical grade reagent.

5. weakly alkaline amino acid salts system according to claim 1 and 2 is handled the method for low-grade zinc oxide ore, it is characterized in that: described Synergist S-421 95 is one or more in Padil, L-glutamic acid, iminodiethanoic acid and the complexon I, or its corresponding sodium-salt form adds.

6. weakly alkaline amino acid salts system according to claim 1 and 2 is handled the method for low-grade zinc oxide ore, it is characterized in that: also comprise step (3), leaching agent regeneration:

Feed CO in the solution after depositing zinc ₂Gas, the flow velocity 0.2～2L/min of control carbonic acid gas, stirring velocity 100～700r/min, 15～95 ℃ of temperature, endpoint pH 7～11.

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