CN108793114A

CN108793114A - A kind of potassium dihydrogen phosphate new process for producing of environmental protection and energy saving

Info

Publication number: CN108793114A
Application number: CN201710315020.1A
Authority: CN
Inventors: 不公告发明人
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-05-07
Filing date: 2017-05-07
Publication date: 2018-11-13

Abstract

The present invention relates to a kind of energy-saving and environment-friendly potassium dihydrogen phosphate new process for producing.Its main feature is that using phosphoric acid by wet process and its manufactured goods（Such as agricultural phosphorus ammonium）For primary raw material, dissolving reaction is carried out in the presence of D=0.25-0.45 and cycle ammonia, it detaches after thick potassium mother liquor carries out one section of conversion to filter residue and ammonium chloride is precipitated, denitrogenation waste liquid obtains finished product potassium dihydrogen phosphate to regenerated low nitrogen solution cycling denitrification after filter residue progress two process transform in the environment of D=0.25-0.45.Low energy, low-carbon environment-friendly have with good investment, small, at low cost, the good product quality of corrosion, a series of advantages such as resource utilization height.

Description

A kind of potassium dihydrogen phosphate new process for producing of environmental protection and energy saving

Technical field

The invention belongs to the technical field of chemical engineering, the new side of potassium dihydrogen phosphate production of specially a kind of environmental protection and energy saving Method.The main target of this method, for using phosphoric acid by wet process and phosphoric acid by wet process manufactured goods（Such as agricultural phosphorus ammonium）Manufacture biphosphate The technical field of potassium.

The present invention includes the removing of the ammonium ion from phosphorus ammonium-potassium chloride dissolving dispensing, raw phosphoric acid potassium dihydrogen, point of ammonium chloride From filter residue processing, the innovation of the overall processes such as cyclic process of technique waste water has reached low-carbon energy-saving, and low consumption is high-quality, safety and environmental protection Etc. comprehensive good effect.

Background technology

Phosphoric acid by wet process and phosphoric acid by wet process manufactured goods are used at present（Such as agricultural phosphorus ammonium）The technology of potassium dihydrogen phosphate is manufactured, mainly There are ion-exchange, solvent extraction and double decomposition etc..The first two method cost is quite high, and it is more difficult to exist simultaneously some The problem of environmental pollution of solution, for example, raffinate processing.Although double decomposition is expected to reach lower cost, but due to wet method There is too many impurity in phosphoric acid, and the Chinese holly of water-soluble phosphorus dissolves loss problem in processing procedure, bring too many difficulty, For example, the generation of a large amount of waste residues, the separation of ammonium chloride is difficult, the harm of objectionable impurities, the deterioration of product quality, equipment corrosion Aggravation, etc. so that although this method industrially more application, produce little effect so far.It may be said that with regard to neither one Make us slightly satisfied successful case.

The present invention is for using phosphoric acid by wet process and phosphoric acid by wet process manufactured goods（Such as agricultural phosphorus ammonium）Manufacture potassium dihydrogen phosphate One package modernization overlay plan of technology, the adversity aspect being generally noted above, all takes distinguished change Leather measure, realizes and removes the evil in removal of impurities, energy conservation and environmental protection, the overall effect of high quality and low cost etc..

Invention content

Solve the measure of technical problem

Definition：" degree of neutralization " herein is defined as, in phosphate solution, with HPO₄ ^-2Phosphorus pentoxide existing for form, Shared percentage, is indicated with symbol D in phosphorus pentoxide total amount.

It is the main feature that the present invention is different from the prior art below：

1, at present there are two types of the solution degree of neutralization of all phosphoric acid by wet process double decomposition operations,（1）Operate the range in D≤0.1 It is interior, and（2）Operation is in the range of D >=0.65.The dissolving operation of this technology, dispensing and the basic phase of general double decomposition Together, but in the temperature of 50-60 degree, and in the presence of recycling ammonia, be strict controlled in the range of 0.20≤D≤0.45 into Row.Under this condition, the exclusion of all impurity and harmful element and innoxious can be realized in phosphoric acid by wet process easily, and a step reaches To the target being fully cleaned up, the rate of filtration is high, moreover, the phosphorus potassium carried secretly in filter residue is minimum, 98% water-soluble phosphorus and potassium oxide can be with Into among filtrate, reach best raw materials recovery rate.

Summarizing one of technical characteristic of the invention is：The key condition of dispensing dissolving reaction is 50-60 DEG C of temperature, P₂O₅= 220-260g/l, 0.20≤D≤0.45, N≤75 and are stirred reaction in the presence of ammonia recycle.

2, the potassium dihydrogen phosphate generally crystallized from double decomposition solution is impure, contains considerable ammonium ion （Quantitative proportion is decided by dispensing）, be commonly used repeated recrystallize or cycle double decomposition, it is necessary to heat to repetitiousness and It is cooling.This programme uses in a denitrification equipment, using the dipotassium hydrogen phosphate solution of two sections of processing acquisitions of filter residue as denitrogenation working medium, The primary room temperature denitrogenation method for completing denitrogenation.

Specific method is to handle the D >=1.0, N≤2g/l, K obtained using two sections from filter residue₂O >=200, solution conduct Denitrogenation working medium, in special denitrification equipment, a constant fixed temperature within the scope of 0-40 degree continuously stirs denitrogenation, makes to contain The potassium dihydrogen phosphate of nitrogen directly becomes qualified potassium dihydrogen phosphate, does not need additional heating and crystallisation by cooling process.The denitrogenation Equipment has been patented separately.

The primary condition of denitrogenation is：0-40 DEG C of temperature（Stablize in range and determines value at one）, raw phosphoric acid potassium dihydrogen is nitrogenous Measure N≤8%, waste liquid after denitrogenation, potassium dihydrogen phosphate N≤0.45% after N≤50g/l denitrogenations.

3, the device of current all producing potassium dihydrogen phosphate with double decomposition method, as soon as the problem of generally existing troublesome, It is the by-product largely very high ammonium chloride inferior of phosphorous potassium, quantity is brought a large amount of considerably beyond the yield of potassium dihydrogen phosphate itself Raw material is lost in.The solution of the present invention is unusual, we are not directly from any related mother liquor directly generated（Such as detach thick phosphorus Mother liquor after acid dihydride potassium）Middle separating ammonium chloride, because whole system is an extremely complex multiphase system, composition is non- Often it is unfavorable for the independent precipitation of ammonium chloride.Our unique technology measure is to use the mother liquor after separation raw phosphoric acid potassium dihydrogen Processing phosphorus ammonium filter residue is removed, is converted in filter residue after solubility in citric acid phosphorus pentoxide, essence change has occurred in the composition that balances each other of solution Change, has fallen within the region of balancing each other for being very beneficial for ammonium chloride precipitation, herein separating ammonium chloride.In this way, ammonium chloride Quality improvement, quantity enter within normal range (NR), then are had lost without excessive phosphorus potassium.

So the third important feature that we invent is：Use raw phosphoric acid potassium dihydrogen mother liquid disposal filter residue（One section turns Change）, ammonium chloride is precipitated from the mother liquor of processing filter residue.

This section conversion key condition be：Temperature 60 C, the composition that solution is completed in conversion meet the following conditions：P₂O₅ ≤160g/l,K₂O≤70g/l, D=0.45-0.85, N >=90.

4, the 4th feature of the invention is that the filter residue of one section of processing carries out two sections using ammonium bicarbonate and potassium chloride as base stock Conversion makes remaining Chinese holly Soluble phosphorus be completely converted into dipotassium hydrogen phosphate solution（As excellent denitrogenation solution）, the impurity such as calcium and magnesium with Carbonate form enters filter residue, side product sodium chloride.Reaction is in 80 DEG C of progress of temperature, terminal pH=9.5-12.0.By two process transform Filter residue, total phosphorus content≤2%, quantity be less than original filter residue 40%.It can be as the raw material of building materials industry, or as production The raw material of aluminium polychloride.When producing aluminium polychloride, calcirm-fluoride can be separately separated out.

5, generally produce potassium dihydrogen phosphate, though make how, have evaporation process and equipment without any exception, and And evaporation solution composition is complicated, corrosivity is very strong, brings the series of malpractice such as equipment and materials costliness and operation and control difficulty.This hair Bright important feature is, since denitrogenation waste liquid is the very high ammonium dibasic phosphate solution of degree of neutralization, it is easy to which heat resolve releases Ammonia recovery utilizes, therefore is easy to recycle the low nitrogen state that can just make it be restored to N≤2g/l with a small amount of sodium bicarbonate, then Processing filter residue is removed, becomes denitrogenation solution again.

So the 5th essential characteristic of the invention is, cancel the evaporation equipment in potassium dihydrogen phosphate production and operation, The sodium bicarbonate of calculation amount is added in denitrogenation waste liquid（Circulating and recovering in systems does not consume substantially）, reacted at 80-88 DEG C Entirely, so that denitrogenation waste liquid is returned to the low nitrogen state of N≤2g/l, remove two sections of processing filter residues, become qualified denitrogenation solution again, realize Low corrosion, low consumed middle water cycle.

The above essential characteristic defines that the present invention is different from the basic fundamental model of other any Methods For The Manufacture of Potassium Dihydrogen Phosphate It encloses.

Embodiment

Following tests result is obtained on the experimental rig of one 3kt/a：

In the 20m3 dissolving reactive tanks of carbon steel manufacture, every batch of puts into the circulating mother liquor 13m3 after separating ammonium chloride, agricultural phosphorus ammonium 4500 kilograms.The content of agricultural phosphorus ammonium is N=11%, P₂O₅=46%, water-soluble rate 75%.Add 1300 kilograms of potassium chloride（K₂O=60%, Similarly hereinafter）, kept for 60 degree and be stirred to react, while the ammonia of absorption cycle recycling, reach D=0.35.Keep 60 to spend filter, filtrate into Enter thick potassium crystallization tank（Same specification）, the thick potassium of crystallisation by cooling precipitation.

2530 kilograms of filter residue quantity, N=4.1%, P₂O₅=23.05%,K₂O=5.10%。

One section of conversion, degree of neutralization D=0.75 are carried out to this filter residue with the thick potassium mother liquor isolated, 60 degree of temperature filters, Filtrate is cooled to 25 degree, is eutectoid out 1485 kilograms of ammonium chloride, N=25.03%, P₂O₅=0.41%,K₂O=0.84%。

With the thick potassium of denitrogenation solution treatment of cycle, reaction reaches set quota after 8 hours, directly dries potassium dihydrogen phosphate 3531 kilograms（750 kilograms of potassium chloride is supplemented in denitrogenation）, quality meets whole indexs of national standard top grade product.

Two process transform is implemented in denitrogenation solution circular regeneration, it is 1035 kilograms to obtain filter residue quality, P₂O₅=1.87%。

Data above is the average value of 20 batches of continuous production.

Claims

1. a kind of production potassium dihydrogen phosphate new method of environmental protection and energy saving is mainly characterized by using phosphoric acid by wet process and its manufactured goods （Such as agricultural phosphorus ammonium）It is primary raw material with agricultural potassium chloride, carries out dissolving and metathesis reaction, 50-60 DEG C of temperature, P₂O₅=220- 260g/l, 0.20≤degree of neutralization D≤0.45, N≤75 and are stirred reaction in the presence of ammonia recycle, it is disposable exclude it is all Impurity and harmful substance, filtering postcooling obtain the raw phosphoric acid potassium dihydrogen of nitrogenous 6-8%.

2. the potassium dihydrogen phosphate new process for producing based on claim 1, in a special denitrification equipment, using from filter residue two The D >=1.0, N≤2g/l, K that section processing obtains₂The solution of O >=200g/l is constant within the scope of 0-40 degree as denitrogenation working medium One fixed temperature, continuously stirs denitrogenation, makes nitrogenous potassium dihydrogen phosphate, directly becomes qualified potassium dihydrogen phosphate, does not need Additional heating and crystallisation by cooling process.

3. the potassium dihydrogen phosphate new process for producing based on claim 1 uses raw phosphoric acid potassium dihydrogen mother liquid disposal filter residue（One section turns Change）, temperature 60 C, conversion complete solution composition meet P₂O₅≤160g/l,K₂O≤70g/l, D=0.45-0.85, N >=90, This solution is cooled to 20-30 DEG C, and qualified ammonium chloride is precipitated.

4. the potassium dihydrogen phosphate new process for producing based on claim 1, one section of filter residue handled is basic with ammonium bicarbonate and potassium chloride Raw material carries out two process transform, and remaining Chinese holly Soluble phosphorus is made to be completely converted into dipotassium hydrogen phosphate solution, and the denitrogenation solution for becoming excellent returns To product systems, 80-100 DEG C of reaction temperature, terminal pH=9.5-12.0.

5. the potassium dihydrogen phosphate new process for producing based on claim 1 adds the sodium bicarbonate of calculation amount in denitrogenation waste liquid（? Circulating and recovering does not consume substantially in system）, at 80-88 DEG C, the reaction was complete, and denitrogenation waste liquid is made to return to the low nitrogen state of N≤2g/l, Two sections of processing filter residues are removed, become qualified denitrogenation solution again, realize low corrosion, low consumed middle water cycle, it is no longer necessary to The evaporation operation and equipment of mill solution.