CN1051530C

CN1051530C - Technology for preparing potasium sulfate by cold salting-out circulation method

Info

Publication number: CN1051530C
Application number: CN96117465A
Authority: CN
Inventors: 邓绍齐
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-02-29
Filing date: 1996-02-29
Publication date: 2000-04-19
Anticipated expiration: 2016-02-29
Also published as: CN1144772A

Abstract

The present invention relates to a technology for producing potassium sulfate by a cold salting-out circulation method. Potassium chloride is added in mother solution II to produce potassium sulfate, and ammonium sulfate is added in the obtained mother solution I; ammonium chloride can be taken out by cold salting-out crystallization by freezing, and the obtained mother solution II is circularly returned to the reaction technological process. Thus, the conversion utilization rate of potassium ions can be improved to more than 90%, which is convenient to carry out super large-scale potassium sulfate production and modify the original double decomposition technology by two steps.

Description

A kind of technology for preparing potasium sulfate by cold salting-out circulation method

The invention belongs to chemical industry and make the field, particularly employing ammonium sulfate, Repone K is produced the production method of vitriolate of tartar for the stock liquid phase reaction.

During vitriolate of tartar is produced owing to adopt ammonium sulfate, potassium chloride liquid phase reaction production method production unit drops into than Mannheim proeess, plain method in chamber and ammonium chloride subliming method are few, product impurity to quality influence than saltcake, sal epsom etc. are little, production process is than adopting the polyhydric alcohol amine base of a fruit to put the conversion method letter, equipment corrosion is than sulfuric acid, in one section of Klorvess Liquid reaction or the two sections ammonia and the mode of production little and widely applied, present domestic employing ammonium sulfate, the mother liquor that the liquid reactive device of Repone K all adopts reaction to obtain carries out condensing crystal and produces Repone K, the ammonium chloride binary is mixed fertile, and reaction adopts two sections metathesiss comparatively general.

Because ammonium sulfate and Repone K are under the equivalent condition, liquid phase replacement(metathesis)reaction per pass conversion is about 65%, adopt two sections replacement(metathesis)reaction the first steps to generate potassium-ammonium sulfate, mother liquor I is used for production binary fertilizer, the second step potassium-ammonium sulfate reacts with Repone K again, obtain vitriolate of tartar, mother liquor II again with ammonium sulfate, Repone K reaction.This method is because reaction needed for two steps carried out; the Repone K total conversion rate still can only reach 78%; mother liquor I needs concentration and evaporation to remove whole process waters; the ammonium chloride thermal etching is very serious; can only adopt the evaporation of enamel reaction kettle; because enamel reaction kettle can't large-scale or hugeization; so adopt ammonium sulfate at present; Repone K liquid phase double decomposition carries out vitriolate of tartar production and all occupies the majority with 0.5 ten thousand tons of following scales, and maximum-norm also only below 20,000 tons, can't be accomplished scale production; process water relies on evaporation and removes balance; energy consumption consumes high, the fertile output of binary, and potassium ion trans-utilization rate is low.

The present invention is directed to ammonium sulfate, Repone K liquid phase compound and separate the various defectives of prepared in reaction technology, through in PH=6.8～10,35～-5 ℃ of (NH ₄) ²⁺, K ₂ ²⁺, //, So ₄ ^2-, cl ₂ ^2-,-H ₂The design experiment checking of o system phase diagram research, and by the phasor obtained to ammonium sulfate, operational path in the potassium chloride liquid phase reaction improves, utilization is in PH=6.8～10 o'clock, control Repone K per pass conversion 60～65%, the potassium ion salting-out effect of Repone K high density, can impel the vitriolate of tartar selectivity to saltout, the ammonium sulfate reaction generates vitriolate of tartar transformation efficiency＞95%, in PH=6.8～10, in the time of 5～-5 ℃, vitriolate of tartar, in the time of in the ammonium alum vitriolization ammonium solution, solubleness is greater than ammonium chloride, because the ammonium ion of ammonium sulfate has salting-out effect to ammonium chloride, can be settled out by salting-out crystallization separately; After 35% and 5～-5 ℃ of reactions and saltouing, solution density changes greatly, can reflect the reaction and the degree of saltouing by variable density, technology is monitored, thereby realized technology for preparing potasium sulfate by cold salting-out circulation method.Technology of the present invention has been exempted the ortho-sulfuric acid ammonium, technological process is removed in the evaporation of Repone K liquid phase metathesis process water, reaction only needs one section reaction and salting-out process, simplified processing step, potassium ion trans-utilization rate improves, production energy consumption is low, during ultra-large application, cold saltouing adopts the cold salt analysis apparatus of soda ash connection alkali can satisfy anticorrosion and production requirement fully, need not to develop specific equipment.

The present invention is achieved in that by ammonium sulfate (mole): Repone K (mole)=1: 0.7～0.8 is made into 0 ℃ of density _ρ〉=1.1700 solution feed ammonia, make PH=6.8～10, promptly get mother liquor II; Add Repone K in the time of 25～35 ℃ in mother liquor II, Repone K add-on (mole): the cold ammonium sulfate add-on (mole)=1.9～2.2 of saltouing: 1, stirring reaction 1-5 hour, 35 ℃ of reaction solution phase densities _ρ≤ 1.1340 get final product, and filter and take out filter cake and PH=6.8～10,35 ℃ of density _ρ≤ 1.1340 mother liquor I; Filter cake is through adding vitriolate of tartar 〉=8%, cl ^-≤ 3% solution is washed and starched and is washed, and filters and takes out wet vitriolate of tartar, and drying gets the product vitriolate of tartar, and washing filtrate is standby; Add ammonium sulfate among the mother liquor I, the cold ammonium sulfate add-on (mole) of saltouing: Repone K add-on (mole)=1: 1.9～2.2,, stirred 1～5 hour solution PH=6.8～10,0 ℃ of density through being refrigerated to 5～-5 ℃ _ρ〉=1.1700, the filtering for crystallizing thing takes out PH=6.8～10,0 ℃ of density _ρ〉=1.1700 mother liquor II leaches crystallisate and gets product ammonium chloride after drying; A washing filtrate part added replenish product among the mother liquor II and leach and take away process water, another part washing filtrate is adjusted into vitriolate of tartar 〉=8%, cl through adding entry, vitriolate of tartar, Repone K ^-≤ 3% solution; Add Repone K again in mother liquor II, add metering method as previously mentioned, thereby realize technological cycle.The control of solution pH value is adjusted by add ammonia in reactor and is realized.

The Figure of description explanation:

Mother liquor II is added reactor, add washing filtrate, add Repone K and react, reaction finishes the I filtration after filtration of back magma, obtains filter cake and mother liquor I, mother liquor I sends into cold salt parser and adds ammonium sulfate, the cold magma III III after filtration that salts out obtains wet ammonium chloride and mother liquor II, and mother liquor II is sent to reactor, the filter cake that magma I filtration obtains be sent to starch again device washing back magma II after filtration the II separation obtain washing filtrate, a part of washing filtrate is sent to reactor and replenishes process water.A part of washing filtrate is used for next washing after entering accent liquid pool adding vitriolate of tartar, Repone K, water adjustment, and filtration II separation obtains the vitriolate of tartar that wets and obtains wet ammonium chloride difference drying with filtration III, produces out vitriolate of tartar, two kinds of products of ammonium chloride.When needing to adjust the control pH value, realize by in reactor, adding ammonia.

Embodiment: get ammonium sulfate 115g, Repone K 85g, 17% ammoniacal liquor 15ml, water 295ml are made into common solution, to adding Repone K 121g in the solution altogether, stirring reaction is 2 hours in the time of 35 ℃, and it is stand-by to filter out filter cake, obtains mother liquor I, (35 ℃ _ρ≤ 1.1300PH=6.8～10) ammonium sulfate 115g is added among the mother liquor I, cooling is refrigerated to 5～-5 ℃ while stirring, and the leaching crystallization gets ammonium chloride, (0 ℃ of leaching mother liquor II after the drying _ρ〉=1.1700 PH=6.8～10); Again with former filter cake sulfur acid potassium 〉=8%, the cl of obtaining ^-≤ 3% solution 300ml starches again, filter wet vitriolate of tartar, filtering washing filtrate 50ml is added among the mother liquor II, remaining part adds entry, vitriolate of tartar, Repone K and transfers to raw state, and mother liquor II heats to 35 ℃, is used for adding Repone K 121g reaction potassium sulfate making again, reciprocation cycle, get vitriolate of tartar after the wet vitriolate of tartar drying, repeatedly after the circulation, the output object mean value that at every turn circulates is vitriolate of tartar (K ₂O 〉=47%, cl ^-≤ 1%) 145g, ammonium chloride N 〉=25.35% 96g.

Claims

1, a kind of technology for preparing potasium sulfate by cold salting-out circulation method method: it is characterized in that Repone K is added among the mother liquor II that the freezing ammonium chloride of saltouing obtains; Reaction 1 ∽ 5 hours under 35 ℃ of conditions of 25 ∽, reaction is taken out mother liquor I behind the vitriolate of tartar after adding ammonium sulfate, is refrigerated to 5 ∽-5 ℃, 1 ∽ 5 hours, the ammonium chloride of saltouing; Filter the mother liquor II that takes out ammonium chloride and loop back reaction process, add Repone K, vitriolate of tartar is produced in reaction; Mother liquor II is ammonium sulfate (mole): Repone K (mole)=1: 0.7 ∽ 0.8,0 ℃ of density, ρ 〉=1.1700 PH=6.8 ∽, 10 solution; Mother liquor I is 35 ℃ of PH=6.8 ∽ 10, the density that obtains after reacting, the solution of ρ≤1.1340; In mother liquor II, add the Repone K amount and in mother liquor I, add the volume of ammonium sulfate ratio and be: Repone K add-on (mole): cold ammonium sulfate add-on (mole)=1.9 ∽ 2.2: 1 of saltouing.

2, according to claim 1, it is characterized in that reaction process generates the vitriolate of tartar filter cake and adopts sulfur acid potassium 〉=8%, Cl ^-≤ 3% solution washing, a part adds reaction process balancing processing water in the washing lotion that leaches after the washing.