CN103818935A

CN103818935A - Method for separating potassium oxide from potassium-containing sodium aluminate solution

Info

Publication number: CN103818935A
Application number: CN201410013134.7A
Authority: CN
Inventors: 赵凿元
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-01-13
Filing date: 2014-01-13
Publication date: 2014-05-28
Also published as: CN104016390A; CN104445277A

Abstract

The invention discloses a method for separating potassium oxide from a potassium-containing sodium aluminate solution, and relates to a method for separating potassium oxide from an evaporated sodium aluminate solution in an aluminum oxide production process. Potassium oxide is converted into potassium sulfate by adding sodium sulfate (or alunite for reaction to produce sodium sulfate) into the sodium aluminate solution and introducing SO4<2->, and is precipitated and separated in a form of aphthitalite, sodium sulfate and a little sodium carbonate mixture. The precipitation is performed under the condition of high caustic alkali and low temperature, and the residual of sodium sulfate in the solution can be avoided. A separation product can separate a potassium sulfate product according to a phase diagram, and sodium sulfate is recycled, or potassium chloride converts the mixture into pure potassium sulfate. The method achieves the output of sodium sulfate, and aluminum oxide and potassium sulfate can be co-produced by employing nepheline and alunite by a parallel serial method, and can be produced by employing high silicon ore such as nepheline and illite by an acid-alkali combined method.

Description

A kind of from the method containing separation of oxygenated potassium potassium sodium aluminate solution

Technical field

From the method containing separation of oxygenated potassium potassium sodium aluminate solution, relate in a kind of aluminum oxide production process the method containing separation of oxygenated potassium in potassium sodium aluminate solution from evaporation.

Background technology

Sylvite is important industrial chemicals and agricultural fertilizer, industrial water-soluble containing potassium resource production Repone K by salt lake saline, sylvite ore etc., wherein a part changes into other sylvite products such as potassium sulfate.Insoluble potassium ore, for another is containing potassium resource, has done a large amount of research to its utilization in the world, but does not realize large-scale industrial production higher than water-soluble sylvite because of production cost.China's water-soluble potassium resource scarcity, insoluble potassium ore reserves are huge, and the latter, also because of not industrial application with high costs, therefore still needs a large amount of import Repone K.

In bauxite, lime, have a small amount of potassium-bearing mineral, under alumina producing condition, most of potassium enters solution circulated accumulation, finally by red mud, carbon alkali, discharge scabs.Although the useful flow process of potassium oxide, its price, far above sodium oxide, loses very unfortunate.

In the time producing aluminum oxide by rich potassium aluminum-containing raw material sintering process, decompose and make caustic alkali change carbon alkali into containing the first carbonating of potassium sodium aluminate solution, follow again the difference according to salt of wormwood and sodium carbonate solubleness, realizing the two by evaporation and separate, because the solubleness of salt of wormwood is much larger than sodium carbonate, is to obtain salt of wormwood, need be by whole carbon mother liquid evaporates to dryness, and evaporative process is separated out the mixture of potassium, sodium carbonate in a large number, and separation costs is high, this method is only in former Soviet Union industrial application.

Summary of the invention

For above deficiency, the present invention is separation of oxygenated potassium from the circulating mother liquor containing potassium seed precipitation of sodium aluminate, makes it change potassium sulfate into and separate out with the form of double salt.Invention does not affect bayer process, energy-conservation, can Comprehensive utilization of mineral resource, realize the coproduction of aluminum oxide, potassium sulfate.

The object of the invention is to be achieved through the following technical solutions.

From the method containing separation of oxygenated potassium potassium sodium aluminate solution, it is characterized in that seed precipitation solution to be evaporated to Na ₂o _kafter 180g/l～280g/l, be cooled to 20 ℃～70 ℃, by the K in mother liquor ₂o total overall reaction generates potassium sodium sulfate decahydrate (3K ₂sO ₄na ₂sO ₄) 1.5～2.5 times of theoretical amount add powdered anhydrous sodium sulfate (or not lower the temperature and add alumstone ore, Tai-Ace S 150 in ore is reacted with hot mother liquor and generates sodium aluminate and sodium sulfate, then removal of impurities, plant point, evaporation, cooling), stirring reaction 120～210 minutes, now, the K in mother liquor ₂o and the Na adding ₂sO ₄there is replacement(metathesis)reaction and generate K ₂sO ₄and Na ₂o, K ₂sO ₄again with excessive Na ₂sO ₄generate the less 3K of solubleness ₂sO ₄na ₂sO ₄separate out, separating effect is in table 1.Solid product is 3K ₂sO ₄na ₂sO ₄, Na ₂sO ₄with a small amount of Na ₂cO ₃mixture, after washing, can isolate potassium product according to phasor, the remaining sodium sulfate containing a small amount of sodium carbonate impurity recycles; Or first adding a small amount of sulfuric acid makes negatively charged ion change SO completely into ₄ ^2-, then be separated into potassium sulfate and sodium sulfate; Also can after acid adding, by Repone K, mixture be converted into pure potassium sulfate.When the conditions such as sodium sulfate add-on and sodium aluminate solution concentration, temperature, reaction times are outside given interval, or first add sodium sulfate, then lower the temperature, also potassium oxide can be separated from sodium aluminate solution, but separation yield or economy can be given a discount.

Under table 1 different condition, add Na containing in potassium sodium aluminate solution ₂sO ₄the potassium oxide separating effect producing

A kind of from the method containing separation of oxygenated potassium potassium sodium aluminate solution, it is characterized in that the sodium sulfate adding need first dissolve in solution, separate out again, the temperature range of 20 ℃～70 ℃, adopt high density, high-temperature, lower concentration, the favourable sodium sulfate of reaction conditions of low temperature dissolves, and can improve potassium oxide transformation efficiency.

Method of the present invention, takes when reaction can reduce residual in solution of sodium sulfate with the speed slow cooling of 1 ℃/20min, the measure such as organism, rapid stirring in sodium aluminate solution removed.In addition sodium aluminate solution Na, ₂o _kconcentration, temperature and precipitate and separate mode all remain considerable influence to reacting sodium sulfate in rear solution: Na ₂o _kconcentration raises, and temperature reduces, residual minimizing.The reaction conditions that adopts high concentrated low temperature, the sodium sulfate adding can be not residual in solution, but now soltion viscosity increases, and the precipitated product settling time is extended, and even needs to filter; Work as Na ₂o _kwhen concentration reduces, the residual increase of sodium sulfate, if need desulphurization, can add in separation solution normally producing supplementary liquid sodium hydroxide, makes concentration reach 280g/l, then adds 0.5g/l～1g/l Na ₂sO ₄crystal seed, stirs 150～210 minutes, filters, and stays the Na in filtrate ₂sO ₄be no more than 2g/l.

Method of the present invention, can be from alumina producer sodium aluminate solution the potassium oxide of Separation and Recovery accumulation, can improve byproduct potassium sulfate output toward allocating the rich potassium ore deposits such as nepheline in bauxite; Can nepheline, the rich potassium such as alunite adopts mixed combining method coproduction aluminum oxide and potassium sulfate containing aluminium ore because solved the outlet of sodium sulfate, alumstone ore can be without roasting or thermolysis directly with containing the stripping of potassium mother liquid evaporation; Also can adopt using acid and alkali combination method to process nepheline, the rich potassium of the contour silicon of illite ore deposit: sulfuric acid to leach generates potassium alum, by recrystallization removal of impurities, again with alkaline process seminal fluid in and production of chemicals aluminum oxide, after neutralizer separating potassium sodium sulfate decahydrate, add again alkaline process kind to divide separation of oxygenated potassium in mother liquid evaporation.When mother liquid evaporation separation of oxygenated potassium, also can reclaim in passing Vanadium Pentoxide in FLAKES.

Embodiment

From the method containing separation of oxygenated potassium potassium sodium aluminate solution, by Na ₂o _kthe kind of 180g/l～280g/l is divided mother liquid evaporation, is cooled to 20 ℃～70 ℃, analyzes k ₂o, Na ₂sO ₄content, generates potassium sodium sulfate decahydrate (3K by its contained potassium oxide total overall reaction ₂sO ₄na ₂sO ₄) 1.5～2.5 times of theoretical amount add sodium sulfate, stirring reaction filters for 120～210 minutes, analyzes k in filtrate ₂o, Na ₂sO ₄content.

Embodiment 1

Bayer process mother liquid evaporation is diluted to Na ₂0 _k180g/l, analyzes k ₂o41.93g/l, Na ₂sO ₄2.11g/l, gets 50ml mother liquor and adds 2.0g analytical pure anhydrous Na ₂sO ₄, stirring reaction 200 minutes under the room temperature of 17 ℃～21 ℃, leaves standstill 10 hours, gets supernatant liquor and analyzes k ₂o28.50g/l, Na ₂sO ₄17.82g/l.In 30ml clear liquid, add analytical pure NaOH to Na ₂o _kreach 280g/l, separately add 0.03g Na ₂sO ₄, stir 210 minutes, drip filter, analyze Na in filtrate ₂sO ₄1.74g/l.

Embodiment 2

The high steaming of Bayer process mother liquor is filtered, and filtrate is diluted to Na ₂o _k220g/l, analyzes k ₂o51.25g/l, Na ₂sO ₄2.13g/l, gets 50ml mother liquor and adds 3.2g analytical pure anhydrous Na ₂sO ₄, stirring reaction 180 minutes under the condition of 40 ℃, leaves standstill 14 hours, gets supernatant liquor and analyzes k ₂o25.19g/l, Na ₂sO ₄10.53g/l.

Embodiment 3

By high Bayer process mother liquor filtration, the analysis Na of steaming ₂o _k276g/l, k ₂o65.89g/l, Na ₂sO ₄2.01g/l, gets 50ml mother liquor and adds 2.5g analytical pure anhydrous Na ₂sO ₄, stirring reaction 210 minutes under the condition of 61 ℃～38 ℃, drips filter, filtrate analysis k ₂o35.00g/l, Na ₂sO ₄1.75g/l.

Claims

1. from the method containing separation of oxygenated potassium potassium sodium aluminate solution, it is characterized in that: with sodium sulfate (or alunite, alum, Tai-Ace S 150 etc. make reaction generate sodium sulfate) as precipitating agent, separation of oxygenated potassium from contain potassium sodium aluminate solution.

2. according to claim 1 a kind of from the method containing separation of oxygenated potassium potassium sodium aluminate solution, it is characterized in that: before sodium sulfate adds or alunite need sodium aluminate solution liquid temp to be down to 20 ℃～70 ℃ after adding.

3. according to claim 1 a kind of from the method containing separation of oxygenated potassium potassium sodium aluminate solution, it is characterized in that: add after sodium sulfate, contain potassium sodium aluminate solution concentration at Na ₂o _kbetween 180g/l～280g/l.

4. according to claim 1 a kind of from the method containing separation of oxygenated potassium potassium sodium aluminate solution, it is characterized in that: in solution, the precipitation process of potassium oxide needs stirring reaction 120～210 minutes.

5. from the method containing separation of oxygenated potassium potassium sodium aluminate solution, while it is characterized in that needing getting rid of after separation of oxygenated potassium sodium sulfate residual in solution, can add and separate in mother liquor normally producing supplementary liquid sodium hydroxide, make concentration reach Na ₂o _k280g/l, then add 0.5g/l～1g/l Na ₂sO ₄crystal seed, stirs and sodium sulfate was separated out in 150～210 minutes to filter.