CN105036157A - Method for preparing potassium sulphate through kainite-containing potash-bearing salt - Google Patents

Abstract

The invention provides a method for preparing potassium sulphate through kainite-containing potash-bearing salt. The method includes the following steps of firstly, conducting ore blending on kainite-containing mixed mineral and potassium chloride according to a certain proportion, and then adding an appropriate amount of fresh water, and conducting mixing; secondly, stirring and converting the ore pulp material mixed in the first step at the temperature of 35-55 DEG C, wherein the converting time is 1-2 h; thirdly, conducting solid-liquid separation on the material pulp converted in the second step, and conducting drip washing on a filter cake through fresh water, wherein the amount of water used for drip washing is 10-20% of the mass of the filter cake; fourthly, returning mother liquor obtained through solid-liquid separation to a flotation system to be recycled. The method is short in technological process, low in device investment and operating cost and easy to operate; no three wastes are generated in the processing process, and the method is green and environmentally friendly. The obtained rough potassium sulphate product is good in quality, high in potassium yield, low in cost and obvious in economic benefit.

Description

A kind of method that prepares potassium sulfate with potassium-containing langbeinite potassium mixed salt

technical field

The invention relates to a method for preparing potassium sulfate by using a potassium-containing langbeinite potassium mixed salt, in particular to a method for preparing potassium sulfate by transforming a potassium-containing langbeinite mixed ore and potassium chloride.

Background technique

Potassium fertilizer is one of the three basic fertilizers (nitrogen, phosphorus and potassium) in agriculture. At present, the area of potassium-deficient cultivated land in China accounts for 60% of the total cultivated land area. Potassium deficiency seriously affects the yield and quality of crops. China is the world's largest consumer of potash fertilizers. According to statistics from the China Inorganic Salt Industry Association, the total apparent consumption of potash fertilizers in China reached 17.42 million tons in 2014, an increase of 19.1% over 2013. Among the seven most scarce mineral resources in China (oil and gas, iron-rich ore, potassium salt, copper ore, bauxite, manganese ore, and chromium ore), potassium salt is very dependent on external sources. In 2014, the output of potassium chloride domestically produced potassium fertilizer It has reached a record high of 8.77 million tons (converted to potassium chloride), imported potassium fertilizer has reached 8.03 million tons (in kind), and the import dependence is about 50%.

In the present technology, Chinese patent CN1321893C discloses the method for producing potassium sulfate with potassium-containing magnesium sulfate subtype brine, the method obtains langbeinite through conversion, decomposition and flotation of sun-dried kabeinite mixed salt, Then use langbeinite and potassium chloride to add water to convert it into potassium sulfate. However, in this method, langbeinite needs to add water to convert it into zoleinite, and then combine it with potassium chloride to synthesize potassium sulfate. The process is more complicated.

Contents of the invention

The technical problem to be solved in the present invention is to provide a method for preparing potassium sulfate with a potassium-containing langbeinite-potassium mixed salt with a relatively simple technical process for the deficiencies or blanks in the prior art.

The technical scheme that the present invention solves its technical problem adopts is, a kind of method that produces potassium sulfate with sylvite-containing potassium mixed salt, comprises the following steps:

(1) Blend the mixed minerals containing kainite with potassium chloride in a certain proportion, and then add an appropriate amount of fresh water to mix. The mass ratio of the mixed minerals containing kainite, potassium chloride and water is 1.0: (0.7～0.9): (1.5～2.5);

The mixed minerals containing langbeinite refer to minerals containing kabeinite, which can be the higher kabeinite-containing mixed minerals (including kabeinite, potassium chloride and \Or kaleite and other potassium salts);

The fresh water refers to water with a salt content≤5wt%;

(2) Stir and convert the pulp material mixed in step (1) at 35-55°C, and the conversion time is 1-2 hours;

(3) Separating the slurry converted from step (2) into solid and liquid, and rinsing the filter cake with fresh water. The amount of rinsing water is 10% to 20% of the mass of the filter cake, and finally the initial product of potassium sulfate is obtained; the initial product of potassium sulfate Repulp washing, separation and drying to obtain potassium sulfate product;

(4) Return the mother liquor obtained from solid-liquid separation in step (3) to the flotation system for recycling (the flotation system refers to the flotation and washing mixed ore system, part of the returned mother liquor is used for washing mixed minerals; the other part is used for beneficiation and pulping, and participates in conversion).

In the present invention, the mixed minerals containing langbeinite, potassium chloride and fresh water are used as raw materials to directly produce potassium sulfate in one conversion, and the mixed minerals containing kabeinite are added to suitable potassium chloride and fresh water, potassium chloride and The amount of fresh water added is based on the phase diagram of K ⁺ , Mg ²⁺ //Cl ^- , SO ₄ ^2- —H ₂ O quaternary system as a theoretical guide. Through laboratory experiments, the composition point of the mixture after adding potassium chloride falls on potassium sulfate In the phase area, that is, on the line connecting the three-phase saturation points of the potassium sulfate material point, langbeinite and potassium chloride, the amount of water added is properly adjusted according to the theoretical calculation of the phase diagram, and the solid phase point of the material after conversion and separation is as close as possible to sulfuric acid The potassium phase point and the liquid phase composition point fall near the three-phase saturation point of potassium sulfate, langbeinite and potassium chloride.

The present invention uses magsonite mixed ore containing potassium salt and potassium chloride as raw materials to prepare potassium sulfate through direct transformation at different temperatures. During the conversion process, it is not necessary to convert langbeinite into langbeinite first, and then synthesize it with potassium chloride to produce potassium sulfate, but directly synthesize it with potassium chloride to produce potassium sulfate, and the solid-liquid separation in the process of production The liquid phase of the potassium sulfate conversion mother liquor is recycled before being returned to the system. Therefore, the present invention has a short process flow, low equipment investment and operating costs, and simple operation; no three wastes are generated in the processing process, and it is environmentally friendly. The obtained potassium sulfate crude product has good quality, high potassium yield, low cost and obvious economic benefits.

Detailed ways

The present invention will be further described below in conjunction with specific examples.

Example 1

(the sylvitite described in the embodiment is an intermediate product, which is obtained by flotation of the sylvite sylvite sylvite, and is generally a mixed potassium salt, which may contain potassium chloride, soft One or more of magnesite, potassium glauberite, etc.; potassium chloride can be potassium chloride on the market, generally for agricultural standards; it can also be an intermediate product in the production process of the enterprise, that is, carnallite decomposition- Potassium chloride product or primary product obtained after flotation)

(1) Mix the potassium-containing langbeinite, potassium chloride, and water at a mass ratio of 1.0:0.84:2.1, and the quality composition of the potassium-containing langbeinite is: K ⁺ 14.21%, Mg ²⁺ 8.323%, Cl ^- 13.99%, SO ₄ ^2- 36.22%, Na ⁺ 2.115%, H ₂ 025.15%;

(2) Convert the pulp material mixed in step (1) at 35°C, and the conversion reaction time is 2 hours;

(3) Separating the slurry converted from step (2) from solid to liquid, washing the filter cake with fresh water, the amount of washing water is 10wt% of the mass of the filter cake, and repulping, washing, separating and drying the initial product of potassium sulfate Dry to obtain potassium sulfate product; Potassium sulfate product composition (mass percentage): K ⁺ 43.60%, Mg ²⁺ 0.270%, Cl ^- 0.883%, SO ₄ ^2- 53.54%, Na ⁺ 0.068%, H ₂ 01.644%; mother liquor ( The mother liquor after filtration and separation, the composition is mass percentage) Composition: K ⁺ 8.633%, Mg ²⁺ 2.772%, Cl ^- 14.47%, SO ₄ ^2- 4.303%, Na ⁺ 1.119%, H ₂ 068.70%;

(4) The remaining mother liquor in step (3) is returned to the flotation system for recycling.

The product quality of potassium sulfate obtained in the present embodiment reaches the requirements of "Potassium Sulfate for Agricultural Use" (GB20406-2006) powder crystalline excellent product.

Table 1 shows the modified content of the national standard GB20406-2006 "Potassium Sulfate for Agriculture".

Note: The production process of potassium sulfate with water as the medium is the water-salt system method, including the sulfate salt lake brine method, Glauber's salt method, ammonium sulfate method, associative method, and epsom salt method.

Example 2

(1) Mix kaleite, potassium chloride, and water at a mass ratio of 1:0.78:1.75. The mass composition of the kaleite: K ⁺ 16.60%, Mg ²⁺ 7.008%, Cl ^- 9.118%, SO ₄ ^2- 40.35%, Na ⁺ 2.045%, H ₂ 024.88%;

(2) Control the mixed material at 40°C for transformation, and the transformation reaction time is 1.5h;

(3) After the reaction, the slurry is separated from solid and liquid, and the filter cake is rinsed with fresh water. The amount of rinse water is 20% of the mass of the filter cake. The initial product of potassium sulfate obtained is repulped, washed, separated, and dried to obtain potassium sulfate product. Product composition: K ⁺ 43.53%, Mg ²⁺ 0.300%, Cl ^- 0.791%, SO ₄ ^2- 53.65%, Na ⁺ 0.043%, H ₂ 01.688%, mother liquor composition: K ⁺ 8.585%, Mg ²⁺ 2.697%, Cl ^- 14.92%, SO ₄ ^2- 4.166%, Na ⁺ 1.514%, H ₂ 068.12%;

(4) The mother liquor returns to the flotation system for recycling.

The product quality of potassium sulfate obtained in the present embodiment reaches the requirements of "Potassium Sulfate for Agricultural Use" (GB20406-2006) powder crystalline excellent product.

Example 3

(1) Mix kaleite, potassium chloride, and water at a mass ratio of 1:0.81:2.37. The mass composition of kaleite: K ⁺ 15.41%, Mg ²⁺ 7.665%, Cl ^- 11.56%, SO ₄ ^2- 38.28%, Na ⁺ 2.081%, H ₂ 025.015%;

(2) Control the mixed material at 35°C for transformation, and the transformation reaction time is 1h;

(3) After the reaction, the slurry is separated from solid and liquid, and the filter cake is rinsed with fresh water. The amount of rinse water is 10% of the mass of the filter cake. The initial product of potassium sulfate obtained is repulped, washed, separated, and dried to obtain potassium sulfate product. Product composition: K ⁺ 43.58%, Mg ²⁺ 0.282%, Cl ^- 0.838%, SO ₄ ^2- 53.62%, Na ⁺ 0.065%, H ₂ 01.613%, mother liquor composition: K ⁺ 8.611%, Mg ²⁺ 2.720%, Cl ^- 15.25%, SO ₄ ^2- 4.231%, Na ⁺ 1.700%, H ₂ 067.49%;

(4) The mother liquor returns to the flotation system for recycling.

The product quality of potassium sulfate obtained in the present embodiment reaches the requirements of "Potassium Sulfate for Agricultural Use" (GB20406-2006) powder crystalline excellent product.

Example 4

(1) Mix kaleite, potassium chloride, and water at a mass ratio of 1.0:0.9:2.3. The composition of the kaleite minerals: K ⁺ 13.01%, Mg ²⁺ 8.98%, Cl ^- 16.43%, SO ₄ ^2- 34.15%, Na ⁺ 2.15%, H ₂ 025.28%;

(2) Control the mixed material at 35°C for conversion, and the conversion reaction time is 2 hours;

(3) After the reaction, the slurry is separated from solid and liquid, and the filter cake is rinsed with fresh water. The amount of rinse water is 15% of the mass of the filter cake. The initial product of potassium sulfate obtained is repulped, washed, separated, and dried to obtain potassium sulfate product. Product composition: K ⁺ 43.47%, Mg ²⁺ 0.262%, Cl ^- 0.895%, SO ₄ ^2- 53.40%, Na ⁺ 0.100%, H ₂ 01.868%, mother liquor composition: K ⁺ 8.679%, Mg ²⁺ 2.664%, Cl ^- 15.02%, SO ₄ ^2- 4.268%, Na ⁺ 1.635%, H ₂ 067.73%;

(4) The mother liquor returns to the flotation system for recycling.

The product quality of potassium sulfate obtained in the present embodiment reaches the requirements of "Potassium Sulfate for Agricultural Use" (GB20406-2006) powder crystalline excellent product.

Claims (3)

1. a kind of method that produces potassium sulfate with sylvite potassium mixed salt, is characterized in that, may further comprise the steps: (1) Blend the mixed minerals containing kainite with potassium chloride in a certain proportion, and then add an appropriate amount of fresh water to mix. The mass ratio of the mixed minerals containing kainite, potassium chloride and water is 1.0: 0.7～0.9: 1.5～2.5; The fresh water refers to water with a salt content≤5wt%; (2) Stir and convert the pulp material mixed in step (1) at 35-55°C, and the conversion time is 1-2 hours; (3) Separating the slurry converted from step (2) into solid and liquid, and rinsing the filter cake with fresh water. The amount of rinsing water is 10% to 20% of the mass of the filter cake, and finally the initial product of potassium sulfate is obtained; the initial product of potassium sulfate Repulp washing, separation and drying to obtain potassium sulfate product; (4) Return the mother liquor obtained from solid-liquid separation in step (3) to the flotation system for recycling. 2. the method for producing potassium sulfate with potassium-containing langbeinite potassium mixed salt according to claim 1, characterized in that, in step (1), the mixed minerals containing potassium-beinite are obtained by flotation The obtained mixed minerals containing kainite. 3. according to claim 2, produce the method for potassium sulfate with potassium-containing langbeinite potassium mixed salt, it is characterized in that, the potassium-containing kabeinite mixed minerals that described flotation obtains comprises basilite, chloride Potassium and\or langbeinite.