Method for preparing calcium sulfate whisker by-product magnesium hydroxide and magnesium ammonium nitrate by decomposing phosphate tailings by nitric acid

A calcium sulfate whisker and magnesium hydroxide technology, applied in the chemical industry, can solve the problems of high energy consumption, low added value of products, and effective utilization of calcium and magnesium grades, achieving high economic efficiency, simple and feasible production process, The effect of improving stability

Inactive Publication Date: 2018-04-06
HUBEI SANNING CHEM
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  • Claims
  • Application Information

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Problems solved by technology

[0004] Patent CN201510226291 "A Method for Using Phosphorus Tailings to Produce Calcium Ammonium Phosphate and Calcium Magnesium Ammonium Nitrate" Although the operation is relatively simple, it does not effectively utilize the main components of calcium and magnesium, and the added value of the product is low; while the patent CN 201510226291.0 "A Method for Extracting Phosphorus Concentrate from Phosphorus Tailings and Co-producing Calcium Ammonium Ni

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  • Method for preparing calcium sulfate whisker by-product magnesium hydroxide and magnesium ammonium nitrate by decomposing phosphate tailings by nitric acid

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Embodiment 1

[0038] Adding phosphorus tailings and water to the slurry mixing tank is adjusted to a slurry with a solid content of 35%, and then, the phosphorus tailings slurry and the mass fraction of 40% nitric acid are mixed and reacted by pumps to the upper and lower parts of the leaching tank, respectively. , the ratio of nitric acid to the sum of the molar amounts of CaO and MgO in phosphorus tailings is 1.8:1, the reaction temperature is controlled at 50°C, and the reaction time is 1.5h. Filter residue I and mother liquor I are obtained by filtration and separation, and filter residue I is used to make cement; The mother liquor I enters the metathesis tank, and ammonium bisulfate is added to the metathesis tank according to the molar ratio of CaO of 1:1, the reaction temperature is controlled at 85°C, the stirring speed is 250r / min, and the reaction material is cooled to 40°C after 1.0h of reaction. And keep warm for crystallization for 2.0h, then filter and separate, and wash the fi...

Embodiment 2

[0041] Phosphorus tailings and water are added to the slurry mixing tank to prepare a slurry with a solid content of 10%, and then the phosphorus tailings slurry and dilute nitric acid with a mass fraction of 45% are mixed and reacted to the upper and lower parts of the leaching tank through a pump. Among them, the ratio of nitric acid to the sum of the molar amounts of CaO and MgO in phosphorus tailings is 2.0:1, the reaction temperature is controlled at 70°C, the reaction time is 1.0h, and the filter residue I and mother liquor I are obtained by filtration and separation. Fertilizer; according to the molar ratio of CaO 1:1.05, add sulfuric acid with a mass concentration of 40% to the mother liquor I, control the reaction temperature at 100°C, and the stirring speed at 200r / min, cool down to 50°C after reacting for 1.0h, and then keep warm for crystallization After 2.0 hours, filter and separate, and wash the filter cake with water to obtain calcium sulfate whiskers and mother...

Embodiment 3

[0044] Phosphorus tailings and water are added to the slurry mixing tank to prepare a slurry with a solid content of 45%, and then the mixed reaction of phosphorus tailings slurry and 30% dilute nitric acid with a mass fraction of 30% is input to the upper and lower parts of the leaching tank simultaneously through a pump. The ratio of nitric acid to the sum of the molar amounts of CaO and MgO in phosphorus tailings is 2.05:1, and the reaction temperature is 95°C. After 1.5 hours of reaction, filter and separate to obtain filter residue I and mother liquor I, and filter residue I is used to make cement; Add ammonium sulfate to the mother liquor I with a molar ratio of 1:1, control the reaction temperature at 85°C, cool down to 40°C after reacting for 1.0h, then crystallize for 2.0h to filter and separate, the filter cake is washed with water and dried to obtain calcium sulfate whiskers and Mother liquor II circulates to decompose phosphorus tailings; after the mother liquor has...

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Abstract

The invention discloses a method for preparing calcium sulfate whisker by-product magnesium hydroxide and magnesium ammonium nitrate by decomposing phosphate tailings by nitric acid. The method comprises the following steps: 1) adding water into phosphate tailings to prepare phosphate tailing pulp, adding a nitric acid solution, carrying out an acidolysis reaction, and filtering reaction slurry toobtain a mother liquor I and a filter residue I; 2) adding sulfuric acid or a sulfate into the mother solution I, carrying out a reaction, then carrying out cooling crystallizing, and carrying out filtering separation to obtain a filter cake II and a mother liquor II, washing and drying the filter cake II to obtain calcium sulfate whiskers, and bringing the mother liquor II back to the step 1) for an acidolysis reaction; 3) adding a calcium salt into a mother solution II subjected to multiple times of reaction, carrying out a reaction, and carrying out filtering separation to obtain a filterresidue III and a mother liquor III; and 4) introducing ammonia into the mother liquor III, carrying out a reaction, carrying out filtering separation to obtain a filter cake IV and a mother liquor IV, washing and drying the filter cake IV to obtain a magnesium hydroxide finished product, adding nitric acid into the mother liquor IV, carrying out a reaction, and carrying out concentration and granulation on the mother liquor IV to obtain the byproduct magnesium ammonium nitrate. According to the invention, comprehensive utilization of phosphorus tailing resources is realized, waste is changedinto wealth, and the green chemical concept is conformed.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for decomposing phosphorus tailings magnesium hydroxide and calcium sulfate whiskers by nitric acid to produce magnesium hydroxide and magnesium ammonium nitrate. Background technique [0002] my country's phosphate rock reserve resources are relatively abundant, but most of them are of medium and low grade, and cannot be directly used in the production of industrial phosphoric acid and downstream industries, such as phosphorus compound fertilizers and fine phosphate. P 2 o 5 High-grade phosphate rock with a grade greater than 30%, but at the same time, a large amount of phosphorus tailings are also produced. Due to the low grade of these phosphorus tailings, the main components of phosphorus tailings are calcium, magnesium, P 2 o 5 Compounds with high metal content are difficult to deal with. At present, most phosphorus chemical production enter...

Claims

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Application Information

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IPC IPC(8): C01F5/20C01F5/00C30B29/46C30B29/62
CPCC01F5/00C01F5/20C30B29/46C30B29/62
Inventor 李攀红肖林波方超田承涛徐思红
Owner HUBEI SANNING CHEM
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