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Method for preparing micron-sized calcium sulfate particles and crystal whiskers from phosphogypsum

A phosphogypsum, micron-scale technology, which is applied in the field of solid waste utilization in the chemical industry, can solve the problems of low-micron calcium sulfate particles, no phosphorus and fluorine impurity content at the same time, and complicated preparation process, so as to reduce environmental pollution, Easy operation and simple method

Inactive Publication Date: 2012-08-15
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In a word, the disadvantage of preparing calcium sulfate whiskers with phosphogypsum as raw material is that it is only aimed at preparing calcium sulfate whiskers, and there is no micron-sized calcium sulfate particles with low phosphorus and fluoride impurity content at the same time, and the preparation process is complicated.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Embodiment 1: this phosphogypsum prepares the method for micron-level calcium sulfate particles and crystal whiskers, and the concrete steps are as follows:

[0019] Add 200 ml of sulfuric acid with a concentration of 20% by mass and 0.02 g of calcium chloride to the beaker, heat the mixture to 60 °C, add 30 g of phosphogypsum under constant stirring, and stir the reaction at a stirring speed of 300 rpm. After 1.0 h, the filtrate was filtered, and the obtained filtrate was separated. After natural cooling, calcium sulfate whiskers were obtained. The crystals obtained by filtration and separation were washed with water and dried at 45 °C to obtain the whisker product; Dry at 45°C to obtain micron-sized calcium sulfate particles. After analysis of the sample, the aspect ratio of the whiskers is 50-100; the particle size is less than 50 μm, the whiteness is 80.2, and the phosphorus and fluorine content is less than 0.1%.

[0020]

Embodiment 2

[0021] Embodiment 2: this phosphogypsum prepares the method for micron-level calcium sulfate particles and crystal whiskers, and the concrete steps are as follows:

[0022] Add 300 ml of sulfuric acid with a concentration of 30% and 0.15 g of magnesium chloride into a beaker, heat it to 80 °C, add 30 g of phosphogypsum under constant stirring, and stir for 2.0 h at a stirring speed of 400 rpm. , the obtained filtrate was separated, and after natural cooling, calcium sulfate whiskers were obtained. The crystals obtained by filtration and separation were washed with water, filtered and separated, and dried at 50 °C to obtain whisker products; Dry at 50 °C to obtain micron-sized calcium sulfate particles. After analysis of the sample, the aspect ratio of the whiskers is 50-100; the particle size is less than 50 μm, the whiteness is 84.1, and the phosphorus and fluorine content is less than 0.1%.

[0023]

Embodiment 3

[0024] Embodiment 3: this phosphogypsum prepares the method for micron-level calcium sulfate particles and crystal whiskers, and the concrete steps are as follows:

[0025] Add 200 ml of sulfuric acid with a concentration of 35% and 0.1 g of hydrochloric acid to the beaker, heat it to 70 °C, add 25 g of phosphogypsum under the condition of constant stirring, stir and react for 3.0 h under the condition of stirring speed of 350 rpm, filter , the obtained filtrate was separated, and after natural cooling, calcium sulfate whiskers were obtained. The crystals obtained by filtration and separation were washed with water, filtered and separated, and dried at 55 °C to obtain whisker products; ℃ drying to obtain micron-scale calcium sulfate particles. After analysis of the sample, the aspect ratio of the whiskers is 50-100; the particle size is less than 50 μm, the whiteness is 83.5, and the phosphorus and fluorine content is less than 0.1%.

[0026]

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Abstract

The invention discloses a method for preparing micron-sized calcium sulfate particles and crystal whiskers from phosphogypsum, which comprises the following steps: treating phosphogypsum with a hot sulfuric acid mixed solution; then separating while the solution is hot; cooling the leach solution to obtain calcium sulfate crystal whiskers; and pickling the solid phase to obtain micron-sized calcium sulfate particle products having a phosphorus-fluorine content of less than 0.1% and a higher whiteness, wherein the pickling process conditions are as follows: the temperature is 60-90 DEG C, the mixed solution is a sulfuric acid solution containing assistants, the concentration of the sulfuric acid is 15-40%, the pickling time is 0.5-4.0h, and the stirring speed is 200-500rpm. The method disclosed by the invention is simple and easy to operate, can take full advantage of industrial waste phosphogypsum, develops a new application way for the utilization of phosphogypsum, changes the waste into valuables, reduces environment pollution and saves resources.

Description

technical field [0001] The invention relates to a method for preparing particulate calcium sulfate particles and crystal whiskers from phosphogypsum, which belongs to the field of solid waste utilization in the chemical industry. Background technique [0002] Phosphogypsum is a solid waste produced when wet-process phosphoric acid reacts with phosphate rock and sulfuric acid to produce phosphoric acid. In industry, 4-5 tons of phosphogypsum can be produced for every ton of phosphoric acid produced. At present, the total amount of industrial by-product phosphogypsum in the world is stacked. It has reached 5.6 billion tons, with an annual increase of 110 million to 150 million tons, and the number of new additions is expected to double between 2025 and 2040. The total amount of phosphogypsum stacked in my country has exceeded 200 million tons, and the annual emission is 40-50 million tons. Because the industrial by-product phosphogypsum is basically stacked in the open air, it...

Claims

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Application Information

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IPC IPC(8): C30B7/14C30B29/46C30B29/62C01F11/46
Inventor 罗康碧李沪萍孔霞韩青苏毅赵榆林李国斌
Owner KUNMING UNIV OF SCI & TECH
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