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Method for preparing calcium sulfate whiskers from phosphogypsum

A technology of calcium sulfate whiskers and phosphogypsum, which is applied in chemical instruments and methods, single crystal growth, crystal growth, etc., can solve the problems of complex process routes and difficult removal of calcium sulfate whiskers, and achieve high purity and whiteness , Whisker aspect ratio is large, the effect of large dissolution rate

Active Publication Date: 2020-05-22
SOUTHWEAT UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the defects such as difficulty in removing impurities and complicated process routes for preparing calcium sulfate whiskers from phosphogypsum in the above-mentioned prior art, the purpose of the present invention is to provide a method for preparing calcium sulfate whiskers with phosphogypsum with simple process and one-step removal of impurities. method

Method used

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  • Method for preparing calcium sulfate whiskers from phosphogypsum
  • Method for preparing calcium sulfate whiskers from phosphogypsum
  • Method for preparing calcium sulfate whiskers from phosphogypsum

Examples

Experimental program
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Effect test

example 1

[0049] The method for preparing calcium sulfate whiskers with phosphogypsum comprises steps as follows:

[0050] 1) The phosphogypsum raw material is ground by a ball mill to obtain a phosphogypsum powder with a particle size of 100 mesh.

[0051] 2) The phosphogypsum powder obtained in step 1) and dilute hydrochloric acid with a mass percent concentration of 25.0% are mixed according to a solid-to-liquid ratio of 200Kg / m 3 Mix and place in a reactor with a stirring device to stir evenly; then, heat the material in the reactor to 100°C with electricity, and stir for 2 hours to obtain an acidic mixed solution containing calcium, sulfate ions and acid insolubles; The obtained acidic mixture was separated by filtration while hot to obtain acidic filtrate and filter residue respectively. Discard the filter residue or use it for other purposes.

[0052] 3) Aging the above-mentioned acidic filtrate, cooling it naturally to 20° C., and crystallizing it for 24 hours to obtain an aci...

example 2

[0056] The steps of the method in this example are basically the same as those in Example 1, and will not be repeated here.

[0057] The difference is that in the following steps:

[0058] 1) The phosphogypsum raw material is ground by a ball mill to obtain a phosphogypsum powder with a particle size of 20 mesh.

[0059] 2) The phosphogypsum powder obtained in step 1) and dilute hydrochloric acid with a mass percent concentration of 1.0% are mixed according to a solid-to-liquid ratio of 10Kg / m 3 Mix and place in a reactor with a stirring device to stir evenly; then heat the material in the reactor to 60°C with steam, and stir for 8 hours to obtain an acidic mixed solution containing calcium, sulfate ions and acid insolubles; The obtained acidic mixture was separated by filtration while hot to obtain acidic filtrate and filter residue respectively.

[0060] 3) Aging the above-mentioned acidic filtrate, cooling the temperature to 20°C by air cooling, and crystallizing for 24 h...

example 3

[0064] The steps of the method in this example are basically the same as those in Example 1, and will not be repeated here.

[0065] The difference is that in the following steps:

[0066] 1) The phosphogypsum raw material is ground by a ball mill to obtain a phosphogypsum powder with a particle size of 600 mesh.

[0067] 2) The phosphogypsum powder obtained in step 1) and dilute hydrochloric acid with a mass percent concentration of 7.2% are mixed according to a solid-to-liquid ratio of 70Kg / m 3 Mix and place in a reactor with a stirring device to stir evenly; then heat the material in the reactor to 95°C with steam, and stir for 0.5h to obtain an acidic mixed solution containing calcium, sulfate ions and acid insolubles; The obtained acidic mixture was filtered and separated while hot to obtain acidic filtrate and filter residue respectively.

[0068] 3) Aging the above-mentioned acidic filtrate, using water cooling to lower the temperature to 10° C., and crystallizing for...

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Abstract

The invention discloses a method for preparing calcium sulfate whiskers from phosphogypsum. The method comprises the following steps: 1) crushing and grinding a phosphogypsum raw material to obtain phosphogypsum powder; 2) mixing the obtained phosphogypsum powder with diluted acid, putting the mixture into a reactor with a stirring device, and reacting while controlling the temperature to a certain temperature to obtain an acidic mixed solution containing calcium, sulfate ions and insoluble substances; 3) filtering the obtained mixed solution while the mixed solution is still hot to obtain anacidic filtrate; and 4) cooling and crystallizing the filtrate, performing filtration, washing and drying to obtain a calcium sulfate whisker product. The raw materials used in the method are not pretreated for impurity removal, and the calcium sulfate dihydrate whiskers with a large length-diameter ratio are directly prepared by adopting a one-step acid leaching impurity removal method; the process flow is simple, the production cost is low, the energy consumption is low, and acid waste liquid and washing water can be recycled; the obtained calcium sulfate whiskers have the characteristics ofhigh purity, large long diameter and the like. The method is beneficial to popularization and application.

Description

[0001] The patent application of the present invention belongs to the divisional application of the Chinese patent application with the filing date of January 07, 2015 and the application number of 201510007196.1. technical field [0002] The invention relates to a method for preparing calcium sulfate whiskers from phosphogypsum, and belongs to the technical fields of resource utilization of industrial solid waste, inorganic non-metallic materials and environmental protection. Background technique [0003] Phosphogypsum is a solid waste with CaSO4·2H2O as the main component discharged during the production of phosphoric acid, and contains phosphate, fluoride, other sulfates and organic matter. About 5 tons of phosphogypsum are produced for every ton of phosphoric acid produced, and the storage capacity of phosphogypsum in China is as high as more than 1 billion tons. The large stockpiling of phosphogypsum not only occupies land, but also causes different degrees of pollution...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B7/14C30B29/46C30B29/62
Inventor 孙红娟梁亚琴彭同江段涛
Owner SOUTHWEAT UNIV OF SCI & TECH
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