Method for preparing calcium sulfate whisker from phosphogypsum

A technology of calcium sulfate whiskers and phosphogypsum, 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 cost saving

Inactive Publication Date: 2015-04-29
SOUTHWEAT UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] 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

Method used

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

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0048]The method for preparing calcium sulfate whiskers with phosphogypsum comprises steps as follows:

[0049] 1) The phosphogypsum raw material is ground by a ball mill to obtain a phosphogypsum powder with a particle size of 100 mesh.

[0050] 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.

[0051] 3) Aging the above-mentioned acidic filtrate, cooling it naturally to 20° C., and crystallizing it for 24 hours to obtain an acid...

example 2

[0055] The steps of the method in this example are basically the same as those in Example 1, and will not be repeated here.

[0056] The difference is that in the following steps:

[0057] 1) The phosphogypsum raw material is ground by a ball mill to obtain a phosphogypsum powder with a particle size of 20 mesh.

[0058] 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.

[0059] 3) Aging the above-mentioned acidic filtrate, cooling the temperature to 20°C by air cooling, and crystallizing for 24 h...

example 3

[0063] The steps of the method in this example are basically the same as those in Example 1, and will not be repeated here.

[0064] The difference is that in the following steps:

[0065] 1) The phosphogypsum raw material is ground by a ball mill to obtain a phosphogypsum powder with a particle size of 600 mesh.

[0066] 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.

[0067] 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 whisker from phosphogypsum. The method comprises the following steps: (1) crushing and grinding phosphogypsum serving as a raw material to obtain phosphogypsum powder; (2) mixing the obtained phosphogypsum powder and diluted acid to obtain a mixture, placing the mixture in a reactor with a stirring device, reacting by controlling a certain temperature to obtain an acidic mixed solution containing calcium, sulfate ions and insoluble matters; (3) filtering the obtained mixed solution while the solution is hot to obtain an acidic filtrate; and (4) cooling the obtained acidic filtrate and crystallizing, filtering, washing and drying to obtain the calcium sulfate whisker product. The calcium sulfate dihydrate whisker with large length-diameter ratio is directly prepared from the raw material by virtue of one-step acid leaching impurity removal method instead of pretreatment impurity removal and thus the advantages that the process flow is simple, the production cost is low, the energy consumption is small and the acidic wastewater and washing water can be recyclable are achieved; the obtained calcium sulfate whisker has the characteristics of high purity, large length-diameter ratio and the like and is conductive to popularization and application.

Description

technical field [0001] 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 [0002] Phosphogypsum is emitted during the production of phosphoric acid in the form of CaSO 4 2H 2 O is the main component of solid waste, 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 to the environment. Therefore, the resource utilization of phosphogypsum has very important resource and environmental significance. [0003] Calcium sulfate whiskers grow in the form of single crysta...

Claims

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Application Information

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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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