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A method for preparing high-purity calcium sulfate dihydrate whiskers by metallurgical flue gas desulfurization gypsum recrystallization method

A technology of calcium sulfate dihydrate and desulfurized gypsum, applied in chemical instruments and methods, single crystal growth, crystal growth, etc., to achieve the effects of fast response, low energy consumption, and high added value

Active Publication Date: 2017-11-24
KUNMING METALLURGY INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The purpose of the present invention is to solve the deficiencies in the prior art, and to provide a method for preparing high-purity calcium sulfate dihydrate whiskers by metallurgical flue gas desulfurization gypsum recrystallization method, which solves the environmental problems brought by metallurgical flue gas desulfurization gypsum, Provide a new application path for metallurgical flue gas desulfurization gypsum

Method used

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  • A method for preparing high-purity calcium sulfate dihydrate whiskers by metallurgical flue gas desulfurization gypsum recrystallization method
  • A method for preparing high-purity calcium sulfate dihydrate whiskers by metallurgical flue gas desulfurization gypsum recrystallization method
  • A method for preparing high-purity calcium sulfate dihydrate whiskers by metallurgical flue gas desulfurization gypsum recrystallization method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Such as figure 1 As shown, the metallurgical flue gas desulfurization gypsum is crushed to a particle size of less than 80 mesh, weighed 100.00g, and then added to a 1000mL beaker at the same time as the pre-prepared 1.0mol / L sulfuric acid solution, and stirred for 30min to make a small amount of calcium carbonate and calcium oxide, etc. Convert to calcium sulfate, after the reaction is complete (there is no air bubbles in the slurry, then stir and react for 10 minutes), raise the temperature to 60°C, stir at a speed of 150r / min, and react for 2 hours, after the reaction is complete (desulfurized gypsum recrystallization and stratification ), let it stand for stratification, pour out the supernatant (filtrate 1) (recycled), and the lower layer of gypsum (filter cake 1) is washed with water, suction filtered, and dried for later use.

[0044] Weigh 50.00g of the above-mentioned acid-washed and dried desulfurized gypsum, add it together with 500mL, 2mol / L hydrochloric aci...

Embodiment 2

[0046] Recover 500ml of the filtrate 2 in Example 1, and add 50.0g of desulfurized gypsum after pickling into a 1000mL beaker at the same time, immerse more than two-thirds of the volume in a 90°C constant temperature water bath, keep the temperature and stir for 4h, after the reaction is completed, while the Hot suction filtration, the filter cake can be recycled, the filtrate is transferred to a 1000mL beaker, and 0.5wt% MgCl is added as a crystallization agent 2 In the filtrate, place it in a constant temperature water bath at 50°C for cooling and crystallization for 12 hours. After the crystallization is completed, filter with suction and wash with water. The filtrate can be recycled, and then the filter cake is dried in an oven at 80°C for 12 hours to obtain 16.2g of high-purity calcium sulfate dihydrate whisker product. Its appearance is shown in Figure 3, and the SEM picture is as follows Figure 4 shown. Calcium sulfate dihydrate content ≥ 99.00% (wt%), whiteness grea...

Embodiment 3

[0048] Take by weighing 50.00 g of desulfurized gypsum after pickling and drying in Example 1, and mix it with 500 mL, 2mol / L of mixed salt (Al 2 (SO 4 ) 3 1.0wt% and CaCl 2 4.0wt%) hydrochloric acid solution into a 1000mL flask, immerse more than two-thirds of the volume in a 90°C constant temperature water bath, keep the temperature and stir for 1h, after the reaction is completed, suction filter while it is hot, the filter cake can be recycled, Transfer to a 1000mL beaker, add a mixed crystallization agent (containing 0.5wt%MgCl 2 , 0.5wt% sodium oleate) in the filtrate, placed in a constant temperature water bath at 20°C for cooling and crystallization for 12 hours. Suction filtration after the crystallization is completed, the filtrate 2 can be recycled, and then the filter cake is dried in an oven at 80°C for 12 hours to obtain 22.6 g of high-purity calcium sulfate dihydrate whisker product. Calcium sulfate dihydrate content ≥ 99.00% (wt%), whiteness greater than 98%...

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Abstract

The invention discloses a method for preparing high-purity calcium sulfate dihydrate crystal whiskers by metallurgical flue gas desulfurization gypsum recrystallization method. The method comprises: metallurgical flue gas desulfurization gypsum pickling to remove a small amount of calcium carbonate or calcium oxide and soluble impurities; The acid solution of salt dissolves gypsum, which is used as the raw material for the preparation of high-purity calcium sulfate dihydrate whiskers; the addition of mediators controls the controllable growth of calcium sulfate whiskers, so as to form calcium sulfate whiskers with controllable aspect ratio and complete crystal morphology, Filter and dry to obtain calcium sulfate dihydrate whiskers. Under normal pressure and mild conditions, the invention utilizes the principle of recrystallization to realize resource utilization of high value-added calcium sulfate whiskers prepared from metallurgical flue gas desulfurization gypsum. The raw materials used in the invention are easy to obtain, the production process conditions are simple, the high-purity whiskers have high added value, and the produced calcium sulfate dihydrate whiskers have the characteristics of small diameter, high aspect ratio, complete and uniform appearance and stable performance, and can be used as reinforcing materials It is used as an additive in industries such as plastics, rubber, paper and ceramics, and has broad application prospects.

Description

technical field [0001] The invention belongs to the technical field of calcium sulfate whiskers in the field of chemical engineering, and relates to a method for preparing high-purity calcium sulfate dihydrate whiskers by a metallurgical flue gas desulfurization gypsum recrystallization method, in particular to a method of using recrystallization technology under normal pressure conditions The invention discloses a method for preparing high-purity calcium sulfate dihydrate whiskers, which provides a new industrialization approach for resource utilization of the industrial by-product of metallurgical flue gas desulfurization gypsum. Background technique [0002] my country is rich in natural gypsum and industrial by-product gypsum resources. In 2013, the national production of industrial by-product gypsum desulfurization gypsum was 78 million tons, with a comprehensive utilization rate of about 72%, and the by-product phosphogypsum was about 60 million tons, with a comprehensi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B29/46C30B29/62C30B7/14
Inventor 和晓才郑绍聪杨妮谢刚余强徐庆鑫徐俊毅李雨耕赵云
Owner KUNMING METALLURGY INST
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