Process for preparing calcium sulphate whiskers from ardealite

A technology of calcium sulfate whiskers and phosphogypsum, which is applied in chemical instruments and methods, crystal growth, phosphorus compounds, etc., can solve the problems of poor product quality, difficult promotion and utilization, and large investment, and achieves wide conditions, wide application range, high quality effect

Inactive Publication Date: 2008-11-26
YUNNAN MINZU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the existing phosphogypsum sulfuric acid co-production cement process requires large investment and poor product quality, and its phosphogypsum deco

Method used

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  • Process for preparing calcium sulphate whiskers from ardealite

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Experimental program
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Embodiment 1

[0023] Embodiment 1: raw material phosphogypsum main chemical composition weight percentage / is: CaO 35.36%, SO 2 47.12%, Fe 2 o 3 3.01%, Al 2 o 3 2.05%, P 2 o 5 1.20%, F 0.06%, SiO 2 11.20%. Phosphogypsum is formulated into a phosphogypsum slurry with a concentration of 10% by weight, which is added to the synthesis reactor, and the pH regulator sodium hydroxide is added to adjust the pH of the solution to 9, and the temperature is controlled at 95°C. Stir evenly for 25 minutes to obtain The first intermediate product of calcium sulfate crystal whisker; Utilize the box type filter to filter the first intermediate product prepared in front, and the water content weight percentage of filter residue obtained by filtering is 32%, and this is the second intermediate product of calcium sulfate crystal whisker; The second intermediate product is formulated into a slurry with a concentration of 15% by weight. When the temperature is 120°C, it is uniformly stirred for 25 mi...

Embodiment 2

[0024] Embodiment 2: The main chemical composition / % of raw material phosphogypsum is: CaO=37%, SO 2 =50.17%, Fe 2 o 3 =0.1%, Al 2 o 3 =0.59%, P 2 o 5 =1.01%, F=0.01%, SiO 2 = 11.12%. Prepare phosphogypsum slurry with a concentration of 12% by weight, add it to the synthesis reactor, add pH regulator potassium hydroxide to adjust the pH of the solution to 10, and stir evenly at a temperature of 95-100°C 30min, obtain the first intermediate product of calcium sulfate whisker; Utilize the centrifugal filter to filter the first intermediate product prepared in front, filter the water content weight percentage of the filter residue gained is 43%, be the second intermediate product of calcium sulfate whisker; Prepare this second intermediate product into a slurry with a concentration of 16% by weight. When the temperature is 140°C, stir evenly for 30 minutes. During the stirring process, add 0.2 times the weight of raw materials MgNO 3As a crystal growth agent, the diameter...

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Abstract

The invention relates to a method for preparing calcium sulphate crystal whisker by using phosphogypsum, which belongs to the technical field of phosphorous chemical preparation. Solid drogs phosphogypsum is used as raw material; after a synthetic reaction, filtering, heating and dissolving, thermal filtering and cooling crystallization for the raw material, the calcium sulphate crystal whisker product with the controllable diameter and length is prepared, the diameter of the crystal whisker is 1-4mum and the length of the crystal whisker is 50-200mum. The adoption of the solid drogs phosphogypsum for preparing the calcium sulphate crystal whisker reduces the production volume of natural plaster, saves resources, turns the waste into benefit, lowers the production cost of the calcium sulphate crystal whisker and improves added value of the product in the process of utilizing the phosphogypsum. The obtained calcium sulphate crystal whisker has excellent property, low cost and wide application.

Description

1. Technical field: [0001] The invention relates to a method for preparing calcium sulfate whiskers by using solid waste phosphogypsum, and belongs to the technical field of phosphorus chemical preparation. 2. Background technology: [0002] Phosphogypsum is the industrial waste produced by the reaction of phosphate rock and sulfuric acid in the production process of wet-process phosphoric acid. It is calculated that every ton of phosphoric acid produced will produce 4-5 tons of phosphogypsum. At present, the annual discharge of phosphogypsum in the world reaches 200 million Tons, but the utilization rate of phosphogypsum is not more than 10%. The treatment, disposal and comprehensive utilization of phosphogypsum has become a worldwide problem. my country's phosphate fertilizer output ranks first in the world. The production of high-concentration phosphate fertilizers (such as ammonium phosphate, heavy calcium, etc.) requires a large amount of wet-process phosphoric acid, wh...

Claims

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Application Information

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IPC IPC(8): C30B29/14C30B29/62C30B7/08C01B25/32
Inventor 马林转宁平卿山杨敏刘天成杨月红
Owner YUNNAN MINZU UNIV
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