Method for producing building gypsum powder using phosphrus gypsum

A technology for making building gypsum powder and gypsum, which is applied in the field of making building gypsum from phosphogypsum. It can solve the problems of unreachable, low flexural and compressive strength, and fast initial setting time of building gypsum powder, so as to improve the flexural and compressive strength. , large production capacity, and the effect of prolonging the initial setting time

Inactive Publication Date: 2005-11-09
TONGLING CHEM IND GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The problem to be solved by the present invention is that the building gypsum powder produced by the above rapid dehydration has a fast initial setting time, low flexural and compressive strength, and cannot meet the requirements of building gypsum standards.

Method used

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  • Method for producing building gypsum powder using phosphrus gypsum
  • Method for producing building gypsum powder using phosphrus gypsum
  • Method for producing building gypsum powder using phosphrus gypsum

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Example 1: The phosphogypsum by-product of wet-process phosphoric acid and the high-temperature flue gas at 400-700°C are sent to the dryer, and the phosphogypsum and the high-temperature gas are fully mixed in the dryer for calcination and dehydration, and are sent to the cloth bag with the airflow The dust collector is used for separation, and the temperature of the airflow at the inlet of the bag filter is controlled at 150-160°C. The calcined product collected by the bag filter is sent to the mill, and the additive citric acid is added to the mill at the same time. The amount of citric acid added The content is 0.1-0.22% of the weight of the calcined product, so that the D50 value of the pulverized product is reduced to 0.7 times of the D50 value of the calcined product before grinding, and the building gypsum powder is prepared. After testing, the initial setting time of the product is greater than 6 minutes, the final setting time is less than 30 minutes, the flexu...

Embodiment 2

[0016] Embodiment 2: by the method for embodiment 1, the D50 value of the product after grinding is reduced to 0.65 times of the D50 value of the calcined product before grinding, and the initial setting time of the prepared building gypsum powder is greater than 6 minutes, and the final setting time is less than After 30 minutes, the flexural strength is greater than 2.0Mpa, and the compressive strength is greater than 3.2Mpa, meeting the requirements of the national standard GB9776-88 for building gypsum powder.

Embodiment 3

[0017] Embodiment 3: by the method for embodiment 1, wherein the airflow temperature of bag filter inlet is controlled at 160-170 ℃, the additive that adds to mill is citric acid, and addition is 0.15-0.3% of calcined product weight, makes The obtained building gypsum powder has an initial setting time greater than 6 minutes, a final setting time less than 30 minutes, a flexural strength greater than 1.8Mpa, and a compressive strength greater than 3.0Mpa, meeting the requirements of the national standard GB9776-88 for building gypsum powder.

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Abstract

The production process of building gypsum powder with ardealite, the side product of wet phosphoric acid production process, as material includes fast dewatering in stoving machine to obtain half-hydrated gypsum product, adding citric acid or sodium citrate, and pulverizing to decrease the medium size D50 value to 0.7 time the original value. The building gypsum powder product has pre-hardening time, fracture strength and compression strength meeting the requirement of national standard GB9776-88, and may be used to replace natural gypsum. The present invention can utilize ardealite effectively and protect environment.

Description

technical field [0001] The invention relates to a method for preparing building gypsum from phosphogypsum, in particular to a method for rapidly dehydrating phosphogypsum by calcining phosphogypsum with high-temperature hot gas to prepare building gypsum. Background technique [0002] Phosphogypsum is a waste produced in the production process of wet-process phosphoric acid. Its emission is very large, which is five times that of phosphoric acid production. It not only causes great pressure on the stacking of production enterprises, but also pollutes the environment. Therefore, how to process and utilize phosphogypsum in large quantities is an urgent problem to be solved. [0003] Since the main components of phosphogypsum and natural gypsum are calcium sulfate dihydrate, the research on the utilization of phosphogypsum mainly focuses on the processing of phosphogypsum into a substitute for natural gypsum. At present, the main research abroad is to ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B11/02C04B11/26C04B28/14
CPCC04B28/143
Inventor 胡成军石庆忠叶丽君潘建程传生汪明星花勇
Owner TONGLING CHEM IND GRP
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