Method for preparing high-purity metastable vaterite calcium carbonate from gypsum

A calcium carbonate and metastable state technology, applied in the direction of calcium carbonate/strontium/barium, etc., can solve the problems of increasing the synthesis cost of aragonite calcium carbonate, the complex synthesis process of organic crystallization agents, and increasing the difficulty of experiments, etc., to achieve easy industrialization Production, crystal form high purity, low cost effect

Active Publication Date: 2014-07-16
EAST CHINA UNIV OF SCI & TECH
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Problems solved by technology

The introduction of organic solvents increases the synthesis cost of aragonite calcium carbonate; the complex synthesis process of organic crystallization agents increases the difficulty of experiments, and the introduction of toxic organic substances also pollutes the environment

Method used

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  • Method for preparing high-purity metastable vaterite calcium carbonate from gypsum
  • Method for preparing high-purity metastable vaterite calcium carbonate from gypsum
  • Method for preparing high-purity metastable vaterite calcium carbonate from gypsum

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Effect test

Embodiment 1

[0029] Please see attached Figure 1-3 , add 3mol / 1 ammonium sulfate solution into the reactor, keep the temperature at 25°C, add gypsum into the reactor, and start the stirring speed at 1.0m.s -1 , Slurry for half an hour; Add 3mol / 1 ammonium carbonate solution to the slurry, the material ratio of ammonium carbonate and gypsum added is 1.1; Add sodium stearate with 2.5% gypsum mass to the slurry, and react at constant temperature for 2h. After the reaction, filter with suction, wash the filter cake 5 times with deionized water, and dry it in an oven at 80° C. for 12 hours.

Embodiment 2

[0031] Add 2mol / 1 ammonium sulfate solution into the reactor, keep the temperature at 45°C, add gypsum into the reactor, and start the stirring speed at 0.7m.s -1 , pulping for half an hour; add 2mol / 1 ammonium carbonate solution to the slurry, the material ratio of ammonium carbonate and gypsum added is 1.05; constant temperature reaction for 2h. After the reaction, filter with suction, wash the filter cake 5 times with deionized water, and dry it in an oven at 80° C. for 12 hours.

Embodiment 3

[0033] Add 2mol / 1 ammonium sulfate solution into the reactor, keep the temperature at 55°C, add gypsum into the reactor, and start the stirring speed at 1.0m.s -1 , pulping for half an hour; add 2mol / 1 ammonium carbonate solution to the slurry, the material ratio of ammonium carbonate and gypsum added is 1.1; add hexyl orthosilicate with 3% gypsum mass to the slurry, and react at constant temperature for 2h . After the reaction, filter with suction, wash the filter cake 5 times with deionized water, and dry it in an oven at 80° C. for 12 hours.

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Abstract

The invention relates to a method for preparing high-purity metastable vaterite calcium carbonate from gypsum. The method comprises the following concrete steps: (1) adding an ammonium sulfate solution into a reactor from the constant temperature to the reaction temperature, adding the gypsum into the reactor, and stirring for pulping for 25-35 minutes; (2) adding an ammonium carbonate solution into the reactor; (3) adding an anionic surfactant accounting for 0.1%-5% by mass of the gypsum into the reactor in the step (1); (4) adjusting the rotary speed of a stirring paddle and reacting at the constant temperature to obtain a reaction product; and (5) filtering the reaction product in the step (4) in a conventional way, washing, and drying to obtain the high-purity metastable vaterite calcium carbonate. The vaterite calcium carbonate produced by adopting the method adopts the gypsum as a raw material, a technical support can be provided for solving the problem of recycling of industrial solid wastes-gypsum, and wastes are turned into wealth; the vaterite calcium carbonate is high in crystal purity and easy to prepare, the yield of the vaterite calcium carbonate is increased due to high-concentration ammonium carbonate reaction, and the production cost of the vaterite calcium carbonate can be greatly reduced.

Description

【Technical field】 [0001] The invention relates to the technical field of high-purity single-crystal vaterite calcium carbonate, in particular to a method for preparing high-purity metastable vaterite calcium carbonate from gypsum. 【Background technique】 [0002] my country needs to discharge a large amount of waste gypsum every year, such as phosphogypsum, desulfurization gypsum, fluorine gypsum, etc., and the trend is increasing year by year, becoming one of the main industrial solid wastes in my country. At present, stacking is the main method, which not only pollutes the environment but also occupies land resources. How to realize the resource utilization of waste gypsum is an urgent problem to be solved. The main component of waste gypsum is calcium sulfate dihydrate, and the reaction of calcium sulfate and ammonium carbonate to prepare calcium carbonate and ammonium sulfate can turn waste into treasure and effectively utilize sulfur resources. [0003] Calcium carbonat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/18
Inventor 宋兴福于建国许妍霞赵精彩孙玉柱孙泽孙淑英
Owner EAST CHINA UNIV OF SCI & TECH
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