Method for preparing light calcium carbonate and magnesium hydroxide from magnesium tailings

A light calcium carbonate, magnesium hydroxide technology, applied in the removal of magnesium hydroxide, calcium carbonate/strontium/barium, solid waste, etc., can solve problems such as pollution, and achieve the effects of safe operation, high purity, and wide sources

Inactive Publication Date: 2012-11-14
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
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Problems solved by technology

[0011] Purpose of the invention: the present invention provides a method for preparing light calcium carbonate and magnesium hydroxide with magnesium tailings, in order to utilize a large amount of discharged magnesium tailings and other raw materials to prepare light calcium carbonate and magnesium hydroxide, and to realize intermediate Product recycling, reducing the consumption of externally purchased auxiliary materials and water in the process, in order to solve the problem of environmental pollution and make full use of calcium and magnesium resources

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  • Method for preparing light calcium carbonate and magnesium hydroxide from magnesium tailings

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Effect test

Embodiment 1

[0028] (1) The bulk magnesium tailings (calcium oxide content accounts for 24%) are crushed to obtain small pieces with a diameter of 16 to 19 mm, which are uniformly mixed with an additive of 1.4% by weight, wherein the additive is calcium chloride, and the additive The source of the calcium chloride solution is: the part of the calcium chloride solution mentioned in step (2) is obtained after evaporation and drying; then the mixture of the above-mentioned small magnesium tailings and additives is calcined at 670 ° C for 70 minutes to obtain calcined powder (mainly containing MgO and CaCO 3 ) and CO 2 , where CO 2 For subsequent digestion, carbonization and chlorination reactions;

[0029] (2) The calcined powder and calcium chloride solution were digested, carbonized, and chlorinated in a carbon dioxide atmosphere and stirred at 60°C for 120 minutes (the pH at the end of the reaction was 6.6-7.4), and then the solid-liquid separation was performed to obtain MgCl-containing...

Embodiment 2

[0033] (1) The bulk magnesium tailings (calcium oxide content accounts for 21%) are crushed to obtain small pieces with a diameter of 0.3 to 5 mm, which are uniformly mixed with an additive of 1.1% by weight, wherein the additive is calcium chloride, and the additive The source is: chemical reagent calcium chloride; then the mixture of the above-mentioned small magnesium tailings and additives is calcined at 840°C for 130min to obtain calcined powder (mainly containing MgO, CaO and CaCO 3 ) and CO 2 , where CO 2 For subsequent digestion, carbonization and chlorination reactions;

[0034] (2) The calcined powder and calcium chloride solution were digested, carbonized, and chlorinated for 80 minutes under the condition of stirring in a carbon dioxide atmosphere and 25°C (the pH at the end of the reaction was 6.6-7.4), and then the solid-liquid separation was carried out to obtain MgCl-containing 2 solution and CaCO 3 Precipitation; wherein the molar ratio of calcium chloride ...

Embodiment 3

[0038] (1) The bulk magnesium tailings (calcium oxide content accounts for 28%) are crushed to obtain small pieces with a diameter of 11 to 14 mm, which are uniformly mixed with an additive of 0.7% by weight, wherein the additive is magnesium chloride, and the source of the additive is It is: the part of the magnesium chloride solution mentioned in the step (2) is obtained after evaporation and drying; then the mixture of the above-mentioned small magnesium tailings and additives is calcined at 770°C for 30min to obtain calcined powder (mainly containing MgO, CaO and CaCO 3 ) and CO 2 , where CO 2 For subsequent digestion, carbonization and chlorination reactions;

[0039] (2) The calcined powder and calcium chloride solution were digested, carbonized, and chlorinated in a carbon dioxide atmosphere and stirred at 40°C for 100 minutes (the pH at the end of the reaction was 6.6-7.4), and then the solid-liquid separation was performed to obtain the MgCl-containing 2 solution an...

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Abstract

The invention discloses a method for preparing light calcium carbonate and magnesium hydroxide from magnesium tailings. A raw material is the magnesium tailings contain 18 to 36 weight percent of calcium oxide. The method comprises the following steps of: crushing and calcining the magnesium tailings to obtain calcined powder and CO2; performing digestion, carbonization and chlorination reaction on the calcined powder and the CO2 in the CO2 atmosphere under the condition of stirring so as to obtain MgCl2-containing solution and light CaCO3 precipitate; and reacting MgCl2 with a precipitator to generate Mg(OH)2 precipitate. In the method, the light calcium carbonate and magnesium hydroxide are prepared from the magnesium tailings discharged in a large quantity and other raw materials so asto solve the problem of environmental pollution and fulfill the aim of fully utilizing calcium and magnesium resources.

Description

[0001] Technical field: the invention belongs to a method for preparing chemicals, in particular to a method for preparing light calcium carbonate and magnesium hydroxide from magnesium tailings. Background technique: [0002] Magnesium resources are my country's dominant mineral resources and one of the important export mineral products. With the increase in the mining of magnesium ore resources, the number of high-quality resources is constantly decreasing, and wastes such as low-grade lean ore and tailings continue to accumulate. If they are not used, it will not only waste resources but also pollute the environment. Therefore, the use of magnesium tailings has become a trend. It must be done. The main components of magnesium tailings are calcium and magnesium compounds. At present, the main ways to use them are goaf fillers, acidic soil improvers, blast furnace slagging agents and other low-value-added utilization. In addition, magnesium tailings are raw materials. In the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F11/18C01F5/14B09B3/00
Inventor 薛向欣张悦朱世玲杨合单琪堰
Owner NORTHEASTERN UNIV LIAONING
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