Process of preparing high purity light calcium carbonate fine powder with carbide residue

A technology of calcium carbonate micropowder and carbide slag, applied in the direction of calcium carbonate/strontium/barium, etc., to reduce pollution, reduce loss, and reduce manufacturing costs

Inactive Publication Date: 2007-08-22
NAT UNIV OF DEFENSE TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0015] The technical problem to be solved by the present invention is: aiming at the problems existing in the above-mentioned prior art preparation methods, to provide a kind of calcium carbide slag as raw material, without high-temperature calcination pretreatment, and without adding expensive additives, ammo...

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  • Process of preparing high purity light calcium carbonate fine powder with carbide residue
  • Process of preparing high purity light calcium carbonate fine powder with carbide residue

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Experimental program
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Effect test

Embodiment 1

[0044] Take 40g of calcium carbide slag (dry basis), add it to ammonium chloride solution with a mass fraction of 20% and an excess of 30%, stir and react at room temperature for 4 hours, filter (or suction filter) with ordinary filter paper, and obtain a clear and transparent Basic CaCl 2 solution. The resulting CaCl 2 The solution was placed in a 1L three-necked flask and diluted with water to a solution concentration of 4%, and stirred at room temperature (stirring speed was 500rpm), while the air flow rate was 800mL / min, and the CO concentration was 600mL / min. 2 Gas flow rate into air and CO 2 The mixed gas starts carbonation reaction, the solution becomes turbid after about 5 minutes, the solution temperature rises gradually, and the system temperature rises to about 30°C after 25 minutes of reaction. The pH value of the solution was measured. The pH value was 10.6 at the initial stage of the reaction, slowly decreased to 8.6 during the reaction, and rapidly decrea...

Embodiment 2

[0046] Prepare CaCl by carbide slag with embodiment 1 2 After the solution was placed in a 1L three-necked flask, diluted with water to a solution concentration of 10%, stirred at room temperature (stirring speed was 700rpm), while the air flow rate of 1500mL / min, 1000mL / minCO 2 The carbonation reaction was started by feeding the mixed gas at the gas speed, and the pH value of the solution dropped to 7.0 after 21 minutes of reaction, and the reaction was stopped. The product was filtered with suction, washed with water for 1-2 times and dried at 60°C. Observed by a scanning electron microscope, it is uniform spherical particles with a diameter of 2-4 μm, a sedimentation volume of 2.6ml / g, and a whiteness of 97%. Its composition was analyzed by ICP-AES method, and the results are shown in Table 1. It can be seen that the content of heavy metal elements in the product is extremely low, reaching the national food grade calcium carbonate national standard.

Embodiment 3

[0048] After recovering the filtrate after the product filtration in Example 1, measure the nitrogen content of the solution, add a small amount of water and ammonium chloride to make the solution reach the same volume and ammonium chloride concentration as in Example 1. After adding 40g calcium carbide slag in this solution, carry out the processing of carbide slag by the same condition of embodiment 1, the CaCl obtained 2 After solution adds a small amount of ammoniacal liquor, carry out carbonation reaction by the same condition as embodiment 1, product light calcium carbonate micropowder is spherical particle (particle diameter is 1~4 μ m), and the sedimentation volume of product is 2.6ml / g.

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Abstract

The process of preparing high purity light calcium carbonate fine powder with carbide residue includes reacting carbide residue as one kind of industrial waste directly with ammonium chloride solution to produce mixture solution of calcium chloride and ammonia water, filtering, introducing CO2 gas for carbonating reaction, filtering the produced slurry, water washing the filter cake and stoving to obtain calcite type spherical light calcium carbonate fine powder, and circulating ammonium chloride solution for reuse. The present invention has simple technological process, lowered production cost, high product purity and high product quality.

Description

Technical field: [0001] The invention relates to a method for manufacturing chemical raw materials, in particular to a method for manufacturing high-purity light calcium carbonate micropowder. Background technique: [0002] Calcium carbide is an important chemical raw material, mainly used in the production of PVC, carbon black, dissolved acetylene and other industries. When calcium carbide is used to produce acetylene gas, PVC and other products, a large amount of solid waste-calcium carbide slag will be generated. According to statistics, the annual production of calcium carbide in the country is about 20 million tons, of which domestic use is about 15 million tons. Calculated as 1.2 tons of waste residue for every ton of calcium carbide consumed, the annual production of calcium carbide slag reaches more than 18 million tons. The main component of calcium carbide slag is calcium hydroxide (the content reaches more than 90%), and it also contains some other impurities suc...

Claims

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Application Information

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IPC IPC(8): C01F11/18
Inventor 宋永才
Owner NAT UNIV OF DEFENSE TECH
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