Method for extracting high-purity calcium oxide from carbide slag

A calcium carbide slag, calcium oxide technology, applied in the direction of calcium/strontium/barium oxide/hydroxide, etc., can solve the problems of difficult control of process conditions, high energy consumption of calcium oxide, low recovery rate, etc., to meet the needs of industrial production , The method is scientific and reasonable, and the extraction rate is high.

Inactive Publication Date: 2011-06-15
NORTHEAST DIANLI UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The physical extraction method has the disadvantages of extracting calcium oxide due to high energy consumption and low purity of the prepared calcium oxide, which leads to low utilization rate of finished calcium oxide and weak market competitiveness.
Traditional chemical extraction uses a certain concentration of carbon dioxide as a precipitating agent, and the extracted calcium oxide has a high purity, but there are disadvantages such as difficult control of process conditions, high production cost and low recovery rate.
So far, there are no literature reports and practical applications of using ammonium oxalate as a precipitant to extract calcium oxide from carbide slag

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Example 1: take carbide slag and dry it at 80°C for 2 hours to obtain dry carbide slag; then roast the dried carbide slag at 800°C for 1 hour to obtain pretreated carbide slag; carry out primary purification, take the pretreated carbide 20 g of calcium carbide slag and 50 g of ammonium chloride were dissolved in 500 ml of water to obtain a calcium carbide slag emulsion, which was subjected to centrifugal separation to obtain a calcium chloride leaching solution. For secondary purification, firstly acidify the calcium chloride leachate with 10% hydrochloric acid until the pH of the solution is 1, then add 24g of precipitant ammonium oxalate, and then add 10% ammonia water dropwise to the solution at a rate of 3mL / min, To neutralize the hydrogen ions in the solution and detect the pH value of the solution, stop dripping 10% ammonia water when the pH of the solution is 4.4. At this time, oxalate ions and calcium ions form coarse and pure calcium oxalate precipitates. Then...

Embodiment 2

[0018] Example 2: take carbide slag and dry it at 115°C for 1.5 hours to obtain dry carbide slag; then roast the dried carbide slag at 900°C for 1 hour to obtain pretreated carbide slag; carry out primary purification, take the pretreated carbide 30 g of calcium carbide slag and 50 g of ammonium chloride were dissolved in 625 ml of water to obtain a calcium carbide slag emulsion, which was subjected to centrifugal separation to obtain a calcium chloride leaching solution. For secondary purification, firstly acidify the calcium chloride leachate with 10% hydrochloric acid until the pH of the solution is 1, then add 36g of precipitant ammonium oxalate, and then add 10% ammonia water to the solution dropwise at a rate of 3mL / min, To neutralize the hydrogen ions in the solution and detect the pH value of the solution, stop dripping 10% ammonia water when the pH of the solution is 4.4. At this time, oxalate ions and calcium ions form coarse and pure calcium oxalate precipitates. T...

Embodiment 3

[0019] Example 3: take carbide slag and dry it at 130°C for 1 hour to obtain dry carbide slag; then roast the dried carbide slag at 1000°C for 1 hour to obtain pretreated carbide slag; carry out primary purification, take the pretreated carbide slag 40 g of calcium carbide slag and 50 g of ammonium chloride were dissolved in 750 ml of water to obtain a calcium carbide slag emulsion, which was subjected to centrifugal separation to obtain a calcium chloride leaching solution. For secondary purification, the calcium chloride leachate was first acidified with 10% hydrochloric acid until the pH of the solution was 1, then 48g of precipitant ammonium oxalate was added, and 10% ammonia water was added dropwise to the solution at a rate of 3mL / min, To neutralize the hydrogen ions in the solution and detect the pH value of the solution, stop dripping 10% ammonia water when the pH of the solution is 4.4. At this time, oxalate ions and calcium ions form coarse and pure calcium oxalate p...

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Abstract

The invention relates to a method for extracting high-purity calcium oxide from carbide slag. The method is characterized by comprising the following steps: drying the carbide slag; carrying out high temperature roasting pretreatment; preparing carbide slag emulsion; carrying out centrifugal separation to produce a calcium chloride leaching liquid; acidifying the leaching liquid; adding a precipitator ammonium oxalate in the acidified solution; dropwise adding a basifier in the solution to neutralize hydrogen ions in the solution, and obtaining the precipitated ammonium oxalate by centrifugal separation; re-drying the separated ammonium oxalate particles; and roasting the dried ammonium oxalate particles at a high temperature to obtain the calcium oxide product with the purity of 98-99%. The invention provides the method for extracting the calcium oxide from the carbide slag by using the precipitator ammonium oxalate. The method is scientific and reasonable, and can meet industrial production requirement so that the extraction efficiency of the calcium oxide product is high, the extraction time is short, the cost is low, and the purity is up to 98-99%.

Description

technical field [0001] The present invention is a method for extracting high-purity calcium oxide from calcium carbide slag. Background technique [0002] Calcium carbide slag is a kind of industrial waste slag discharged in large quantities during the hydration of calcium carbide to produce acetylene gas, and the emission is about 75% to 85% of the output of calcium carbide. The main component of carbide slag is calcium hydroxide, which contains a small amount of inorganic and organic impurities. Carbide slag contains a small amount of carbon and impurities such as magnesium oxide, iron oxide, silicon dioxide, sulfide, phosphide and so on, which is gray-white and has a slight odor. Carbide slag particles have very small particle size and strong surface adsorption. Therefore, it has strong water retention, even if it is placed for a long time, the water content is as high as 45%. Calcium hydroxide in carbide slag is a strong alkaline substance, and its solution pH value i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/02
Inventor 郗丽娟胡杨张瑛洁魏晓煊武倩
Owner NORTHEAST DIANLI UNIVERSITY
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