What are the mechanisms and influencing factors of copper segregation process?
The segregation process is more complicated. Although many experimental studies have been done on the segregation of copper , there are still some different opinions on some issues. Most believe that the segregation process of copper oxide ore is roughly divided into three stages.
First, the decomposition stage of salt
In the process of segregation, the first step is the formation of hydrogen chloride at 700 ° C in the salt water and the crystal water in the ore. The reaction formula is as follows:
4NaC1+A1 2 0 3 ·2Si0 2 ·2H 2 0 ==== Na 4 A1 2 0 3 ·2Si0 3 +4HC1↑
2. The volatilization stage of cuprous chloride reacts with copper oxide minerals to produce volatile cuprous chloride. There are many types of copper oxide minerals. For the sake of simplicity, simple Cu 2 0 is used as a representative. The reaction formula is:
6HC1+3Cu 2 0 ==== 2Cu 3 Cl 3 ↑+3H 2 0
3. Reduction and Segregation Stage The cuprous chloride (Cu 3 Cl 3 ) vapor is reduced by hydrogen (hydrogen adsorbed by the carbon particles) to form isolated copper and covers the carbon particles. Its reaction formula is:
2Cu 3 Cl 3 +3H 2 ==== 6Cu+6HC1↑
The isolated copper (Cu) can be efficiently recovered by flotation. The hydrogen chloride (regenerated HCl) produced by the reduction of cuprous chloride can continue to react with the silver oxide mineral to form cuprous chloride. The above reaction cycle is cycled.
There are many factors affecting the segregation process, among which the following are the main factors;
(1) Ore properties. The ore particle size and the material composition of the ore should affect the segregation process, especially when dealing with calcareous gangue, especially calcite , limestone, etc., the formation of calcium oxide will hinder the segregation of copper.
(2) The effect of temperature. The temperature directly affects the rate of chlorination. Accurate temperature control is an important condition for the separation process. The upper limit of the separation temperature depends on both the ore properties and the heat exchange conditions, as well as the economic factors. If the temperature of the separation is high, not only the fuel is wasted, but also the sintering of the material occurs, and the phenomenon of "knotting the kiln skin" occurs. If the temperature is below the separation temperature, the segregation effect is deteriorated.
(3) Residence time. The residence time of the material in the separation kiln (chamber) depends on the volume of the kiln (chamber), the specific gravity of the material, and the passage speed of the material. In short, the residence time of the material in the kiln (chamber) should be sufficient to achieve a higher recovery rate.
(4) Reduction conditions. The effect of reducing conditions on the segregation process is significant. Moderate reduction conditions favor the progress of the chlorination reaction.
(5) The amount of chlorinating agent. The salt itself has no effect on the nitriding reaction. The initiation reaction of segregation is hydrogen chloride produced by hydrolysis of salt. The chlorination reaction rate is proportional to the hydrogen chloride pressure. If the amount of salt added is too small, the supply of hydrogen chloride cannot meet the needs of the initial chlorination reaction rate. Excessive use of salt is also harmful, it will dissolve cuprous chloride, reducing the recovery of segregation.
(6) Water vapor. Shuiyan gas plays an important role in the decomposition of chlorinating agents and the formation of hydrogen chloride. Tests have shown that if the ore loses crystal water, the segregation process cannot proceed.
First, the decomposition stage of salt
In the process of segregation, the first step is the formation of hydrogen chloride at 700 ° C in the salt water and the crystal water in the ore. The reaction formula is as follows:
4NaC1+A1 2 0 3 ·2Si0 2 ·2H 2 0 ==== Na 4 A1 2 0 3 ·2Si0 3 +4HC1↑
2. The volatilization stage of cuprous chloride reacts with copper oxide minerals to produce volatile cuprous chloride. There are many types of copper oxide minerals. For the sake of simplicity, simple Cu 2 0 is used as a representative. The reaction formula is:
6HC1+3Cu 2 0 ==== 2Cu 3 Cl 3 ↑+3H 2 0
3. Reduction and Segregation Stage The cuprous chloride (Cu 3 Cl 3 ) vapor is reduced by hydrogen (hydrogen adsorbed by the carbon particles) to form isolated copper and covers the carbon particles. Its reaction formula is:
2Cu 3 Cl 3 +3H 2 ==== 6Cu+6HC1↑
The isolated copper (Cu) can be efficiently recovered by flotation. The hydrogen chloride (regenerated HCl) produced by the reduction of cuprous chloride can continue to react with the silver oxide mineral to form cuprous chloride. The above reaction cycle is cycled.
There are many factors affecting the segregation process, among which the following are the main factors;
(1) Ore properties. The ore particle size and the material composition of the ore should affect the segregation process, especially when dealing with calcareous gangue, especially calcite , limestone, etc., the formation of calcium oxide will hinder the segregation of copper.
(2) The effect of temperature. The temperature directly affects the rate of chlorination. Accurate temperature control is an important condition for the separation process. The upper limit of the separation temperature depends on both the ore properties and the heat exchange conditions, as well as the economic factors. If the temperature of the separation is high, not only the fuel is wasted, but also the sintering of the material occurs, and the phenomenon of "knotting the kiln skin" occurs. If the temperature is below the separation temperature, the segregation effect is deteriorated.
(3) Residence time. The residence time of the material in the separation kiln (chamber) depends on the volume of the kiln (chamber), the specific gravity of the material, and the passage speed of the material. In short, the residence time of the material in the kiln (chamber) should be sufficient to achieve a higher recovery rate.
(4) Reduction conditions. The effect of reducing conditions on the segregation process is significant. Moderate reduction conditions favor the progress of the chlorination reaction.
(5) The amount of chlorinating agent. The salt itself has no effect on the nitriding reaction. The initiation reaction of segregation is hydrogen chloride produced by hydrolysis of salt. The chlorination reaction rate is proportional to the hydrogen chloride pressure. If the amount of salt added is too small, the supply of hydrogen chloride cannot meet the needs of the initial chlorination reaction rate. Excessive use of salt is also harmful, it will dissolve cuprous chloride, reducing the recovery of segregation.
(6) Water vapor. Shuiyan gas plays an important role in the decomposition of chlorinating agents and the formation of hydrogen chloride. Tests have shown that if the ore loses crystal water, the segregation process cannot proceed.
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