Method for separating fluoride salt and carbon in aluminum electrolysis carbon residues

Abstract

The invention discloses a method for separating fluoride salt and carbon in aluminum electrolysis carbon residues, relates to a method for treating anode carbon residues generated in an aluminum electrolysis process, and in particular relates to a method for recycling fluoride salt and carbon in the anode carbon residues. The method is characterized by comprising the following steps: separating fluoride salt and carbon in carbon residues in the separation process by adopting a vacuum distillation furnace, condensing and collecting the fluoride salt on the upper part of the vacuum distillation furnace, and collecting the reaction carbon residues on the lower part of the vacuum distillation furnace. According to the method disclosed by the invention, the fluoride salt separation effect is good, the separated fluoride salt is low in impurity content and can directly return to an electrolytic cell, the content of carbon in the rest carbon residues is greatly improved, the carbon can be returned to a carbon plant for utilization, and the fluoride salt and carbon in the aluminum electrolysis carbon residues can be efficiently recycled.

Description

technical field [0001] A method for separating fluoride salt and carbon in aluminum electrolysis carbon slag, relates to a treatment method for anode carbon slag produced in the aluminum electrolysis process, especially a method for recovering fluoride salt and carbon in anode carbon slag. Background technique [0002] With the continuous expansion of aluminum electrolysis capacity, the demand for carbon anodes continues to increase, and the quality of carbon materials continues to decline, resulting in a gradual decline in the quality of carbon anodes. During the aluminum electrolysis process, due to selective oxidation, unburned aggregate particles enter the electrolyte solution to form carbon slag. Generally, the carbon slag will burn off on the surface of the electrolyte, but in the case of excess, it needs to be manually salvaged in time , to reduce the adverse effects of carbon slag on electrolysis. Excessive carbon slag will increase the electrolyte resistance, pull ...

AI Technical Summary

Problems solved by technology

Excessive carbon slag will increase the electrolyte resistance, pull down the pole distance, reduce the current efficiency, and increase power consumption; too much carbon slag on the surface of the electrolyte will increase the electrolyte pressure drop, increase the power income, increase the bath temperature, and generate a hot bath ;When a large amount of carbon slag floats on the surface of the aluminum electrolyte solution, the carbon slag forms a current path with the carbon anode and cathode, causing current loss; too much carbon slag in the electrolyte will reduce the dissolution rate of alumina, resulting in increased precipitation at the bottom of the furnace and deterioration of the tank condition ;The carbon slag taken away will take away a large amount of electrolyte, and some fluoride salt will be lost due to incomplete recovery

[0003] There will be 60%-70% fluoride salt in the fished carbon residue. At present, flotation method or combustion method is mainly used to recover the fluoride salt in the carbon residue, but the recovery is difficult to complete, and there will be a part of the fluoride salt flow. due to loss

In the flotation process plant, the waste liquid is more difficult to deal with, while the combustion method not only wastes most of the carbon, but also causes the volatilization loss of fluoride salts, and the most serious thing is that it pollutes the environment