Process for treating electrolytic aluminum carbon residues through supercritical water oxidation

Abstract

The invention relates to the technical field of electrolytic aluminum, in particular to a process for treating electrolytic aluminum carbon residues through supercritical water oxidation and recycling electrolyte.The process comprises the steps that smashed carbon residues, water and an oxidizing agent are added into a reaction kettle, the temperature is increased to 374-380 DEG C, meanwhile, after the pressure in the reaction kettle is increased to 20-23 Mpa, heat preservation and pressure maintaining are conducted for 1-2 h, after the reaction is finished, a pressure relief valve is opened, and after the reaction is finished, the pressure relief valve is opened; and starting a cooling water cooling reaction system, carrying out gas-liquid separation, and then separating a solid-liquid mixture in the kettle. Compared with a traditional high-temperature roasting method for carbon removal, the supercritical treatment temperature is low, the supercritical treatment is carried out in a closed system of a reaction kettle, fluorine in the electrolytic aluminum carbon residues is not prone to volatilization, in other words, electrolyte cannot be denatured, and pollution caused by volatilization of the electrolyte cannot be caused; and secondly, oxygen dissolved in the supercritical water can completely oxidize carbon in the carbon residues in a short time, so that the treatment time of the electrolytic aluminum carbon residues is greatly shortened.

Description

technical field [0001] The present application relates to the technical field of electrolytic aluminum, in particular, to a process for treating electrolytic aluminum carbon slag by supercritical water oxidation. Background technique [0002] The anodes used in industrial aluminum electrolytic cells are all made of carbon materials. Due to the inhomogeneity of carbon materials, carbon slag will be generated during the electrolytic production of metal aluminum. Generally speaking, carbon slag mainly includes carbon and aluminum electrolyte. The main components of aluminum electrolyte are sodium fluoride, cryolite, subcryolite and a small amount of calcium fluoride, magnesium fluoride, alumina, etc. It is equivalent to discharge 600-700kg of fluoride salt, 300-370kg of carbon powder and 30kg of alumina. [0003] The traditional treatment method is the carbon residue roasting method. That is, the carbon is removed by roasting in a reverberatory furnace, and the electrolyte is...

AI Technical Summary

Problems solved by technology

The main disadvantages are as follows. First, the roasting temperature is not easy to control. If the temperature is too high, it will not only increase the volatilization of the electrolyte, but also cause the denaturation of the electrolyte, which will affect the use; and if the temperature is too low, the carbon in the carbon residue will not be completely burned; the second is From the perspective of environmental protection, a large amount of F-containing flue gas will volatilize during the roasting process of carbon slag, and direct emission will have a great impact on the environment

Images