The general products are casting, die casting, stretching and extrusion forming. The former two species can make more complicated processes, and the latter two have certain production limitations. The production process of aluminum electrolysis is cryolite alumina molten salt electrolysis in modern aluminum industry. The molten cryolite is a solvent, and the alumina is dissolved in the solute, with carbon as the anode (prebaked anode block) and the aluminum liquid as the cathode. After the direct current, the electrochemical reaction of the two poles of the electrolyzer is carried out at 940 to 970 C, that is, electrolysis. The anode products are mainly carbon dioxide, and carbon monoxide gas, but it contains a certain amount of hydrogen fluoride (HF) and other harmful gas and solid dust. It is necessary to purify the anode gas and remove the harmful gas and dust into the atmosphere. The cathode product is aluminum liquid. The aluminum liquid is pumped out of the trough through a vacuum bag and sent to the foundry. After purification and clarification in the mixing furnace, it is poured into aluminum ingot, or produced into billet, profile and so on. The production process flow chart is like Figure 3-1: aluminum fluoride aluminum fluoride carbon anode DC anode gas aluminum liquid waste gas exhaust back electrolyzer carrying aluminum aluminum ingot alloy and wire billet. The second section of aluminum electrolysis production of raw and auxiliary materials 1. Alumina: alumina is usually called "aluminum oxide". It is a white powder with a melting point of 2050 degrees, a boiling point of 3000 degrees, and a true density of 3. 6g/cm3. It has good mobility, insoluble in water, and can be dissolved in molten cryolite. It is the main raw material in the production of aluminum electrolysis. The role of alumina in the production of electrolysis is: a. Continuously replenish the aluminum ions in the electrolyte, keep the concentration in a certain range, and ensure the continuous production of electrolysis; b. Alumina covered on the electrolyte shell can play a good role in thermal insulation, covering the oxidation of anodic carbon blocks; C. It acts as an adsorbent in the flue gas purification system to adsorb hydrogen fluoride (HF) gas in anode gas. In terms of chemical purity, impurities and water content in alumina are required. Because the oxides of aluminum in alumina, such as SiO2 (silica) and Fe2O3 (iron oxide), will be reduced by aluminum in the electrolysis process, or to the precipitation of aluminum ions in the cathode. The precipitation of silicon, iron, into the aluminum, reduce the grade of aluminum, and those negative to the aluminum oxide, such as Na2O, CaO (calcium oxide) will break down the cryolite, one is to cause the fluoride consumption, two is to increase the hydrogen content in aluminum, the three is the production of hydrogen fluoride gas, polluting the environment. P2O3 (phosphorus pentoxide) affects current efficiency.