Electrolytic aluminum is aluminum obtained by electrolysis, it is used for extraction of aluminium from alumina. The modern electrolytic aluminum industry uses cryolite-alumina molten salt electrolysis. Molten cryolite is a solvent, alumina is used as a solute, carbon is used as an anode, and aluminum liquid is used as a cathode. After the powerful direct current is applied, the electrochemical reaction is carried out on the two electrodes in the electrolytic cell at 950°C-970°C.
Aluminum is produced by electrolysis in industry. The aluminum electrolysis industrial production adopts Hall-Heroult process. The cryolite-based fluoride salt is used as the flux, and the alumina is the melt to form the multiphase electrolyte system.
Aluminum Extraction Process
The reduction unit of an aluminum plant consists of reduction pots or cells which are connected in series. Each pot is made of a steel shell lined with carbon.
Molten cryolite (a fluoride mineral) containing aluminum oxide is poured into each pot and carbon electrodes are inserted into the solution from the top.
As the current passes through the cryolite solution, aluminum separates from oxygen, forming carbon dioxide gas. Liquid aluminum collects at the bottom of the pot.
Liquid alumina is then sucked from the reduction pots at regular intervals into vacuum buckets. This is transferred into a furnace and cast into ingots in molds, or by a continuous casting machine. AdTech offers hot top casting parts (Distributing Launder, Ceramic Sprue Bush, Hot Top Casting Cap), aluminum liquid flow control products (Alumina Porcelain Rod, Refractory Fiber Cone ) for continuous casting. Aluminum produced through this process is approximately 99.8% pure.
Extraction of Aluminium from Alumina
Aluminum electrolysis process: Cryolite-alumina molten salt electrolysis is used in modern aluminum industry production. The chemical reaction mainly proceeds through this equation: 2Al2O3+3C==4Al+ 3CO2↑. Anode: 2O2ˉ+C-4eˉ=CO2↑ Cathode: Al3++3eˉ=Al.
The anode products are mainly carbon dioxide and carbon monoxide gas, which contains a certain amount of harmful gases such as hydrogen fluoride and solid dust. In order to protect the environment and human health, the anode gas needs to be purified, and harmful gases and dust should be removed and discharged into the atmosphere.
The cathode product is aluminum liquid. The aluminum liquid is drawn from the tank by vacuum bag lifting and sent to the casting workshop. After being purified and clarified in the holding furnace, it cast into aluminum ingots or directly processed into wire billets.