Dow process refers to a particular method of manufacturing aluminum that involves the extraction of aluminum from its oxide, known as alumina. Named after its inventor, Charles Martin Hall, and his commercial partner, the Dow Chemical Company, the Dow process revolutionized the aluminum production industry.
The process starts with the extraction of alumina from bauxite ore, which is the primary source of aluminum. First, the ore is heated to remove excess water and impurities, leaving behind impure alumina. This alumina is then refined, resulting in a high-purity white powder known as aluminum oxide or alumina.
To utilize the Dow process, the alumina is mixed with a molten fluoride salt, such as cryolite, to lower its melting point. The mixture is then placed in an electrolysis cell, where a powerful electric current is passed through it. This causes the aluminum oxide to dissolve and break down into aluminum and oxygen ions.
Due to the electric current, the aluminum ions are attracted to the cathode, a negatively charged electrode, where they combine to form molten aluminum metal. At the same time, the oxygen ions are attracted to the anode, a positively charged electrode, where they react with carbon to produce carbon dioxide gas.
The molten aluminum metal is collected at the bottom of the cell and periodically drained off, ready to be used in various industries such as automotive, aerospace, and packaging. The Dow process enables the production of aluminum on a large scale and has significantly contributed to the growth of the aluminum industry worldwide.
