Slag alkali recovery is the process of recovering alkali from slag left over from the manufacture of pig iron. Alkali recovery from slag has been practiced for centuries and has been of major commercial importance in Europe for nearly two hundred years.
The most common alkali recovery operations in the iron and steel industry use the soda ash process. In this process, slag is melted with soda ash and heated in a furnace to separate alkali from the slag. The resulting products are a high-purity alkali and slag with a high limestone content. The alkali produced is generally free of undesirable elements such as lead and chlorine, and can be used in a variety of ways, such as fertilizer, animal feed and in the manufacture of glass.
Another process used in some plants is the Kupang process. In this process, the slag is heated to a high temperature and pressure. The oxygen and sulfur content of the slag is removed during this process, leaving behind a slag with a high alkali content. The kupang process yields a black powder, which is then heated to release the alkali. The powder is then mixed with water or other liquid, depending on the desired use.
In the past few years, some research has been conducted on the recovery of alkali from slag via leaching. The process involves breaking down the slag into smaller particles so that the alkali can be leached from the slag. This process can be used to recover alkali from waste slag that cannot be processed by other methods.
Slag alkali recovery can also be done by treating the slag with certain chemicals. These chemicals dissolve the alkali in the slag, allowing it to be recovered. This process is often used for slag that has been in contact with metals such as lead, zinc or nickel.
Slag alkali recovery is important in the iron and steel industry because it can reduce the amount of waste produced during the manufacture of pig iron. In addition, recovered alkali can be used in other applications, such as fertilizer and glass production. Finally, recovering alkali from slag helps conserve natural resources, as it reduces the need for mining and processing raw materials.
