Upper slag and lower slag
Slag is a by-product of metal smelting and is also known as “purifying slag”. It is produced when smelting is completed and used to improve the quality of the product. Slag is divided into upper slag and lower slag, and each has different properties and uses.
Upper slag is formed mainly through oxidation of iron and other elements near the furnace hearth. It has a high temperature when it is flowing out and reacts almost flexibly with its environment. The color of upper slag varies, it may be brownish black, dark yellow, or even brown. Its particle size is generally determined by the depth of its reaction with the furnace bottom atmosphere. As a result, it has a medium or coarse particle size and is mainly used for filtration and deoxidation.
Lower slag is formed at the top of the slag, where there is less oxygen and a less severe reaction with the furnace heat. Therefore, it has a lower temperature than the upper slag and is less reactive to its environment. It usually has a green, blue, or black color. Lower slag is mostly fine grained and contains a certain amount of metal liquid, so it can be used as raw material for other products.
In the processing of iron and steel, the upper slag and lower slag are both important components. The upper slag can improve the quality of the product by removing impurities and metals contaminants, while the lower slag can provide raw materials for other products. Therefore, the accurate and economical control of upper slag and lower slag is an important part of the iron and steel production process. Appropriate measures should be applied to detect and control the specific elements of the slag, in order to obtain the desired results from the slag and make the production process more efficient.
