Kinds of Wastes Occurring in Steel Industry and Present Condition of Their Disposal

Abstract

Steel industry is making great efforts to recycle the wastes which occur in various stages of iron and steel production with success of high recycling rates. Slags account for major portion of the wastes, about 90%, followed by dust, 9%, and sludge and others, 1%. More than 90% of the slags is used as raw material of ce-ment and aggregates for road building, and especially it can be said the blast furnace slag is recycled 100%. The dust is overwhelmingly of iron oxide and, after treated in sintering process or pelletizing process, is recharged into blast furnaces. The rate of its recycling is more than 90%. Wasted acid resulting from cleaning surface of steel and containing iron is treated to recover iron, which is recycled and used as raw mate-rial for ferrite and pigment, and also recover acid.
Thus the recycling of wastes occurring in the steel industry is being made at high rates, but the total volume of the wastes is considerable, about 40 million tons a year, and the volume of wastes to be disposed finally cannot be said small. So, there are problems such as finding sites for their disposal such as reclamation and land filling.