Experimental Research On Wet Treatment Of Steel Slag

Steel slag is main solid waste discharged during steelmaking progress. And it is not only production is big, but also chemical composition is very complex. Meanwhile, there are many phases in steel slag, such as calcium oxide, tricalcium silicate, dicalcium silicate and so on, which can decrease the chemical stability and restrict the application fields of steel slag. Because the utilization ratio of steel slag is low in China at present, effective comprehensive utilization steel slag has signify practical significance for the development of steel industry.In the present study, the steel slag of a certain enterprise in China as raw materials, the effects of the technological parameters of the addition of additive, reaction temperature and time, and the grain size of steel slag on the leaching behavior of calcium, magnesium and aluminum of steel slag were systemically investigated by the combined technology of wet leaching and permanent magnetic separation. The results not only can eliminate the unstability of steel slag, but also can improve the utilization ratio of steel slag, which has guidance and reference significance for the resource of solid waste in our country. In the present study, the conclusions are as fllows:(1) By the wet treatment process, free calcium oxide, calcium hydroxide, tricalcium silicate and dicalcium silicate almost disappear and form calcium silicate, which can resolve the unstability of steel slag and the mass of steel slag can decrease by above23%.(2) After magnetic separation of leaching steel slag, the content of iron in magnetic substance is above29%, the yielding rate of iron is above29%, and the content of iron in tailings is less than5%. The mass percent of tailings with magnetic separation is40%of steel slag.(3) With increasing of reaction temperature and time, the leaching rate of calcium, magnesium and aluminum and the weight loss rate of steel slag are all increased. In addition, the free calcium oxide, calcium hydroxide and tricalcium silicate of steel slag almost disappear.(4) With increasing of reaction temperature and addition of additive and decreasing of grain size and liquid-solid ratio, the content of iron in magnetic substance, the yielding rate of iron and the weight loss rate of tailings all increase.(5) With increasing of reaction time, the content of iron in magnetic substance and the yielding rate of iron increase, but the weight loss rate of tailings and steel slag is increased at first and then decreased.