Kaushal Kishore, Materials Engineer, Roorkee
For the last 20 years, the use of by products of various origins in the production of concrete has become an increasingly widespread practice in the world. The main advantages are all the elimination of scraps and a reduction in the over exploitation of quarries.
Figure 1: Induction Furnace SlagBlast furnace slag is used in blended cement. Although many studies have been conducted on the evaluation of the electric arc furnace slag to be use in concrete as aggregates replacing natural aggregates, no studies have been performed regarding the use of induction furnace slag in concrete as aggregates replacing natural aggregates.
In making mild steel ingot scrap to sponge iron is fed into the induction furnace which produces large quantity of slag. For example Kotdwar a small town of Uttarakhand Steel Mills induction furnances alone generates 15,000 tonnes of slag per year and about 1,50,000 tonnes of slag is lying in dumps around this city posing an environmental problem. If about 20 steel factories of Kotdwar generate such quantity of slag it can be calculated how much slag is being generated by about 600 induction furnace units of India.
The purpose of this study is to utilize this waste as useful building material, save the steel mills from transport and disposal problems. In place of river sand, alternate sand may be available to builders at cheaper rates. This will prevent over exploitation of quarries and save our environment.
The slag while making mild steel contains iron oxides, silica, alumina, Manganese oxide and Magnesium Oxide. Pollution Control Board of various state has considered slag while making mild steel in induction furnaces as hazardous. The emission from induction furnace include suspended particulate matter, oxides of sulphur, oxides of nitrogen, and CO2 emissions will be more during charging of material to furnace. It could be recommended that slag could be effectively utilized as aggregates in all concrete application. The consumption of slag which is waste generated by steel industry, in concrete not only helps in reducing green house gases but also help in making environmently friendly material.
Figure 2: Slag is Being Crushed in First Crusher, Figure 3: Slag is Being Crushed in the 2nd Crusher & Figure 4: Fine Slag
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