UTILISATION OF SMALL INDUSTRIAL SOLID WASTE WELDING WORKSHOPS CARBIDE AS A RAW MATERIAL FOR GYPSUM (CASO4) PRODUCTION

In order to increase the effectiveness of the clean production program in the small carbide welding workshop industry, it is necessary to make efforts to reduce the existence of the waste produced because it pollutes the soil, water and air environment. To minimize the presence of waste, research was carried out by utilizing solid carbide welding waste as a raw material for making gypsum (CaSO4) which is widely used for industrial needs. The implementation is by reacting the waste with various concentrations of H2SO4 solution by adjusting the reaction time and reaction temperature. The results of the initial analysis of carbide welding workshop solid waste in the form of Ca(OH)2 slurry contained relatively high levels of CaO, namely 71.58%. From the results of the research that has been done, it can be concluded that the largest conversion value of 34.98% was obtained by using 12N H2SO4 with a reaction temperature of 50oC and a reaction time of 40 minutes.