The utilization of carbonized coffee in purifying zinc dross waste by pyrometallurgy method

Abstract

The purification of zinc oxide has been carried out from zinc dross waste by pyrometallurgy method. The amount of zinc dross waste was cleansed by using aqua DM liquid with ratio of 1:10, then this amount was characterized using XRF to determine chemical compounds contained within the 90% of zinc dross waste, while impurity compositions of Fe, Al, and Mg were found. Hence, the amount of zinc dross waste was mixed to carbonized coffee within two ratios, i.e. 87.5%wt: 12.5%wt, and 75%wt: 25%wt. Carbonized coffee is obtained from carbonization of coffee grounds waste from the coffee industry. The mixture samples were then dissolved by aqua DM, followed by milling treatment by performing Planetary Bill Mill for 40 min, so that the muddy-phase were obtained. This sample was then filtered and it was heated inside an oven at 100 °C for 24 h to powder. The mixture powder of zinc dross and carbon was then placed in pyrolysis vessel at 1200 °C for 2.5 h. The obtained amount of zinc oxide powder was characterized by using XRF, and this has 98% of purity with impurities element i.e. Al2O3, Fe2O3, MgO, and SiO2. Thermal testing was performed for ZnO sample by using DT instrument to investigate the effect heating to the reaction events. The analysis of DTA showed that the mixture sample of zinc dross and carbon had reaction sequences at 800 °C. The morphological analysis conducted by SEM and OM depicted that ZnO has agglomeration characteristics with uniformity shape among particles. The size of the particles is between 1900 μm and 9378 μm.