KINETIC STUDY AND PRODUCT CHARACTERIZATION OF FERRONICKEL SLAG GRINDING WITH VARIATION OF BALL FILLING AND RATIO OF FEED AND GRINDING BALL

• Main Author: Ikhwanto, Muhammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/64769
• Institution: Institut Teknologi Bandung

At ferronickel (FeNi) smelting process, waste of the process (namely slag) will be produced in large amount. Until recently, some researches have been performed in utilizing the MgO content in the FeNi slag. These researches mainly were focused on grinding-leaching and grinding-reverse flotation processes, and the others were mixtures of FeNi slag grinding product, bauxite and limestone as raw material to produce a high alumina cement (HAC). The same process of these three studies is a grinding process as an initial stage of the research. In this research, experiments have been done to determine the effect of variables such as ball filling and ratio of feed and grinding ball on the size of grinding products, the kinetics of FeNi slag grinding process, and the characteristics of the grinding products. The FeNi slag samples were firstly characterized by sieving, mineragraphy, XRD and XRF analyses, respectively. After characterization, the samples were crushed by a roll crusher to produce <3 mesh product. This product, after sampling and sample dividing processes, was then used as feed for grinding. The grinding was performed with variations of grinding ball filling and ratio of feed and grinding ball for 150 minutes. At every certain time interval, particle size analysis was carried out on the grinding product. The results of the experiments were also used to develop linear regression model of the effect of grinding variables on P80 of the product. Besides, mineragraphy analysis on the grinding product was also studied. Based on this study, it was shown that the size of grinding products was decreased as the grinding time was increased. P80 values of the grinding products declined sharply until 70 minutes of grinding time due to the dominant mechanism of impact breakage and then decreased slowly after 70 minutes until 150 minutes of grinding time due to dominant mechanism of attrition breakage. Kinetics study of the grinding process on variations of grinding ball filling showed that the optimum rate of formation of fine particles for 20%, 30%, 40% and 50% mill volume was achieved at a particle size of 400 ?m in which the best initial rate of formation occured in 50% volume of mill. Kinetics study on variations of ratio of feed and grinding ball showed that the optimum rate of grinding for the ratio of 1:10, 1: 8 and 1: 6 was achieved at a particle size of 400 ?m and for the ratio of 1: 4 was at 841 ?m in which the best initial rate of formation occurred at a 1:10 ratio. In this study, it was also produced two regression models that can predict the P80 value of the grinding product as a function of the variables of grinding time, ball filling and the ratio of the feed and grinding ball. Based on the analysis of mineragraphy on the grinding products, it was shown that silicate compounds start to be relatively liberated at the size of -40 +60 mesh (-400 m +250 ?m).