STUDY OF THE UTILIZATION OF FERRONICKEL SMELTING SLAG AS RAW MATERIAL FOR FERROSILICON-CHROMIUM AND MAGNESIUM PRODUCTION

• Main Author: AGUSTINA - Nim: 12514055 , NURDEDANI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/29775
• Institution: Institut Teknologi Bandung

<p align="justify">In Indonesia, slag is categorized as hazardous waste by The Indonesian Government based on government regulation of the Republic of Indonesia number 101 of 2014. Ferronickel smelting slag highly contains element such as silicon, magnesium and iron, so that ferronickel smelting slag has potential as a raw material for extract these three elements. Based on Factsage calculation, ferrosilicon-chromium and magnesium can be produced by reduces ferronickel slag by carbothermic reaction at temperature 1400°C under vacuum environment. <br /> <br /> <br /> A series of experiment were conducted to investigate the effect of the addition of graphite and vacuum or argon environment towards final product of carbothermic reduction of ferronickel slag. A set of experiment starts with a preparation and the initial characterization of ferronickel smelting slag. Experiment is carried out by mixing ferronickel slag and graphite and stirred before placed on graphite crucible. Then, mixed of ferronickel slag and graphite were reduces in tube vacuum furnace at temperature 1500°C and 1550°C under vacuum environment at -0,1 MPa or argon environment with a flow rate of 1 liter/min. After that, final product was analyzed using SEM-EDS to investigate composition and spreading of elements in selected area. XRD analysis were conducted to identify phase which are formed in the final products. <br /> <br /> <br /> The results showed that the process of carbothermic reduction of ferronickel slag can produces ferrosilicon-chromium. However, magnesium metal is not formed because magnesium vapor, which are formed in these experiments, reacts with CO gas and formed MgO and carbon. Vacuum or argon environments did not have a significant impact on the physical appearances and element composition in final products, while the effect of varying graphite in addition have a significant impact on the physical appearances and element composition in final products. Graphite addition using ratio C/O=0,5 shows optimal results by forming metal on matrix and on the outside of matrix. Reduction process at temperature of 1500°C, ferrosiliconchromium with composition 68,48%, Si 13,21% dan Cr 15,56% is formed and in temperature of 1550°C ferrosilicon-chromium with composition Fe 67,10%, Si 21,77% dan Cr 10,27% is formed.<p align="justify"> <br />