COMPARISON STUDY ON MELTABILITY OF REDUCTION PRODUCT OF IRON SAND CONCENTRATE WITH ISOTHERMAL AND ISOTHERMAL-TEMPERATURE GRADIENT METHOD

• Main Author: AMRI FIRDAUS - Nim: 12514006 , MUHAMMAD
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/29120
• Institution: Institut Teknologi Bandung

<p align="justify">Direct reduction process usage to produce sponge iron and nugget increases. This phenomenon is caused by high-quality scrap supply shortage and its increasing price every year. Steel scrap price has increased by 78% from final quarter of 2015 to mid-year of 2018. In steelmaking industry, the melting process of sponge iron and scrap can be done using electric arc furnace and induction furnace. However, the melting process of sponge iron requires a lot more time compared to scrap so that the energy requirement for the process increases. Therefore, there are needs to initiate an observation to study the reduction method to produce sponge iron and nugget with best meltability among the others. <br /> <br /> Iron sand concentrate briquettes with composite (mixed with coal) and noncomposite (unmixed with coal) variations within the coal bed were reduced using muffle furnace with different reduction method of isothermal and isothermaltemperature gradient. In isothermal method, reduction was carried out at 1300°C for 120 minutes. In isothermal-temperature gradient method, reduction process was done in three stages. In first stage, briquette was reduced at 1000°C for 40 minutes, then the temperature was raised to 1380°C with 6,67°C/minutes gradient for 57 minutes, and lastly it was hold at 1380°C for 40 minutes. Briquette and nugget then were melted using induction furnace with operation current of 300 A. The melting process was recorded using handycam Sony HDR-XR160. The melting process was also done in muffle furnace at 1550°C for 20 minutes. Melting products were analyzed with SEM-EDS to determine the chemical composition of metal and slag. <br /> <br /> Nugget from isothermal-temperature gradient (composite) method had the best meltability with average total melting time of 4 minutes 50 seconds, followed by briquette from isothermal-temperature-gradient method with 18 minutes 51 seconds, and briquette from isothermal method with 20 minutes 29 seconds. In briquette of isothermal method reduction product, the melting process is initialized by the formation of molten metal drops at the briquette surface. In briquette of isothermaltemperature gradient (non-composite) method reduction product, the melting process is initialized by the formation of molten metal area at the cracks on briquette surface. Nugget melts progressively until it melts completely. The metal zone in the melting product is composed of >99% Fe and <1% Si. Slag zone is composed by MgO, Al2O3, and TiO2.<p align="justify">