STUDY ON MECHANISM OF FORMING IRON NUGGET DURING THE REDUCTION PROCESS OF COAL-IRON SAND COMPOSITE BRIQUETTE WITH ADDITION OF CAO AND NACL USING ISOTHERMAL-GRADIENT TEMPERATURE

• Main Author: WIDIASTUTI, EKA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/26883
• Institution: Institut Teknologi Bandung

<p align="justify">Iron sand generally consist of dominant element are iron and titanium. Reduction of iron sand with carbon used blast furnace (BF) causes the formation of Ti (C, N) compounds that cause problems in the tapping process. The problem was stimulated the development of appropriate technology to process iron sand. One of technology that used was Ironmaking Technolgy Mark Three (ITmk3) which utilizes direct reduction process using Rotary Hearth Furnace (RHF) to produce Pig Iron Nugget (PIN). The quality of the nuggets is determined by the mechanism the reduction. Therefore, this research was conducted to study the mechanism of nugget formation. <br /> <br /> <br /> The experiments was conducted the initial identification of iron sand concentrate by the characterization method of X-ray diffraction (XRD) and X-ray Flourescence (XRF). Afterward, sample was dried. Then, iron sand concentrate was mixed with coal, CaO and NaCl and agglomerated into briquettes. The obtained briquettes were reduced using the isothermal-gradient method of the temperature of 1000 ° C - 1400 ° C with the parameters varied were the final isothermic temperature, heating rate and the holding time at the final isothermal temperature. The final temperature varied i.e. 1300° C, 1320° C, 1340° C, 1360° C, 1380° C, and 1400° C. The heating rate varied i.e. 6.67°C/min, 7.75°C/min, 8.83°C/min, 9.42°C/min, and 10°C/min. The holding time were varied 47 minutes, 53 minutes, 56 minutes, and 59 minutes. The result of reduction were analyzed by OM, SEM / EDS, X-ray mapping and XRD. <br /> <br /> <br /> Mechanism of nugget formation was occured in several stages include reduction processes, carburization, reacting fluxs with impurity oxide, nucleating and coalesence metal and separation processes between slag and metal. Based on the results was obtained the iron nugget only formed at the final isothermal temperature of 1380°C and 1400°C with the recovery of each metal were 64% and 78%. Nugget recovery at the heating rate variation were 67%, 50%, 43%, 36%, and 28%. Nugget recovery at the variation holding time in the final isothermal were 28%, 21%, 18%, and 12%. <p align="justify">