Direct Reduction of Limonitic Laterite Nickel Ore with Variation Type of Reducing Agents to Fe, Ni Content and Recovery by Using Coal-Dolomit Bed Method

The increasing demand for stainless steel and the scarcity of sulfide nickel ore affect the increase of laterite nickel ore processing. One of the processes that has been proven can be applied to process laterite nickel ore is direct reduction. In the direct reduction, the reduction atmosphere was adjusted by controlling the volume of CO and CO2 from carbon source materials, such as coal, charcoal, and green cokes. This research aims to analyze the effect of reducing agents type on nickel limonitic nickel briquettes on Ni and Fe content and recovery of Ni and Fe. The direct reduction process was conducted at 1400°C for six hours. The EDX test was conducted to analyze the elemental composition of the product, especially for Ni and Fe content. On the other hand, the XRD can be applied to analyze the compound formed in the product Greencoke will produce the highest Ni content (15.23%). The highest Ni recovery (96%) was obtained by the addition of green coke reducing agent. On the other hand, the highest Fe recovery (18.8%) was obtained by the addition of coal reducing agent.

Development of a Novel Shaft Dryer for Coal-Based Green Needle Coke Drying Process

The industry of coal-based green needle coke develops rapidly in recent years. The green coke produced by the delayed coking process usually has a moisture content of 10%–25%, which damages the calcining kiln and needle coke quality. A standing dehydration tank is currently used to reduce the moisture content of green coke. However, this process has several weaknesses such as unstable operation, large land area occupation, and low productivity. To solve this issue, a novel drying system with a shaft dryer proposed in this work is suitable for green coke drying. Moreover, the performances of the green coke are investigated to design the proposed shaft dryer. The experimental result shows that the average vertex angle of the pile of green cokes is 109.2°. The pressure drop of the dryer increases linearly with the green coke bed height, and the green coke with a larger size has a smaller pressure drop. The specific pressure drops are 5714, 5554, 5354, and 5114 Pa/m, with median green coke sizes of 26.85, 29.00, 30.45, and 31.80 mm, respectively. Tooth spacing is another important parameter which influences the mass of green coke leakage. The optimal tooth spacing and rotary speed of the rollers are determined by the required production yield.

PENGARUH SUHU DAN WAKTU AKTIVASI TERHADAP KAPASITAS ADSORPSI KOKAS MINYAK BUMI

ABSTRACT The effect of activation temperature and duration on the activity of petroleum coke has been investigated. A mixture of green coke and KOH (1:1) was heated in an oven furnace at 450°C for 1 h, then continued to activation process at 450-900°C for 1-3 h. The product mixture was immersed in a solution of 10% H2SO4 before being washed with deionized water to neutral pH. After being dried, activated cokes were tested with a solution of phenol, 4-nitrophenol, 2,4-dinitrophenol or methylen blue. Experimental data showed that the activity of coke imcreased with temperature and time. The effective condition of the activation process is at temperatures higher than 750°C and activation time of longer than 1,5 h. Adsorptive behavior of phenolics dan metylene blue onto activated coke agreed with Langmuir rather than with Freundlich isotherm. Keywords: temperature effect, activation time, petroleum coke, adsorption capacity, phenolics, methylen blue.