THE EFFECT OF ADDITIVES AND REDUCTORS IN SELECTIVE REDUCTION PROCESS OF LATERITE NICKEL ORE. Selective reduction of laterite nickel ore followed by magnetic separation was carried out to produce ferronickel products. The effect of adding additives and reductor types in the selective reduction process was studied in this study. Reductors used were anthracite coal and palm shell charcoal with variations of 5 to 15% by weight, while the additive used was sodium sulfate (Na2SO4). The reduction process was carried out at temperatures of 950 ºC, 1050 ºC and 1150 ºC for 60 minutes. The addition of 10% sodium sulfate additives by weight in the reduction process of laterite nickel ore produced higher concentrations of nickel as 6.09%, compared to no additives, i.e. 2.45%. The addition of reductors in the selective reduction process of laterite nickel ore shows that the higher the amount of reductors causes a decrease in the concentrate level of nickel. Furhtermore, the type of reductors used shows that the concentrate from the reduction result using anthracite coal reductor produces higher level of nickel and lower level of iron compared to the use of palm shell charcoal reductor.

Conservation of natural enemies on maize can be done by utilizing grass weeds as Beetle banks. Natural enemies of shelter and get food from the weed grasses that are in the land irrigated corn. Natural enemies observed in this research were the predator of ground arthropods in the form of ground beetles, tomcat, and predators arthropods in other lands. The trap used is the Pitfall trap. The percentage of arthropod predators was 69%, and arthropods herbivore was 31%. The abundance of soil arthropods in the treatment of weeds grass is higher than the control treatment It is because of the treatment of weed grass soil arthropods get habitat for a place to stay. Weed grasses provide food sources for the arthropods and get protection from an environment that is less supportive. The use of weed grasses in addition to Beetle banks also serves as a place to breed. The highest abundance of arthropods was situated on the treatment Eleusine indica that has a lush lawn and has a characteristic odor favored by arthropods. Arthropods that acts as a predator in the land are the family of Formicidae, Philodromidae, Carabidae, Staphylinidae, Pentatomidae. Some Arthropods from the Pentomidae family have a role as a pest and others as natural predators or predators. Arthropods found in the research was an arthropod that had a role as natural enemies or predator. The Pentomidae family that has a position as a predator is Picromerus Bidens. Ground beetles were found in the C. fossor and Pheropsophus sp. Ground beetles are dominant picking weeds Setaria sp. and Eleusine indica as habitat and place in search of food and life’s survival. Keywords: Beetle bank, soil arthropods, weeds.

A two-stage thermal upgrading process with the addition of 10 wt.% sodium sulfate and sodium chloride followed by magnetic separation was conducted for treatment low-grade nickeliferous laterite ore to produce a ferronickel product. The aim of this experiment was to investigate the effect of reduction temperature and holding time in two-stage thermal upgrading process, which was carried out from 950°C to 1150°C for 30 to 90 minutes, into the grade and recovery of nickel also the morphology of ferronickel particle. A wet magnetic separation with 500 gauss magnet was conducted to produce ferronickel in concentrate. Increasing the reduction temperature of nickel laterite increased the nickel grade and recovery. The nickel grade and recovery also increased along with the longer holding time in the reduction process. Nevertheless, it decreased the iron recovery.

A low-grade nickel laterite ore from Indonesia was selected to investigate the effect of temperature and time of reduction upon the extraction of nickel through the selective reduction-magnetic separation process to produce the ferronickel. The nickel ore was mixed with5 wt.% of anthracite coal and 10 wt.% of sodium sulfate additive. The mixed ore was pelletized into 10-15 mm of diameter. A series of selective reduction processes were carried out into the pellet ores at various temperatures of 950-1150 °C for 60-120 minutes. The optimal selective reduction parameters of nickel laterite ore were observed clearly. The experimental results indicated that the reduction reactions proceed more completely at a higher temperature and longer reduction time. The optimum of nickel grade and recovery in the ferronickel concentrate was obtained at the reduction temperature of 1150 °C for 120 minutes, which was 8.45% and 72.1%, respectively. The increasing of temperatures and times of reduction process resulted in higher of troilite phase formation which suppressed the iron metallization and also increased the ferronickel particle size.