Development of atmospheric leaching method for selective nickel-cobalt recovery from Gördes lateritic ores

Abstract

In recent days, studies on battery technology, which has a very popular place and is developing rapidly, continue intensively. Nickel, which is one of the important raw materials of batteries and whose fields of use are expanding gradually thanks to its physical and chemical properties, is widely used in the production of alloys with various metals, turbine production, battery, paint additive and catalyst production. There are approximately 140 million tons of nickel reserves and 7 million tons of cobalt reserves in the world, 60% of which are lateritic and 40% are sulphides. Although the reserve amount is higher, 42% of the nickel production is made of lateritic 58% of the sulphide ores. However, due to the decrease in the amount of sulphide ores over time, studies on developing technically and economically suitable production methods from lateritic ores have been intensified. Industrially, nickel and cobalt are recovered from lateritic ores by pressurized acid leaching. Atmospheric leaching is both cheaper and safer than the pressure leaching method if long leaching time, high acid consumption and selectivity can be solved. In this study, leaching behavior of Gördes lateritic ore mixture of 70% limonite and 30% non-tronite with both sulfuric acid and phosphoric acid was investigated in atmospheric conditions. Selectivity was provided against nickel and cobalt both by pre-heat treatment to the ore and step leaching process. With the using phosphoric acid, passing through the liquid efficiency of iron was reduced by about 80% compared to using sulfuric acid. Nickel and cobalt yields also obtained in high pressure acid leaching were achieved by sequential leaching and leaching of leaching solids.