CSIRO researchers, working through the Parker CRC for Integrated Hydrometallurgy Solutions, are helping high-pressure acid leaching (HPAL) operations to increase production from low-grade nickel laterite ores by modifying the slurries processed so they flow more freely through their plant.
The group says that reducing the slurry viscosity allows operators to pump a higher density through the autoclaves at the centre of the HPAL process, says Senior Research Scientist Dr Goutam Das.
Das says this gives a higher nickel input into the autoclave and a higher nickel production.
In an ongoing study of nickel laterite slurries being conducted through the Minerals Down Under Flagship, researchers have identified a number of steps that industry can take to achieve this.
Das says the quality of process water is an important factor in determining the viscosity of the ore slurry. He says that if the plant is using salt water, then viscosity will be low, but if it is a freshwater plant then the viscosity is higher. This is why blending is very important.
The team’s studies showed a plant processing fine particle smectite ore could increase the pulp density and nickel feeding to its autoclave by seven to ten per cent by weight by using saline water for the ore slurry and blending it with coarser quartz or iron oxide minerals.
Das says every one per cent increase in slurry density would translate into nickel production gains of about two per cent.
Das says gaining even one per cent in production through such measures equates to a significant result on the bottom line.
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