DN

The Direct Nickel (DNi) Process is a hydrometallurgical process for nickel laterite deposits. It is believed to be the only process capable of treating the full laterite profile, from limonitic to saprolitic ores in a single flowsheet. It is a tank leach process that operates at atmospheric pressure, or with the option of mild pressure, and treats the ore at relatively low temperatures. The leach process uses a special reagent package to liberate more than 95% of the nickel, cobalt and other metals into solution. The insoluble residue is neutralised and sent to a waste disposal facility. The solution is then sequentially processed to extract the individual metals. The metal solution processing produces:

1. A marketable mixed hydroxide (or oxide, or sulphide) product containing nickel and cobalt.
2. Co-products Fe2O3, Al2O3 and MgO.
3. A barren solution that is sent to the recycle circuit which recovers +95% of the reagent for reuse.

The high recovery of the reagent package is a unique feature in the DNi Process. Consequently, reagent consumption in the DNi Process is as low as 30kg/t of feed material compared to sulphuric acid leaching processes, which consume 300 to 1000kg/t.

1. Treats whole laterite profile (limonite and saprolite ores) with one flowsheet
2. Extraction of Nickel exceeds 95% and Cobalt 85%
3. Reagent recovery +95%
4. Operates at atmospheric pressure and low temperature, significantly reducing operating costs compared to other existing technologies
5. Comparatively low technology risk, with a much lower operating intensity than HPAL and smelting plants
6. Uses commercially available equipment and standard materials of construction
7. Environmental benefits – reduced tailings, process emissions captured and recycled
8. Low capital threshold to entry- ability to freely scale up from 5 ktpa of Nickel to any size

All steps in the process have been demonstrated at bench scale.