DNi Process™
The future of nickel laterite processing
High-grade nickel laterite ore will be imported from New Caledonia for processing at the TECH facility using a patented recovery and recycling process called the DNi Process™. The DNi Process™ is owned by the Altilium Group. Queensland Pacific Metals has obtained the rights to use the DNi™ process from Altilium. You can find more information about Altilium on its website (Altilium Group).
The DNi Process™ is an environmentally friendly process for extracting nickel, cobalt and other precious metals from laterite ore that ensures the sustainability of natural resources. Key features of the DNi Process™ include >98% nitric acid recycling, no tailings dam requirements and minimal waste.
CSIRO DNi Process™ Pilot Plant in Perth
OUR EXTRACTION PROCESS
The Ore Preparation process starts by drying ore to 1.0% moisture and milling oversized material to a D100 of 300 microns. 10-15% of the ore is milled based on particle size distribution.
The Extraction Plant uses the DNi Process™ to leach ore using recycled nitric acid, which results in high metal recoveries and low acid consumption. The leached ore then undergoes iron and aluminum hydrolysis to precipitate iron as high-grade hematite, which is filtered, agglomerated and pelletized for sale to steel manufacturers. Our process also includes steps for strong and weak acid regeneration, hydroxide precipitation, barren evaporation, thermal decomposition, and sulfate refinement to produce battery-grade nickel and cobalt sulfate.
The sulfate refinery process includes sulfuric acid releach, aluminum removal, impurity solvent extraction, cobalt and nickel solvent extraction, and ammonium sulfate crystallization.
DNi™ Process advantage over traditional High Pressure Acid Leach (HPAL)
Historically, nickel laterite ores are processed by High Pressure Acid Leach (HPAL). HPAL operations use sulphuric acid leach under high temperature and pressure conditions. This creates environmental concerns due to the requirement of tailings dams and, in some cases, the dumping of tailings into the ocean. HPAL operations are characterised by high capital cost, long construction time due to exotic construction materials required, poor performance and failure to reach nameplate capacity.
The DNi process is able to extract ALL valuable metals from the laterite ore as opposed to HPAL which leave some value unrealised.
- The TECH project recycles all process liquids. Additionally, >98% of the nitric acid is recycled. This is a major contrast to HPAL plants (for example), which either dispose of effluents to the ocean (either treated or untreated) or are evaporated from tailings impoundment.
- The DNi Process™ leaches almost all of the ore feed, with leach residue consisting mostly of quartz and precipitated silica. This residue amounts to ~0.25 t residue/t ore and is inert. This contrasts with HPAL which has a residue footprint of 1.2 – 1.4 t residue/t ore, leading to large and expensive tailings dams or even more expensive tailings filtration and dry stacking. On this comparison, the TECH project is already world-leading. However, testwork undertaken by James Cook University indicates this inert residue can be utilised as engineered fill leading to true zero solids waste.
- In addition, the DNi™ process enjoys a shorter construction time as stainless steel can be used in plant construction.