Hydro-Metallurgical Extraction (HME)

Electronic waste and other heterogeneous metalliferous waste streams are continually increasing in volume over the years. In the process/remediation sector, highly toxic and dangerous practices are being employed in the developed and developing world to simply extract high value commodities (primarily gold) from these streams.

To combat the proliferation of toxic and unsafe practices in the processing and remediation sector, in April 2015, BlueStem commenced research and development for the Hydro-Metallurgical Extraction (HME) project. We desired a process to extract gold and precious metals from heterogeneous waste streams in a cost-effective and environmentally sustainable manner. As a result of our endeavours over the years, the HME process now has the following performance metrics:

• Uses non-toxic liquors, instead of the highly hazardous and toxic cyanide (the world’s gold recovery standard) and Aqua Regia liquors.

• Uses a unique precipitation agent which is capable of achieving precious metal recovery rates of 99.85%.

• Uses a closed-loop regenerative process to reduce chemical consumption and it's associated costs.

• Employs machine-learning methods to maximise precious metal yields while minimising reagent consumption.

• The HME operating costs are significantly lower than current techniques (35% less than cyanidation or any other technique).

• The capital expenditures required to build a HME plant are considerably lower than anything else used in industry (450% less than cyanidation).