Newlox Gold Ventures Corp’s affiliate has reported what it says are “excellent results” from Stage 1 testing of the new Organic Aqua Regia (OAR) gold leaching technology on high-grade gold ore samples.
Newlox Research and Development Corp’s final analysis of the results from Stage 1 testing indicated not only is a gold recovery of 94.68% achieved at ambient temperature, but also a 100% recovery is achieved at 80°C.
The company is investigating the use of OAR technology as a non-toxic and water-free alternative to cyanidation to produce both gold and other precious metals. This will benefit Newlox Gold Ventures Corp’s ambition to recover residual precious metals and contaminants from historical tailings.
Newlox R&D is developing OAR in conjunction with the University of British Columbia in Canada and Chiba University in Japan to leach gold with this reagent, which is both non-toxic and widely used in other industries, according to the company. The main advantages include that it is non-toxic, is recyclable, extracts gold faster than cyanide, does not use water, and does not require carbon or electrowinning.
The company undertook Stage 1 testing on a high-grade gold ore grading an average of 48.87 g/t. The ore was ground in a BICO mill to reach a point where 80% of the material was below a grain size of 0.12 mm (P80 -0.12 mm) before leaching with OAR. Newlox’s research team used the Yates model in 16 experiments to investigate several combinations of reagent dosage and leaching time, it said.
Newlox R&D Corp undertook leaching tests in Vancouver, with the gold dissolution in the OAR calculated based on the gold grade in residues obtained after filtration. A third-party metallurgical laboratory (Global Mineral Resources) in Burnaby, British Columbia, was used to verify the results using aqua regia digestion and Atomic Absorption Spectroscopy (AAS).
The company explained: “The R&D team used the Yates testing protocol to modify various factors during testing and evaluate their effects and relevant interactions. The Yates protocol identified the most significant factors in overall gold recovery. Most encouragingly was the feature that all samples returning over 90% recovery during Stage 1 testing had reagent dosage commonalities, indicating a clear route forward for Stage 2 testing.”
Parallel testing was undertaken at the University of Chiba in Japan on the same ores tested by Newlox R&D in Vancouver. The Japan-based team experimented with alternative reagent additives and different leaching temperatures and found significant effects based on those factors.
Leaching tests undertaken in Japan at 80°C achieved 100% gold recovery in four hours, followed by precipitation of the dissolved gold by adjusting the solution’s pH. The pH control enabled pure gold recovery while concurrently suppressing the precipitation of other elements in the precipitate.
“This promising result indicates that gold may be recovered from the solution without the need for electrowinning,” the company said.
Stage 2 testing is now underway to both reproduce the results seen in Stage 1 testing and further investigate the effect of reagent dosage, time, and temperature on leaching mechanics. Additionally, the R&D team is focused on testing both the recyclability of the OAR reagent, and methods for recovering gold from the solution.
Ryan Jackson, President & CEO of Newlox, said: “We are most encouraged to report that the first round of testing achieved up to 100% gold recovery, using the cutting-edge OAR leaching technology. This initial round of testing forms part of the Newlox R&D 12-month OAR development program.
“We are gratified to realise such early positive results. OAR leaching promises to become a paradigm-shifting technology applicable not only to the $180 billion formal global gold mining industry but also as a method to bring the $27 billion informal gold mining industry into the 21st century.”