Unlock tomorrow's metals
with Glycine Leaching Technology

Glycine leaching is low cost because the main reagent, Glycine, is chemically regenerated. Glycine is reacted with a solution of sodium hydroxide to provide sodium glycinate as the major reagent. This has a natural pH value of around 11 to 12. For example, when the copper mineral malachite is put into solution, the released copper is chelated onto the glycine, with each copper molecule sequestering 2 molecules of glycine. This releases Sodium (Na) from the glycine that is then paired with the carbonate ion and hydroxide ions from the malachite. Glycine is completely regenerated when the stripped solution is reacted with lime or calcium hydroxide. This precipitates all of the carbonate and sulphate (from the oxidation of sulphides), and regenerates the caustic which then pairs with the glycine again. Thus it is in a locked cycle, not being consumed. The loss is limited to the glycine that is not physically recovered from the tailings and this will be low.

As a rule of thumb, if it is economical to recover precious and base metals using traditiona leaching methods, then it will most likely also be economical for GLT.  However, we could potentially lower the head grade compared to cyanidation because the GlyCat^™ requires less reagent and incurs lower costs compared to cyanidation, even factoring in the cost of glycine.  This is particularly true with ores that contain copper, where considerably more cyanide is needed to leach the gold.  In this case, the cyanide savings are significant.

The short answer is no. Glycine is added to the process water, so if it is used in flotation then it will be present during flotation.  Our tests have demonstrated that glycine will improve the selectivity and “floatability” of metal sulfides where metal selectivity is achieved through pH.  We have observed the use of glycine to clean the sulfide surface to improve flotation.