Draslovka's patented Glycine Leaching Technology (GLT) addresses many of the challenges currently faced by the mining industry. GLT helps mines extract metals in a way that is safer, more environmentally friendly and more cost effective than any other process available today. Our solutions assist in extending the life of your assets, reducing cut-off grades, and enabling recovery from tailings.
GLT is the most cost-effective and environmentally sustainable way to produce precious metals and critical minerals. Glycine is a cost effective and non-toxic amino acid that is fully bio-degradable. As an environmentally friendly and stable reagent, glycine is easily metabolized by living organisms and plants. In fact, it is used as a food additive for both humans and animals.
Glycine is unique in its ability to selectively leach certain base and precious metals. It isn't chemically consumed, so it's recoverable and recyclable – providing a major cost advantage. This patented technology from Draslovka enables our clients to achieve their goals while minimizing their environmental impact.
Partner with the recovery innovation experts as you journey towards sustainable mining.
Reduces processing costs
Reduces cyanide consumption
Improves ESG footprint
GlyCat™ enables an average reduction in processing costs of 25%. It also provides significant ESG benefits by replacing the majority of cyanide with a non-toxic, biodegradable reagent called Glycine which is commonly used as a food additive.
With GlyLeach™, production is significantly improved by replacing acid with a non-toxic, food-grade reagent. This unlocks significant new production from previously unviable deposits.
Glycine is a totally non-toxic chemical that is fully bio-degradable. It is used as a feed supplement in animals and is even used therapeutically to reduce inflammation in humans. It is a slightly sweet tasting crystalline solid that looks like sugar.
Glycine is a readily available chemical that is manufactured in large quantities in the USA, Germany, Japan, China, and India. It is manufactured by combining chloroacetic acid and ammonia and is mainly used in producing herbicides, food supplements, and nutrients. Prices vary between manufacturers, but it is generally cheaper than cyanide and readily available from at least 20 different manufacturers.
Glycine can leach most of the nonferrous transition base metals, specifically copper, but also nickel, cobalt and zinc. It is also capable of leaching precious metals under certain conditions - gold, silver, some of the platinum group metals, and finally lead under special circumstances. Various minerals leach at varying speeds and different chemical conditions. As an example, all copper minerals except silicates and copper that is chemically bound within iron oxides are leached by glycine. Leaching takes place at pH values between approximately 8 and 12.5, with the higher pH values being used to leach the sulphides and in particular chalcopyrite. This supplies the base needed to fix the Fe that is leached from this mineral. In contrast to acid leaching, Fe, Mn, Ca, Mg and many other elements are simply not put into solution. There is no soluble unfixed Fe to deal with, or difficult solids like jarosite to dispose of.
Glycine leaching is low cost because the main reagent, Glycine, is chemically regenerated.
Glycine (a dry, harmless powder) 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 wholly 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.
Cupric glycinate solution can be treated in a number of ways. First, it can be contacted with a conventional copper SX reagent such as LIX64 or other series to replace the copper with hydrogen ions that have been charged into the solvent. The loaded solvent is then stripped of the copper with a high acid spent electrolyte. This is then sent to the Electrowinning, where the copper is plated as commercial LME Copper cathode, and the anode acid added back into the solution preparing it to strip solvent again. There is no need to purchase an outside source of acid unless impurities demand a bleed from the electrolyte circuit.
Where SX is not available, one could use precipitation or ion exchange. Chelating ion exchange resins will extract cupric copper from solution releasing the glycine for further leaching. The loaded resin is stripped the same as SX where it can be electrowon or alternatively, the cupric glycinate in solution can be precipitated using NaHS or even Na2S as a high purity CuS product that can then be sold to a smelter in the normal manner.