INNOVATIONS IN WEEE RECYCLING Screening of Non-cyanide Leaching Reagents for Gold Recovery from Waste Electric and Electronic Equipment Alexander Birich1 • Seifeldin Raslan Mohamed1 • Bernd Friedrich1
Although new processes are being proposed on a regular basis there have in fact been no dramatic changes in the metallurgical techniques for gold extraction since the introduction of the cyanide process (cyanide leaching or cyanidation) by McArthur and Forrester in 1887.
Nearly all gold-mining companies use this toxic gold leaching process to sequester the precious metal. “The elimination of cyanide from the gold industry is of the utmost importance environmentally” said Sir Fraser Stoddart the Board of Trustees Professor of Chemistry in the Weinberg College of Arts and Sciences.
Recently the price of Sodium Cyanide is rising not because of the cost but the governments control it to avoid environment issue and claims from NGO and local communities. In China many of Non-cyanide leaching regents are developed to replace the sodium cyanide like JinChina Goldix Earth Gold
Cyanide in the form of a very dilute sodium cyanide solution is used to dissolve and separate gold from ore.  The process used to extract gold using cyanide was developed in Scotland in 1887 and was first used in large scale commercial mining by the New Zealand Crown Mines Company at Karangahake in 1889.
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The second is hydrometallurgy in which leaching chemicals like cyanide solution or aqua regia—Latin for king's water which is a mixture of concentrated nitric acid and hydrochloric acid—are used a process Foley called "expensive very …
Non Toxic Leaching Of Gold - … non toxic leaching of gold. Aurorra Gold Mining: Non Cyanide Leaching. CLS as a gold and silver leach was designed to leach concentrates Extremely toxic fumes will Get More Info.
The results for leaching gold with alternative reagents sodium thiosulfate and ammonium hydroxide show that the best extraction was achieved at 0.1M sodium thiosulfate and 0.2M ammonium hydroxide when adding 0.1M of hydrogen peroxide as an oxidation agent obtaining approximately 11% of gold.
However leaching by cyanide solutions has a set of substantial drawbacks: process duration high cost of the reagent nonadaptability of “stubborn” ores and concentrates absence of possible regeneration of cyanide solutions and the main thing is high toxicity of cyanide compounds.
The specs of the non-cyanide leach product are: Na2O - 35% to 50%. N - 12% to 20%. NH4 - 7% to 12%. H2O - 1% to 4%. Ca - 1% to 5%. Fe - 1% to 5%. Insoluble substances - 3% to 8%. Also this is a new ore that hasn't been tested with cyanide and we don't have the full mineral assay available but there is some Pt group in there.
cyanide solution and follows the gold through the process sequence. Iron sul- fide minerals which are common constituents of gold ores are oxidized to some extent during the cyanide leach thus resulting in the formation of acid. These acids are neutralized by the lime used in the cyanide leach sequence.
Introduction Cyanide is the wide-spread leaching reagent for the recovery of precious metals as it is cheap well established and efficient for gold extraction. Considerable attention has been given to alternative leachants since the beginning of the 1980's.
Keywords: gold iodine-iodide lixiviantsolution leaching precipitation. Received 14 July 2016 Accepted 16 December 2016 Journal of Chemical Technology and Metallurgy 52 2 2017 326-332 INTRODUCTION Cyanide leaching has been the most applied tech-nique in the world for recovering gold for over a century.
Despite the research interest and pilot plant trials on many non-cyanide gold lixiviants a viable alternative gold process is still at the early developmental stage. The most advanced is the thiosulfate heap leaching of low grade carbonaceous preg-robbing ores by Newmont Mining Co.
Iberian Minerals Ltd has filed a patent with the US Patent and Trademark Office (USPTO) for its HM X-leach a proprietary environmentally-friendly non-cyanide based leach formula for the extraction of precious metals from ores concentrates tailings and electronic waste (e-Waste).
non toxic leaching of gold. Aurorra Gold Mining: Non Cyanide Leaching. CLS as a gold and silver leach was designed to leach concentrates Extremely toxic fumes will result from the cyanide that
and comparison of gold leaching reagents will follow to determine an alternative reagent to cyanide. 2. Environmental Effects of Cyanide Cyanide compounds occur naturally as part of sugars or other compounds in certain plant-derived foods includ-ing almonds millet sprouts lima beans soy spinach bamboo shoots sorghum and cassava roots.
HM X-leach is a privately branded reagent under license to Mineworx by Enviroleach Technologies Inc. Eco-friendly gold extraction comparable leach kinetics to that of cyanide or acid based lixiviants on ores concentrates tailings and E-Waste.
Accelerated leaching of gold silver and copper gold ores with glycine or cyanide . Accelerated leaching of gold silver and copper gold ores with glycine or cyanide glycine a low cost non toxic reusable reagent AusIMM Branch Meeting Kalgoorlie Australia Prof Jacques Eksteen Western Australian