Other non-cyanide reagent immersion gold

Other non-cyanide immersion gold reagents mainly include amino acids, cyanide compounds and humic acids.

The amino acid molecule is characterized by the fact that the molecule contains two coordination atoms of nitrogen and oxygen. From a thermodynamic point of view, they can form a favorable soluble chelate complex with gold, and thus can be used as a gold immersion reagent. The amino acid immersion gold must also be carried out in the presence of a suitable oxidizing agent. Preferably the oxidant amino acid leaching of gold in general is potassium permanganate, it can make the partial oxidation of amino acid-based compound, hindered gold dissolution and destruction of carbohydrate. The concentration of amino acid leaching gold must be higher than 5g / L, the optimum concentration of potassium permanganate is 2 ~ 4g / L, the best pH value, temperature, pulp concentration are 9 ~ 10.5, 90 ~ 95 ° C, 20% ~25%.

Cyanide-based agents have malononitrile, bromine cyanide, thiocyanate, calcium amino acid. These agents are less toxic than cyanide. However, there is not much research on such agents, and there is basically no research in China.

The humic acid immersion gold reagent has a wide range of sources and is inexpensive. Generally, it has an alkaline condition of pH 10 or higher. In the presence of an oxidant, the gold concentration in the immersion gold solution can reach 10 mg/L. The humic acid after sulfonation or nitration has a leaching capacity of 15 to 16 times higher than that of natural humic acid, and the gold leaching rate can reach 87%. Although there are not many people studying this law, it is one of the economic immersion methods.

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