SU46845A1 - The method of deposition of gold or silver from cyanide solutions - Google Patents

Description

The present invention relates to processes for the deposition of gold or other metals from metallurgical cyanide solutions, especially in TQK cases, when metal precipitating agents are used, such as naprik, er, cyck.

The purpose of the present invention is to obtain a new process of the indicated nature, in which zinc or a similar metal precipitating agent becomes more effective and fast-acting. Another object of the invention is to obtain a precipitation process that maintains the best concentration of hydrogen ionosis in the presence of a zinc solvent and the resulting zinc compounds.

In addition, it is highly desirable to obtain a precipitation process, particularly suitable in cases where, due to the low concentration of cyanide compounds in solution, the usual precipitation processes are not effective.

It is generally accepted to precipitate metals from cyanide solutions, bringing the solution into contact with a metal precipitating agent, such as zinc

or passing the solution through the chip chips, or entering zinc dust and collecting the deposited metals on the filter. In cases where the solutions contain sufficient free cysnide, such precipitation is usually effective, especially if it is air-tight. was previously removed from the solution mechanically. However, in cases where the solution has relatively little free ianide. the precipitating effect may be very slow and incomplete due to the poorly effective dissolving effect of the weak cyanide solution on the zinc precipitating agent and on the very poorly soluble compounds, which are formed by dissolving zinc in cyanide solutions. These compounds tend to form insulating plaque on zinc, thereby slowing precipitation. The presence of significant amounts of alkalis in the cyanide solution not only accelerates the precipitation of the gas, but may even slow down the process, since such alkalis form insoluble compounds that give a deposit; -; z zinc.

In order to efficiently precipitate cyanide solutions containing, for example, less than 0.003% sodium cyanide, no practical methods have been found yet aside from enhanced: 1 solution by adding Ooly 1 th; cyanide counts. This is a very expensive reception.

The authors found iTO when alkaline Og. Sulfite, for example sodium bisulfite NaHSOr, is in the form of a free solution and a pianist solution, free. From alkali hydroxide, precipitation of g metallose on zinc is rapid and r; oh, regardless of the amount of cyanide present.

 give Gshsu.n-fit to osadzhl-T-mom pjjCTiiOpy, or you can o6p; i ;; o1 ;; gn oisulirit in raspore by supplementing other chemicals. If the solution contains a significant amount of alkali hydroxide, then acid can be added, for example, sulfuric or sulfuric acid to neutralize the alkali hydroxide, and then add alkaline bisulfite, or you can add a sufficient amount of bisulfite for neutralization and alkali hydroxide, leaving an excess of bisulfite in the free solution . If a sufficient amount of sulphuric acid is taken, the reaction between the sulphuric acid and the alkaline hydroxide itself forms calcium bisulphite (or sodium) in solution. Such a modified solution is brought into contact with zinc or a similar metal precipitating agent, either by passing the solution through zinc boxes, or, better, by introducing zinc dust into the solution and collecting the precipitate on the filter.

Sodium and calcium bisulfites are solvents for zinc and themselves have a pH value of 6.5 to 6.7 (concentration of hydrogen ionosis, expressed in Sorensen units). When such salts are in the form of a free solution in a cyanide solution, the solution takes a pH value that can correspond to 6.5-6.7, or differ somewhat from it in aniiclness from the nature of the solution; ac; about the cyanide solution.

Bisulphite acts as a buffer, a salt for the maintenance of ccptrap; ; hydrogen ions and, consequently:; meaningfully,.-il .--, maintaining the dissolution rate of the c-. i during the deposition operation, dapp, - :. Thus, a good precipitation of r-::; tall in the form of a relatively pure | About the oszdka with a relatively fecal pacxo.z :: zinc. Due to the dissolution of bisulfite, the formation of :: ::; orbital byproducts; ln prpl / its, rsC; DN1.1X for 11 ° c; cСо cca; i ;;; f; H., and) podsrzh oams for cleansing and; G; and; .1 (og, state.

The total amount of alkaline bisulfite required depends on a significant degree1) and on the nature of the cyanide solution treated.

There are many cyanide solutions for which the proposed method can be applied with benefit and economy, especially in cases where the known methods do not precipitate; in any significant amounts, or are not effective. For example, solutions with a low content of alkali and cyanides can be quickly and efficiently precipitated using the described method without using an excessively large amount of a buffer salt and with minimal zinc consumption.

Although the invention has: a special value for the production of precious metals (such as gold and silver), it can also be applied to precipitate each ;. metals, for example, copper.

The subject matter of the invention.

The method of deposition of gold or sulfur. Cyanide sconce with razorosis with zinc, characterized in that the precipitates are produced in the presence of b: cy; xpit sodium or calcium (XaHSO-, or Ca (H50D.)