An investigation of the leaching of copper tailings by means of potassium cyanide, precipitation of the dissolved copper by means of aluminum, with consequent regeneration of the cyanide consumed

One of the principal disadvantages attending the use of most of the usual solvents for Copper, such as Sulphuric Acid, Ferrous Chloride, etc., in the treatment of tailings products, is that the solvent is not regenerated upon precipitation by iron, and in fact is destroyed by the precipitant. This of course involves a dead loss of a definite portion of acid or other reagent, proportional to the amount of Copper dissolved. A solvent which would be regenerated upon precipitation is eminently desirable. At the same time, a carbonate gangue, or one of such a nature which will react with the solvent used, also entails an unavoidable loss. It is a well known fact that Aluminum forms no Cyanide compounds...With these results in mind, and knowing the strong tendency of Copper to go into a Cyanide solution, a series of tests were made with a view of determining the value of a process of Cyaniding Copper tailings, and precipitating the Copper with Aluminum --pages 1 -2