The copper era., 1909-08-26
ANDERSON PROCESS.
Description of EIectrOIytic Method For Reduction of Metallic SuIphides,
 CarbOnateS and Oxides.

 provements in processes of reducing metallic sulphides, carbouates, oxides and other metallic compounds and ores, electrolytically, with aqueous solution, the art to which it pertains being known as Hydro-Metallurgy, and consists in the novel series of steps or reactions more fully described below.
 This process provides method whereby the metals are obtained in a refined condition, and at the same time saving, as by-products, such ele- ments as sulphur, arsenic and anti mony, without the use of heat, and at low cost.
 A brief outline of the chemical and electro chemical reactions involved will first be given, together with an example of the working of complex sulphide ore. Later, details will be furnished showing results obtained in a commercial plant giving per cent of extraction, loss of acid, cost of treat ment, etc.
 Due to the fact that certain inn provements covering the method of treating gold, silver, cobalt and nickel are now pending in the United States Patent Office, description of these reactions cannot be given at this time.
 In operating this process, using complex ores or compounds, four diff ferent operations are used, each oper- tion requiring one or more reactions, defined as follows:
 Operation Reduction of me tallic sulphides and other compounds with electrolytic hydrogen, resulting in the foi nation of gaseous hydrogen compounds of certain elements.
 Operation "B'5Dissolving of the gaseous electrolytic hydrogen.
 Operation ''C'-Precipitation within their respective condensers, of the elements carried over by the gaseous electrolytic hydrogen.
 Operation "D"-Precipitation of the metals from their solutions in a refined condition electrolytically.
 Operation "A" is carried out in a suitable reduction tank of the proper shape and dimensions in which is contained an aqueous solution of the electrolytic. On the bottom of the reduction tank is arranged a carbon or copper electrode which serves as a primary cathode. On top of this pri- mary cathode is placed the sulphide or other metallic compound to be re- duced.
 Suspended from above the tank and partly immersed in the electro lyte, but not in contact with the ore or compound, are a number of car bon plates or rods, which serve as the anodes. The ore or compound, by it's proximity to the primary cath ode, serves as an additional or sec ondary cathode, the secondary Ca th- ode being decomposable under the action of the electric current.
 As an example of the reactions talk ing place in this operation, we will assume that copper sulphide is the ore or compound to be treated. An electric current of the proper electro motive force and current density is caused to flow from the carbon anodes through the electrolyte toward the ore and cathode. During. the passage of the electric current, the water contained in the electrolyte is decom- posed, the hydrogen being disengaged upon and through the body of ore or compound.
 The nascent or electrolytic hydro gen combines with the sulphur of the ore forming sulphuretted hydrogen gas, which passes off through a col lecting hood, and is conveyed to suit able storage tanks for further treat ment. The electric current continues to flow toward the ore or sulphide until all or most of the sulphur has been eliminated in the manner stated at which time the copper will be reduced to spongy metallic form.
 Operation ''B". When the desired amount of sulphur has been elimi- hated as mentioned above, the cleo tric current is discontinued. Now the spongy copper, which has been re- duced at the cathode, together with the carbon auodes, and electrolyte, in which the copper is soluble, form an electric couple, which, when con nected to a voltmeter, will be found to give out an electric current. In order to dissolve the reduced copper and form a soluble salt herewith, the carbon anodes and cathodes are connected with suitable wires, which complete the electric circuit, causing the copper to enter the electrolyte, but not depositing upon what were the carbon anodes. Reference is here made to the fact that the cleo tric current causing the solution of the copper to take place is an in ternal current produced by the ele- ments in the reduction tank, and is not an external current. Where an external electric current is used, the copper would not only enter the sol