This section is from the book "Leaching Gold and Silver Ores. The Plattner And Kiss Processes: A Practical Treatise", by Charles Howard Aaron. Also available from Amazon: Leaching Gold And Silver Ores.
205. The use of alkaline or earthy hyposulphites for the extraction of silver from ores, also originated in Europe, having been suggested by Dr. Percy, in 1848, and first applied in practice by Von Patera, in 1858, at Joachimsthal. Von Patera used the sodium hyposulphite for the leaching, and the sodium polysulphide for the precipitation. This method was modified by Kiss, who substituted the calcium salts for those of sodium.
The Kiss process was first successfully introduced on this coast by Kustel and Hofman, in Mexico, after abortive attempts had been made by others in Lower California. It met with such success as to supercede amalgamation in the treatment of silver ores, throughout the State of Sonora, and the Territory of Lower California, and was even known among ill informed people as the "Mexican process." It has been gradually growing in public favor, the principal obstacle to its extensive adoption in the silver regions of Nevada being the circumstance that the ores of that State usually carry more or less gold, which, while frequently not justifying the application of the Plattner process, is but partially, and almost by chance, extracted in the Kiss silver process.
One great objection to the use of the Plattner process in these cases is, the cost of acid, the transportation of which is troublesome and expensive. It is therefore desirable that some means of developing pure chlorine from salt cheaply, without the use of acid, should be devised.
Section Of The Bruckner Furnace.