The dry method consists in an oxidizing roasting of the ores, and a subsequent chloridizing roasting with either common salt or Abraumsalz in reverberatory or muffle furnaces.
The material is moistened with a solution of common salt and placed in very large heaps to ferment for some weeks.
Extensive deposits of borax and common salt have been found in the same region, which with several other products of these saline deposits, such as iodine, add considerably to its exports.
Steam is turned on, and, the mass being brought to a clear condition with weak lye or water, strong lye is added and the boiling continued with close steam till the lye attains such a state of concentration that the soap is no longer soluble in it, and it will separate from the caustic lye as from a common salt solution.
One part of cream of tartar, two of alum and two of common salt are dissolved in boiling water, and the solution is boiled with granulated metallic tin (or, better, mixed with a little stannous chloride) to produce a tin solution; and into this the articles are put at a boiling heat.
Either common salt or strong brine in measured quantity is added to the charge, and, the soap being insoluble in such salt solution, a separation of constituents takes place: the soap collects on the surface in an open granular condition, and the spent lye sinks to the bottom after it has been left for a short time to settle.
While the proportion of common salt to sulphate of magnesia is as r r to r in the water of the Black Sea and as 2 to 1 in the Caspian water generally, it is as 12.8 to 5.03 in the Kara-boghaz.
Obviously no more than this is possible until physiologists are able to state much more precisely than at present what is the influence of common salt on the plants of salt-marshes, of the action of calcium carbonate on plants of calcareous soils, and of the action of humous compounds on plants of fens and peat moors.
Schimper had previously maintained that the action of common salt in the cell-sap is detrimental as regards assimilation.
The nitrate and borax deposits are extensive and productive, and common salt is a natural product of large areas in the elevated desert regions of the Andes.