To these leached guanos and phosphatized limestones the name sombrerite has been given.
deep if the leached ore is to be removed by sluicing, 5 ft.
The residue, consisting of alumina and potassium sulphate, was leached with water to separate the insoluble matter which was dried as usual.
On permeable soils, especially those of the terrace lands along the valleys, the soluble salts commonly known as alkali were gradually leached out and carried by the percolating waters towards the lower lands, where, reaching the surface, the alkali was left as a glistening crust or as pools of inky blackness.
Siemens and Halske introduced a combined process in which the ore, after being part-roasted, is leached by solutions from a previous electrolytic operation, and the resulting copper solution electrolysed.