To these leached guanos and phosphatized limestones the name sombrerite has been given.
The residue, consisting of alumina and potassium sulphate, was leached with water to separate the insoluble matter which was dried as usual.
Of a metalliferous vein is generally more or less altered by oxidation, and often a part of the valuable mineral has been converted into a soluble form and leached out.
The liquors are run off from the vats to the electrolysing baths or precipitating tanks, and the leached ores are removed by means of doors in the sides of the vats into wagons.
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.