Method of manufacturing colours of iron, or crystallized sulphate of iron or other soluble salts of iron from pyrites cinders

摘要

Residues from the combustion of pyrites are at their outlet from the ovens collected in a state of incandescence in a chamber containing no oxygen, so that they are quickly cooled without oxidation to ferric oxide. After optional purification in an electromagnetic separator, the cinders may be pulverized and employed as a black pigment, or without pulverization, treated with 50--52 Bae sulphuric acid to produce a paste of iron sulphates. This paste may be crystallized, or calcined to produce a "red" pigment. Alternatively, it may be partially calcined and extracted with water. The washing liquors, or a solution of the uncalcined paste, may be treated with soda, potash or lime (oxide or carbonate) to produce various "iron yellows," e.g. iron hydrate, or "French yellow" (a mixture of iron hydrate and calcium sulphate). The different pigments obtained may be mixed in various proportions. Other crystallized iron salts may be obtained similarly to the sulphate.