The Ores actually Impure.-As these five minerals actually exist in the earth's crust they are usually more or less impure chemically, and they are almost always mechanically mixed with xlv.
The impure glycerin obtained as above is purified by redistillation in steam and evaporation in vacuum pans.
Powdered galena is dissolved in hot hydrochloric acid, the solution allowed to cool and the deposit of impure lead chloride washed with cold water to remove iron and copper.
For several years prior to 1902 Harrisburg suffered much from impure water, a bad sewerage system, and poorly paved and dirty streets.
Thick, there are cheaply mined but poor and impure ores near Prague, and important ore beds in both northern and southern Hungary.
Bort (or Boart) is the name given to impure crystals or fragments useless for jewels; it is also applied to the rounded crystalline aggregates, which generally have a grey colour, a rough surface, often a radial structure, and are devoid of good cleavage.
The principle usually followed in the electrolytic refining of metals is to cast the impure metal into plates, which are exposed as anodes in a suitable solvent, commonly a salt of the metal under treatment.
The fire may well have caused the natron, an impure form of carbonate of soda, to combine with the surrounding sand to form silicate of soda, which, although not a permanent glass, is sufficiently glass-like to suggest the x11.4 FIG.
Extensive deposits of the salt (called caliche in its crude, impure state) in the provinces of Tacna, Tarapaca, Antofagasta and Atacama owe their existence to the rainless character of the climate.
During the alcoholic fermentation of grape juice it is deposited in the form of an impure acid potassium tartrate which is known as argol, and when purified as cream of tartar.