This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1899 Excerpt: ... the Society of Chemical Industry, 1S96, p. 813. At 1200 to 1250 calcium sulphate exerted no retarding influence on the reduction of zinc oxide, even in presence of lead andiron silicates, which might convert reduced calcium sulphide to silicate and facilitate the formation of zinc sulphide. Magnesium sulphate, which at a high temperature is decomposed by carbon into magnesia and sulphur dioxide, favors the production of zinc sulphide. Experiments with a mixture of ZnO, PbO, and Si02 heated together at 1000 C. and reduced by carbon at 1200 to 1250 C, indicated the formation of a double silicate irreducible at that temperature, but completely reducible at 1450 to 1500. Antimony.--Antimony occurs either as a sulphide or an oxide. The antimony sulphide behaves on the whole like lead sulphide,'' but is much more volatile. If decomposed by metallic iron the resulting metal is more likely to combine with the lead than it is to form a speise with any excess of iron that may be present. It may also be volatilized. The oxide is generally present as an antimoniate of lead or iron, and this, being reduced to an antimonide, combines with the lead or the speise, if any is made, or with the matte. The two main injurious effects of antimony, therefore, are that it causes loss by volatilization and impairs the character of the lead. Antimonial speise is rare, and in making up an ore-charge no account need be taken of the small quantity of iron likely to be consumed by the antimony. It forms occasionally in smelting antimony skimmings (see § 128). Two difficulties have to be contended with in treating the antimonial by-products of refining works in the blast-furnace. If the slag contains but little iron, thus requiring a high temperature, much antimony and lead are vola...