Silicon dioxide reaction with calcium oxide

Calcium oxide is known commercially as quicklime, or simply lime. Much of the calcium oxide produced is used in the manufacture of iron from its ores. Iron is obtained by reducing iron ore (containing iron oxides with sihcate impurities) in a blast fiimace. A charge of iron ore, carbon, and calcium oxide is added at the top of the furnace, and a stream of compressed air flows in from the bottom. The purpose of calcium oxide is to combine with silicon dioxide (sand) and silicate impurities in the iron ore to produce a glassy material (called slag). The slag is molteu at the tempraatures of the blast furnace, and it flows to the bottom of the furnace and is withdrawn. The essential reaction is that between a basic oxide (calcium oxide) and an acidic oxide (silicon dioxide). ... 

Silicon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. Chemical reactions do, however, take place between silicon carbide and a variety of compounds at relatively high temperatures. Sodium silicate attacks SiC above 1300°C, and SiC reacts with calcium and magnesium oxides above 1000°C and with copper oxide at 800°C to form the metal silicide. Silicon carbide decomposes in fused alkalies such as potassium chromate or sodium chromate and in fused borax or cryolite, and reacts with carbon dioxide, hydrogen, air, and steam. Silicon carbide, resistant to chlorine below 700°C, reacts to form carbon and silicon tetrachloride at high temperature. SiC dissociates in molten iron and the silicon reacts with oxides present in the melt, a reaction of use in the metallurgy of iron and steel (qv). The dense, self-bonded type of SiC has good resistance to aluminum up to about 800°C, to bismuth and zinc at 600°C, and to tin up to 400°C a new silicon nitride-bonded type exhibits improved resistance to cryolite. 

A broader definition than that confined to solutions is demanded in some fields of chemistry (e.g., in high temperature reactions of acids, bases, and salts). In the foimation of metallulgical slags, at furnace tempeiatuies, calcium oxide is used as base and silicon oxide and aluminum oxide as acids calcium aluminosilicate is produced as a fused salt. Sodium carbonate and silicon oxide when fused react to form the salt sodium silicate with the evolution of carbon dioxide. In this sense ... 

ACIDE CHLORHYDRIQUE (French) (7647-01-0) Hydrogen chloride gas is quickly absorbed in water, forming hydrochloric acid. Hydrochloric acid is a strong acid. Violent reaction with bases, strong oxidizers (with release of chlorine gas), acetic anhydride, cesium cyanotridecahydrodecaborate(2-), ethylidine difluoride, hexalithium disilicide, metal acetylides. sodium, silicon dioxide, tetraselenium tetranitride, and many organic materials. Incompatible with aliphatic amines, alkanolamines, alkylene oxides, aluminum, aluminum-titanium alloys, aromatic amines, amides, 2-aminoethanol, ammonia, ammonium hydroxide, calcium phosphide, chlorosulfonic acid, ethylene diamine, ethyleneimine, epichlorohydrin, isocyanates, metal acetylides, metal carbides, oleum, organic anhydrides, perchloric acid,... 

Violent reaction or incandescent reaction with ammonia, hydrogen, lead chloride, mercury, phosphorus(V) oxide, silicon, sulfur, titanium dioxide in the presence of heat. Contact with hydroxylamine forms a heat-sensitive explosive. Molten calcium reacts explosively with asbestos cement. 

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