Electrically fused dolomite

The largest reactors used at Iowa State College were 35 cm in diameter and 120 cm high, made of standard-wall seamless steel pipe. They were closed with a welded steel plate at the bottom and a cover bolted to a flange at the top. The liner was made of electrically fused dolomitic lime which was finely powdered and packed into the steel tube to form a dense layer... 

Excessive reaction between the container material and the products or reactants must be avoided, and this may impose a limit upon the peak temperature which is allowable, or upon the materials of reactor construction. Reactors take different forms and are made from or lined with a variety of refractory materials. Lime, magnesia, electrically fused dolomite, calcium fluoride, nickel, stainless-steel, molybdenum, tantalum, niobium or graphite have all been used, for different purposes. 

The reaction takes place in a closed steel vessel, 45 in. long by 12 in. internal diameter, which is lined with electrically fused dolomite or lime, as in the American uranium metal production process. Initiation is carried out in a gas-fired furnace at a temperature of 640°C. A thorium/zinc alloy is formed, from which the zinc is removed by distillation under vacuum, between 1000°C and 1100°C in graphite pots. About 85 per cent of the zinc can be recovered for re-use. 

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