Abstract: A method and apparatus to measure the temperature of a slab in a reheat furnace with increased accuracy using either a single or dual pyrometer system through use of a multiplicity of temperature correction functions involving temperatures of slab and wall, distance between a pyrometer and the slab at which it is aimed, a ratio of air and fuel supplying the furnace heat and radiation interferences. The functions are chosen by a microprocessor in the system dependent on temperature differentials, emissivity setting of the pyrometer, target distance between pyrometer and slab, and air and fuel flow rates existing and fluctuating in the system.

Abstract: Fouling of an ammonia still, used for removal of ammonia from weak ammonia liquor derived from a coal coking operation, is alleviated by pre-precipitating insoluble calcium salts from the ammonia liquor by treatment of the liquor with lime prior to introduction into a single-leg still.

Abstract: A slurry of ferrosilicon powder is applied to both sides of a low carbon steel strip. The particle size of the ferrosilicon powder is controlled so that, after the slurry coatings are dried, there exists on each side of the steel strip at least a single layer of closely packed particles. The coated strip is then compacted. It is next heated in a protective environment to cause uniform diffusion of silicon throughout the strip.