A NEW METHOD OF EMBEDDING ~(60)Co TRACING SPOTS IN THE STUDY OF EROSION OF BLAST FURNACE LINING

In this paper, a new method——tube embedding method for monitoring the erosion feature of blast furnace lining with~(60)Co tracers is described. Instead of the traditional"refractory boring method″, the present method is embedding specific carbon steel tubes at the predetermined spots in advance during the lining of blast furnace. After the lining work was accomplished, holes were bored on the furnace casing and ~(60)Co tracers were put into the tubes with special tools and then the holes were padded and sealed with carbon trimmed materials. This will eliminate the interference caused by the parallel and crossing processes of embedding ~(60)Co and refractory lining, and avoid the constructors from being irradiated by ~(60)Co. The construction and usage of the special tools, such as container for transporting ~(60)Co and spray gun are also described in this paper. As the radiation absorbing coefficient of the tubes sealed with carbon trimmed materials is low, the dose of ~(60)Co used at every spot and the specific polution activity of the site and molten iron can be decreased to lower than the requirement of National Specification. Thus, the operators and overhaul persons may have little worry of being over irradiated, this method was adopted by Anshan Iron and Steel Complex during the major overhaul in 1985 for the supervision of high-grade refractory lining-silicon nitride and carbofrax fire-bricks. It was shown that this method was easy to carry out and safe, and the detection was precise. Hence, as a means of determining the remain lining of blast furnace,the ~(60)Co tracer method is reborn.