Improving the return water supply system for production of plates for slide gates

Abstract

In the area for machining of slide gate plates at Magnesite Combine a local return water supply system (Fig. i) constructed according to the plan of the Eastern Refractory Institute is in operation. In comparison with a general one the use of this system has made it possible to decrease the length of the lines, to simplify cleaning of the contaminated waste water as the result of establishment of individual (lower) requirements for the quality of the treated return water, and also to create the conditions for possible utilization of the sludge, which is not contaminated by the waste of other production operations.The water contaminated by the products of machining of the plates after the drilling and grinding machines is directed by gravity flow through troughs into a collecting pit equipped with a system for bubbling of air and then periodically fed by a vertical submerged pump in succession to four cylindrical and tapered settling tanks located in a separate building. The treated water is returned to the system and once a day the settled sludge is pumped out in the form of a slurry and removed by a specially equipped automatic machine to the dump.The sludge which has precipitated in the settling tanks compacts and in unloading of it the final portion of the settling tank must be unloaded manually. The operation of the area is continuous for two shifts. The return water supply system is operated by one worker in a daily shift for a five-day week.During repeated use of the water in the return water supply system its composition undergoes significant changes (Table i): the pH increases from 7.8 to ii.0, the bicarbonate alkalinity disappears and hydrate and carbonate alkalinity appears, the calcium content doubles, and the magnesium content decreases by five times. Fig. i. Plan of the return water supply: i) machine; 2) trough; 3) pit; 4) submerged pump; 5) air bubbler; 6) settling tank; 7) sludge pump; 8) treated water pump; 9) production water for makeup of the system. Donets Branch of the All-Union Scientiflc-Research and Design Institute for Power Cleaning in Ferrous Metallurgy. Magnesite Combine.