Reclaiming water used in grinding hollow glassware contg. lead oxide - where acids and alkali are added to ppte. glass and lead salts, so water can be re-used in grinding

摘要

Contaminated water leaving the grinding plant is treated with acid to obtain pH 4, esp. 3, and to coagulate materials in the water. Alkali(ne earth) hydroxides or salts are then added with stirring to obtain a neutral pH, pref. 6-8, and esp. 7.0-7.5, followed by sepg. the water from the sludge. Reclaimed water is pref. recycled to the grinding plant, whereas the sludge is pref. dried and either (a) mixed with oxidants and heated above 1000 degrees C to form a glass contg. lead oxide; or (b) heated with reducing agents to over 1000 degrees C to form metallic Pb and a glass slag.