Entwicklung eines schadstoff- und abfallarmen Einbadverfahrens fuer das saeurepolieren von Kristallglas Schlussbericht

The traditional etching methods to polish surfaces of cut glass have caused hereditary discharges into air (Fluorine), into waste water and due to sludge disposals as a result of the chemical sewage treatment process. The goal of this project was to find a new chemical polishing method (single bath method) for traditional glass cutting by reducing the environmental burdens. During the research work an etching method for crystal glass and for lead crystal glass was developed, tested and partially transferred into production. Furthermore the basis for a computer controlled process automation has been worked out. In addition to this a new process water treatment system has been conceived, which substantially reduces about 40% burdens of the treated waste water (ready for discharge into the sewage systems). A pilot plant of 'crystal glass' is already working; the pilot plant for lead crystal glass is under construction and will be available in 6 months. For the exhaust air in the sludge disposal a four-chamber air washer has been developed and tested. During research work the high-speed glass grinding process has also been improved and a cooling medium circuit with a subsequent treatment step has been found and established. Compared to standard, the following improvements are realized: reduction of excavated glass by about 40 %, reduction of acid by about 40 %, reduction of fluorine discharges into air by about 40 %, reduction of company's fresh water consumption by about 60 % due to the installed process water circulation and treatment. (orig.)SIGLEAvailable from TIB Hannover: F94B1949+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman