REDOX CONTROL DURING INDUSTRIAL MELTING OF CULLET RICH GLASS BATCHES

An industrial method has been developed for control of the redox state of glass melts during production with high percentages of recycled cu llet. The method is based on redox characterisation by oxygen activity measurements in melts of representative cullet samples. In this paper ; the newly developed oxygen measuring system for cullet melts, called Rapidox, and some examples of the industrial use of this system are p resented. The examples include: evaluation of the redox effects of rec ycled culler in stockpiles and redox characterisation of various indus trial culler types. For interpretation of the measuring results with t he Rapidox system a computer program can be used. By using this progra m the redox related properties of the produced glass (Fe-redox ratio, optical properties and residual sulphate content) are predicted on the basis of the batch composition (raw materials and culler) and the mea sured redox state of the recycled cullet.