OF ANALYTICAL CONTROL FOR SILICA BRICK*

The prevalent use of silica brick has focused attention upon the need for control and improvement in quality. A review of the methods available reveals that many laboratory tests have been developed to avert expensive trial testing. It is significant, however, that the chemical knowledge of this product has lagged owing to (1) difficulty in sampling, (2) the tedious and time-consuming aspects of wet chemical methods, and (3) the consequent lack of knowledge of the deleterious effects of certain secondary constituents. One of the newer analytical tools is the spectrograph. A total-energy method has been developed to permit analysis of A1₂O₃, MgO, Fe₂O₃, CaO, Na₂O, TiO₂, K₂O, ZrO₂, MnO₂, and Li₂O. Thirty minutes are required for sample preparation and twenty-five minutes for the spectrographic process. Present accuracy is well within production limits. This method is also suitable for the analysis of glass sand.