PROCESS FOR MANUFACTURING A VITREOUS MATERIAL, FOR USE, IN PARTICULAR, IN THE JEWELLERY TRADE

摘要

Process for the manufacture of a material having a characteristic coloration ranging from orange-yellow to beef red, based on lead silicate, characterized in that it comprises the following stages: a) preparation of a bath or cast of silicate of lead, produced by mixing lead oxide PbO and silica SiO2 in proportions such that the ratio between these two components is 65% by weight of lead oxide and 35% by weight of silica, the temperature being chosen between approximately 1000 and 1300 ° C. b) introduction into the molten bath obtained in the above step of copper oxide and a reducing agent, the amount of this addition being such that the concentration by weight of the oxide in the final product is Approximately 6 to 8% the temperature of the molten bath being maintained between 1000 and 1300 ° C. c) maintaining the molten bath at rest always at the same temperature of around 1000 to 1300 ° C, so as to remove the bubbles. d) heat treatment of the material thus obtained at a temperature between approximately 500 and 800 ° C. for a time sufficient to carry out the formation and growth of cuprite micro-crystals (Cu2O). e) slow cooling down to room temperature of the mass obtained in order to avoid the formation of residual stresses in this mass.