Hydrothermal process for the treatment of lead glass with recovery of lead metal, soluble and insoluble silicates and silica

摘要

There is described a process completely performed in aqueous phase, which provides a heat etching of lead glass with aqueous solutions of strong alkali followed by an electrolytic treatment of the suspension so obtained, in order to recover metallic lead and obtain soluble silicates, separated from insoluble silicates, both lead-free. The process also provides for the production of pure silica, derived from the soluble silicates, and a possible use thereof to increase the ratio between silica and sodium oxide, which characterizes the specifications of the soluble silicates. The electrolysis for the recovery of metallic lead is implemented in a cell in which the polarity of the electrodes is periodically reversed, to obtain the detachment of the metallic lead deposited on the cathodes.