Process of cleaning metal surfaces

摘要

In a process for cleaning metal surfaces by means of aqueous alkaline silicate- and surfactant-containing cleaning solutions, circulating the cleaning solution via ultrafiltration, a solution is employed which contains sodium silicate or potassium silicate of the general formula Na2O.2SiO2.xH2O or K2O.2SiO2.xH2O as the sole silicate component. The cleaner solution is preferably adjusted to a pH between 7 and 12 and to a concentration (calculated as SiO2) of 0.1 to 20, in particular 0.5 to 10 g of silicate per litre.