Treating steel surfaces of electric precipitators - using coating contg. colloidal graphite particles in liquid carrier also contg. vinyl carboxy resin or xanthan gum

摘要

The inner steel walls and fluid handling and moving devices in electrical precipitation installations are treated by cleaning and applying a penetrating coating (I) of a liquid suspension of micro-micron colloidal particles of graphite to build up a smooth lubricating coating on their surfaces. The suspension comprises (by wt) 5-25% graphite particles, 34-75%aq sodium silicate soln contg 40% sodium silicate, 2-10% conc. hydrochloric acid, 33-75% of an aq. soln of carboxy vinyl polymer resin or xanthan gum contg.1-10% resin or gum, and 15-25% water. It is dried to form a slick, smooth surface. Pref several coats are applied, esp by spraying. The surfaces are pref heated to expand the grain structure of the steel and facilitate penetration of (I) The treatment is applied to electrical precipitators for cleaning flue gases in power plants, blast furnaces, coke ovens, etc. It prevents tar or other liquid or solid deposits from forming on the inner walls and fan blades or blower parts of the devices. An example of (I) which has been found satisfactory comprises (by wt). 8% micron particles highly pure synthetic graphite, 7% conc. HCl (90% purity), 18% water, 34% aq. sodium silicate soln (40% strength) and 33% aq. soln. contg. 8% carboxy vinyl polymer resin. (e.g. 'Carbopol').