DESCALING LIQUID FOR SILICA
ROCHEM DESCALING LIQUID (SILICA) has been developed for rapid and thorough cleaning of heat transfer surfaces by chemically removing rust and water scale. It is a non-volatile liquid, which is compounded of liquid acid, inhibitors, and wetting agents.
ROCHEM DESCALING LIQUID (SILICA) is inhibited against attack on all metals except aluminium, zinc and magnesium. It has unlimited shelf-life.
ROCHEM DESCALING LIQUID (SILICA) can be used with confidence for cleaning nearly every type of equipment subject to rust and scale buildup. By lowering labour requirements and reducing equipment down time, ROCHEM DESCALING LIQUID (SILICA) has proven itself to be efficient and highly economical in the following situations; fire-tube and water-tube boilers, condensers, superheaters, economisers, evaporators, steam and water lines, distillery equipment, air conditioning units, water jackets of internal combustion engines, cooling and piping systems etc.
The cleaning method and time required depend on the character and thickness of the rust and scale, size of equipment to be cleaned, availability of circulation equipment, concentration of ROCHEM DESCALING LIQUID (SILICA), temperature of solution, and presence of oily compounds covering rust and scale, our ROCHEM service engineers are available to recommend exact procedures to be followed in each specific case. However, the following is a general procedure that will prove effective in most cases:
1. The heat exchange equipment to be cleaned is filled with solution comprised of 1 to 3 litres of
ROCHEM DESCALING LIQUID (SILICA) per 10 litres of water. This solution is circulated throughout the
system for 8 to 16 hours.
2. The system is then flushed with fresh water, which removes particulate matter and soluble salts.
3. Then a 1% water solution of ROCHEM ALKLEEN LIQUID is circulated throughout the system for at least an hour to neutralise the acid and to prevent redepositing undissolved soils on the metal surfaces by its sequestering action: pH of solution should remain above 8, if it drops below add more ALKLEEN.
4. Drain the ALKLEEN and flush twice fresh water.
a) An alternative to continuous circulation is the soaking method in which the system is filled with the
DESCALING solution and is allowed to soak for up to 24 hours. This method is recommended where
adequate circulation cannot be provided.
b) The cleaning procedure can be speeded up by maintaining the DESCALING solution at a temperature between 60°C (140°F) and 77°C (170°C0, as well as by increasing the concentration. Circulation time could be cut 4 to 8 hours.
c) Small amounts of oil deposits on the scale will not hamper the cleaning efficiency. However, large amounts of oily compounds covering the surface, or scale containing calcium sulphate and or silicates will normally require a pretreatment by boiling out with a 5% solution of ROCHEM ALKLEEN for up to 24 hours. ROCHEM DEGREASOL can also be used to remove the oily compounds before descaling.
d) It takes 20 Litres of ROCHEM DESCALING LIQUID (SILICA) to remove 10 kilos of calciumcarbonate scale.
ROCHEM DESCALING LIQUID (SILICA) is acid in nature and should be handled with rubber gloves and safety glasses. In case of contact flush skin or eyes with plenty of water, for eyes get medical attention. Avoid inhaling of vapour. Use with adequate ventilation.