Knowledge of cleaning
Knowledge of industrial cleaning with acid&Nbsp; ) hydrochloric acid hydrochloric acid (HCl) is the solution of hydrogen chloride gas, is a strong acid. Pure hydrochloric acid is a colorless, transparent solution. Industrial hydrochloric acid with impurities (containing iron) and yellow. Commercial hydrochloric acid by weight concentration 31-37%, density of 1.19. Hydrochloric acid has a strong sense of volatile and pungent odor. When in use, should pay attention to protective or join fog inhibitor. Hydrochloric acid is the most commonly used scale remove scale, rust solution. Chemical cleaning, the concentration of hydrochloric acid used is reckons, generally not more than 25%, or accelerated corrosion, bad for equipment, vehicles. As hydrochloric acid cleaning ability, fast, and affordable, so is widely used, especially for clear calcium iron oxide scale effects.
&Nbsp; (b) sulfur trioxide sulfuric acid dissolved in water generates sulphuric acid (H2SO4). Pure sulfuric acid is a colorless, oily liquid, concentration of 98.3%. Sulphuric acid density is 1.84, lively is a binary acids. Industrial sulfuric acid with impurities and is light brown. Sulfuric acid has a strong water absorption and oxidation, odor-free, in any proportion of soluble in water. Sold in concentrated sulfuric acid concentration 98%, reckons the sulfate concentration in industrial cleaning, iron scale can be removed. However, due to its low volatility, must be heated to a certain temperature in order to effectively scale. In addition, the concentration 98% sulfate is sometimes also used with other acids such as nitric acid, can remove dirt and algae bio-coke and other bio-fouling. Sulfuric acid danger to persons and equipment, diluted to add acid to water and stir, cannot add water to acid to prevent splashing.
&Nbsp; (c) nitric acid nitric acid (HNO3) is a strong oxidizing agent. Pure nitric acid is a colorless liquid, the density of 1.50. Concentrated nitric acid for industrial use are often yellow, heavy smoke in the air and water absorption, concentration of 66-70%. Concentrated nitric acid is soluble in water, diluted to concentration. Commonly used inhibitors, detergents and other additives in nitric acid is not stable and therefore should not be used for carbon steel and copper alloy. Its iron-passivating effect, can slow down the corrosion.
&Nbsp; (d) phosphate phosphoric acid (H3PO4) is pentavalent phosphorus oxy-acid, pure is a colorless rhombic system, density of 1.834, normally colorless syrupy liquid. Phosphoric acid is soluble in water and ethanol, is a medium strength acid. Its corrosive stronger as temperatures rise. It is also a strong complexing agents. Because of its ability to break down dirt is weak, especially for common salts of calcium and magnesium salts to dissolve gradually phased out in the industrial and chemical cleaning. Sometimes, clean the rusted surface with phosphoric acid, use concentration for cent at a temperature of 40-80 c, low temperature cleaning ability is poor.
&Nbsp; (e) hydrofluoric acid hydrofluoric acid (HF) is aqueous solution of hydrogen fluoride, is a colorless liquid, soluble in water, is a weak acid. It's smoke in the air, strong corrosive and toxic. In use, it not only has a pickling, and because the fluoride ion complexation and its dissolving ability is stronger. It can also corrode glass and ceramics. When used with other acids can effectively decomposes silicates, effectively removing casting sand. If there is no hydrofluoric acid, available ammonium bifluoride salt be hydrofluoric acid. In industrial cleaning, hydrofluoric acid (or use hydrogen fluoride ammonia and hydrochloric acid) is used to dissolve insoluble dirt containing Silicon.
&Nbsp; (vi) amino acid amino sulfonic acid (H2NSO2OH) is a strong acid, colorless, odorless crystals, nonvolatile, does not absorb moisture, dry state more stable. Density of 2.126, dissolved in water, can be used to remove calcium or other carbonates, but removal of iron scale is not valid. This acid stability at room temperature and high temperature decomposition, so when used, must be heated to 60 degrees Celsius. It is equipped with corrosion inhibitor for the only acid that can be used in galvanized metal or stainless steel cleaning.