Citric acid and its salts widely use in the food-processing industry as flavouring additives, an acidity regulator and preservative, for manufacture of drinks, dry sparkling drinks. As components of buffer solutions, for protection of fats from damage, in a pharmaceutical industry as components of many medical products. Citric acid is used for removal of a rust and scale from metal surfaces, at copper electroetching, in tannin solutions in textile industry, by manufacture diazopapers. It is used in cosmetics as an acidity regulator, chelate agent, buffer, for sparkling compositions (bath). In a petroleum industry at drilling of oil and gas chinks it is used for cement neutralisation in a solution. Citric acid deletes ions of calcium from a chisel solution.