The precipitation method is also called the wet method, and the main raw materials are quartz sand, soda ash, industrial hydrochloric acid or sulfuric acid or nitric acid or carbon dioxide. The process route is generally: the first use of fuel oil or high-quality coal at high temperature reaction of quartz sand and soda ash to produce industrial water glass, industrial water glass is prepared into a certain concentration of dilute solution, and then under certain conditions to add some acid, so that the silica precipitate out, and then after cleaning, filtering, drying (drying or spraying), grinding, to produce the product white carbon black. Precipitation method is divided into acid method, sol method, carbonization method and many different specific methods. (1) Acid method In general, the acid method is to react with soluble silicate and sulfuric acid (or other acids), when the reaction liquid reaches a certain value, stop the acid reaction, aging, and then filter and wash with water repeatedly, remove Na2S04, send dry, crushed to get the product. (2) Sol method This is considered a better process route, but the process is more complex than the acid method, and the condition control requirements are higher. First, hydrochloric acid and sodium silicate react to produce a certain concentration of dilute sol, under the condition of slightly heating and stirring, the dilute solution of sodium silicate is added to the prepared sol, and a certain amount of NaC1 solution is added to react to pH=7~8, and the H value is maintained with alkaline regulator, heat preservation and aging, and then rinsed to remove chlorine, and then filtered, dried and packaged. (3) Carbonization method In this method, carbon dioxide gas is carbonized by soluble silicate solution to produce precipitated Si02 and sodium carbonate. After the reaction is completed, the product is pre-filtered, and Na2C03 is removed by acid aqueous solution, and then filtered, dried, crushed and packaged.