Precipitation method is mainly used by silica factory
Date : 2017/3/22 17:22:30
The production method of silica white, according to the data at home and abroad, mainly the two types of precipitation and gas phase. As the precipitation method used in cheap raw materials, easy to get, the production process and equipment is relatively simple, the product price is low, so the current silica factory is mainly used to prepare silica white by precipitation. Now the relevant method is as follows:
The main raw materials used in the silica factory are quartz sand, soda ash, industrial hydrochloric acid or sulfuric acid or nitric acid or carbon dioxide. The process route is basically: the first use of fuel or high-quality coal at high temperatures will be quartz sand and soda ash reaction of industrial water glass, industrial water glass water prepared into a certain concentration of dilute solution, and then under certain conditions to add a certain acid, so that the precipitated silica, and then by washing, filtration, drying (drying or spraying), crushing, the product of silica white. Precipitation method and sub-acid method, sol method, carbonization and many other specific methods.
In general, the acid method is the soluble silicate and sulfuric acid (or other acid) together, when the reaction reaches a certain pH value to stop adding acid reaction, aging, and then filter and repeatedly washed with water. In addition to Na2SO4, send dry, crushed to get the product.
Sol method is a better process route, but the process is more complex than the acid method, conditional control requirements are higher. The first hydrochloric acid and sodium silicate reaction to generate a certain concentration of dilute sol, in a slight heating and stirring conditions, the sodium silicate solution added to the prepared sol, while adding a certain amount of NaCl solution, the reaction to the pH = 7 ~ 8, and with alkaline adjustment liquid to maintain this PH value, insulation aging, and then rinse off the chloride, and then filter, dry, packaging.
Carbonation is the use of carbon dioxide gas through the soluble silicate solution for carbonation operation, the formation of precipitated SiO2 and sodium carbonate, the reaction is completed after the pre-filtration, and acid water solution to remove the product of Na2CO3, and then filter, dry, crushed, packaging.