Anhydrous calcium chloride (CaCl2) is a white or off-white solid (granular, massive or powder), slightly bitter, odorless, soluble in water, soluble in water release a lot of heat. Has a strong hygroscopicity, easy to deliquescence in the air, should be sealed storage.
CaCl2 can be used as antifreeze, coagulant antifreeze, fabric fire retardant, food preservative and so on for desiccant, dehydrating agent, refrigerant, aviation and automobile internal combustion engine.
First, the production principle
Available limestone and hydrochloric acid reaction in the system. The main chemical reactions are as follows:
CaCO3 + 2HCl → CaCl2 + H2O + CO2 ↑
Second, the operation process
1. Calcium chloride dihydrate (CaCl2 · 2H2O): hydrochloric acid (31%) and limestone powder, according to the ratio of 2.2: 1 into the reaction tank, the reaction under stirring to produce acidic calcium chloride solution, Clarify the trough. Add lime milk, adjust the solution pH value of 8.9 ~ 9, then ferric hydroxide, magnesium hydroxide precipitation. After clarification, filtration, the filtrate was transferred to the evaporator and heated to 172-174 DEG C. After crystallization, the mixture was dried and dehydrated at 200 to 240 ° C to obtain calcium chloride dihydrate.
2. System of anhydrous calcium chloride: calcium chloride dihydrate and then heated to 260 ~ 300 ℃, dry and dehydrated, that is white into anhydrous calcium chloride.