1. Dihydrate calcium chloride (dehydration method) method:
Dry and dehydrate edible calcium chloride dihydrate at 200-300 ℃ to obtain edible anhydrous calcium chloride finished product.
The chemical reaction equation is: CaCl2 · 2H2O -- [260 ℃] → CaCl2+2H2O
For neutral calcium chloride solution, spray drying tower can be used to conduct spray drying and dehydration under 300 ℃ hot gas flow to obtain anhydrous calcium chloride powder products.
2. Spray drying dehydration method:
The refined neutral calcium chloride solution, which has removed arsenic and heavy metals, is sprayed from the top of the spray drying tower through a nozzle to form a mist, and is dried and dehydrated by countercurrent contact with the 300 ℃ hot gas flow to obtain powdered anhydrous calcium chloride, and the finished edible anhydrous calcium chloride is prepared.
3. Mother liquor method:
The mother liquor of the ammonia alkali method for producing pure alkali is added with lime milk to obtain an aqueous solution, which is then evaporated, concentrated, cooled, and solidified.
4. Decomposition method:
Obtained by the reaction of calcium carbonate (limestone) with hydrochloric acid.
Chemical reaction equation: CaCO3+2HCl=CaCl2+H2O+CO2 ↑.
After completing the above steps, heat up to 260 degrees Celsius and evaporate for dehydration.
5. Refining method:
The by-product of producing sodium hypochlorite is refined.
Refined from by-products of the Solvay process for preparing sodium carbonate. (Ca(OH)2 + 2 NH4Cl → CaCl2 + 2 NH3 + 2 H2O)