CALCIUM IODIDE HYDRATE

white crystalline lumps

The direct synthesis method is based on the weight ratio of iodine: sulfuric acid: sodium sulfide: calcium oxide: distilled water=1:0.75:0.75:1:3.3, first add sodium sulfide to water to make a 30% solution, and then drip 50% dilute under stirring Sulfuric acid is slightly acidic (pH=6), and the generated hydrogen sulfide is washed with distilled water. Add iodine to distilled water, add hydrogen sulfide while stirring, cool with water outside the absorber, keep the pressure below 0.049MPa, and absorb the temperature at 25～30℃ to completely dissolve the iodine and react with hydrogen sulfide to produce a milky white hydrogen iodide solution After filtering, add pre-prepared calcium hydroxide until it is alkaline (pH 7.5-8), and then filter to obtain calcium iodide solution. Add activated carbon for decolorization, filter, heat to 200°C for concentration, then dilute with water to a relative density of 1.54, and let it stand overnight. Filter, then heat to 218～230℃, evaporate and concentrate, quickly cool with ice water (the speed should be fast, otherwise it will turn yellow), after crushing, the finished product of calcium iodide is obtained. The H2S+I2→2HI+S2HI+Ca(OH)2→CaI2+2H2O residue was washed twice with an appropriate amount of distilled water, and the washing liquid and the filtrate were combined and refined. In the ferrous iodide method, add distilled water into the reactor, add the iron filings that have been cleaned of oil under stirring, add iodine in batches, and control the temperature not to exceed 40°C during the reaction process until the iodine is completely dissolved, then add distilled water and slowly heat to Boiling, fully react iodine and iron filings. Then add slaked lime to pH 14 in portions. Then heat to boiling and stir for 1 hour to fully react ferrous iodide and calcium hydroxide to generate calcium iodide. After cooling to 50°C and discharging, the filtrate is obtained after centrifugal separation, and then the filter cake is mixed with a double amount of water, boiled, cooled and centrifuged, and the two filtrates are combined and refined. The filtrate is adjusted to pH 2 to 3 with hydroiodic acid, concentrated by evaporation, cooled, and broken at 220-230°C to obtain a finished product of calcium iodide. Its I2+Fe→FeI2Fel2+Ca(OH)2→CaI2+Fe(OH)2

Mainly used in medicine, as a substitute for potassium iodide; photographs are used as photosensitive emulsion; can also be used as a mineral water, fire extinguishing agent, hydrogen iodide desiccant and analytical reagents.