Preparation method of toothpaste-grade tin chloride

[0026] Such as figure 1 Shown, a kind of preparation method of toothpaste grade stannous chloride comprises the following steps:

[0027] (i) Synthesis reaction and primary filtration

[0028] Add deionized water into reaction kettle 1, then add concentrated hydrochloric acid, the amount of concentrated hydrochloric acid added is 3% to 8% of the total aqueous solution mass, then slowly add anhydrous tin tetrachloride dropwise, and finally put in metal tin, react The temperature is 110-120° C., and the reaction time is 1-3 hours. Wherein, the total aqueous solution quality refers to the sum of the aqueous solution contained in deionized water and concentrated hydrochloric acid; the molar ratio of deionized water, anhydrous tin tetrachloride and metallic tin is 4~8:1:1~1.2, the The mass concentration is 38%. The chemical reaction formula is:

[0029] Sn+SnCl 4 +4H 2 O→2SnCl 2 2H 2 o

[0030] The addition of concentrated hydrochloric acid effectively avoids the hyd...

[0039] 2.7kg of deionized water, 0.7kg of hydrochloric acid, 10kg of anhydrous tin tetrachloride, and 4.5kg of metal tin are added to the reactor successively, and the reaction temperature is 110°C, and the reaction time is 3h; after the reaction is completed, the metal solid impurities are filtered out; Add 42ml of sulfuric acid (10g / 100ml) to the filtrate, then add 42ml of strontium chloride (saturated solution), filter out solid impurities; take the clear solution and place it in a vacuum distiller for vacuum distillation with a vacuum of 0.01MPa and a temperature of 45 ℃; the distilled solution is introduced into the crystallization tank to stir and crystallize, the temperature is 0 ℃; after the white crystals are precipitated, the entire material system is placed in a centrifuge for solid-liquid separation, and the solid white crystals are put into a vacuum drying oven for drying , the vacuum degree is -0.05MPa, and the finished product is obtained. The weight of the obta...

[0041] 4.1kg of deionized water, 0.7kg of hydrochloric acid, 10kg of anhydrous tin tetrachloride, and 5.0kg of metal tin were added to the reactor successively, the reaction temperature was 115°C, and the reaction time was 2h; after the reaction was completed, the metal solid impurities were filtered out; Add 40ml of sulfuric acid (10g / 100ml) to the filtrate, then add 40ml of strontium chloride (saturated solution) to filter out solid impurities; take the clear solution and place it in a vacuum distiller for vacuum distillation with a vacuum of 0.03MPa and a temperature of 70 ℃; the distilled solution is introduced into the crystallization tank to stir and crystallize, the temperature is -5 ℃; after the white crystals are precipitated, the entire material system is placed in a centrifuge for solid-liquid separation, and the solid white crystals are put into a vacuum drying oven Drying, the vacuum degree is -0.08MPa, and the finished product is obtained. The weight of the obtai...