| 摘要 |
1,194,732. Bromites. SOC. D. ETUDES CHIMIQUES POUR L'INDUSTRIE. 12 July, 1967 [22 July, 1966; 16 May, 1967; 22 May, 1967], No. 32142/67. Heading C1A. Calcium bromite is prepared by mixing bromine and hydrated lime in an aqueous medium at below 20‹ C. The rates of addition are controlled so that the pH does not fall below 10, and so that, before the quantity of calcium bromide present reaches 20% by weight and up to the end of the mixing, the proportions of bromine and hydrated lime are kept close to the stoichiometric, that is 1 mole Br 2 to 1 mole Ca(OH) 2 . When the total quantity of reactants has been added the pH is adjusted to between 9À3 and 10À5, and the mixture stirred until the quantity of hypobromite remaining in the mixture represents less than 15% of the total oxidizing power. The solid precipitate containing calcium bromite is then separated from the mother liquor. The weight ratio of Ca(OH) 2 to water of the reaction medium is between 30 and 40% and does not exceed 45%. Alkali metal bromides may be prepared from the calcium bromide obtained in the process by submitting the solid product together with an alkali metal carbonate, sulphate or hydroxide to double decomposition. |
