Preparation Of High Purity Boric Acid

Boron compounds has been widely used in industrial, agricultural and cutting-edge technology. Because boric industrial development in China is lagging behind, it has restricted the scope of the use of boric acid products in China, boric acid used in many important areas also largely dependent on imports. In order to solve the monopoly of foreign technology on high-purity boric acid and more convenient and inexpensive to provide high purity boric acid to the domestic high-tech fields, the development of China’s independent intellectual property rights of high-purity boric acid production technology is very urgent. This dissertation is designed to produce boric acid for the use of high-tech fields and to provide a theoretical basis for industrial production and future research. The detailed contents are listed below:1. Purification of industrial boric acid to prepare high purity boric acid. The Experiments using ion exchange resin method and complex crystallization process for the purification of industrial boric acid. This experiment selects732strong acid cation exchange resin, to carry out static and dynamic experiment: In the Centigrade from25to80, the ion exchange resin with boric acid is less affected by temperature change; Processing time to reach35min when the system is in exchange equilibrium; The resin treated with boric acid saturation is0.75kg(boric acid) per kg of the resin. We chose the niacin, isonicotinic acid as a complexing agent for experiment. The experiment has studied the two kinds of complexing agents application amount and complexation time on the treatment effect:Using nicotinic acid as a complexing agent in accordance with the complex crystallization process, the best complexing agent nicotinic acid dosage is0.8g/L, effect of complexing in0-35min increased with time,35min tends to the balance; Isonicotinic acid as complexing agent dosage is0.8g/L, less influenced by complexation time.2. Experiment used borax nitric acid acidification method for boric acid product, The laboratory improved this process, we put into sodium hydroxide to promote the removal of impurities, Addition of sodium hydroxide is15g(NaOH)/kg (borax) amount in dissolved material, have a good impurity removing effect, Obtained the boric acid products with the content of99.6%and the iron impurity content5.4x10-5%; Laboratory in the process of production first used complexation crystallization method,0.8g/L of isonicotinic acid after nitric acid acidification was added. We obtained the high purity boric acid products with the content of99.6%and the iron impurity4.5x10-5%.