| 摘要 |
PURPOSE:To again use waste Ga-As grinding water as Ga-As grinding water by filtering waste Ga-As grinding water by a filter membrane and passing the obtained filtrate through a column packed with an anion exchange resin and a chelate resin. CONSTITUTION:As a filter membrane, an ultrafiltration membrane or precise filter membrane with a pore size of 10Angstrom -2mum is used because the size of fine Ga-As particles is several mum. As an ion exchange resin used in the adsorption of an arsenite ion and an arsenate ion contained in a filtrate, an OH type anion exchange resin is used. In the OH type anion exchange resin the OH-ion of the resin is replaced with the arsenite and arsenate ions to be reacted with the H-ion in the filtrate and the pH of the filtrate is neutralized. The ion exchange resin and the chelate resin lowered in adsorption efficiency during long-time use are brought into contact with a strong basic conc. aqueous solution to be regenerated. For example, when both resins are treated with 1-4N sodium hydroxide, they can be washed with a small amount of sodium hydroxide and an adsorbed arsenic compound can be conc. and recovered. |
