| 摘要 |
<p>PURPOSE:To produce the sodium sulfite which does not decrease purity, and suppresses color by absorping a SO2 gas contd. in an exhaust gas with an aqueous solution of NaOH contg. a salt of gluconic acid followed by depositing the Na2SO3, and then separating it. CONSTITUTION:The SO2 gas contd. in the exhaust gas which generates in a metal refining, a petroleum refining and a boiler, etc., contacts with the aqueous NaOH solution contg. 10-5,000ppm the salt of gluconic acid such as a potassium gluconate, and then absorbs and reacts to form an aqueous solution of acid sodium sulfite. And then, the obtd. aqueous solution is neutralized with NaOH and Na2 CO3, etc., followed by depositing a crystal of Na2SO3 and separating and drying it. Thus, as an impurity of a metal ion contd. in the aqueous solution of the acid sodium sulfite makes it soluble in the aqueous solution with the gluconate, the impurity does not take in the crystal of the Na2SO3, thereby obtaining the white crystal of Na2SO3 having a high purity.</p> |
