| 摘要 |
PURPOSE: A manufacturing method of a high yield and high purity sodium hydroxide solution is provided to inexpensively and simply manufacture the high yield and high purity sodium hydroxide solution with the causticizing efficiency of 95 % or more in sodium carbonate. CONSTITUTION: A manufacturing method of a high yield and high purity sodium hydroxide solution comprises the following steps: preparing a 20% sodium carbonate solution and a 25% calcium hydroxide solution; causticizing the solutions with an iron salt catalyst in 55~75°C; producing the high yield and high purity sodium hydroxide solution; neutralizing sodium hydroxide solution fume produced in a centrifugal step of calcium carbonate and the sodium hydroxide solution in a sulfuric acid solution; removing the calcium carbonate contained in the sodium hydroxide solution with a polymer flocculant. |
