| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of stably recovering an industrially useful inorganic material including a high purity KCl salt without any heating and cooling units but with a simple operation. <P>SOLUTION: In this method, a dust (chlorine by-pass dust) contained in a combustion gas extracted from the combustion gas of a cement kiln is collected, water is added to the collected dust and made a slurry, then separated into a cake and a filtrate, and after heavy metals are removed from the filtrate, the treated water is separated into a concentrated salt water and a desalted water through an electric dialysis unit, then the desalted water is recycled and used as a washing water of the chlorine by-pass dust and an inorganic material containing alkali metal salts is recovered from the concentrated salt water by crystallization. The treated water after removal of the heavy metals may be separated into a concentrated salt water and a desalted water containing selenium by using a monovalent-ion selective permeating membrane. The obtained inorganic material can be used as a manure, etc., by making the content of potassium chloride not less than 90 wt%. The drain generated during crystallization of the concentrated salt water may be reused for washing of the dust. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
