| 20080199385 | Process for Producing Silica and Sodium Sulfite with Sodium Sulfate - Provided is a process for producing silica and sodium sulfite with sodium sulfate, wherein a mixture of quartz sand, sodium sulfate and carbon is reacted to produce solid sodium silicate and sulfur dioxide, which are used to produce silica and sodium sulfite through the following steps: (1) Said solid sodium silicate is dissolved in water and then filtered to obtain a sodium silicate solution; a sodium hydrogen sulfite solution is added to said sodium silicate solution to produce precipitated silica and sodium sulfite solution and the resultant mixture is filtered; (2) One part of the filtrate obtained at the end of step (1) is brought into contact with said sulfur dioxide and the product, sodium hydrogen sulfite, is recycled to step (1); (3) The filter cake obtained at the end of step (1) is acidified, followed by filtration, washing and drying to obtain silica; and (4) The other part of the filtrate obtained at the end of step (1) is concentrated and dried to obtain solid sodium sulfite. The process of the present invention is of great industrial value due to its simple steps, useful by-products and low production cost. | 08-21-2008 |
