What is called alkali recovery
Extraction equipment extraction status is good or bad, largely depends on the extraction of equipment. Different pulp, there are different equipment selection. At present the factory application is the most four series of drum-type vacuum washer. Its technology is mature, easy to operate, from the pulp into the pulp, the basic completion of the separation of pulp and black liquor, the extraction rate is also high. Pulp washing degree and the production of black liquor indicators are basically able to meet the choice of more manufacturers. The disadvantage is the big investment, power consumption.
For alkali recovery, the assessment of the extraction section is the concentration and temperature. Concentration: 8 ° Be; Temperature: 70-80 ° C.
Alkali recovery treatment method is to solve the problem of black liquor is more effective way, through the black liquor extraction, evaporation, burning, causticization of the four main sections, black liquor can be SS, COD, BOD together and completely removed, and recyclable Alkali, resulting in secondary steam (energy). However, the alkali recovery system has high technical requirements and high investment in equipment. Since the small and medium sized paper mills are generally unable to bear the high cost of building the alkali recovery system, the alkali recovery system is only mainly used in large paper mills. In addition, the straw pulp produced white mud in the high silicon content, easy to burn back into lime, white mud may cause secondary pollution.
