A method of producing fly ash using pulping and papermaking white mud

Abstract

The invention discloses a method of utilizing pulping and papermaking white mud to produce fly ash. The method mainly includes following steps: (1), gradually heating the white mud to 900-1200 DEG C for drying for 20-30 min to enable water content to be less than 10%, and calcining at below 1200 DEG C for 20-30 min; (2), adding furnace slag and coal ash into the white mud after being calcined, controlling a mass ratio of the white mud, the furnace slag and the coal ash to be 4:3:3, milling for 1-1.5 h through a Raymond mill to 280-320 meshes to obtain the fly ash. The white mud, the furnace slag and the coal ash which are waste are utilized to produce secondary fly ash which is a concrete blending material meeting national statutory detection standards, so that the problems of environment pollution and land occupation caused by land treatment of the white mud are solved, the white mud is recycled, waste utilization value is increased, and environment protection cost is lowered; the method is simple in production process, and comprehensive utilization technology of the white mud can be popularized and applied in a short time.

Description

technical field [0001] The invention relates to a process for recycling white mud, in particular to a process for preparing fly ash by recycling white mud produced in pulping and papermaking. Background technique [0002] Papermaking white mud is a kind of solid waste produced after chemical pulping wastewater (also called black liquor) is treated in an alkali recovery system. In order to prevent environmental pollution, the black liquor in the pulp mill is generally treated with the current mature alkali recovery technology, the organic matter in the black liquor is burned to use heat energy, and the caustic soda (NaOH) consumed in pulping can be recovered. The alkali recovery system treats 90% of the pollutants in the pulp mill, but also produces a large amount (about 0.8 tons of lime mud / 1 ton of pulp) of lime mud waste. The main component of white mud is calcium carbonate (CaCO 3 ), its state is paste, with a water content of about 40%. Because it contains a certain am...

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Problems solved by technology

At present, the vast majority of white mud can only be disposed of by open-air stacking or land burial, which not only causes secondary pollution to the environment, but also wastes a lot of calcium carbonate resources. Enterprises have to pay huge sewage charges. It has become a difficult problem that many enterprises urgently need to solve

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