Method for preventing alkali efflorescence of pulverized coal ash slurry

The invention belongs to the technical field of comprehensive utilization and treatment of fly ash, and particularly relates to a method for preventing alkali efflorescence of fly ash slurry. The method comprises the following steps: grinding first fly ash slurry, introducing flue gas to carry out an alkali reduction reaction to obtain second fly ash slurry, and introducing flue gas into the second fly ash slurry to carry out a passivation reaction. The method not only can effectively reduce the alkalinity of the fly ash slurry, but also can avoid the problem of alkali efflorescence after the alkalinity of the fly ash slurry is reduced, so that the fly ash slurry meets the environmental protection requirement of a backfill mine. 本发明属于粉煤灰综合利用处理技术领域，具体涉及一种防止粉煤灰浆液返碱的方法。该方法将第一粉煤灰浆液进行研磨处理，同时通入烟气进行降碱反应，得到第二粉煤灰浆液，向所述第二粉煤灰浆液中通入烟气，进行钝化反应。该方法不仅能够有效降低粉煤灰浆液的碱性，还能避免粉煤灰浆液降碱后的返碱问题，使得粉煤灰浆液达到回填矿井的环保要求。