Method for the determination of polyaluminum chloride content The method for detecting the content of aluminum trioxide in polyaluminum chloride is as follows: The slag is weighed, pulverized, stirred, added with hydrochloric acid solution (known concentration), filtered and weighed to calculate the content. Weighing: to a certain amount of slag crushed, weighed m1 grams, the sample with sufficient amount of 0.1molNaOH solution treatment, filtration, washed residue, the container three times, the lotion was poured into the filtrate. Add a large amount of hydrochloric acid solution until the precipitate is completely dissolved. Ammonia was added dropwise to the filtrate until a precipitate no longer formed. The precipitate was filtered off and rinsed three times with deionized water, fully weighed to obtain a weight of dry m2, the resulting dry Al (OH) 3,2Al (OH) 3 - Al2O3, 78 × 2 102 Al2O3 polyaluminum chloride content : (M2 × 102/156) / m1 × 100% = percentage content of Al2O3.