The proportion of aluminum and acid in the production of basic aluminum chloride determines the alkalinity (basicity) of basic aluminum chloride
Basic aluminum chloride is a kind of water purification agent. At present, Baike polyaluminum chloride produces basic aluminum chloride. Its raw materials are aluminum ash and hydrochloric acid. In the production of its alkalinity index is very important, because other indicators are closely related. The degree of alkalinity of basic aluminum chloride is called basicity, which indicates the presence of OH in basic aluminum chloride products. According to the flocculation principle, it can be seen that the more hydroxyl groups, the better the hydroxyl flocculation ability. If the hydroxyl group content is too high, it is easy to generate precipitation, which reduces the flocculation ability of the product and even loses its stability.
basic aluminum chloride
Alkalinity generally need to be controlled within the range of 50 to 80%. Since basic aluminum chloride is composed of a mixture containing different hydroxyl numbers, the alkalinity measured in the production of the product is the average value, so the control of the alkalinity of basic aluminum chloride in the actual production process should not be too high. According to the literature report, the alkalinity in the production process should be controlled at about 65%, and the flocculation performance of basic aluminum chloride products is better. If the alkalinity control is too high, the performance of basic aluminum chloride products is unstable, which is unfavorable to the use and storage. It can be seen that the size of the alkalinity is closely related to the flocculation effect of basic aluminum chloride, which is an important control index in the production process. To make the basic aluminum chloride products to maintain a certain degree of alkalinity, it is necessary to ensure that the ratio of [OH], [Al] unchanged, and the amount of [OH], [Al] in the product is determined by the reaction of hydrochloric acid and aluminum in the aluminum ash. In this way, the control of alkalinity is transformed into the control of aluminum and acid ratio, so the reaction should be carried out under a fixed aluminum and acid ratio, and a suitable aluminum and acid ratio can be obtained through experiments.
Different aluminate ratios have been tested and the results are as follows:
1, when the aluminum, acid ratio (molar ratio) is 1:0.8. Alkalization degree in 70 a 60, alumina content (refers to liquid products) in more than 10%, the acid decomposition rate is also high, 60% a 56.
2. When the ratio of aluminum to acid is 1:1, the alkalinity is about 50%, the alumina content is low, and the acid decomposition rate is also low, about 50%.
3. When the aluminum ratio is 0.5, the alkalinity is above 80%, the alumina content is also low, and the acid decomposition rate is about 45%. When the aluminum content in the aluminum ash is low and it is powdery, the bottom of the reactor is easy to scar, which is not conducive to production operation.
The suitable ratio of aluminum and acid is controlled according to the specific conditions of the aluminum ash used. According to the different composition of aluminum ash, the ratio of aluminum and acid can fluctuate up and down within a 0.8 range of 1:0.75. According to the actual situation of aluminum ash and the different requirements of the product, the control of aluminum, acid ratio, can produce any kind of alkalinity standard basic aluminum chloride products. Aluminum, acid ratio in 1:0.75 a 0.8 range, alkalinity in 65% of the small test conclusion, for 50 liters reactor test effect is the same. It is used in the production of 2000 reactor and also meets the control index requirements of basic aluminum chloride alkalinity. The effect is stable and reliable.
Basic aluminum chloride physical and chemical indicators
Analysis Project Analysis results Analysis Project Analysis results
AL2O3% ≥ 27 PH value (1% water solution) 3.5-5.5
Salt base degree% 56-95 Water insoluble matter (1% aqueous solution) ≤ 2
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