Abstract: The present invention provides a method for preparing an early-strength liquid accelerator free of alkali, chlorine, and fluorine. In percentage by mass and on the basis of the sum of the usage amounts of aluminum sulfate, diethanolamine, a pH regulator, a complexing agent, Tween 20, and water, aluminum sulfate accounts for 56%-58%, diethanolamine accounts for 5%-6%, the pH regulator accounts for 0.7%-0.8%, the complexing agent accounts for 1.3%-1.4%, Tween 20 accounts for 0.6%-0.8%, and the remainder is water. The preparation method comprises: after uniformly mixing water, a pH regulator, and a complexing agent, adding the mixture into a reaction kettle, and heating the reaction kettle; adding aluminum sulfate into the reaction kettle, and stirring the mixture until the aluminum sulfate is completely dissolved; adding diethanolamine into the reaction kettle to obtain a premix; and adding tween 20 into the premix to obtain a liquid accelerator.

Abstract: The present invention provides a continuous crystallization method under control of the multistage membrane modules, and belongs to the technical field of crystallization engineering. A crystallization solution is added to a crystallizer, and a stirring apparatus and a temperature control apparatus are started. After the system running stability, the loop of crystallization is started. Meanwhile, the coolant or antisolvent feed liquid loop is also started. The crystallization solution can respectively conduct crystal nucleation, growth and ripening in the multistage membrane modules, and then the crystallization solution is transported into a filter device and a drying apparatus to obtain the final crystal products. The desired crystal products can be obtained by the systematical control of the nucleation and crystal growth through the flow and the temperature of the crystallization solution, coolant or antisolvent feed liquid, and the contact time between two liquid phases.

Abstract: The present invention provides a continuous crystallization method under control of the multistage membrane modules, and belongs to the technical field of crystallization engineering. A crystallization solution is added to a crystallizer, and a stirring apparatus and a temperature control apparatus are started. After the system running stability, the loop of crystallization is started. Meanwhile, the coolant or antisolvent feed liquid loop is also started. The crystallization solution can respectively conduct crystal nucleation, growth and ripening in the multistage membrane modules, and then the crystallization solution is transported into a filter device and a drying apparatus to obtain the final crystal products. The desired crystal products can be obtained by the systematical control of the nucleation and crystal growth through the flow and the temperature of the crystallization solution, coolant or antisolvent feed liquid, and the contact time between two liquid phases.