Aluminum diethylphosphinate crystal with low fine powder content, preparation method therefor and use thereof

A preparation method for an aluminum diethylphosphinate crystal with a low fine powder content, comprising:

• uniformly dispersing a phosphorus-containing aluminum salt complex, as a seed crystal, in an aqueous solution of soluble diethylphosphinate, adding a water-soluble aluminum salt solution containing a strong acid to carry out a reaction at 70-95° C., and after the reaction is completed, filtering, washing and drying a solid product to obtain the aluminum diethylphosphinate crystal with a low fine powder content;
• wherein the phosphorus-containing aluminum salt complex has a structure as shown in a formula (I) below:
• in the formula (I), a, b, c, d and e are all molar ratios, a is 0.1-0.5, b is 0.5-0.9, c, d and e are 0-0.3, and a+b+c+d+e=1;
• R1 and R2 are independently selected from H and C1-C6 alkyl, and when one of the R1 and R2 is ethyl, the other one is not ethyl and butyl;
• R3 is C1-C6 alkyl;
• calculated with a theoretical mass of the aluminum diethylphosphinate product as 100%, an added amount of the phosphorus-containing aluminum salt complex is 0.01-10%;
• and an average particle size (D50) of the phosphorus-containing aluminum salt complex satisfies 10 μm<D50<50 μm.