Production process of fly ash treatment selenium removal agent

The invention discloses a fly ash treatment selenium removal agent production process, which comprises: S1, respectively weighing 30-50% by weight of N-methyl pyrrolidone, 3-5% by weight of sodium silicate, 2-6% by weight of 2-hydroxyphosphoryl acetic acid, 5-10% by weight of N, N-dicarboxymethyl alanine trisodium salt, 1-3% by weight of potassium tannate, and the balance of deionized water; s2, after it is checked that the operation function of the reaction kettle is normal, the reaction kettle is started, deionized water is added, the temperature in the reaction kettle is controlled to be 25-35 DEG C, and the constant temperature is kept for 4-10 min; s3, slowly adding the N, N-dicarboxymethyl alanine trisodium salt into the reaction kettle, continuously stirring for 6-10 minutes, raising the temperature to 45-55 DEG C, and keeping the constant temperature for 5-12 minutes; s4, gradually adding the potassium tannate into the reaction kettle, controlling the temperature to be 34-50 DEG C, and keeping the con