Treatment method of waste sulfuric acid

The invention relates to a waste sulfuric acid treatment method, which belongs to the field of waste sulfuric acid treatment, is suitable for waste sulfuric acid with the concentration range of 32-70%, and comprises the following steps: S1, conveying to-be-treated waste sulfuric acid with the mass of m into a reaction kettle, with the mass fraction of sulfuric acid in the waste sulfuric acid being C; s2, MgO is added into the waste sulfuric acid for a neutralization reaction, and the addition amount m1 of MgO is equal to (m-mC + 18C/98) S/(300 * C1); s3, after the neutralization reaction is completed, filter pressing is conducted through a filter press while the mixture is hot, and filtrate enters a crystallization kettle; s4, cooling and crystallizing, separating out magnesium sulfate heptahydrate and acidic mother liquor containing dilute sulphuric acid, preferably, a centrifugal separation mode, and drying solids after centrifugation to obtain a magnesium sulfate heptahydrate product; the waste sulfuric ac