Abstract: The adsorption effect and mechanism of diatomite on COD and heavy metal manganese ions in wastewater were discussed by taking the multi-metal beneficiation wastewater of Shizhuyuan in Hunan as the object. By comparing the treatment effects of different adsorbents (activated carbon，D401 chelating res‐ in，alumina，diatomite)，it was found that diatomite had the highest COD removal rate (more than 60%) and good adsorption capacity for manganese ions. The results of further optimization of adsorption conditions showed that the effect was the best when the diatomite dosage was 7.5 g/L，pH=8 and reaction time was 60 min. The kinetic analysis showed that the adsorption process of COD and manganese ions by diatomite was more in line with the pseudo-first-order kinetic model，indicating that it was mainly physical adsorption. Studies have confirmed that diatomite，as a low-cost，efficient and environmentally friendly adsorption ma‐ terial，has significant application potential in the treatment of multi-metal beneficiation wastewater，and provides a feasible solution for wastewater reuse.

Key words: polymetallic mineral processing wastewater, diatomite, adsorption