Preparation of granulated adsorption material of water-quenched slag/rectorite composite for removal of Cu(II) ions from copper smelter wastewater

Abstract

The preparation of granulated adsorption material of water-quenched slag/rectorite composite and the treatment of Cu (II)-containing copper smelter wastewater with the adsorption material were studied. The experimental results showed that under the conditions with the mass ratio of water-quenched slag to rectorite of 1:1, 10% additive of industrial starch (IS), and 50% water, and a calcination temperature of 400 °C, the granulated adsorption material prepared had a density of 1.06 kg/m3, a porosity of 62.29%, water absorption rate of 58.82%, and compressive strength of 2.22 MPa. The efficiency of wastewater treatment was the best, whereas the rate of spallation loss was low. Under the conditions of natural pH, with the addition of the granulated adsorption material of 0.05 g/mL, a reaction time of 40 minutes, and temperature of 25 °C, the efficiency of the granulated adsorption material for the removal of Cu (II) ions from the copper smelter wastewater attained 98.2%, and the quality indexes of the wastewater after treatment conformed with the first level of integrated wastewater discharge standard (GB8978-1996). The reclamation of the used granulated adsorption material was carried out by de-sorption of the Cu (II) ions from the surface with 1 mol/L sodium chloride solution. The de-sorption rate was 96.4%, and the adsorption material can be reused many times to treat copper smelter wastewater.