Establishment of regularities of electroflotation extraction of non-ferrous metal (Cu, Ni, Zn, Co, Fe) hydroxides from wastewater of various compositions in the presence of industrial surfactantsстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Дата последнего поиска статьи во внешних источниках: 25 августа 2021 г.
Аннотация:The electroflotation process of extracting a mixture of Cu, Zn, Ni, Co, Fe hydroxides from wastewater containing NaNO3,NaCl, Na2SO4, Na2CO3, Na3PO4, NH4OH has been investigated. It was found that the maximum recovery rates of97–99% are observed in the pH range from 8 to 11 for NaCl solutions. The electroflotation process is the least effectivein Na3PO4 solutions with recovery rates of 10–20%. The cationic surfactant SeptaPAV-SKhV-70 (СептаПАВ-СХВ-70)added to the solution increases the extraction ratio in the presence of phosphates by 40–50%. Low efficiency of theelectroflotation process in Na3PO4 is associated with a small particle size (about 20–30 μm) and a -potential highnegative value, what has an injurious effect on the formation of the flotation complex, negatively charged bubbles(H2, O2) and negatively charged particles. The addition of a cationic surface-active substance (SAS) reduces negativepotential of the dispersed phase and increases particle sizes. All this contributes to the efficient passing of electroflotationprocess. Presence of a ligand (ammonia solutions) in the sewage reduces the recovery efficiency by 20–30%,especially for copper ions, which are strong complexing agents. Adding to the solution of small amounts (5 mg/l) ofindustrial surfactants STMs(a) (СТМх(а)) and Flon-1(c) (Флон-1(к)) at total concentration of hydroxides of 100 mg/lleads to a more efficient passing of the electroflotation process. A process flowsheet for removing suspended matters(a mixture of metal hydroxides) using an electroflotation cell and a microfiltration module is proposed. A modelseries of electroflotation devices with a capacity of 1–10 m3/h was proposed for application of the described technicalsolutions. The separation time in the devices does not exceed 10 minutes, power inputs is up to 0.6 kW·h per 1 m3of the treated wastewater with a recovery rate of 97–99%. The cost of an installation for 10 m3/h does not exceed1.5 million rubles.