Xanthate is the most widely used and effective collector in the flotation of sulfide minerals. However, the residual xanthate in flotation wastewater may cause serious environmental pollution and even human health hazards. At present, a variety of treatment technologies have been developed to degrade xanthate pollutants in wastewater, with the aim of meeting safe discharge standards. This work reviews the research status of xanthate wastewater treatment technologies in recent years. Treatment technologies are evaluated, including coagulation flocculation, adsorption, microbiological, Fenton, ozone oxidation, and photocatalytic methods. The reaction mechanisms and advantages, as well as disadvantages, of the various treatment technologies are summarized. Future research on the treatment of xanthate wastewater should focus on combined methods, which will be conducive to achieving a high efficiency and low cost, with no secondary pollution, and with the aim of generating further original and innovative technologies.

The beneficiation of low-grade oxidized lead and zinc ore from the Lanping mine has attracted extensive interest in the mineral processing field due to the extremely rich resource reserves and the challenge in lead and zinc recovery. This study’s objective is to analyze the process mineralogy characteristics and to conduct the flotation optimization of this ore. Mineralogy parameters of the ore, such as mineral composition, mineral liberation degree, and intergrowth relationship, were investigated using an X-ray fluorescence spectrometer (XRF), an X-ray powder diffractometer (XRD), and an electronic probe microanalyzer (EPMA). The effect of the main experimental factors on the lead and zinc flotation is determined and compared. The results confirm that the low content of lead and zinc and the complex co-occurrence relationships between minerals bring a challenge to the efficient separation of the ore. Furthermore, a flow sheet consisting of “lead preferred flotation-zinc flotation” is performed, and an all-open flotation process consisted of “two-times lead rougher-one-time lead cleaner-two-times zinc rougher-one-time zinc cleaner” is finally employed for the beneficiation of this ore with the aids of mixed depressants and cationic-anionic collectors for zinc recovery. The Pb grade in the lead rougher concentrate is 2.83%, and the Pb recovery is 57.56%. The Zn grade reaches 28.64% with a recovery of 83.45%. Thus, the findings provide important technical supports for the processing of similar ores.

The efficient treatment of mineral-processing wastewater has attracted soaring interest recently. This study’s objective was to degrade xanthate from flotation tailings wastewater using a pyrite-catalyzed Fenton system. A sodium butyl xanthate (SBX) removal rate of more than 96% was achieved via the method under optimal conditions (a H₂O₂ concentration of 0.5 mM, a FeS₂ concentration of 0.5 g/L, an initial SBX concentration of 100 mg/L, and a natural pH of 9.36 ± 0.5), which is 12.85% higher than with a H₂O₂ system. An appropriate concentration of natural pyrite can act as a catalyst to significantly improve the oxidation capacity of H₂O₂. Additionally, the results of electron paramagnetic resonance and quenching measurements suggest that hydroxyl radicals (•OH) are the main active species in the H₂O₂-FeS₂ system. The possible reaction mechanism is proposed. The H₂O₂ adsorbs onto the pyrite surfaces and reacts with Fe²⁺, triggering the formation of •OH and Fe³⁺. The •OH most likely attacks the SBX that adsorbs on the pyrite surface or exists in the solution and promotes the transformation of the SBX anion (C₄H₉OCS₂⁻) into the intermediate butyl xanthate peroxide (BPX, C₄H₉OCS₂O⁻). Finally, BPX intermediates are likely further oxidized to smaller products such as SO₄²⁻, CO₂, and H₂O under the ongoing attack of •OH.