A comparative study on the degradation of ethyl xanthate collector by O3, UV254nm, UV185+254nm, O3/UV254nm and O3/UV185+254nm processes. Issue 1 (February 2020)

• Record Type: Journal Article
• Authors: Fu, Pingfeng; Wang, Lianghua; Ma, Yanhong; Hou, Zongwu
• Is Part Of: Journal of environmental chemical engineering. Volume 8:Issue 1(2020)
• Publication Date: 2020-02
• Subjects: Xanthate -- Flotation effluent -- Ozone -- Vacuum-UV -- Mineralization -- Byproducts; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2019.103628
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: Highlights: EX degradation rate: O3 /UV185+254nm >O3 /UV254nm >UV185+254nm >UV254nm > O3 . O3 /UV185+254nm has 3–6 folds higher k app and mineralization extent than O3 . Less than 2 % of sulfur in EX emits into gas. 13 byproducts are identified and most can be further degraded. Abstract: To separate sulfide minerals from ores, xanthates are widely used as flotation collectors in global mining industry. However, nearly half of xanthates dosed into flotation circuits are discharged into flotation effluents. Residual xanthates and byproducts must be removed because of their toxicity to animals and detrimental effects on mineral flotation. In this work, the degradation of ethyl xanthate (EX) collector by O3, UV254nm, UV185+254nm, O3 /UV254nm and O3 /UV185+254nm was compared. The TOC and SO4 2− concentrations were measured to study the mineralization of EX. The generation of CS2 and H2 S byproducts was investigated in both aqueous and gaseous phases. The degradation rate and mineralization extent of EX had the order O3 /UV185+254nm >O3 /UV254nm >UV185+254nm >UV254nm >sole O3 . The EX removal by O3 /UV185+254nm reached 99.13 % within 15 min with the half-life of 2.29 min. The higher solution pH promoted the EX degradation for the O3 /UV185+254nm and sole O3 . After 90 min, 1.72 % of total sulfur in EX had emitted into gas for the O3 /UV185+254nm, slightly higher than that (0.49 %) for sole O3 . The solid phase extraction and gas chromatography‒mass spectrometry (SPE/GC–MS) and UV–vis spectroscopic analysis revealed that 13 organic byproducts were generated from EX collector and most of them could be further decomposed by O3 /UV185+254nm . Because the O3 /UV254nm and UV185+254nm photolysis were included, the O3 /UV185+254nm was the most efficient process in the removal and mineralization of xanthate collectors among five processes.