Flow injection analysis of ethyl xanthate by gas diffusion and UV detection as CS2 for process monitoring of sulfide ore flotation

TALANTA

卷:82

Article

Cordeiro, Thiago G.¹  Hidalgo, Pilar²  Gutz, Ivano G. R.²  Pedrotti, Jairo J.¹ 

[1] Univ Presbiteriana Mackenzie, Ctr Ciencias & Humanidades, BR-01302907 Sao Paulo, Brazil

[2] Univ Sao Paulo, Inst Quim, Sao Paulo, Brazil

关键词: Ethyl xanthate;    Flow analysis;    Gas-diffusion;    Spectrophotometry;    Flotation process;    Mining industry;   

DOI  :  10.1016/j.talanta.2010.05.055

来源: Elsevier

【 摘 要 】

A sensitive and robust analytical method for spectrophotometric determination of ethyl xanthate, CH3CH2OCS2- at trace concentrations in pulp solutions from froth flotation process is proposed. The analytical method is based on the decomposition of ethyl xanthate. EtX-, with 2.0 mol L-1 HCl generating ethanol and carbon disulfide. CS2. A gas diffusion cell assures that only the volatile compounds diffuse through a PTFE membrane towards an acceptor stream of deionized water, thus avoiding the interferences of non-volatile compounds and suspended particles. The CS2 is selectively detected by UV absorbance at 206 nm (epsilon = 65,000 L mol(-1) cm(-1)). The measured absorbance is directly proportional to EtX- concentration present in the sample solutions. The Beer's law is obeyed in a 1 x 10(-6) to 2 x 10(-4) mol L-1 concentration range of ethyl xanthate in the pulp with an excellent correlation coefficient (r = 0.999) and a detection limit of 3.1 x 10(-7) mol L-1, corresponding to 38 mu g L. At flow rates of 200 mu L min(-1) of the donor stream and 100 mu L min(-1) of the acceptor channel a sampling rate of 15 injections per hour could be achieved with RSD < 2.3% (n = 10, 300 mu L injections of 1 x 10(-5) mol L-1 EtX-). Two practical applications demonstrate the versatility of the FIA method: (i) evaluation the free EtX- concentration during a laboratory study of the EtX- adsorption capacity on pulverized sulfide ore (pyrite) and (ii) monitoring of EtX- at different stages (from starting load to washing effluents) of a flotation pilot plant processing a Cu-Zn sulfide ore. (C) 2010 Elsevier By. All rights reserved.

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