Pyrite depression by dextrin in flotation with xanthates. Adsorption and floatability studies
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Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí
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Facultad de Ingeniería, Universidad Autónoma de San Luis Potosí
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Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí
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Departamento de Ingeniería Metalúrgica y Minas, Universidad Católica del Norte
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Departamento de Ingeniería Química y Procesos Minerales, Universidad de Antofogasta
Corresponding author
Alejandro López-Valdivieso
Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí, Av. Sierra Leona 550, CENTRO, 70000 SAN LUIS POTOSI, Mexico
Physicochem. Probl. Miner. Process. 2018;54(4):1159-1171
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ABSTRACT
Depression of pyrite by dextrin in flotation with xanthates has been studied. The adsorption of dextrin and xanthates at the pyrite/aqueous solution interface has been investigated through electrokinetics, Raman spectroscopy and batch adsorption studies using oxidized pyrite. Microflotation studies were undertaken to evaluate the pyrite depression with dextrin using ethyl and propyl xanthates as the collector. The surface density of ferric hydroxide on pyrite depended on pH and was highest about the iep (pH 7.5) of the oxidized pyrite. Dextrin adsorption was directly related to the surface density of ferric hydroxide and took place through two steps suggesting two adsorption mechanisms on ferric hydroxide. Xanthate adsorption as dixanthogen occurred along with ferric hydroxide dissolution causing partial dextrin desorption from the pyrite surface; consequently, co-adsorption of xanthate and dextrin occurred on the surface. Depression of pyrite flotation with xanthate was determined by the oxidation level of the pyrite surface. Floatability of pyrite with xanthate was highly impaired by dextrin at pH 8 only when the surface density of ferric hydroxide on the pyrite surface was very high.