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Title: Studies in the adsorption of xanthate on galena
Author: Rau, Musiri Govindarau Subba
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 1961
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The adsorption density of potassium ethyl xanthate on galena was determined by the column method, under controlled conditions. The xanthate was assayed spectrophotanetrically. It was established that when working with properly washed galena, the amount of xanthate abstracted from solution, on passing through a bed of galena, was equivalent to the amount of xanthate that could be recovered from the surface of the galena by sodium sulphide solution. When the galena had oxidation products on its surface, the amount of xanthate abstracted fram the solution was always larger than the quantity which could be extracted from its surface by sodium sulphide. The adsorption isotherm for the xanthate - galena system was determined, and the observed maximum adsorption density was approximately equal to that of a monolayer. The isotherm followed the Freundlich relation at low concentrations and the Langmuir relation at high concentrations of xanthate. Study of the adsorption density of xanthate on galena at different pH and xanthate concentrations showed that the relation established by Gaudin, de Bruyn and. Mellgren far pyrite applied also to this system. The decrease in adsorption density with increasing pH was qualitatively explained as being due to the decomposition of the film of lead ethyl xanthate on the surface of galena. Sodium sulphide also reduced the adsorption density of xanthate but this was shown to be due to the xanthate being displaced from the surface of the galena by the sulphide. Neutral salts and potassium cyanide did not have any appreciable effect on the adsorption density. Desorption studies of adsorbed xanthatashowed that the xanthate was firmly attached to the galena surface and that the adsorption appeared irreversible. The isotherm established is therefore not a true isotherm. The rate of adsorption was studied at different xanthate concentrations in solution and different flow rates through the mineral bed. Both fixed and stirred beds of galena were used in these investigations. During the initial stages of adsorption, diffusion appeared to be the rate determining step. At higher surface coverages, the rate of adsorption seemed to be governed by some other unknown process. Ion exchange, involving an exchange of xanthate ion and sulphov ion , appeared to be the most likely mechanismof adsorption.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available