laboratory report on hydomet, Lab Reports of Chemistry

Download laboratory report on hydomet and more Lab Reports Chemistry in PDF only on Docsity! ENG 326 Laboratory 5 Paige Dallywater 33408932 Recovery of Gold Using Activated Carbon (Carbon-in-Pulp Processing) Introduction Carbon-in-pulp processing (CIP) is an effective processes of extracting gold from low grade ores 2. The process of CIP involves leaching gold in a cyanide solution to form Au(CN)2 -, which is then adsorbed onto activated carbon 2. The carbon with adsorbed Au(CN)2 - is screened off and the gold is then re dissolved into a hot cyanide solution, gold is then recovered by electrowinning processes 2. CIP process is classified as a first order reaction: −d ¿¿ Equation 1First order reaction of [ Au ] The aim of this experiment is to observe and evaluate the kinetics of gold adsorption using fresh activated carbon, stripping gold of loaded carbon. Experimental Method Refer to Experiment 5, EXM357 Extractive Metallurgy Laboratory Manual. Results/Disscusion Table 1 [Au] concentration in the CIP with sodium ethyl xanthate addition With S.E.X Sample Time (mins) Au Concentration (mg/L) log Au (mg/L) 0 10 1.000 15 9.38 0.972 30 9.05 0.957 45 8.46 0.927 60 8.44 0.926 90 7.84 0.894 120 7.36 0.867 Table 2 [Au] concentration in the [Au] concentration in the CIP Without S.E.X Sample Time (mins) Au Concentration (mg/L) log Au (mg/L) 0 10 1.000 15 8.97 0.953 30 8.15 0.911 45 7.66 0.884 ENG 326 Laboratory 5 Paige Dallywater 33408932 60 7.04 0.848 90 6.16 0.790 120 5.28 0.723 0 20 40 60 80 100 120 140 0.000 0.200 0.400 0.600 0.800 1.000 1.200 f(x) = − 0 x + 0.99 R² = 0.997 Log Au vs Time S.E.X added Linear (S.E.X added) No S.E.X Linear (No S.E.X) Time (mins) Lo g A u ( m g/ L) Figure 1 [Au] concentration vs time The concentration of [Au] concentration was higher (up to 2 mg/L) with sodium ethyl xanthate addition added to the cyanide solution. This is due to the sodium ethyl xanthate affecting the carbon activity and resulting in less gold being adsorbed onto the carbon and staying in cyanide solution. In figure one you can see the gold concentration with added sodium ethyl xanthate addition stays fairly consistent in the 120minutes, while the gold concentration without sodium ethyl xanthate addition decreased over time. Rate constant for gold adsorption (S.E.X) = -0.0011 Rate constant for gold adsorption (without S.E.X) = -0.0022 The rate of the gold adsorption is higher in the test without S.E.X, due to the reaction of S.E.X with carbon, resulting in less carbon for the gold to be able to attach to the activated carbon. Table 3 [Au] concentration using organic solvent elution Sample Time (mins) volume (L) AAS Concentration (mg/L) Dilution Factor AAS Concentration before dilution (mg/l) [Au] eluted in each sample (mg) Cumulative [Au] eluted (mg) 1 4 0.02 no sample 2 8 0.02 0.506 1 0.506 0.01012 0.01012 3 12 0.02 0.326 1 0.326 0.00652 0.01664 4 16 0.02 0.336 1 0.336 0.00672 0.02336