| Thiosulfate gold leaching has been considered to be the most promising alternatives to cyanidation of a nontoxic gold extraction technology. This method has faster leaching speed, non-toxic, higher leaching index, no corrosion to the equipment, and it is easier to process gold ore which contain copper, arsenic, antimony and carbonaceous. However, thiosulfate gold leaching technology should be solved the following two key problems before it's industrialization:the one is how to reduce the thiosulfate consumption sharply in the leaching process; another is how to effectively recover gold from thiosulfate leached solution. In this thesis, the process of the recovery of gold from thiosulfate leaching solution were studied. Ion exchange resin recovery of gold from thiosulfate leaching solution has been investigated. The suitable ion exchange resin and proper process conditions which content gold adsorption and gold desorption from loaded gold resin were tested. The results could be beneficial to further research of thiosulfate gold leaching.The atomic absorption spectrophotometry (AAS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis method were be used for determine of gold in gold leaching liquor. The results showed that the optimum conditions of AAS are shown as follows:determination of wavelength 242.8nm, acetylene and air flow 2.06,10.24L/min, slit 2.7/1.35, the flame height about 10cm. The optimum conditions of ICP-AES are shown as follows:RF 1150W, pump speed 50rpm, auxiliary gas flow 5L/min, mist flow 0.45L/min, displacement of gas flow is a large group. Two analysis methods are more accurate, good selectivity, fast analysis speed, simple operation.The test results indicate that D296 anion exchange resin could adsorb the gold in thiosulfate gold leaching solution. The adsorption properties of gold by resin such as pH value, concentration of copper sulfate, ammonia concentration, adsorption time, concentration of sodium thiosulfate, sodium sulfite concentration, the amount of resin, stirring speed at room temperature and atmospheric pressure have been investigated. The results shown that the copper ion was harmful to absorb gold on resin, and the higher copper concentration was, the worse adsorption effect of gold. Ammonia was good for gold adsorption. At a certain range of concentration, properly increase the ammonia concentration is beneficial to improve resin adsorption of gold. If the sodium sulfite concentration below 0.01 mol/L in the leaching solution, it could be used to improve gold adsorption on resin. The lower concentration of sodium thiosulfate was, the better adsorption effect of gold. The appropriate experimental condition was mixing speed 150rpm, the adsorption equilibrium time is about 400 minutes, the amount of the resin 0.3g, pH 11. The result of adsorption kinetics of gold on resin showed that the first-order kinetic equation could be describe the adsorption behavior of resin adsorbing gold, calculated by particle diffusion control.Different formulations of the eluate were selected to test gold loaded resin elution of gold. Based on normal temperature and normal pressure, rotating speed of 150rpm and eluate contained 3% thiourea and 7% hydrochloric acid solution, the elution rate was above 95%. After five recycling, the resin adsorption rate of gold decreased by 9%, the desorption rate dropped 6% on gold loaded resin and the resin powder ratio was less than 15%.The methods of gold adsorption in thiosulfate leaching solution which came from refractory gold ore and elution on gold loaded resin with D296 type anion exchange resin were studied. The adsorption and elution conditions of leaching solution of thiosulfate gold were researched. The optimum conditions were shown as follows:resin adding amount of 0.8g, pH values 11, stirring speed 150rmp and the adsorption time 6 hours. The test results shown that gold adsorption rate with resin could amount to 57.95% after a actual adsorption and gold loaded resin elution rate with hydrochloric acid and thiourea solution reached to 84.97% after a elution. |
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