Studies On The Enrichment And Separation Characteristics Of The New Ion Exchange Fiber To The Ions Of Precious Metals

In this dissertation, the basic properties of precious metals and the basic methods of enrichment and separation of the precious metals have been summarized. The status to the research of ion exchange fiber are reviewed. On the basis of the above, the enrichment and separation characteristics of a new ion ex-change fiber to the ions of precious metals such as gold, palladium, platinum and silver have been studied. The main contents and the conclusions are as follows:1. The enrichment rate of gold by the anion exchange fiber was not greatly influenced by the temperature. Under the normal temperature, the anion exchange fiber adsorbs and rich the gold quickly. When the solution current velocity is 7 mL/min, enrichment rate of gold reaches 98%. The saturated exchange capacity reaches 4.04mmol/g. This result is better than the theoretic value (The maximal exchange capacity of the new exchange fiber is 3.0mmol/g).This is a result that some gold ions are reduced to gold on the fiber. The result also shows that the exchanged gold can be quantitatively desorbed with the mixed solution of 1% thiourea and 1mol/L hydrochloric acid .The effect is good. When the velocity is 5mL/min, the desorption rate of gold attains 95% above. And the anion exchange fiber easily reborn and was reused again and again.2. The enrichment and separation characteristics of the anion exchange fiber to palladium have been studied, the results show that the enrichment rate of palladium reaches 98% in the condition of the pH 2 and the solution current velocity is 7mL/min. The exchange capacity is great and the adsorption capacity reaches 2.62mmol/g. The effect of the other ions to the enrichment rate of palladium is negligible, but the concentration of chloric anion influenced greatly. The results also show that the exchanged palladium can be quantitatively desorbed with the mixed solution of 1% thiourea and 2mol/L hydrochloric acid .The effect is good. When the velocity is 3mL/min, the rate of desorption attains 97% above .And the anion exchange fiber was easily reborn and was reused again and again. 3. The enrichment and separation characteristics of the anion exchange fiber to platinum have been studied. The result shows that the enrichment rate of platinum reaches 96% in the condition of the pH 2.5 and the solution current velocity 3mL/min. The exchange capacity is great, and the adsorption capacity is 2.47mmol/g. The results also show the exchanged platinum can be quantitatively desorbed with the mixed liquid solution of 5% thiourea and 2mol/L hydrochloric acid. The effect is good, when the velocity is 3mL/min, the desorption rate of platinum attains 96% above .And the anion exchange fiber was easily reborn and was reused again and again.4. The enrichment and separation of the ion exchange fiber to silver has been studied, the results show that the enrichment rate of silver achieves 96% in the condition of the pH 3 and the solution current velocity is 5mL/min, The exchange capacity is great, the adsorption capacity is 4.21mmol/g. The result also shows the exchanged silver can be quantitatively desorbed with the solution of 5mol/L nitric acid .The effect is good ,when the velocity is 2mL/min,the desorption rate of silver attains 90% above .And the anion exchange fiber easily reborn and was reused again and again.