جداسازي كادميم از پسماندهاي كارخانه ذوب روي با روش استخراج حلال اونتراسونيكي

چكيده انگليسي :

Cadmium Recovery from Zinc Plant Residues using Ultrasonic assisted Solvent Extraction Mahboobeh Daryabor m daryabor@ce iut ac ir september 21 2014 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111Degree M Sc Language Farsi Supervisors Hamid Zilouei hzilouei@cc iut ac ir Ali Ahmadi a ahmadi@cc iut ac ir Abstract Cadmium is one of the valuable metals in the oxidic and sulfidic ores of zinc which is separated as a solid slag namely cold filter cake from the zinc effluent This metal has several applications in the strategic indus tries The purpose of this study was the separation of cadmium from zinc using solvent extraction process The potential of ultrasonic waves to improve the rate and selectivity of the Cadmium extraction was evaluat ed and compared to the conventional method by mechanical stirrer First of all the filter cake was obtained from Isfahan Zinc Smelting Company IZSC and its chemical characterization was analyzed Then primari ly leaching experiments were performed in the presence of 20 pulp concentration temperature of 60 C 20 v v sulfuric acid for 2 hours Results of leaching experiments showed that the recovery values of zinc and cadmium are 93 and 88 respectively In the next step the solvent extraction experiments were per formed using 20 v v D2EHPA diluted in kerosene at ambient temperature and organic to aqueous phase ratio O A 1 1 using both mechanical stirrer and ultrasonic methods The experiments of mechanical stir ring were conducted at stirring rate of 550 rpm for 10 min in the different values of pH 1 2 3 and 4 The experiments of ultrasonic stirring were carried out in 3 min different values of pH and ultrasound power 30 Watt Desired zinc extraction higher than 50 and undesired cadmium extraction in both mechanical and ultrasonic stirring systems were obtained for the leachate of filter cake To investigate the conditions of cad mium extraction synthetic sulfate solutions of cadmium and zinc were simulated and used Then effects of type of the stirring system the ratio of zinc and cadmium metals pH value contact time of two phases and ultrasound power on the separation of metals were investigated The results showed that using the ultrasonic stirring system increased the extraction efficiency of cadmium 20 and reduced the extraction time to 1 min towards the mechanical stirring system however zinc extraction had not significant improvement using the ultrasonic stirring compare to mechanical system Furthermore it is observed that in the mechanical and ultrasonic stirring systems the highest rate of extraction of two metals occur in the pH values of 4 and 1 respectively The results indicated that by increasing the ultrasound power to 60 watt the extraction rate of cadmium was increased and in the higher power values the emulsion formation was prevented the phase dis engagement According to the results despite of increasing cadmium extraction using the ultrasonic system zinc extraction was higher than cadmium under different conditions Therefore in the environments where the values of zinc metal were high using D2EHPA extractant is not appropriate for cadmium extraction and it is suggested that the zinc was extracted by solvent extraction route follow by cadmium extraction by the other rotes such as cementation and vacuum distillation Key words Solvent extraction ultrasonic cadmium zinc D2EHPA

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جداسازي كادميم از پسماندهاي كارخانه ذوب روي با روش استخراج حلال اونتراسونيكي

D2EHPA