Study On The Recovery Of Scandium From Red Mud By A New Nitrogen Neutral Phosphorus Extractant

Scandium is an important strategic resource.Because scandium has many advantages,includinghigh chemical activity,good conductivity,soft quality and easy cutting,it has been widely applied in many fields,such as national defense,electric light source,aerospace,electronics,nuclear technology,superconducting technology and so on.At present,scandium is mainly recovered as a secondary resource due to the lack of scandium independent mineral resources.And solvent extraction is the most important method to separate and purify scandium.In recent years,designing and synthesizing of novel extractants which can use to separate and recover scandium from waste resources and improve the recovery effect,have received more and more attentions.In this paper,several neutral phosphorus?phosphonic acid?extractant were designed and synthesized,and their properties and mechanism in the separate extraction of scandium were studied.Based on that,the experiment was designed to extract scandium from red mud.A series of?-aminophosphonate extractant,such as Cextrant 230?C230?,L1,L2,L3,L4 were synthesized and studied for the extraction of scandium.Suitable extractant was selected from these extractant to separate and recover scandium.The extraction performance of Scandium with?-aminophosphonate extractant?Cextrant 230?under different experimental conditions was systematically investigated.The factors such as mineral acids,acid concentration,the extractant concentration,and temperature were studied.The saturated loading capacity of extractant and the effect of stripping were studied and The mechanism of the extraction reaction was discussed simply.The effect of sulfuric acid leaching of red mud was studied,and then the factors such as sulfuric acid concentration,reaction temperature,reaction time and liquid-solid ratio on the leaching effect of red mud were inspected.The optimum leaching conditions are:sulfuric acid concentration is 20%;the reaction temperature is 80?,the reaction time is 100 min;the ratio of liquid to solid 6:1,the leaching rate of scandium in red was 78.5%.The extractant C230 was used to extract and recover Sc³⁺from the sulfuric acid leaching solution of red mud.Through experiments,the best acidity of the leaching solution was 0.1mol/L,the extractant concentration was 5%,phase ratio was 1:5,and the extraction rate of Sc³⁺reached over 90%.And the cascade experiment was been conduct,with 5 stages of extraction,5%C230 for extraction of organic phase;and 2stages of washing,deionized water as detergent;with 1 stage stripping,0.05%EDTA as stripping agent,organic phase,feed and stripping agent flow ratio is 1:5:1,after concentration,precipitation,calcination,a scandium oxide products with a purity of70%was obtained.