Study On The Recovery Of Ruthenium From Low Concentrations Of Ruthenium Containing Organic Waste Liquid

The chemical industry produces a large amount of rhodium-containing organic waste during the production of rhodium acetylacetonate(Rh(acac)3),which is much higher than the mineral resources,but accumulates for a long time due to the lack of a suitable rhodium recovery process.In this paper,based on the literature review of rhodium-containing organic waste,rhodium recovery process based on sulfide precipitation-sodium nitrite complex method was proposed for the waste solutions: the waste solution was precipitated by adding sodium sulfide solution-sodium nitrite complex method to obtain rhodium solution-moderate temperature chlorination method to purify rhodium-hydrogenation reduction method to obtain rhodium powder.The main findings are as follows:1.The thermodynamics research of sulfide precipitation process shows that when the temperature is constant,the reaction pH,and the potential have a significant impact on rhodium precipitation rate.During the precipitation process,the potential and pH can be proper controlled to allow the rhodium to precipitate from the solution as a sulfide.In the experiment,saturated sodium sulfide solution was used to precipitate rhodium from the organic waste liquid and adjust the reaction pH value.2.The kinetic study of sulfide precipitation process shows that the reactant solubility,reaction temperature and stirring speed have a significant effect on rhodium precipitation rate.During the precipitation process,the appropriate reactant concentration,reaction temperature and stirring speed can be controlled to allow rhodium to precipitate rapidly from the solution in the form of sulfide.3.The optimum conditions were as follows: reaction temperature 80?,reaction time 6h,reaction initial pH value 6 ~ 7,end point p H value less than 9.5,saturated sodium sulfide solution dosage 20 times the theoretical amount,and stirring speed 300 r/min.Under these conditions,the rhodium yield is more than 80%,and after the secondary precipitation,the rhodium yield is over 85%.4.The content of rhodium in the slag is 54.83%.The rhodium-containing dross was dissolved in aqua regia,and crude rhodium was prepared by sodium nitrite complexation method.The crude rhodium and sodium chloride were well ground and mixed thoroughly,placed in the tube furnace for the temperature chlorination.The results show that 1.3 ~ 1.5 times of the theoretical amount of NaNO2,1.2 ~ 1.5 times of NH4 Cl and 1.2 ~ 1.5 times of the theoretical amount of sodium chloride need to be used to obtain rhodium black.The rhodium black was prepared by liquid phase reduction,and the purity of rhodium powder was not less than 99.95% after calcination and hydrogen reduction.The final rhodium recovery rate was over 86%.The process and parameters of rhodium recovery from the organic waste liquid were established by the experimental study.The rhodium recovery rate was high and the operation was simple,which could be used for the recovery of rhodium in different types of organic waste and provides guidance for the recovery of valuable metal from organic waste.