Study On Micro-enrichment Of Trace Rare Earth Elements In Phosphate Acid Solutio

With the rapid development of new energy and intelligent manufacturing and other fields,the demand for rare earths in the market has been continuously increasing.Due to the excessive consumption of rare earth mineral resources in China,the resource security situation is quite severe.Therefore,actively seeking rare earth substitutes,exploring new rare earth deposits,and exploring other rare earth-associated resources are urgent key issues to be solved.However,the development of rare earth-associated resources is a work with high technical difficulty and high cost,requiring a lot of investment and resource support.The rare earth resources associated with the Zhijin phosphate mine in Guizhou have high utilization value.By exploring suitable separation and extraction technologies and realizing the efficient utilization of associated resources of phosphate mines,it can provide a new growth point for the Guizhou phosphate chemical industry and support the sustainable development of China’s rare earth industry.This article focuses on the nitric acid leaching solution of the Zhijin phosphate mine,and a simple and efficient rare earth enrichment method was developed using modified resin,based on the analysis of the characteristics of phosphate mineral features,nitric acid leaching solution composition and properties.This method can not only adapt to strong acid environment containing a large amount of impurity ions but also achieve the reuse of adsorption resin.Through experiments,732 hydrogen type strong acid cation exchange resin with good adsorption performance under strong acidic conditions was screened out,and several different modification methods were used to modify it to improve the extraction rate of rare earth ions in phosphate acid solution.The study found that multi-step modification can cause damage to the resin ball structure and affect its rare earth enrichment efficiency.This is also the main reason for the unstable adsorption performance of modified resin.Therefore,the two-step amination modified resin was used,and the modifier Z was selected as the modifier.Under the conditions of reaction temperature of 80 °C and reaction time of 6 h,the modified resin had the best effect and stability of rare earth enrichment.The modified resin was characterized by FT-IR and XPS,which indicated that the amination reaction can significantly increase the surface roughness,thereby providing more adsorption sites and further improving the adsorption performance of the resin.Through single-factor experiments of rare earth ion enrichment in the nitric acid leaching solution of phosphate ore using modified resin,the optimal enrichment conditions were explored: resin dosage of 1.0 g,stirring time of 20 min,acid leaching solution pH of 0.8,stirring temperature at room temperature.The highest enrichment rate can reach 91.74%.According to ICP measurement,most of the rare earth ions were separated out by precipitation during the resin adsorption process.mingx It was found that the content of rare earth elements in the precipitate was 12841.5 μg/g,which is13.79 times that of the original ore.This is because a large number of amino groups are introduced into the modified resin,and the surface pH of the aminated resin is higher in strong acid solution,which causes a micro-area balance of adsorption-desorption of metal cations to occur on its surface,thereby achieving rare earth enrichment and separation.Considering the characteristics of the modified resin,the modified resin can be recycled while ensuring the integrity of the resin structure,and the rare earth enrichment rate can still reach 90% after multiple cycles of use.