Preparation Of Carbon Materials Based On Urea Formaldehyde Resin And Its Properties Of Removing Fe³⁺ Impurity From Rare Earth Materials

Rare earths are very important strategic resources. However, non rare earth impurities have great adverse impact on the properties of rare earth materials. Fe³⁺ is the main impurity found in the rare earth materials. In order to meet the demands in many high-tech fields, it is necessary to purify the rare earth materials, mainly removing Fe³⁺ from them. Therefore, the research of efficient and convenient methods of removing impurities in rare earth materials from high purity rare earth solution is extremely important.Carbon materials was synthesized based on homemade urea formaldehyde resin（UF）precursor together with starch and melamine as raw materials through carbonization at high temperature with sodium bicarbonate as pore-forming activator. Carbon materials based on urea formaldehyde resin was characterized by fourier transform infrared spectroscopy（FT-IR）,scanning electron microscopy（SEM）, static nitrogen adsorption instrument and so on. The static and dynamic methods were also adopted to study the binding properties and recognition characteristics of carbon material based on urea formaldehyde resin towards Fe³⁺. The research includes the following four parts.AC_UF possesses strong adsorption affinity and excellent recognition selectivity for Fe³⁺.The AC_UF adsorption capacity could reach to 13.0 mg·g-1; relative selectivity coefficients was28.0, compared with La3+. Besides, carbon materials has excellent elution property: with a diluted aqueous solution of HCl（2 mol·L-1） as the eluent,the desorption ratios of pirimicarb reach 98% in 28 BV.By adding starch in the preparation process of carbon precursor, it can not only improve the adsorption capacity of the carbon materials towards Fe³⁺, and also promote the recognition selectivity for Fe³⁺. The AC_UF-ST adsorption capacity could reach to 22.3 mg·g-1, while relativeselectivity coefficients was 45.4, compared with La3+. Besides, carbon materials has excellent elution property: with a diluted aqueous solution of HCl（2 mol·L-1） as the eluent, the desorption ratios of pirimicarb reach 98% in 30 BV.By adding melamine in the preparation process of carbon precursor, the adsorption capacity of the carbon materials towards Fe³⁺ was improved, but the materials’ recognition selectivity for Fe³⁺ decreased obviously. The ACMUF adsorption capacity could reach to 20.6mg·g-1, meanwhile relative selectivity coefficients was 3.04 relative to La3+.By adding starch and melamine in the preparation process of carbon precursor, the adsorption capacity of the carbon materials towards Fe³⁺ was improved, but the materials’ recognition selectivity for Fe³⁺ slightly decreased. The ACMUF-ST adsorption capacity could reach to 18.7 mg·g-1, and relative selectivity coefficients relative to La3+ was 21.3.