Abstract: At present， the study of rare earth leaching only focuses on one aspect of inhibiting the impurity leaching or the swelling of clay minerals in the process of rare earth leaching. In order to comprehensively consider the synergistic effects of high effective aluminum inhibition and clay mineral swelling inhibition during rare earth leaching， leaching agents are composed of ammonium chloride and ammonium acetate， ammonium tartrate， ammonium citrate three ammonium carboxylate assist leaching agent to reduce the leaching efficiency of impurity aluminum and ensure the efficiency of rare earth， at the same time， the best swelling inhibition conditions were obtained. The effects of the assist leaching agent concentration ， leaching temperature and solution pH on the leaching process of weathered crust elution-deposited rare earth ore and the swelling properties of clay minerals were also studied while 0.2 mol/L ammonium chloride mixed with the three carboxylic acid ammonium salts. The results showed that the optimal addition concentration of the three ammonium carboxylate were: 0.04 mol/L ammonium acetate， 0.07 mol/L ammonium tartrate， 0.005 mol/L ammonium citrate， the aluminum inhibition capacity was: ammonium acetate＞ammonium citrate＞ammonium tartrate， and the swelling ratio of clay minerals was: δacetate＜δtartrate＜δcitrate. At normal temperature， the mixed solution of 0.2 mol/L ammonium chloride and 0.04 mol/L ammonium acetate as the leaching agent had the best effect of aluminum inhibition and swelling inhibition. The optimal pH condition was 4， the leaching efficiency of rare earth was 90.08%， the leaching efficiency of aluminum was 26.37%， and the swelling ratio of clay mineral was 2.705%.

Key words: Weathered crust elution-deposited rare earth ores, Assisted leaching, Aluminum inhibition, Swelling