Abstract:To avoid the problem of residual ammonia nitrogen during in-situ leaching of ion-type rare earth ores, calcium chloride was selected as a new type of non-ammonia leaching agent to carry out leaching process simulation and parameter optimization. The effects of leaching solution concentration, pH value, and solid-liquid ratio on rare earth leaching rate were mainly tested. The results showed that: 1) the leaching capacity of CaCl2 and MgSO4 was 84.5% and 74.6% of that of ammonium sulfate under the same leaching solution concentration, pH and solid-liquid ratio. 2) When the leaching solution concentration was 7%, the solid-liquid ratio was 1: 1, and the pH value was 4.6, the leaching effect of calcium chloride was the best. 3) Calcium hydroxide was used to remove impurities and precipitate the mother liquor of rare earth chloride. Pure rare earth hydrogen and oxygen products can be obtained by controlling the pH value between 5.1～5.4 and 6.0～6.5 during impurity removal and precipitation.