The invention discloses a method for preparing
lithium phosphate with high efficiency and low cost, which comprises the following steps:
roasting spodumene concentrate and
phosphoric acid, and carrying out slurrying leaching and
solid-liquid separation to obtain a
lithium dihydrogen
phosphate solution; the method comprises the following steps: evaporating and concentrating a
lithium dihydrogen
phosphate solution, regulating the pH value of the lithium dihydrogen phosphate solution to 7-8 by adopting
ammonia water, adding
calcium phosphate seed crystals, inducing to remove residual
calcium ions and
magnesium ions in the solution, and carrying out
solid-liquid separation to obtain a phosphate solution containing lithium ions; and then adjusting the pH value back to 11-13 by adopting alkali for lithium
precipitation to obtain a
lithium phosphate solid, and washing and
drying to obtain a battery-grade
lithium phosphate product. According to the preparation process of the
lithium phosphate, the
spodumene is acidized and roasted by adopting
phosphoric acid, and pulpified and leached, and
calcium ions and
magnesium ions in a solution are directly induced by adopting calcium phosphate seed crystals to form crystals to be separated out on the basis of a weakly alkaline condition, so that the process steps are simple and convenient, the subsequent purification procedure is omitted, and the preparation process is more suitable for industrialization; meanwhile, the lithium
phosphate product with high purity and high yield can be obtained through the simple and convenient process, the purity can reach 99.5% or above, and the yield can reach 92% or above.