METHOD FOR PRODUCING HIGH-PURITY AQUEOUS LITHIUM SALT SOLUTION

Provided is a method for producing a high-purity aqueous lithium salt solution, the method allowing filtering aluminum phosphate in a short time. The method for producing a high-purity aqueous lithium salt solution includes: a step of adjusting the pH of a slurry containing a mixture of lithium phosphate and aluminum hydroxide obtained from a first aqueous lithium salt solution being a raw material to a range of 2 to 3 to obtain a precipitate of aluminum phosphate; a step of filtering off and removing the precipitate of aluminum phosphate to obtain a second aqueous lithium salt solution; and a step of purifying the second aqueous lithium salt solution to obtain a high-purity aqueous lithium salt solution.