In a method and an apparatus for recovering chemicals from an alkaline lignin material, the alkaline lignin material (3) which comprises NaOH or KOH is precipitated in presence of an acid in a precipitation stage (6) for forming a precipitated lignin (7), the precipitated lignin (7) is supplied to a separation stage (8) in which a purified lignin (9) is recovered and from which at least one fraction (10) which comprises Na or K is supplied to a crystallization stage (11), and the fraction (10) which comprises Na or K is treated by crystallization in the crystallization stage (11) for forming a crystallized compound (12). Further, the invention relates to use of the purified lignin, and lignin and chemical products.