Patent ID: 7416740

Claim:
A method for preparing a dry granulated product containing L-lysine and having the following composition: L-lysine content in solid matter: 40 to 85% by weight equivalent ratio of anion/L-lysine: 0.68 to 0.95 moisture content: 5% by weight or less wherein the equivalent ratio of anion/L-lysine is a value calculated in accordance with the following equation by using L-lysine (L-Lys) content, sulfate ion content, chloride ion content, ammonium ion content, sodium ion content, potassium ion content, magnesium ion content and calcium ion content in the solid matter of the dry granulated product: equivalent ratio of anion/L-lysine=(2×[SO 4 2− ]+[Cl − ]−[NH 4 + ]−[NA + ]+[K + ]−2×[Mg 2− ]−2×[Ca 2+ ])/[L-Lys] where [ ] means a molar concentration which method comprises adding hydrochloric acid or sulfuric acid to a raw material L-lysine solution having an equivalent ratio of anion/L-lysine lower than 0.68 to adjust the equivalent ratio of anion/L-lysine of the raw material solution to be in the range of 0.68 to 0.95, and obtaining the dry granulated product from the obtained L-lysine solution or a concentrate thereof.