(1) Add purified water (deionized water) to L-Lysine hydrochloride, the weight ratio of L-Lysine hydrochloride to purified water is 1:1, mix well and dissolve completely, set aside for use ;
(2) Column adsorption
Add the lysine obtained by step (1) into the ion exchange column equipped with cation exchange resin at a flow rate of 13 L/min until the resin cation exchange resin completely absorbs lysine, and the discharge of the column does not contain lysine , then wash with purified water by the resin in the exchange column, and wash to the effluent of the column without Cl (the pH of the effluent at this moment is 7);
Then use 2mol/L NH4OH (ammonia) to elute L Lysine, NH4OH flows through the ion exchange column at a flow rate of 13L/min, when the pH value of the effluent of the ion exchange column rises to 8.0, the effluent begins to There is a ninhydrin reaction, that is, L-lysine starts to flow out, and the effluent is collected; when the pH value of the effluent of the ion-exchange column rises to 9.0-12, the color of the ninhydrin reaction is dark, and the L-lysine content is high at this time. Elute until there is no ninhydrin reaction in the effluent to stop the collection;
(4) Concentration under reduced pressure
Concentrate the collected solution under reduced pressure at 0.2Mpa and 60-62°C to catch ammonia, concentrate to 1/3 of the volume of the original collected solution, add activated carbon with a weight of 3.5% of the concentrated solution at this time to decolorize, filter, cool and crystallize, and obtain L ‑Lysine.
The purity of the product detected and calculated by a potentiometric titrator is 98.5%.