Optimization of Separation Process of Eggshell and Shell Membrane

The two must be separated first to exploit the eggshell and the eggshell membranes. In this paper, a combination of mechanical crushing, water flotation and dilute acid treatment was used for shell membrane separation, and the conditions of eggshell and subshell membrane separation were screened. The effects of hydrochloric acid volume, reaction time and hydrochloric acid concentration on the rate of eggshell membrane decalcification were investigated by single-factor tests. And the response surface method (RSM) was applied to optimize the process conditions for removing the residual eggshells from the eggshell membranes with dilute hydrochloric acid. The results showed that the shell-membrane separation effect was the best when the eggshells were crushed under the condition that the crusher runs for 5 s/time and crushes 3 times. The powder extraction rate was 58.72%, the membrane removal rate was 87.91%, and the comprehensive score was 72.91. The best conditions for removing the residual eggshell in the eggshell membrane with hydrochloric acid were 1 g crude eggshell membrane, 20 mL hydrochloric acid, 19 min reaction time, and 0.5 mol/L hydrochloric acid concentration, and the decalcification rate could reach 89.21%. This process would provide the technical support for the intensive processing of the eggshell.