Recycling of waste hydrochloric acid during chitin production process from Litopenaeus vannamei processing leftover

To decrease environment pollution and reduce the cost of in production of chitin, the waste hydrochloric acid in the process of chitin production was studied, and the process conditions were optimized by single factor test and orthogonal test, using the reaction of sulfuric acid and calcium chloride to recover and recycle hydrochloric acid solution. The best regeneration parameters were obtained:room temperature, concentration of the sulfuric acid of 98%, the molar ratio of sulfate radical and calcium ion of 2.3 : 1, reaction time of 13 min, standing time of 3.5 h. Under these conditions, the regeneration rate was 91.51%, and the hydrochloric acid could be recycled five times and the calcium carbonate residues of the shrimp shell were no less than ≤1.2%.