New method for neutralizing and extracting cystine in two steps

Abstract

The invention provides a new method for neutralizing and extracting cystine in two steps and relates to the new method for extracting the cystine. The method decreases the consumption of acid and alkali and saves the production cost by decreasing operation steps of one-step acid dissolution and alkali neutralization. An added washing step is simple to operate and the time is relatively short, so the production period is shortened in comparison with the omitted acid dissolution and neutralization steps; besides, mother solution of a previous batch is completely recycled to wash crude cystine I of a next batch, so problems of treating the mother solution difficultly and causing environmental pollution easily do not exist any longer. Moreover, the mother solution is filtrate obtained after neutralizing and precipitating the cystine and tyrosine, so both the cystine and the tyrosine in the mother solution have saturated concentration, washing the crude cystine I by using the mother solution does not cause the loss of the cystine and the tyrosine, and the yield of the cystine and that of the tyrosine are increased finally.

Description

Technical field: [0001] The invention relates to a new method for extracting cystine, in particular to a new method for extracting cystine by two-step neutralization. Background technique: [0002] The production of amino acids by extraction is the earliest amino acid production method, and it is also a very important amino acid production method. my country began to extract cystine from hair in the 1970s, and has experienced more than 40 years of development. [0003] The current process of extracting cystine from hair has not changed much compared with the early stage. It is still a three-step neutralization method, that is: first hydrolyze the hair into amino acids with acid, and then obtain cystine through three neutralizations. The process is as follows figure 1 shown. [0004] In the process of extracting cystine, one, two, three mother liquors are produced by-product, which contain not only salt, but also a large amount of amino acids, which are of high value. Peo...

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Problems solved by technology

[0005] After extracting tyrosine from the three mother liquors, a large amount of mother liquor will still be produced. The amino acid content of this mother liquor is already low, and the content of ammonium chloride is not high enough. It has no economic value and has to be discharged.

Because its ammonia nitrogen content seriously exceeds the standard, it will inevitably cause serious environmental pollution.

[0006] The production process of the three-step neutralization method is relatively long, especially the static storage time after the first and second neutralization is longer, which prolongs the production cycle

Each step of the three-step neutralization will produce a corresponding mother liquor, which will cause the loss of cystine product, resulting in a decrease in product yield

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