The sixth step in making corn starchProtein separation and starch cleaning
The starch milk after separation of coarse and fine residues has a concentration of 6 to 8 BoM and contains about 11 to 14% dry matter. The chemical composition of the starch here is analyzed in the table below.
As can be seen from the above table, the dry matter in the starch milk is mainly protein and water-soluble substances in addition to starch, so protein separation and starch cleaning must be performed.
The separation of protein is generally done by flow separation, which is gradually changed to centrifuge separation due to the large area and low separation efficiency. However, it is required that the starch milk contains less residue to prevent the nozzles in the disc from clogging and causing mechanical vibration.
After separating the protein crude starch milk must be cleaned. Most of the starch cleaning is done in the cleaning pool, but the cleaning time is long and the starch loss is large. Starch cleaning in modern corn starch plants is carried out with a cyclone separator, which is generally treated with a 9 to 14-stage cyclone separator. It is measured that the protein content of starch milk from the centrifuge is not more than 2.5%, and after the 9-stage spin-liquid separator treatment, the protein content in the finished starch can be reduced to 0.35%.