The crustaceans of shrimps and crabs, after a series of chemical treatments, can be made into acid-soluble chitin, which can be dissolved into a white transparent colloidal solution in 0.5%-2% dilute acetic acid. It has a strong adhesiveness and is a textile, printing and dyeing. One of the important raw and auxiliary materials for industries such as food, cosmetics, artificial fibers, wood processing, plastics, and pharmaceuticals. Coastal crustaceans produce a wealth of production and can increase chitin production. The extraction process is as follows (the ratio of the materials in the article can be increased or decreased compared to the same period).
Raw shrimp and crab crust, dilute hydrochloric acid, caustic soda (sodium hydroxide) solution, potassium permanganate solution, sodium sulfite solution, glacial acetic acid.
Tools Casseroles, iron pans, brick drying rooms, acid tanks, salinity meters, thermometers, stoves, etc. Wash the collected shrimp crab shells with tap water or high-pressure water gun while washing and turning to attach the meat and mud attached to the shell Sand removal.
Softening and decalcifying 50 kg of shrimp crab crusts were immersed in 75 kg of dilute hydrochloric acid with a concentration of about 5%. Mix well with wooden sticks, add weights on top of the board, add weight to the board, and seal so that the carapace can be completely submerged in hydrochloric acid. At this time, the hydrogen ions in the hydrochloric acid react with the carapace. After a chemical reaction for 24 to 28 hours, the calcium in the carapace is displaced. Then remove the softened shells in a basket and rinse them repeatedly with water until they are not acidic.
Digestion of protein and degreasing 40 kg of caustic soda solution in an amount of 8% -10% is boiled in a pot, and then the softened shell is poured into a pot and boiled for 1.5 hours to completely dissolve the protein and lipid contained therein. Then the shrimp and crab shells are picked in a basket and rinsed repeatedly with water until it is not alkaline. Forcefully dry the shells.
80 grams of potassium permanganate was poured into a sand jar, and 40 kg of water was added to stir. Then the shell of the alkali was put in. The solution in the sand jar became brown due to oxidation, and the shell was collected after 1 hour. In the pan, rinse repeatedly with water.
Decolorize 450 g of sodium sulfite, add 50 kg of water, stir well into the casserole, then pour the oxidized shell. Stir for 10 minutes. The surface of the carapace is gradually bleached. Add water (20-50 kg) for 15 minutes. Add 5%. Dilute hydrochloric acid 1.5-2.5 kg and stir for 10 minutes. When the shell becomes pure white, it can be picked up.
Semi-finished products will be decolorized and bleached shrimp crab shells on the water and repeatedly rinse with fresh water, and then squeezed water, row on the flat bottom bamboo dried, ready to dry.
The finished product will be 40% caustic soda solution 40 kg can be immersed semi-finished chitin 10 kg, with a suitable Tao Tao put, stir evenly into the drying room, the room temperature can be gradually increased from 40 °C to 60 °C and maintain a constant temperature, every other After stirring for a few times, after stirring several times, it can be stirred every 5 hours. After 20-24 hours, a small amount of sample can be taken out and washed, and placed in 1% glacial acetic acid. If it can be completely dissolved, it means that it has been successfully produced. Otherwise, it is necessary to extend the constant temperature time to 30 hours. Wash the chitin removed in the drying room with cold water so that it does not contain alkali. After squeezing the water, spread it on a flat bamboo basket and dry it. The dried white chips are the acid-soluble chitin.
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