The production process of alginate mainly includes raw material pretreatment, digestion process, condensation process, full mixing of alginic acid and sodium salt, etc.
The raw material of alginate is seaweed or kelp. Therefore, the pretreatment of the raw material refers to the soaking, washing and cutting of feeding seaweed.
Fresh kelp must undergo dilute acid treatment, water washing, and formaldehyde treatment before it can enter the digestion process.
Digestion treatment refers to the conversion of the water-insoluble alginate in the seaweed into water-soluble alkali metal salt under the condition of alkali and heating.
Condensation process is divided into acid precipitation method and calcium precipitation method.
The acid precipitation method uses sulfuric acid or hydrochloric acid as the acid precipitation agent. In comparison, the effect of hydrochloric acid is better than that of sulfuric acid.
The calcium precipitation method uses calcium chloride as the acid precipitation agent.
Alginic acid is a natural polymer with very unstable properties. It is easily degraded at room temperature.
Alginate is relatively stable. So the last step is to fully mix alginic acid and sodium salt to form sodium alginate.