Producing the Key Ingredient in Alginate Impression Material

Producing the Key Ingredient in Alginate Impression Material


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Sodium alginate manufacturing uses two processes; 1) The calcium alginate process; and 2) The algenic acid process.

Alginate is an important raw material made from refined seaweed which is used in a number of industries: Such as in a wide array of medical and clinical applications. It has a number of applications in the pharmaceutical industry. In the food and beverage industry, it is used as a thickener, softener and binder. Alginate is also used for a large number of industrial applications such textiles, printer and welding. In the leisure industry it is used as a beauty treatment. Alginate is also used in the craft industry as a skin-safe mold making ingredient

Refined alginate is derived from the cells of brown seaweed which is available throughout the world, but primarily from Northern Europe, Chile, China and our west coast

Alginate is refined using two methods – the calcium alginate process and the algenic acid process. The processes are identical through the first 6 steps, but then diverge in the last three of the refining steps.

In the first step, consists of the harvesting of the brown seaweed. It is then dried and chopped before it can be used.

The seaweed can be gathered in the open sea using specially build ships or from seaweed farms which have developed to conserve our ocean environment. Once harvested, it is hung up to dry on large poles. After drying it is chopped into small pieces so that it can be better processed.

Dilute formalin which is added to each batch of chopped seaweed. This is a solution of formaldehyde containing a small amount of methanol. This chemical causes the seaweed to swell up.

When the seaweed has swollen, the next step adds a sodium carbonate solution. This alkaline solution begins the extraction process.

It takes a large capital investment in extraction machinery to refine the alginate into a useable raw material.

The extraction process uses centrifugal force to separate out the liquid from the solid matter.

At the end of this phase the seaweed has been separated into an algin containing liquid and a solid seaweed slurry. The slurry isn't wasted as it is used for feed and fertilizer.

In the sixth processing step, sodium alginate is produced.

In the alginic acid process, hydrochloric acid is added to the sodium alginate creating a gel-like substance

In step 8, the some of the liquid is evaporated off in a dewatering process

In the last step sodium carbonate is added and the resulting mixture is heated to 50-95 Celsius to completely evaporate the liquid leaving behind solidified alginate which is ground to different finesses depending on the customer needs.

Final processing is the packaging of the refined alginate and loading it for export on trucks and cargo ships for distribution around the world.

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