The average American citizen is probably unaware that production of sodium carbonate, also known as soda ash, is used to measure the strength of the nation's economy. Soda ash has applications in both the automobile and construction industries, meaning production trends of soda ash can, qualitatively at least, indicate near-term economic activity.

Also known as washing soda and by its chemical symbol Na2CO3, natural soda ash is refined from trona or from sodium-carbonate-bearing brines. It can also be chemically reproduced using the Solvay method.

Nearly half of the soda ash produced in the United States annually is used in the manufacture of glass. Other applications of soda ash include the manufacture of chemicals, paper and detergents.

Characteristics and Challenges:

Generally soda ash is free flowing, granular and may be mildly abrasive. Soda ash is made in three main grades — light, medium and dense. These have the same chemical properties and only differ in physical characteristics, such as bulk density and particle size and shape (which affect flow characteristics and angle of repose).

If the soda ash is being pneumatically conveyed into a processing system, the blower used to move the soda ash through the convey line must be sized to meet the demands of system. Soda ash can be degradable, so care must be taken to maintain an air-line velocity that does not damage the material.

If the soda ash arrives at the processing facility in bulk bags, the frames used to discharge the bags should be equipped with additional accessories to completely empty the soda ash from the bag. This includes features such as spring-loaded frames that will stretch the bags as they empty and lighten, making them rigid and removing any residual accumulations of material in the bags. Bag-activating devices are usually effective in agitating the soda ash, dislodging agglomerations and promoting a better flow. Some of these bag-activating devices also serve as a dust tight seal between the bulk bag and the receiving hopper.

Soda ash has been identified as an eye and lung irritant, meaning the systems used to transport it should be equipped with dust collection devices. After the bulk bag containing soda ash has been connected to the receiving hopper and the product begins to flow, the air inside the hopper is forced out. Unless this air passes through a filter, airborne dust particles can escape into the surrounding atmosphere. A dust collector mounted on the discharger frame will contain the soda ash inside the conveyance system, lowering the risk of a potentially dangerous dusting. Soda ash dust trapped in the filter media can be returned to the receiving hopper by a pneumatic pulse through the filter. This reduces waste and the time necessary to perform the routine cleaning and sanitation typically required in most chemical processing environments.

Coarser particles of soda ash will tend to interlock in hoppers, impeding its flow into downstream processing equipment. To promote flow, the feed hoppers may need to incorporate devices such as mechanical agitators or vibrators.

Soda Ash
If the soda ash is packaged in smaller bags, a bag dumping station with a dust hood and filtration devices may be sufficient to support the manual unloading of the material in hoppers. A bag compactor connected to the dumping station will permit operators to pass empty bags directly to a compactor, creating a dust-contained disposal method for the empty bags. A hopper screen above the receiving vessel will help to prevent the introduction of foreign objects and protects the operators from potentially dangerous conveying equipment.

If a flexible screw is being used to convey the soda ash, it is important to use a screw that matches the material's characteristics and other application requirements. Generally a screw with a round profile will be effective in moving soda ash to a filling machine undamaged and with no separation of fine particles.

Should your soda ash application feature the loading the material into bulk bags, the bag capacity will be maximized by use of a vibratory densification deck to de-aerate the soda ash as it fills the bag and by the application of load cells to achieve the desired weight. Seals and other dust containment devices will ensure a dust-tight operation.

Flexicon Applications:

Flexicon's Flexible Screw Conveyors are simple, compact, and widely used to convey soda ash horizontally. A Flexicon-designed and manufactured bulk handling system is at work for a leading bottle producer in the UK.

Flexicon's Dust Suppression and Collection Systems ensure proper containment of soda ash throughout the conveyance process. Flexicon's High Flow Hopper, purpose-built for flexible screw conveyors, increases the flow of both free- and non-free-flowing bulk materials while eliminating or decreasing the amount of residual material in the hopper as well as the need for flow promotion devices is perfectly suited for soda ash handling.

Flexicon's product line of advanced flow promotion conveyors, high-flow hoppers, deaeration/densification decks and a host of other components and accessories are proven performers that promote flow while reducing degradation, dusting and/or the separation of blends comprised of disparate particles.

Flexicon's test lab will simulate your soda ash handling applications before the system is installed in your plant.

Sources: Where noted. All other information courtesy of Flexicon Corporation.


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