Ultrasonic Preparation of Brines

• Brines are a solution of salts, e.g. NaCl, KCl, KNO₃, KClO₃, CaCl₃ in water, which are prepared for the food industry, fish farming or drilling fluids.
• The process of dissolving salts in water can be time-consuming, when no or insufficient agitation is applied.
• For the industrial preparation of brines, ultrasonic dissolving is an excellent technique to achieve high dissolution rates and high saturation.

Ultrasonic Preparation of Brines

Materials to Dissolve:

Many industrial formulations require the dissolving of ingredients such as salt as and sugars. In the industry, salt brines are used as anti-freeze, as stabilizers, as condiment and preservative (e.g. in the food industry), for the preparation of saline water (e.g. in the fish farming industry) or as starting material for electrolysis.
Salt brines are known for their effects on lowering of the freeze point, that makes it a useful secondary refrigerant. Furthermore, salt helps to stabilize particles in suspension and prevent their settling. This makes brines a widely used additive in product formulations.

Problem:

Salt at the bottom of a batch or tank needs several days to dissolve without mechanical mixing. With increasing salt concentration, dissolving rates decrease substantially. Especially the last percentages of a highly saturated solution (e.g. 90°SAL) take a long time to dissolve.
Salts, which are difficult to dissolve such as BaSO₄, PbS, HgS, AgCl, need intense agitation to be completely dissolved.

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Solution:

Powerful ultrasound shear forces supply the required energy to dissolve soluble substances, e.g. salts or sugar. The intense shear is generated, when intense ultrasonic waves are coupled into liquids and slurries resulting in strong cavitation. In the cavitational “hot-spot”, extreme conditions are prevailed as locally occurring high temperatures and cooling rates, high pressure differentials and liquid jets.
The streaming and shearing of ultrasonics allows for more solute/solvent contact so that the salt is dissolved significantly faster in the water forming a uniform brine.
The solubility of most materials increases with elevated temperatures. In the cavitational hot-spots, high temperatures of up to 5000K and fast cooling rates can occur, which assist dissolving processes. The salt is dissolved agglomerate-free, achieving a stable product of high quality. After the dissolving process, ultrasound can also used to blend the brine homogeneously into the final product.
The flexibility of ultrasonic processing allows for the fast and simple adjustment of the sonication to the specific requirements so that brine formulations can be exactly prepared to specific requirements.

Ultrasonic Equipment for Brine Preparation

Ultrasonic dissolving of ingredients can be carried out as batch and continuous inline process. The powerful ultrasonic agitation and shearing of the substances in the liquid provide a very fast and efficient dissolution. Whether low, high or even over-saturation is required, power ultrasound offers reliable mixing at high dissolving rates.
Ultrasonic equipment from 50W to 16,000W per unit are available to fulfill reliable dissolving at any process scale. Hielscher’s ultrasonicators are very robust, need only low maintenance and are built for 24/7 heavy-duty operation.