CBU - Efficient Solution For HydroMetallurgy

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Alkaline fumes, sulfuric acid aerosols, hydrocyanide (hydrogen cyanide, prussic acid), mercury, chlorine, nitrogen oxide, sulfur dioxide, inorganic dust - this is by far a not complete list of hazardous materials subject to purification at the gold-processing plants (GPP) prior to release into the atmosphere. Cyanides are used in gold processing more often than other chemical elements because they are capable of absorbing up to 97% of the yellow metal, including the finest particles invisible to an unaided eye.

The downside of the cyanide technology is that even in small quantities they are prone to causing death in organisms – just a teaspoon of 2% cyanide solution is enough to cause fatality in an adult.

Therefore, the issue of GPP atmospheric emissions purification is extremely relevant, and requires the most designated approach. An efficient solution of this task is a patented development of engineers from Novosibirsk - Centrifugal Bubble Units (CBU).

CBU is a unit for perfect mixing of gas and liquid. Principle of CBU operation is based on gas flowing through rotating liquid layer held in turbulence chamber by gas flow and centrifugal force.

Advantages of the CBU:

1) High heat and mass exchange ratio (i.e. high efficiency) due to:

  • high gas velocity (way higher than in other units), increasing phase contact specific area by dozens (phase contact specific area in the CBU amounts to SEVERAL THOUSAND!!! m2/m3; chemical reaction volumetric rate in the CBU is 40-60 times higher than in regular bubble columns due to intensified mass transfer);
  • varying velocities of liquid and gas movement in the bubble column that enable liquid to constantly carry the reaction products away from the gas-liquid interface boundary.

2) Small size. With the same output, the CBUs have smaller dimensions compared to other units: diameter and height of a CBU with a gas output of 50,000 m3/hour is 2,100 and 4,100 mm respectively; and weight of such unit is only about 2,100 kg.

3) Simple and reliable structure:

  • no rotating assemblies;
  • no spray nozzles (get clogged often), which does not set strict demands to liquid quality; spray nozzles clogging is a constant headache around collecting coalescent dust particles or using caking absorbing agents;
  • liquid pressure value at the input to the CBU is not important (liquid pressure value at the input to units equipped with spray nozzles is strictly specified).

4) Self-similar operation mode of the CBU at fluctuations in gas discharge – the higher is gas discharge, the higher is centrifugal force holding the bubble column, where heat and mass exchange processes run (therefore, a possibility of the bubble column breakdown is completely eliminated, because it becomes even more stable).

5) Lack of drop enairment due to efficient separating area designed for separation of liquid phase from gas. Therefore, the CBU does not require supplementary drop-collecting extensions in the system.

CBU can be used in various fields: mining and processing, power industry, metallurgy, chemistry, petrochemistry, oil refining, agriculture, building materials manufacture, mechanical engineering etc.

Centrifugal Bubble Units (CBU)