BHS-Sonthofen, Germany, has delivered the largest mixer in the company’s history to an Indian zinc mine operator requiring a mixer with a very large filling capacity. The proven Combimix system with overflow was custom-built by the German engineering firm to an extraordinary capacity of 28,000 litres and shipped to India in the second half of 2019. Installation in the zinc mine took place at the end of that year under the supervision of BHS experts.

To backfill the mines, the operators require high-quality and robust mixing technology with a very high throughput capacity. Overburden and filter cakes, by-products of zinc production, need to be mixed to a homogeneous mass, free of clumping, in order to make the mixture as readily pumpable as possible for backfilling.

The customer’s requirements were very clear: a longer retention time of the material in the mixer and a filling level below the mixing shaft. This means that the mixer required a much larger filling capacity to process the same quantity of mixing material than in the conventional design. Design engineer Sebastian Poppel was responsible for customising the technology. “With a throughput of 263m³/h, we arrived at a retention time of about 137 seconds,” he explained. “During this time, lumps are dissolved to our satisfaction thanks to the high-performance mixing unit.”

A characteristic feature of the twin-shaft mixer from BHS is the three-dimensional mixing action. The turbulent overlap zone of the two mixing circuits generates an intense material exchange, as well as very high relative movement, thus resulting in a highly homogeneous final product.

In addition to ease of maintenance including easy maintenance access, the customer also wanted a product that allowed for high-pressure cleaning. BHS-Sonthofen was able to meet these specific requirements. www.bhs-sonthofen.de
 

The production team in front of the largest twin-shaft mixer ever built by BHS
 

The Combimix system of the DKXC series with a capacity of 28,000 litres was adapted to meet the special backfilling requirements of the world’s largest zinc mine in India

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