Storage of the Concentrates

The control room – from here all of the process sequences are monitored and controlled. The individual zinc concentrate grades and the oxidic starting materials have very different chemical compositions and are therefore prepared according to a mixing plan calculated beforehand. This mixing is carried out with the help of a bridge crane.

In this case the grades are put onto a heap by means of the grab. When an amount of about 150 tonnes has accumulated this mixture is conveyed to charging bins, via screens and conveyor belts into the storage bin of the fluidized bed furnace. On the way to the furnace, the material is systematically moistened with rainwater via a closed-loop control system. The daily concentrate throughput amounts to between 560 tonnes, in the case of single-furnace operation, and an increased rate of approximately 1000 t per day achieved by putting the second fluidized bed furnace into operation. To increase the operating flexibility, the fluidized bed unit can also be supplied by means of bucket wheel loaders.

An important contribution to ensuring correct and proper production is the exact grabbing of the different grades and clearly arranged and orderly storage of the material in the hall. The stocks are recorded on a daily basis and, if necessary, lead to adjustments of the mixture. Contamination from the concentrates such as wood, plastics etc. are separated via the screens and subjected to separate treatment.

In order to avoid dust deposits, the hall is equipped with electric gates which close after each entry and exit. The possible dust emissions are recorded and evaluated at different points within the works. Special attention needs to be given to the sealing of the hall to avoid these emissions.