Waelz kilns

The western WetheriU. furnace is like the eastern furnace except that a block of 12 or more furnaces has a common combustion chamber. This results in improved control and uniformity of product. Clinker usually contains 8—15 wt % zinc, which is often recovered in a Waelz kiln (24). 

Zinc 16.72 Mostly concentrates in filter plant dust as ZnO, allows more profitable recycling in Waelz kiln, etc. 

As Europe has a vast steel industry, there is more furnace dust generated compared to Waelz kiln capacity and as a consequence, some electric arc furnace dust is still landfilled. The addition of primary batteries to the feed within these facilities increases the prospect of the dust being taken for recycling by the Waelz kiln operators. 

The Waelz kiln operation is subjected to the same stringent environmental standards as the EAF steelmaking process. Trials have been undertaken in Europe and the USA to determine whether these same standards are met when operating with mercury free primary batteries as part of the feed. 

Waelz kiln 515 warehousing 570 wash cycle 196 waste... 

The Waelz Plant was commissioned in 1952 and is equipped with thirteen Waelz kilns and two rotary kilns for calcination of the Waelz fumes. The specifieations of both kilns are as follows ... 

The Waelz plant processed 400,000 tonnes/year of zinc carbonate ore typically containing 10 % Zn and 2 % Pb and Zn-Fe residues with zinc contents of about 16-18 %. After running out of zinc carbonate ore deposits and because of environmental reasons, nine kilns were liquidated in 1989. Currently, six kilns are operated 4 as Waelz kilns and 2 for ealeination of the Waelz fumes. 

Neutral slurry is classified in hydrocyclones (3500/12°). Underflow fiom the hydrocyclones is pumped to acid leaching, and the overflow to five Dorr thickeners, each with a diameter of 9.5 meters. Magnafloc 338 is used for this process (0.017 kg per toime of cathode zinc). Underflow from each Dorr thickener is pumped to low acid leaching, and after classification and washing, to Larox filters. The filter cake with a maximum moisture content of 17 % is fed to the Waelz kilns. 

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