Larox filter

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. 

The plant design was carried out on an accelerated schedule. To simplify the construction, we opted to build the facility in phases. The first phase represents the core of the plant. It contains a pneumatic truck unloader coupled to a storage silo, a reactor tank and a Larox filter. This approach enabled us to start up quickly and to provide a good way to determine the compatibility of the washing plant with the rest of the facility. Phase 1 was completed in June 1999 and provided the capacity to wash up to 22,000 tons per year of oxide. 

A more troublesome problem involves the operation of the Larox filter to produce the washed oxide. We selected the Larox filter because of its automation and the performance observed in a laboratory unit. The filter has proven reliable mechanically and does not require continuous operator attendance. However, the cake produced has a higher moisture content than originally expected. This high moisture is explained by the fine nature of the oxide. When we selected the filter, the secondary oxides expected as the feed to the plant were much coarser, filtered easily, and produced a cake that was dry enough to be readily handled. The Larox performance on the finer oxide needs to be improved. 

Variable-Volume Filter Presses These membrane filter presses are covered in the section on filtration. Two designs are used for the presses (1) the typical variable-volume filter press has a normal vertical leaf design (2) other presses, such as those provided by Filtra-Systems and Larox, are designed with horizontally arranged leaves. 

Larox automatic pressure filter showing path of filter belt and mechanism of cake discharge. Larox, Inc.)... 

Figure 1.33 Photographs, with permission from Larox, of a diaphragm press installation (left) and the dry cake produced from a typical filter cycle (right). A detailed schematic of the diaphragm press filter cycle is shown in Figure 6.3.

Figure 5.8 Initial display screen of FDS showing access to the Equipment Selection, Data Analysis and two Simulation modules for vacuum (partially hidden) and pressure filters. Images used with permission from Amafilter, Andritz, atech innovations, Axsia Mozley, Broadbent, Dorr-Oliver Eimco, Filtration Services, Larox, Leiblein, Lenntech, Mavag and Sernagiotto.

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