The first DELKOR Dry Stack Tailings (DST) system to be supplied by TAKRAF Group in Brazil is being commissioned for one of the largest steel producers in the Americas, the company says.

The order for the key equipment for the DST system was awarded in January 2019 and was followed shortly by an order being placed for the supply of a TAKRAF stacker.

The project comprises the following equipment to process iron ore tailings:

• Flocculant plant;
• Coagulant plant;
• 35 m diameter DELKOR high rate thickener;
• 300 sq.m slurry tank with agitator;
• Four double-stage centrifugal slurry pumps;
• Four DELKOR overhead beam filter presses (FP OH): 2 m x 2 m plates;
• Four compressors with tanks (process and instrument air); and
• Four TAKRAF belt feeders.

As part of the client’s initiative to improve the sustainability of its operations, the DST system is being built to enable the filtering and stacking of tailings as the deposit area of the existing tailings dam reaches full capacity by year-end.

In addition, by removing most of the water present in the tailing slurry, enabling the material to be safely stacked, the client can benefit from a secure and environmentally friendly approach to tailings disposal.

“Not only does it obviate the risk of catastrophic tailings dam failures, but also maximises the water recovered for return to and re-use by the beneficiation plant,” the company said.

DST will be applied following beneficiation to treat the tailings generated during the iron ore concentration process by flotation. The raw tailings slurry will be first fed to the thickener where part of the water is already recovered. In the next process step, more water is recovered by the filter press to achieve a moisture level of about 14% (dry basis), thus creating a dry filter cake ready to be deposited.

DELKOR’s equipment is built to withstand harsh mining environmental conditions, with the filter presses designed as an overhead beam type suitable for the prevailing operational conditions, it said. These require, among other features, large volumes of material to be processed and easy access to the filter plates and filter cloths for maintenance.

In line with DELKOR’s holistic solutions approach, the DST system was designed as a fully-integrated dewatering process through sedimentation and filtration, with the material being tested in the lab prior to sizing the equipment.

Tiago Carvalho, TAKRAF Brazil Managing Director, said: “TAKRAF and DELKOR’s world-leading technology and expertise to offer a complete DST solution, together with our outstanding technical proposal, based on comprehensive DELKOR testing during the bid stage and collaboration with specialised partners, were undoubtedly convincing factors in the project award.

“All colleagues involved in this project should be commended for successfully bringing this important DST reference to commissioning. This project serves to reinforce TAKRAF Group as a leading global solutions provider and we look forward to successfully delivering future DST projects.”