LKAB is now recycling mine waste in a new pilot plant

30 April 2020

In the ReeMAP project, LKAB is developing new technology for upgrading mine waste to mineral fertiliser, rare earth elements, fluorine and gypsum.

The first step is to produce apatite concentrate in Malmfälten, which is now being done in a recently commissioned pilot plant.

“The two plants, which we plan to build in Kiruna and Malmberget, will have a combined capacity to produce about 400,000 tonnes of apatite per year,” explains Ulrika Håkansson, Project Manager for the ReeMAP project.

An LKAB group effort

The technology and business development project is being led by LKAB Minerals, but with resources and expertise from throughout the LKAB organization, particularly from the Technology and Process Development organisation.

Producing apatite

Erik Niva, Senior Research Engineer, works with process development at the pilot plant. He explains that both tailings from the concentrating plant and waste material from the sorting plant operations are processed, the latter of which is first milled.

“We upgrade the material in several stages to produce an apatite concentrate. Flotation is the central process whereby we add a coagulation reagent that is attracted to the surface of the apatite grains, to which it adheres. The reagent causes the apatite grains to stick to the air bubbles that are introduced into the flotation cell. The apatite is then carried by the air bubbles to the surface, forming a foam which is then extracted and dried”, says Erik Niva.

Successful tests

The tests have been successful. “Like a full-scale production plant, the pilot plant allows continuous operation and, here, our previous laboratory trials have been confirmed. The mobile plant will soon be moved to Kiruna for a new production campaign during the autumn,” says Erik Niva.

Past experience with apatite

LKAB produced apatite during the period 1978–1988, after which low levels of apatite in the Kiruna ores, in combination with a lower value of the product, meant that production was phased out. Therefore, the key is to develop knowledge and technology that will enable utilisation of the valuable minerals contained in the apatite concentrate.

Prestudy phase

“With the aid of innovative chemical engineering, the next step is to upgrade the products to phosphorus-based mineral fertilisers and rare earth elements. These have been classed by the EU as critical raw materials since we are dependent on them and domestic production is lacking. In the process, large amounts of high-grade gypsum and fluorine will also be produced. We are now in an intensive phase of the prestudy, where we are both developing the technology and considering the best location for establishing this high-tech industry. But, more about that at a later date. For the time being, I would like to highlight the successful work we are doing with the pilot plant for apatite,” says Ulrika Håkansson, Project Manager for the ReeMAP project.