WasserWert

The majority of our raw material supply comes from mining. In some cases, this inevitably negatively impacts water bodies such as surface waters and groundwater. Pollutants such as metals or arsenic are released into these water bodies. In relevant areas of large mining countries, this type of environmental degradation occurs extensively. In South America (copper extraction), with the pre-determined climatic conditions, the general water scarcity and an associated conflict of use in agricultural food production are added.

The “WasserWert” project is concerned with producing materials and applying innovative technologies that reduce the load of metals and arsenic from mining waters on natural water bodies. This water purification task is simultaneously linked to recovering valuable metals to close material cycles.

Thus, on the one hand, water quality is to be noticeably improved and habitats are to be protected. On the other hand, the conflict of use in regions with water scarcity - for example in agricultural food production - is to be reduced.

The project is divided into two thematic areas:

1. Slag treatment for value element recycling and production of water treatment material for arsenic retention.

Slags are waste products resulting from smelting, i.e. from the production and processing of metals. Due to the copper smelting process, these slags still contain residual copper, but above all other valuable metals such as molybdenum.

This topic aims to produce iron-based sorption materials from these slags and at the same time recover the valuable metals.

Furthermore, silica/water glass is produced in the process. The produced sorbent material is then used to remove oxy-anions (e.g. water pollutant arsenic as arsenate or molybdenum as a valuable metal, as molybdate).

2. Water treatment of complex mining waters with valence element removal using ion exchange resins - model-based design and "toolbox" knowledge.

This sub-theme deals with the purification of mining waters using an innovative technological approach. This is because retained metals do not remain in the sludge to be subsequently deposited, but these metals are to be recycled back into metal production.

The problem with mining water is that several metals are usually dissolved as pollutants in the water. With the help of so-called ion exchangers, these (valuable) metals are to be removed from the water, separated from each other and then fed individually as a concentrate to production as secondary raw material.

The project takes both named and tested techniques to the following scale level in Chile. In the process, further essential questions of detail will be clarified in the laboratory pilot plant to improve subsequent use in practice.

The leitmotif of the entire project is thus to link the necessary water treatment with the recovery of value elements (also to close value material cycles) to "let the water regain its value" in a double sense.