PASTE & TAILINGS
Reducing CO 2 emissions and providing sustainable products to customers is the key challenge of this time. Especially, the extensive use of cement in concrete and mortar needs to be lowered by implementing sustainable alternatives without compromising our high-quality standards.
The search for potential cement replacement fosters the use of new aggregates and materials with binding properties sourced as a by-product of other activities. In this regard, mine tailings seem to be a promising cement replacement as they feature to a certain extent pozzolanic properties.
Sika has 188 mortar plants globally, with an annual consumption of 80,000-100,000 t of cement. Many of these mortar plants are strategically positioned near mining areas, lowering the transportation’ s carbon footprint compared to that of natural sand and cement.
The studied iron ore and VMS tailings were successfully used in high performance cementitious grout with replacement levels of up to 10 % cement and 50 % sand without compromising quality. This enabled Sika to significantly reduce its carbon footprint as well as enabling mine facilities to give additional value to their waste product.
The following conclusions are drawn based on experimental results. First, the partial replacement of aggregates by mine tailings influences the one-day mechanical performance negatively, but this effect can be compensated by an addition of a suitable activator. Regarding the use of mine tailings as partial cement replacement, increased grade of replacement leads to decreasing of the mechanical strength after one day, can be also in this case overcome by an addition of appropriate activator.
The accelerator is effective for both types of tailings( VMS and IOT) regardless those mineralogical and chemical composition. Since cement has the greatest influence in greenhouse emissions in the production of concrete, this work contributes to the implementation of more sustainable construction practices.
The inclusion of mine tailings in construction materials also reduces the environmental impact of the mining industry. Sika concludes:“ Our study shows that the use of mine tailings, when combined with an activator, can substitute up to 10 % of cement, saving 8,000 to 10,000 t of cement annually and reducing CO 2 emissions by 5,600 t. Additionally, we demonstrated the potential of mine tailings to cope with the increasing aggregate demand for the construction industry without exploiting natural resources such as beaches and river shores. However,
only if mine tailings are combined with an activator, they can replace up to 50 % of sand needed in mortar formulations.”
Diemme’ s Trust Badge – a new certification for filter press operators
The operation of larger filter presses in mining is very much an ongoing collaboration between the filter press supplier and the customer who is handling the tailings – and this includes the filter press operators themselves.
Diemme Filtration has recognised this with its new Diemme Trust Badge initiative. Andrea Pezzi, Diemme Filtration Director of Marketing and Communications outlined the thinking behind it in a recent Diemme Academy live broadcast:“ The Diemme Trust Badge is what we consider to be a new way to be in touch with our clients and operators. In particular, we want to create a good cooperation with the people who are operating our equipment.”
Pezzi said operators will be able to wear a physical badge as a symbol of their certification, indicating that they have reached the status of a qualified Diemme operator. He said Diemme wants to provide its new service approach in two ways- an online theory test on a new and enhanced Training Area of the Diemme Academy