Abstract
Mine tailings (MT) waste valorization in construction materials can be one possible solution because they may allow an alternative for some applications as an important contribution for a more circular economy. The aim of this work was to study the feasibility of using a sulfidic mine tailing in the production of building materials such as ceramic roof tiles. The introduction of 5, 10 and 20% MT in ceramic roof tiles promoted an improvement on the final properties of these materials. The use of 20%MT has decreased the firing temperature from 1150º to 1050 ºC, hence promoting energy savings and lower costs. Properties as density and water absorption were improved. Firing shrinkage, many times responsible for cracking, also decrease with the use of MT and, in this way, improve the production rate. The 20% MT ceramic formulation achieved the highest value of strength with lowest firing temperature. For the effects of sulphates' emission (SO2 and SO3 gases) upon firing, a solution was proposed involving their reaction with water and, through condensation, providing afterwards sulphuric acid as a process by-product. The use of high sulphide MT in ceramic roof tiles processing could be viewed as a potential safe waste management solution for these particular mine tailings.
Highlights
The world economy has been built based on a linear business model, which is under threat due to the limited availability of natural resources
Mine tailings (MT) thermal analysis was performed to determine the appropriate sulphate decomposition temperature in these mine tailings, and it was found that this reaction occurs around 700 oC (Fig. 7)
The 20% MT ceramic formulation presents the highest value of flexural strength with at the lowest firing temperature (1050 oC)
Summary
The world economy has been built based on a linear business model, which is under threat due to the limited availability of natural resources. It is possible to reduce, reuse, recover, and recycle waste to reduce the exploitation of natural resources as well as production costs and increase job creation in order to reduce environmental problems. Mine tailing storage is an important environmental issue, and these wastes need to be placed in environmentally controlled landfills, which occupies a lot of space [1, 2]. These wastes composition depends on the ore mineralogical composition as well as on the chemical and physical processes used for extracting the final product. The great difficulty of using mine tailings is the presence of heavy metals and sulfates in their composition, the contents of these materials change with the mine and ore extraction process
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