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density is found to be 9 to 15% lower than the density of reference bricks. The environmental behavior (NEN 7375) of selected monolithic bricks showed that the leaching of almost all heavy metals is significantly reduced and all of them are under the requested limits. However, zinc is found to be leachable in the grinded bricks, which simulate the end of life of bricks. Further work bas to be done to stabilize the bricks when demolished.

Based on the physical, mechanical and environniental properties of bricks, it is worthy to mention that sintered bricks may be produced from mixes containing up to 30 wt.% of TCPMT. The use of this type of minę tailings in sintered bricks making could considerably reduce the consumption of finite resources and its harmful environmental impact. Moreover, thanks to the lower density of TCPMT sintered bricks, the use of calamine tailings leads to the production of light bricks with Iow density than the reference brick. Therefore, it is possible to reduce the handling and transport costs and consequently leading to lower energy consumption. Also the use of calamine tailings will lead to reduce the amounts of extracted clays and then the corresponding charges of extraction and preparation.

5.5 Acknowledgements

This work was financially supported through the International Research Chairs Initiative, a program funded by the International Development Research Centre, Canada (IDRC) and supported by the Canadian Research Chairs Program. The authors thank also the research centre REMINEX-MANAGEM (Morocco), for the great help conceming the valuation of its by-product outcome of Calamine hydrometallurgical process.