# Utilisation of Mining Waste for Production of Ceramic Tiles
## 5 Conclusions  
This study demonstrates the innovative approach of simultaneously utilising two mining waste streams--TG3 clay from the Turoszow lignite mine and post-flotation sludge from the KGHM-Gillow copper mine--for ceramic tile production. The novelty of this research study lies in establishing a complete compositional spectrum of these wastes, enabling the production of different ceramic tile classes without additional virgin materials.  
The study on varying mixture ratios and firing temperatures demonstrated that the ratio between waste materials determines the final product properties. Compositions containing \(\leq\)50% post-flotation sludge contamination resulted in sintered stoneware-type ceramics with mechanical bending strength of approximately 45 MPa and water absorption below 5%, suitable for frost-resistant ceramic tiles (group B Ia GL and UGL PN-EN 14411:2016). Conversely, compositions containing \(>\)50% post-flotation sludge produce porous faience-type ceramics with mechanical strength exceeding 15 MPa and water absorption above 20%, appropriate for ceramic wall tiles (group B III GL).  
Microstructural analysis revealed an evolution from isolated closed pores in low-sludge-content compositions to interconnected open pores in high-sludge-content compositions, directly corresponding changes in rational composition, particularly in the increase in carbonate content and decrease in clay minerals as sludge content increases. The presence of dolomite: Post-flotation sludge contains large amounts of dolomite, which significantly affects the sintering interval and firing temperature of ceramics, as well as other functional and technological parameters.  
The economic and environmental viability of this approach is enhanced by several factors: the abundance of these materials, their geographical proximity (within 150 km) and the advantageous physical characteristics of the waste streams. The fine particle size distribution (90% < 0.06 mm) eliminates the need for grinding operations, significantly reducing processing costs and energy consumption compared with conventional ceramic production methods.  
This research study provides a practical pathway to transform mining waste from environmental liability into valuable ceramic products while adhering to circular economy principles. The methodology developed can be applied to similar waste streams in other regions, offering a sustainable waste management strategy that addresses environmental concerns, conserves natural resources and creates economically viable products that meet industry standards.  
Conceptualisation, P.I.; methodology, A.S., J.M.-P. and J.D.; formal analysis J.M.-P. and J.D.; investigation, J.M.-P. and J.D.; writing--original draft preparation, PI; writing--review and editing, A.S. and J.D.; supervision, A.S. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research study received no external funding.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
**Conflicts of Interest:** The authors declare no conflicts of interest.