Carpenito, M, Löwer, E, Kaswalder, F, Grosso, A & Cruciani, G 2026, 'Modelling of filtration properties of representative standards of 
tailings based on quantitative phase analysis', in AB Fourie, M Horta, M Oliveira & S Wilson (eds), Paste 2026: Proceedings of the 28th International Conference on Paste, Thickened and Filtered Tailings, Australian Centre for Geomechanics, Perth, pp. 1-9, https://doi.org/10.36487/ACG_repo/2655_34
(https://papers.acg.uwa.edu.au/p/2655_34_Carpenito/)
Abstract: The large demand for mineral resources and large-scale mining operations produce significant quantities of mining waste, e.g. tailings. One of the most important environmental considerations is how to manage these large volumes of waste to minimise impacts and maximise benefits. Dewatering technologies, e.g. thickening and filtration, can reduce its footprint. Through the filtration process, it is possible to obtain a final residue with solid-like behaviour. The filter press is one of the most popular pieces of equipment for these purposes, thanks to high performance achievable in terms of dewatering efficiencies and solid throughputs. 
Since clay minerals are a challenge in the design of filtration and de-watering processes, it is necessary to describe quantitative relationships between the filterability parameters and the contents of mineral phases; in particular those clay minerals that determine the structure, porosity and inner properties of filter cakes.
Several standards were prepared according to the classification of fine-grained clastic sedimentary rock units. The main minerals that were mixed in different concentrations were quartz, carbonates and clay minerals, swelling and non-swelling, such as smectite and kaolinite. The concentrations of clay minerals vary from 
0.1–40% and the particle size distribution is about 1–20 µm. According to the German guideline VDI 2762-2 (VDI Verein Deutscher Ingenieure e.V. [VDI] 2017), the filtration process has been simulated at the laboratoryscale using a Nutsche filter with a filter area of 20 cm². High-resolution X-ray tomography was used to investigate the filter cake microstructures, the arrangement of the clay particles and the porosity.
The specific resistances of cake were correlated with clays contents and with the properties of cake, such as packing structure. 
From the results, it is clear how clay phases play a crucial role in affecting the throughput achievable by a filter press, how they influence the inner characteristics of the cake and the amount of water recovered. Predicting the behaviour of the material during the filtration process would allow to design a filtration plant with optimised capital expenditure and operating expenses.

Keywords: clay minerals, specific resistance of cake, Nutsche pressure filter, cake properties, X-ray tomography