Clinoptilolite is a precious zeolite mineral that has the most comprehensive physicochemical properties among all the zeolite group minerals. Due to these unique properties, clinoptilolite has a wide range of applications in many different industries. In Poland, the clinoptilolite occurs only as an accompanying mineral in the sedimentary rocks nearby Rzeszów. In Europe, the abundant clinoptilolite-bearing deposits are located in Slovakia and Ukraine, where clinoptilolite mineralization occurs in the volcanic tuffs. Due to clinoptilolite’s rare performance, it is extremely crucial to manage its deposits in a complementary manner. In this paper, the mineralogical and structural characterization of the clinoptilolite powders obtained by mineral processing of the clinoptilolite-rich tuffs from Slovakia and Ukraine deposits were discussed. The scope of research covered determination of the mineral composition of the tuffs, structural analysis of the clinoptilolite crystals, as well as textural and physical properties of the powders obtained by mineral processing of the tuffs. In addition, this paper includes the comparative study of the most significant zeolite deposits in the world and investigated clinoptilolite-rich tuffs. A wide spectrum of methods was used: X-ray powder diffraction (XRD), thermal analysis (DSC, TG), X-ray fluorescence (XRF), optical microscopy, Scanning Electron Microscopy (SEM-EDS), the laser diffraction technique, and low-temperature nitrogen adsorption/desorption. The test results indicated that the major component of the tuffs is clinoptilolite, which crystallized in the form of very fine-crystalline thin plates. The clinoptilolite mineralization in the Ukrainian and Slovakian tuffs exhibited a strong resemblance to the clinoptilolite crystals in Yemeni and Turkish tuffs. With respect to the mineral composition, the investigated tuffs showed excellent conformity with the Miocene white tuffs from Romania. The Ukrainian and Slovakian tuffs do not reveal the presence of the clay minerals, which is quite common for naturally occurring zeolite-rich rocks in various deposits in the world. The textural features together with mineral composition of the investigated samples incline that they are potentially suitable raw materials for the sorbent of petroleum compounds. Moreover, the obtained results can be useful indicators with respect to the crushing and compaction susceptibility of the Ukrainian and Slovakian clinoptilolite-rich tuffs.

Increasing incidents of oil spills and dynamic development of civilization are driving the demand for sorbents. The production of the overwhelming majority of mineral sorbents involves the highly energy-consuming calcination process with CO₂ emissions impacting the environment. Taking into account the environmental issues related to greenhouse gas emissions, we are in urgent need of green products and green technologies. The aim of this study was to investigate the possibility of using natural zeolite dust waste to produce oil sorbents in non-calcination technology. The main advantage of the proposed solution is reduction of greenhouse gas emissions and transformation of the waste material into green, useful product. The scope of the research covered the experimental tests for compaction of the zeolite material from Ukraine and Slovakia in a roller press with different type of binding agent and the performance tests for assessing the suitability of the produced agglomerates as a petroleum sorbent. In order to evaluate the agglomerates’ properties, textural-structural analysis (optical microscopy, SEM microscopy, and low-temperature N₂ sorption), petroleum sorption (Westinghouse method), and physical-mechanical tests (resistance to gravitational drop, abrasion resistance) were carried out. Properties of the manufactured agglomerates were studied in comparison to commercial sorbent DAMSORB, commonly used in Poland. The test results showed that it is doable to produce the effective surface oil-spill sorbent from zeolite waste dust in a roller press by applying the relevant binding agent. The main finding of this study was that optimum feed composition for dry granulation that provides the granular sorbent with the best properties was established: 6% of C binder and moisture content within a narrow range of 20–20.6%. The C-1 sorbent achieved the highest and closely comparable to commercial sorbent parameters of petroleum sorption and drop strength, which are key points of this study. The absorption efficiency of petroleum substances for C-1 sorbent is 8% lower than that of a commercial sorbent, and resistance to gravitational drop is lower by only 3%. However, commercial sorbent exhibited better abrasion resistance compared to produced agglomerates, which is a compelling reason to continue the research in order to enhance the abrasion performance of the manufactured granules. The effectiveness of the dust consolidation method carried out was proved by textural parameters of the obtained zeolite-based sorbents. Specific surface area (S_BET) of B-2 (S_BET = 28.1 m²/g) and C-2 (S_BET = 28.3 m²/g) sorbents was very similar to the commercial sorbent (S_BET = 28.1 m²/g). Interestingly, all granules produced from clinoptilolite dust from Slovakia (A-2, B-2, C-2) achieved an increase of 19%, 33%, and 35%, respectively, in volume of mesopores, compared to the commercial sorbent. Moreover, the presented granulation technology favorably affected the size of the specific surface area as well as volume and surface area of mesopores in the case of obtained zeolite-based sorbent A-1 and B-1, compared with the starting raw material. Zeolite-based sorbent A-1 and B-1 achieved an increase of 17% and 18%, respectively, in specific area surface and an increase of 35% and 12%, respectively, in mesopores volume, compared with the raw material. Finally, the results of this investigation proved that it is possible to produce the efficient oil sorbent in a much more eco-friendly and green way, compared with that of the commercial sorbent.

Wollastonite (CaSiO₃), a low-lime calcium silicate, is not reactive material in an alkaline environment, but after carbonation it can develop binding properties. A material based on wollastonite and other low-lime calcium silicates appears to be a new, innovative supplementary cementitious material, reducing the emissions of cement with its addition. Furthermore, it can capture CO₂ in the process of enforced carbonation. Low-lime calcium silicate-based material was burned in a semi-industrial rotary kiln using secondary raw materials. The obtained material was treated with mineral carbonation. In the following studies, carbonated (CSc) and non-carbonated (CS) low-lime calcium silicate-based material was used as a SCM to replace 30% of clinker (by mass) in Portland cement. The sample with carbonated low-lime calcium silicate-based clinker shows a lower compressive strength compared to the reference sample, but its value oscillates at the level of the strength of the sample with 30%mass fly ash addition. Phase composition analysis (XRD) and thermogravimetric analysis (TG-DTG) were performed on hydrated paste mixtures, after different curing periods. XRD analysis showed the presence of phases typical of the reacting cement. Samples with non-carbonated material show a high content of pseudowollastonite and rankinite even after 180d hydration, which is not observed for samples with carbonated material. TG-DTG analysis showed a decrease in portlandite content during the hydration progression for the sample with carbonated clinker. This indicates the pozzolanic properties of the carbonated material.