Stone Processing Research Articles

Impact Assessment of Natural Stone Processing Techniques on the Grain Composition of Sludge Admixtures for Press Powder

Impact Assessment of Natural Stone Processing Techniques on the Grain Composition of Sludge Admixtures for Press Powder

Evaluating the high‐temperature resistance of self‐compacting mortar incorporating waste andesite powder as a mineral admixture

AbstractSignificant amounts of waste material are generated at various stages of andesite stone processing, including mining, cutting, and polishing. Despite this, limited research has been conducted on the potential use of waste andesite powder (WAP) as a mineral admixture. The impact of WAP on the high‐temperature resistance of cement‐based composites remains largely unexplored. This study aims to evaluate the benefits of incorporating WAP as a partial substitute for Portland cement. Self‐compacting mortars (SCMs) with varying WAP replacement rates (5%–30%) were produced and subjected to temperatures of 300°C, 600°C, and 900°C. Additionally, ternary mixtures of WAP and silica fume were produced for comparative analysis. The results showed that SCMs containing up to 10% WAP exhibited higher 90‐day compressive strength compared to the control sample. Furthermore, WAP inclusion improved high‐temperature resistance, and the use of WAP at higher replacement rates was feasible when combined with mineral admixtures possessing high pozzolanic activity, such as silica fume.

On the Structure of Early Neolithic Societies of the Forest Tobol-Ishim Area: morphology and ornamentation of the pottery

The Early Neolithic complexes located in Western Siberia are characterized by the following common determinant features: chronological position within the end of 7,000 – turn of 6,000 cal BC, flat-bottomed vessels, design layouts of vessel necks (lips, rims, collars), and geometric and tree-like ornamental elements. The ceramic complexes are distinguished by different qualitative and quantitative ratios of the types of pottery (Boborykino, Koshkino, Satyga (with rims), comb ceramics, etc.) identified by researchers. When found in the same occupation layer, such a variety of ceramics might be evidence of an unequal sociocultural structure of the Neolithic population groups. The author stand for the concept that ceramic production and new stone processing skills and technologies were introduced (Zach, 2018, 2020) to the indigenous groups with Mesolithic traditions. It resulted in the interaction of autochthonous groups and newcomers and the subsequent merging of their structures, which ran differently in different territories. The author tend to consider the development of “syncretistic” societies in the first stages of such interaction in the Tobol-Ishim Rivers area as a process of transition from the Mesolithic to the Neolithic. Various types of pottery have been recorded at Boborykino complexes. The variety increases at Koshkino complexes, in different settlements and different proportions, which apparently reflects the formation of a new stable cultural tradition. The Kozlovo ceramics became such a tradition, being characterized by round-bottomed vessels with sags in the interior of the rim and a combination of ornaments in mainly incised-receding and comb techniques.

Noise and frequency propagation in natural stone processing plants

In this study, 510 noise measurements recorded in eight natural stone processing plants operating in Sivas City, Turkey were evaluated and the noise levels and dominant frequency bands of 11 different processing machines used in these plants were determined. The daily equivalent noise level of all natural stone processing plants was around or above the exposure limit value (87 dBA) specified in relevant regulations. Considering the machines and plant environment, the frequency ranges for the highest noise levels were mostly between 630 Hz - 5000 Hz, centering around 3150 Hz. Variations in the noise level of the processing machines in separate plants where similar processes were carried out was primarily related to the plant size and machine layout, the number of machines operating simultaneously and the type of natural stone processed. While the difference between the noise levels of gangsaws, bridge cutting, ST cutting, head/side cutting, trimming, cement filling, slab polishing, narrow polishing, chamfering and splitting machines were statistically significant, aging machines generated similar noise levels.

Investigation on the current situation of occupational disease hazards in stone processing enterprises in Weihai City

Objective: To analyze the occupational disease hazards in stone processing enterprises in Weihai City to provide scientific basis for occupational disease prevention. Methods: From January 2021 to December 2022, 107 stone processing enterprises in Weihai City were selected to collect the detection status of occupational hazard factors in the workplace through on-site investigation and on-site monitoring of occupational hazard factors. The diagnostic reports on occupational diseases and suspected occupational diseases of 780 workers were collected through the Occupational Diseases and Hazard Factors Monitoring Information System of the Chinese Center for Disease Control and Prevention, the occupational health monitoring files of the occupational health examination institutions and the information data of the occupational disease diagnosis institutions. The differences between the measurement data were analyzed by Chi-square test or Fisher exact probability method. Results: 107 stone processing enterprises were mainly focused on granite processing, and the average free silica content in granite was 32.92% (12.78%-47.84%). The over-standard rate of silica dust was 0.31% (6/1920), and the over-standard rate of noise was 86.20% (1324/1536). Among them, the noise intensity of cutting position was the highest[120.5 dB (A) ]. The over-standard rates of noise in cutting, water grinding, dry grinding (polishing) and material preparation (forklift transportation) were 98.05%, 89.55%, 70.00% and 42.62%, respectively, and the differences were statistically significant (P<0.05). Among 780 workers, 31 cases (3.97%) of suspected silicosis were detected, and 13 cases (1.67%) were diagnosed with silicosis. 51 cases (6.54%) of suspected occupational noise deafness were detected, and 11 cases (1.41%) were diagnosed with occupational noise deafness. Conclusion: Silicon dust and noise in some positions of stone processing enterprises in Weihai City exceed the standard, and supervision should be strengthened, prevention and control measures should be implemented to protect the occupational health of workers.

Preliminary Study of Stone Sawing Sludges-based Alkali Activated Materials (AAMs) for the Conservation of Archaeological Ceramics

This paper presents research into the feasibility of using stone sawing sludge-based Alkali Activated Materials (AAMs) for conservation of Cultural Heritage. Sawing sludges are a stone processing waste product resulting from the mixing of rock powder with the water used to cool down the cutting blades. The chemical composition of the sawing sludges, when aluminosilicatic, is suitable for acting as a precursor to produce AAMs. AAMs are known for their low environmental impact and versatility since their existence is drawn from recycling waste materials. One of their possible applications is in the conservation of Cultural Heritage objects. This work presents a preliminary investigation into three sawing sludge-based AAMs with different mineralogical compositions and contributes to formulating guidelines for applying them as fillers on modern and archaeological ceramic pottery based on the evaluation of their workability, appearance and physical properties over time from the moment of application and up to 30 days. Dynamic Vapor Sorption and X-Ray Diffraction results provided an overview of the structural and mineralogical changes under high RH conditions, where the tested AAMs showed a type II isotherm curve, as expected for concrete-like materials, as well as disappearance of thermonatrite after one isothermal cycle. Ultrasonic Pulse Velocity test demonstrated the general homogeneity of the AAMs despite the lower velocity exhibited by one of the formulations, probably due to its internal pore distribution and possible presence of microstratification. The Oddy tests, application tests and colourimetric measurements evidenced the advantages and weaknesses of the AAMs, with overall encouraging results ensuing investment in further in-depth studies of these innovative conservation materials in view of their future use in the field of conservation of Cultural Heritage as a result of a circular economy model.

A laboratory investigation for assessing the effectiveness of wastewater treatment using flocculation process in building stone processing industry on stone surface quality and abrasive tool wear

In this study, the effect of presence and concentration of two synthetic polymeric flocculants with different charging mechanisms (anionic and cationic) on surface quality and abrasive tool wear in polishing process of building stones was investigated. The polishing tests were performed in laboratory scale on two stone samples (granite and marble). An index, entitled improvement index (I) was defined for evaluating the effectiveness of flocculants on surface quality and abrasive tool wear. The results revealed that flocculation process had a noticeable effect on enhancement of surface quality and reduction of abrasive tool wear for both stone samples. The cationic flocculant was more effective for granite sample and anionic flocculant was more effective for marble sample. The granite particles mainly exhibit negative surface charge while the marble particles have positive surface charge in the pH range of wastewater used for polishing tests. Therefore, charge neutralization mechanism plays a major role in flocculation process of granite and marble samples. It was found that the use of flocculation process for treatment of wastewater in stone processing plants leads to increase of abrasive tool lifespan and more high-quality products.

Preparation and property study of sawdust-modified cement mortar

Sawdust, a solid waste generated during stone processing, poses a serious threat to the environment with its untreated accumulation. This paper first analyzes the chemical composition and physical properties of sawdust, and discusses its mechanism of action in cement mortar. By systematically optimizing the blending ratio and modification method of sawdust, the sawdust-modified cement mortar with excellent performance was prepared. This study evaluates the key performance indicators of sawdust-modified cement mortar, such as compressive strength, flexural strength, and durability, through a series of experiments. The experimental results indicate that the incorporation of an appropriate amount of sawdust significantly enhances the mechanical properties of cement mortar, while also improving its durability, particularly in terms of freeze-thaw resistance. Microstructural analysis reveals the mechanism by which sawdust improves the pore structure of cement mortar; the active components in the sawdust react with the hydration products of cement, resulting in the formation of crystalline structures with higher strength.Therefore, the use of sawdust as a modifier in cement mortar can improve its mechanical properties and durability, while simultaneously reducing the accumulation of solid waste and promoting the sustainable development of building materials.

Mechanical vibration signal compression based on speech codecs for intelligent manufacturing

ABSTRACT How to effectively compress mechanical signals so that they can support remote and real-time health monitoring is a hot issue in the context of intelligent manufacturing. Due to the characteristics of small repeatability, high noise, and high numerical accuracy of vibration signal, traditional compression algorithms cannot well balance the compression ratio, reconstruction quality, compression time indicators. Therefore, this paper presents a novel mechanical vibration signal compression scheme based on speech codecs, which can realize signal compression in many scenarios such as tool wear detection and bearing fault diagnosis. In this work, mechanical vibration signal compression is first transformed into a multi-objective optimization problem, and the feasibility of solving this problem from the perspective of speech coding is deeply analyzed. Further, this paper presents five possible compression methods with different compression ratios. The presented methods are evaluated with real-time data for tool wear detection in stone processing and public datasets for bearing fault diagnosis. The experimental results show that the proposed methods achieve high compression ratios (4.0 ~ 24.6) while ensuring low time overhead (the average time for compressing a sample point is not more than 0.0194 ms) and high reconstruction quality (the MSE index all less than 0.008), outperforming other state-of-the-art methods.

Transforming waste into beauty: Sustainable clay mask formulations using ornamental stone processing waste

Waste generated from ornamental stone processing presents a significant opportunity for repurposing in various technological applications. This study investigates incorporating such waste with calcium bentonite to develop an industrial clay suitable for cosmetology. The chemical composition and mineralogical properties of the mixtures were evaluated through comprehensive analysis, such as X-ray fluorescence (XRF) and diffraction (XRD), and scanning electronic microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Specifically, we investigated a 70/30 mixture of ornamental stone processing waste and calcium bentonite. The results revealed a diverse range of beneficial elements. Additionally, the fine granulometry of the sample renders them ideal for cosmetic applications. Microbiological analyses demonstrate the absence of harmful microbial populations, ensuring product safety. By repurposing waste materials, this research offers valuable insights into sustainable practices in cosmetics and environmental science, underscoring the importance of resource optimization in modern industry.

An Evaluation of the Corrosion Inhibition Performance of Chitosan Modified by Quaternary Ammonium Salt for Carbon Steel in Stone Processing Wastewater.

Chitosan was used as the raw material. A quaternization reaction was carried out between 2,3-epoxypropyltrimethylammonium chloride and water-soluble chitosan to prepare quaternary ammonium salt water-soluble chitosan (QWSC), and its corrosion inhibition performance against the corrosion of carbon steel in stone processing wastewater was evaluated. The corrosion inhibition efficiencies of QWSC on carbon steel in stone processing wastewater were investigated through weight loss, as well as electrochemical and surface morphology characterization techniques. The results show that QWSC has superior corrosion inhibition performance for A3 carbon steel. When an amount of 60 mL·L-1 is added, the corrosion inhibition efficiency can reach 59.51%. Electrochemical research has shown that a QWSC inhibitor is a mixed-type corrosion inhibitor. The inhibition mechanisms of the QWSC inhibitor revealed that the positive charge on the surface of carbon steel in stone wastewater was conducive to the adsorption of Cl- in the medium, which produced an excessive negative charge on the metal's surface. At the same time, the quaternary ammonium cation and amino cation formed in QWSC in stone processing wastewater can be physically absorbed on the surface of A3 carbon steel, forming a thin-film inhibitor to prevent metal corrosion.

Comparative analysis of the technological properties of natural and agglomerated stones in epoxy matrix

Brazil occupies a prominent position among the countries that produce the most ornamental stones in the world, with emphasis on the state of Espírito Santo. However, despite this success in production, the sector faces a considerable challenge in relation to waste generation. The objective of this study was to produce and evaluate the technological properties of an agglomerated stone using 87 wt% waste from the processing of Branco Fortaleza stone in a matrix with 13 wt% epoxy resin, using the vacuum vibro-thermo-compression process. The waste was characterized by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The stones were subjected to evaluation of density, apparent porosity, water absorption, abrasion resistance test, staining, chemical attack, 3-point flexural strength and microstructural analysis (SEM). The results showed a density of 2.26 ± 0.02 g/cm3, water absorption of 0.24 ± 0.01%, apparent porosity of 0.55 ± 0.03%, abrasion resistance test of 1.38 mm and flexural strength of 30.13 ± 1.74 MPa. The results compared with the literature reveal a material with technical feasibility to be used as a coating in the construction sector, presenting high mechanical resistance, good interfacial adhesion, application on high traffic floors, as well as environments subject to liquid penetration such as sinks, floors and countertops. Using this waste to manufacturing new materials, such as agglomerated stones, can not only help reduce dependence on raw materials, but also play an important role in minimizing the environmental impact associated with the extraction and processing of natural stones.

Recovery of Synthetic Diamonds from Fines of Natural Stones Processing

Objective: The objective of this study is to investigate the flotation process of the fines from the processing of natural stones - Fibro, and to propose a methodology to recovery synthetic diamonds present in it. For this, this research analyzes the influence of the amount of solid mass in the pulp and the amount of reagents used in the process. Theoretical Framework: The productive chain of natural stones generates millions of tons of Fibro annually, which can cause environmental damage if not disposed of or treated properly. Considering that the principles of circular economy are relevant in the pursuit of sustainable development of the sector, it is emphasized that Fibro contains several mineral resources that can be used in other productive chains. In addition to the rock powders resulting from processing, there are other particles of interest such as synthetic diamond. The synthetic diamonds present in Fibro come from the diamond tools used in rock sawing and polishing. These diamond particles have a high added value, and some recovery methods have been implemented to capture these grains for reuse. Among the methods used for this purpose, flotation has obtained the best results in previous studies. Method: The methodology adopted for this research begins with the collection and sampling of the Fibro in the natural stone production industries. Then, this material was classified granulometrically through sieving, and the samples were then subjected to the flotation process. In flotation, the percentage of solids in the pulp and the amounts of collector and frother used in the process were tested. All untested parameters were kept constant, and only the variables under investigation were modified at different levels. The methodology followed an experimental design and it was applied regression models and response surfaces for data modeling. Results and Discussion: The results show that the most efficient solid percentage was 35% in conditioning and 25% in flotation. Regarding the quantities of reagents tested, the model generated by the response surface indicates which levels obtained the best results in terms of concentrate recovery rate. It was also noted that the amount of collector had little influence on the process, which can be inferred by the natural hydrophobicity of the diamond. Implications of the Research: The implications of this research include economic benefits for the natural stones industry from the possibility of entering a new market in the sector. As well as advances in circular economy by reusing industrial waste and developing new technologies for the use of these materials. These results have the potential to impact industrial sustainability and can expand the mining and metallurgy sector. Originality/Value: This study contributes to the mining industry by proposing an innovative flotation methodology to recover synthetic diamonds from the fines of processing of natural stones. The relevance and value of this research are evidenced by its ability to provide a practical and efficient solution, with potential positive impact on circular economy and industrial sustainability.

The use of point-impact techniques in stone processing (pecking) in the sites of forest Trans-Urals

For processing of stone and manufacture of tools, ancient man mastered a variety of methods and tech-niques — beating, splitting into flakes and plates, impact and spin retouching, grinding, sawing, drilling and some others. Of these, the least studied and insufficiently covered in the literature is the point-impact technique (pe-cking). Pecking could have been used both as an auxiliary technique and as the main one. When processing large tools (axes, adzes, pestles), which subsequently were polished, it was an auxiliary method. But when mak-ing a circular groove for tying and hollowing out a blind or through hole, it would have become the main one. In the forest Trans-Urals, the pecking technique was already known in the Mesolithic. A treasure hoard containing six stone axes has been found at the Mesolithic settlement of Ogurdino (Perm Krai). The axes were treated by beating and pecking techniques, followed by partial surface polishing. Also, two axe blanks with lugs (trunnions) from the site of Beregovaya IX in the Gorbunovsky peat bog (Sverdlovsk Region) belong to the Mesolithic. The edges of the tools and the protruding lugs were processed by pecking. A perforated disk-pommel in the shape of a kind of disguise was found in the Late Mesolithic layer of the 2nd Beregovaya site in the Gorbunovsky peat bog. A rounded hole 2.8–3.1 cm in diameter was made in the center of the disc by deep pecking on both sides. The majority of the items processed by pecking were found on mixed sites and date to a wide chronological range from the Neolithic to Bronze Age. Some of them represent accidental single finds. Stone sculptures, tops of maces, axes, adzes, plows, chisels, pestles, fishing sinkers, “ironings” were processed using point-impact re-touching. Tying lines on hammers made of massive pebbles were designed exclusively by pecking. During the Early Iron Age, the pecking technique only further expanded its application. Moreover, it was used not only for shaping products, but for making complex figured ornaments on sculptures and bas-reliefs.

Extraction and processing of dimension stone in Russia in the 19th century (adapted from Gornyi Zhurnal)

Extraction and processing of dimension stone in Russia in the 19th century (adapted from Gornyi Zhurnal)

Strength characteristics and energy evolution of cement stone under true-triaxial loading conditions

Oil well cement is a commonly used cementing material in oil and gas extraction engineering. Due to the change of stress conditions, it is prone to microcracks or micro annular gaps, leading safety concerns. To study the strength characteristics and energy evolution of oil well cement stone under three-dimensional stress states, a series of true-triaxial compression tests were carried out. Based on the experimental results, the mechanical properties and energy evolution mechanisms during the true-triaxial compression process of cement stone under different stress states were explored. The research results indicate that there is an intermediate principal stress effect on the true-triaxial compressive strength of cement stone specimens. When the minimum principal stress remains constant, the strength of cement stone first increases and then decreases with the increase of intermediate principal stress. When the minimum principal stress is 5 MPa, the specimen exhibits brittle failure, with ε1 at peak stress approximately 0.015. As the minimum principal stress increases to 20 MPa, the specimen gradually transits to plastic failure, with ε1 at failure exceeding 0.04. The type of failure is determined by the energy ratio at the time of failure; when there is more elastic energy, it results in brittle failure, otherwise it leads to ductile failure. Due to the high porosity of cement stone samples, most of the input energy is converted into dissipated energy. At minimum principal stresses of 5 MPa, 10 MPa and 20 MPa, the ratio of peak dissipated energy to total input energy fluctuates around 0.55, 0.73 and 0.85, respectively. There is a strong linear relationship between the peak elastic energy, peak dissipated energy, and total input energy, with fitting correlation coefficients of 0.847 and 0.996, indicating that the cement stone sample also follows the linear energy storage law. A strength criterion for cement stone was established based on the modified Lade criterion, which is more suitable for describing the strength of high porosity materials compared to traditional strength criteria. Finally, based on the interaction mechanism between energy accumulation and energy dissipation, a nonlinear model of energy evolution in cement stone was established. The results of the theoretical model are in good agreement with the experimental data.

Результаты раскопок грунтового могильника Максимовка I в лесостепном Поволжье в 2019 г.

Introduction. The work publishes some results of excavations at the Maksimovka I grave field. Goals. So, the article seeks to introduce materials of the 2019 excavations. To facilitate this, the paper shall describe and characterize the investigated archaeological complexes, establish their cultural and chronological attributions. Materials. Archaeological material from the occupation layer comprises Neolithic, Chalcolithic, Bronze Age, and eighteenth/twentieth century pottery, flint tools, and stone processing waste. Six burials were investigated at the site. Two burials had been destroyed and are nothing but heaps of heavily fragmented bones with no grave goods observed. In the third burial, the skeleton was lying on back in a northern-northwestern direction, accompanied by an iron knife and goat/sheep bones. The next burial consisted of four skulls and compact clusters of skeletal bones located nearby. The latter’s grave goods included flint arrowheads, a scraper, a bone spearhead, a pendant, beads, piercings and marmot incisors. The fifth burial contained a seated skeleton facing northeast and accompanied by a flint plate, an arrowhead and beads. In the last burial, the skeleton was lying on back in a northern-northwestern direction, accompanied by an ornamented clay vessel. A part of structure 1 was also examined. Results. The work shows that a total of three burials date back to the Late Chalcolithic, one — to the Late Bronze Age, and one — to the Middle Ages. The cultural and chronological attribution of the remaining burial has not been determined yet. Conclusions. The excavations at the Maksimovka I grave field have yielded materials from different cultures and periods, including Neolithic, Chalcolithic, Bronze Age, and Medieval complexes.

Enhancing Mechanical Properties and Microstructures of Mass-Manufactured Sand Concrete by Incorporating Granite Powder.

The production of manufactured sand and stone processing can cause dust pollution due to the generation of a significant amount of stone powder. This dust (mainly granite powder) was collected and incorporated as a cement replacement into mass-manufactured sand concrete in order to enhance the mechanical properties and microstructures. The heat of the hydration was measured by adding the granite powder into the cementitious material system. The mechanical properties, autogenous shrinkage, and pore structures of the concrete were tested. The results showed that the mechanical strength of the concrete increased first and then decreased with the increase in granite powder content. By replacing the 5% cement with the granite powder, the 28 d compressive and flexural strength increased by 17.6% and 20.9%, respectively. The autogenous shrinkage was mitigated by the incorporation of the 10% granite powder and decreased by 19.7%. The mechanism of the granite powder in the concrete was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP). The porosity decreased significantly within the 10% granite powder. A microstructure analysis did not reveal a change in the type of hydration products but rather that the granite powder played a role in the microcrystalline nucleation during the hydration process.

Innovative technology and equipment for stone processing sludge recycling

The aim of the study is to substantiate the parameters of technology and equipment for the manufacture of building products using alumina sludge from stone processing as an alumina aggregate. The standard methods of setting up an experiment for laboratory washing of granular sludge from stone processing and studying its physical and mechanical characteristics, manufacturing laboratory samples of polystyrene concrete blocks with further study of their strength characteristics were used. The physical and mechanical characteristics of granular man-made material - sludge waste from the stone processing industry - were experimentally determined. The possibility of using man-made sludge in the manufacture of polystyrene concrete blocks was substantiated by its particle size distribution and mineralogical composition. Average samples of granular material were deslagged using the TurboWash unit. The particle size distribution of the material after washing was analysed. According to the standard technology, recipe and raw materials for D300 polystyrene concrete, polystyrene concrete blocks of standard sizes of three grades were produced. Primary sludge without preliminary processing, sand and dusty loess obtained from the processing of primary sludge were used as an aggregate. The numerical values of the axial compression resistance for the studied grades of polystyrene concrete blocks were determined.

Robustness of hybrid fiber reinforced engineered cementitious composite containing stone processing waste

Robustness of hybrid fiber reinforced engineered cementitious composite containing stone processing waste