Stone Processing Research Articles

Influence of filler/cement and powder/total solids on the mixture design of self-compacting micro-concretes containing waste from the ornamental stone industry

The present work evaluated the effects of incorporating high volumes of waste from the processing of ornamental stones as fillers in self-compacting micro-concretes, considering physical–chemical, mechanical, microstructural and eco-efficiency results. A particle packing method assisted in the mix designs, and the experimental program followed a central composite rotational statistical design. Response surfaces and desirability analyses showed that the residue has a good packing function, filler effect, heterogeneous nucleation and workability, in addition to being effective in reducing the embodied CO2, delivering matrices more eco-efficient for conventional mechanical strengths.

Petrofabric and geochemical constraints on the origin of Liuyang chrysanthemum stone, South China

Chrysanthemum stone refers to a radial and chrysanthemum–like mineral aggregate. Liuyang chrysanthemum stone, distributed in the carbonate of the Permian Chihsian Formation in South China, has become a rare natural art treasure due to its unique radial shape. The lack of effective constraints on the petrography and geochemistry of the chrysanthemum stone in Liuyang restricts the understanding of its origin. Hence, petrography analysis and Raman microprobe spectroscopy were used to study the mineral compositions and textural characteristics of the Liuyang chrysanthemum. Element and isotope geochemistry studies were conducted to discuss the sedimentary environment, material source, and formation mechanism. The Liuyang chrysanthemum stone was formed in the period of aragonite sea, and developed in dark gray limestone as a white radial mineral aggregate. The primary mineral is celestite, a minor amount of which was filled with and metasomatized by calcite. Trace element characteristics (δCe = 0.46–0.70, V/Cr = 1.28–1.51, Ni/Co = 2.14–4.89, Sr/Ba = 14.42–45.17) and carbon and oxygen isotopic compositions (δ13CV–PDB = 3.0 ‰–3.8 ‰, δ18OV–PDB = 5.2 ‰–4.8 ‰) of the host rocks indicate an aerobic marine sedimentary environment. The significant difference in sulfur isotopic compositions between the chrysanthemum stone (δ34S = 29.4 to 28.1 ‰) and the host rocks (δ34S = –29.4 to –28.1 ‰) indicates that bacterial sulfate reduction (BSR) and anerobic oxidation of methane (AOM) has occurred. Petrography, trace element and C–O–S isotope geochemistry of the Liuyang chrysanthemum stone had revealed the formation process of the chrysanthemum stone. The organic matter was decomposed by O2 and produced CO2 in the aerobic marine sedimentary environment. With the continuous sedimentation and the oxygen consumption, the early sedimentary carbonate and bioclastic was gradually separated from the relatively aerobic environment. An anoxic sedimentary–diagenetic environment was formed and the BSR occurred, during which SO42– participated in the degradation of organic matter as an electron acceptor. The bacteria preferentially absorbed the light 32SO42– in pore water to produce 32S–rich FeS2 in the host rocks and the heavy SO42– was combined with the Sr2+ released by aragonite dissolved by the accumulated CO2 to precipitate the celestite. HCO3– accumulated during the AOM and the BSR resulted in the replacement of the celestite by the calcite.

Stone-tool assemblage of the Eneolithic settlement of Tolum-1 in the Konda River Basin

In 2020, the expedition of Poengurr and the Institute of History and Archaeology of the Ural Branch of RAS investigated the settlement of Tolum-1, which functioned during the Neolithic, Eneolithic, Bronze and Early Iron Ages. The site is located in the north of Western Siberia, in Kondinsky District of Khanty-Mansi Autonomous Ok-rug — Yugra. Structure (dwelling) No. 3 containing a complex of stone tools and pottery of the Enyi type, as well as the adjoint area, were investigated by an excavation trench of an area of 499 m2. On the settlement, 108 stone items were found, the large part of which concentrates within the boundaries of dwelling No. 3. The research is based upon the method of technical and typological analysis of stone-tool assemblage, implying the development of a typology of stone tools and the study of their production technology taking into account the quality of the or-namental raw materials used by the ancient population. According to the raw-material composition of the stone-tool assemblage, mainly represented by soft rocks (grey-green slate, burgundy schist, etc.) and, to a lesser ex-tent, by flint of various colors, quartz and quartzite, the ancient population of this region did not have continuous sources of high-quality ornamental raw materials. Prevailing on the settlement are the tools for woodworking (drillbit-shaped tools, adzes, chisels), and also found were knives and a representative collection of arrowheads. Items for stone processing are few: a hammer-stone, a retoucher, and two cores. There is a higher presence of unprocessed pebbles and tiles, and chips and fragments of polished products. The main technological chain on the site was production of polished tools from local gray-green slate by chipping off and subsequent grinding. The production of flint tools by splitting and retouching was insignificant. The stone assemblage of the Tolum-1 settle-ment finds analogies in the complexes of the Enyi type of the north of Western Siberia. Certain categories and types of products are more widespread — double-sided retouched fish-shaped arrowheads are found in quantity in the Trans-Urals, polished leaf-shaped arrowheads with a groove — in the Eneolithic sites of the north of Wes-tern Siberia, while polished arrowheads with a tapered truncated base were found among the Eneolithic materials of the Surgut Ob Basin and on the sites with the Ushya ceramics of the Neolithic Period of the Konda lowland. Polished rounded and teardrop-shaped pendants are found in the funerary and, to a lesser extent, settlement complexes of the Trans-Urals and Western Siberia in the Late Neolithic — Eneolithic. A series of radiocarbon dates obtained for the settlement of Tolum-1 and other sites of the Enyi type in the north of Western Siberia, as well as the technical and technological characteristics and morphology of the stone inventory of the settlement under consideration, and a wide range of analogies leave open the possibility of attributing the structure No. 3 to the Eneolithic Period, within the span of the calibrated dates in the interval of 3600–2600 BC.

Optimization of the physical and mechanical processes of stone crushing by the method of computational scanning

Physical and mechanical processes for processing dry materials such as grinding and crushing are the most resource-intensive ones. It is preferable to carry out the technological process of stone crushing where maximum yield of fine-grained crushed stone with a size of 0-5 mm is obtained. The purpose of this study is to determine the optimal parameters of stone crushing on a vertical impact crusher where the yield of fine-grained crushed stone will be maximum. The physical and mechanical processes of stone crushing were optimized using the computational scanning method. The optimization was performed based on the obtained regression equation describing the output of fine-grained crushed stone from influencing factors on the process. To determine the optimal values of the factors affecting the process of stone crushing an algorithm flowchart has been developed and a calculation program has been compiled in Delphi. As a result the following values of operational factors were obtained: incoming raw material size d = 0.0375 m; the speed of the crusher rotor, n = 1600 rpm; the distance between the accelerator and the ring platform l = 0.2 m; the concentration of crushed stone size 0-5 mm at the output of the crusher will be a maximum of 55.37%.

Unit Weight and Elastic Modulus of Concrete utilizing Volcanic Stone Waste as Coarse Aggregate

Unit weight and elastic modulus of concrete utilizing volcanic stone waste (VSW) as coarse aggregate have been studied at 28 days of hydration. The origin of VSW was the residual of volcanic stone processing for making the handmade ornaments of traditional Balinese buildings. Three types of concrete mixture compositions were made by varying the proportion of cement, fine aggregate and coarse aggregate in concrete. Each mixture composition stirred using four variations of water/cement (w/c) ratio. For each variation in w/c, five cylindrical specimens with a diameter of 150 mm and a height of 300 mm were made to measure the unit weight and modulus of elasticity of concrete specimens after 28 days of hydration. The result shows that the unit weight and the elastic modulus of concrete decrease with increasing w/c at fixed proportions of cement and aggregates and increase with increasing proportion of aggregates at fixed w/c. The increase in elastic modulus with an increase in the a/c ratio for a fixed w/c ratio is more noticeable for a w/c ratio of more than 0.6. Moreover, the elastic modulus increases correspondingly with an increase in unit weight for a given a/c ratio.

Study on the corrosion inhibition performance of composite inhibitor on carbon steel in stone processing wastewater

AbstractThe circular saw blade, which is mainly composed of carbon steel, is used to cut the stone. However, the carbon steel is easily corroded in stone processing wastewater, shortening its lifespan. In this study, a new composite inhibitor of sodium nitrite, sodium molybdate, sodium silicate, sodium tungstate, and sodium citrate was investigated firstly, and then, its inhibition efficiency for carbon steel in stone processing wastewater was explored using electrochemical measurements and weight loss measurements. The results showed that the composite inhibitor as a mixed‐type inhibitor displayed good inhibitory performance. Surface analysis including scanning electron microscope, atomic force microscope, X‐ray photoelectron spectroscopy analysis, and contact angle test further revealed the form of protection of the steel surface by composite corrosion inhibitors. The prepared composite inhibitor exhibited excellent corrosion resistance for carbon steel in stone processing wastewater, and it is believed that the composite inhibitor has certain application potential in industries.

Potential Effect of Combined Exposure of Crystalline Silica Dust and Cigarette Smoking on the Incidence of Silicosis among Chinese Male Stone Processing Workers: A Cross-Sectional Study.

Background: Silicosis is a progressive and irreversible disease primarily caused by exposure to crystalline silica dust and, to a lesser extent, cigarette smoking. However, further research is needed to validate the potential combined effect of these risk factors on the increased incidence of the disease. Methods: A total of 1688 male workers employed at a Chinese stone processing plant between 1 January 1999 and 31 December 2019, were included in the study. Cumulative exposure to industrial crystalline silica dust and packyears of smoking were collected through health surveillance, and odds ratios (ORs) with 95% confidence intervals (CIs) for silicotic changes due to industrial silica exposure and cigarette smoking were estimated using logistic regression models. Results: Among all participants, a significant exposure-response relationship was observed between long-term exposure to industrial silica dust and radiographic findings resembling silicosis (OR 1.74, 95% CI 1.25 to 2.41). However, among middle-aged workers, a weak and statistically insignificant relationship was found between prolonged cigarette smoking and X-ray evidence of lung silicosis (OR 1.59, 95% CI 1.00 to 2.53). Furthermore, significant combined effects, exceeding the additive models, were identified in each age group and employment sector (relative risk due to interaction 0.51, 95% CI 0.08 to 3.42). Conclusions: It is critically important to implement effective dust removal measures and tobacco control strategies in order to enhance respiratory health among employees across all age groups in the stone processing industry.

Identifikasi Risiko Bahaya Pada Proses Produksi Batu Alam Di Stasiun Pemotongan Menggunakan Metode Hirarc Dan Five Why's

PBA Surya Alam is one of the industries engaged in the natural stone processing industry (PBA) which has a fairly high risk of work accidents due to the lack of hazard control in the production process for workers. The application of occupational safety and health at PBA Surya Alam has been implemented, but its application has not been maximized, such as in terms of worker awareness in using personal protective equipment (PPE). From 2020 the cutting station experienced 7 work accident cases, in 2021 the cutting station experienced 4 work accident cases, and in 2022 the cutting station experienced 2 work accident cases. The purpose of this study was to determine the potential for work accidents, risk assessment, and efforts to control hazard risks in natural stone production process activities. In addition, this study aims to determine the most dominant risk controls and provide suggestions for controlling work accident factors in the natural stone production process. Therefore, this study uses the HIRARC (Hazard Identification Risk Assessment and Risk Control) method, which is a method for determining potential hazards that occur, knowing risk assessment to determine risk levels and knowing risk controls to reduce the occurrence of work accidents. The results of calculations using the HIRARC and 5W + 1 H methods show that there are 6 cases of potential hazards recorded at PBA Surya Alam with each risk, namely 6 cases of potential hazards with extreme risk, then as many as 8 potential cases hazard with high risk (high risk), as many as 5 cases of potential hazard with high risk. Whereas for the 5 W + 1 H method in the process of cutting Natural Stone from the results of observations and observations in the field making control proposals such as installing SOP signs at Natural Stone production stations so as a reminder when operators are working, safety controls for employees and safety helmets to minimize falling products (PPE), and controlling the use of gloves.

Characterization and photocatalytic performance of cement mortars with incorporation of TiO2 and mineral admixtures.

As the main components of the building envelope, construction materials have a straight relation with air contaminants from anthropogenic origins. Titanium dioxide has been recently applied in construction industry products since its photocatalytic properties can be used for pollutant degradation purposes. This study evaluated the performance of cement-based mortars with the incorporation of TiO2 nanoparticles and mineral admixtures. Six mortar compositions were defined by considering two reference mixes (with and without TiO2 incorporation), two mineral admixtures (bentonite and metakaolin) as partial cement replacement and one waste from ornamental stone processing in two levels of partial substitution of natural sand. Consistency index, density, and entrained air content of mixtures were investigated at fresh state. Compressive strength, water absorption, sorptivity, and micrographs from scanning electron microscopy were used to characterize mortars at hardened state. It was observed that incorporation of TiO2 does not considerably change mortar's properties at fresh and hardened state, despite a denser microstructure and improved interfacial transition zone. In general, the relation between the water-to-cement ratio and porosity on the performances of TiO2-added mortars was shown, which is strongly related to their photocatalytic efficiency. Metakaolin mixtures were more efficient to NO conversion, and high selectivity was observed for the bentonite mortars.

Effect of Portland cement on the properties of geopolymers prepared from granite powder and fly ash by alkali-thermal activation

Recycling granite powder (GP) and fly ash (FA) is of great significance for ensuring the sustainable development of the stone processing and thermal power industries. In this study, the reactivity of GP and FA was enhanced via alkali-thermal activation (ATA) and subsequently applied to the synthesis of one-part geopolymers. The results showed that the framework of raw material was severely disrupted, and the content of reactive silicon components was increased after ATA, which enhanced their potential as geopolymeric precursors. Furthermore, the effect of a small amount of ordinary Portland cement (OPC) on the mechanical properties of geopolymers cured at room temperature and 60 °C was investigated. The results demonstrated that the incorporation of OPC at room temperature promoted the degree of geopolymerization and the formation of additional calcium-rich aluminosilicate gels, which led to a significant improvement in the microstructure and compressive strength of geopolymers. When the dosage of OPC is 10%, the compressive strength of geopolymers reaches 32.72 MPa at 28d. However, OPC addition deteriorated the strength of geopolymers cured at 60 °C. The reduction in the strength of geopolymers was attributed to the reduction of hydration products and the efflorescence of geopolymers. This study provides a novel approach for preparing prefabricated building products and on-site cementitious material using GP and FA.

Characterization of waste from the ornamental stone processing for incarnation in clay ceramics

Recently, new technologies are introduced to minimize the disorderly disposal of waste, not only from the processing of ornamental stones (OS), but also from other industrial sectors. A technological alternative to reduce the environmental impact and recycle waste is its incarnation into clayey ceramic products. This solution can improve the properties of the final product. Some studies using granite residues, from sawing blocks, showed great potential for their use in red ceramics, due to their characteristics such as a high content of alkaline oxides, fine granulometry, and low cost. The goal of this work is to characterize the residues from the processing of OS, with the aim to incarnate into clayey ceramics. The characterization will contribute to the knowledge of the residue (mud) and, through this fact, will favor the study of a possible solution to the problem of disposal of mud generated in the sawing of rocks, besides contributing to the practice of sustainable development, and the consequent use of waste discarded as unusable.

A research of the effect of an underwater electric explosion on the selectivity of destruction of quartz raw materials

The work is devoted to the study of the effect of an electric explosion on the selectivity of the destruction of quartz raw materials. The object of the study is quartz ore of the Nadyrbay deposit of the Republic of Kazakhstan. An electrohydroimpulse plant for crushing and grinding quartz raw materials has been developed and assembled. Using the electrohydroimpulse method, the granulometric composition of quartz can be adjusted. This makes it possible to adjust the magnitude of the voltage in the discharge channel and time. In this technology, quartz ore processing was carried out with an increase in the discharge voltage of the storage from 14 kV to 25 kV, the length of the interelectrode distance from 8 to 12, the capacitance of the capacitor 0.5 µF, 0.75 µF and the processing time of 5 min. Using the electrohydroimpulse method, quartz ore particles with an initial fraction of 5 mm, 10 mm and 1 mm were crushed to 0.8. The results of the grinding of quartz raw materials with the influence of an underwater electric explosion in a liquid medium allowed us to determine the degree of grinding of the material. The obtained results can be used in the course of studying the characteristics of crushing and grinding of ores. In the food industry, quartz sand within 0.25–0.5 millimeters can be used as a filler to create filters for water purification, as well as products from oil, industrial effluents, etc. Particles ranging in size from 0.5 to 1 millimeter can be used for rough processing of metal, stone and glass. The structural and quantitative analysis of powdered quartzite samples was made using a scanning electron microscope and the stoichiometry of the elements was calculated

Prevalence and risk factors for silicosis among a large cohort of stone benchtop industry workers

ObjectivesHigh silica content artificial stone has been found to be associated with silicosis among stone benchtop industry (SBI) workers. The objectives of this study were to determine the prevalence of...

Green multiple-criteria decision-making method of selection of diamond cutting tool for promoting cleaner production in the natural stone industry

Selection of a reasonable diamond cutting tool (DCT) is a crucial Multiple Criteria Decision-Making (MCDM) problem for promoting cleaner production for a natural stone company. It has severe uncertainties in the decision information, complex interdependences among the DM criteria and needs to balance stakeholders' opinions and adopt the non-complete compensation idea in the DM process. This paper establishes a specialized index system with changing the evaluation object from ontology of DCT to the ‘stone machining system’ within the boundary demarcated by LCA. Decision-Making Trial and Evaluation Laboratory (DEMATEL) method is applied to analyze the interdependence relationships existing in the index system and then the indicators' weights can be obtained by Analytic Network Process (ANP) method. In order to avoid complete compensation among indicators, Preference Ranking Organization Method for Enrichment Evaluations II (PROMETHEE II) method is used to prioritize the alternatives and identify the most reasonable DCT. The new developed MCDM algorithm is expressed based on interval-valued fuzzy set (IVFS) theory to handle the uncertain information in DM process. Integration of IVFS theory with MCDM method allows the decision-maker to use linguistic variables which correspond to interval-valued fuzzy numbers to describe their judgments and ensures all the stakeholders' preferences can be trade-off in the DM process. In the case application, the proposed method has been applied to select a suitable DCT to cut the Lotus red granite (G3768) for a stone processing company in China. As a result, the iron-based DCT (TJ-15) obtained the highest priority net flow (0.373) among five DCT alternatives and it was identified as the most reasonable DCT for the case company. The application study demonstrates the effectiveness and robustness of the developed method and indicates that pursuit of matching DCT with the characteristics of natural stone is more rational than blindly adopting more advanced and expensive DCT.

22 Evaluation of Occupational Exposure to Respirable Crystalline Silica in Processing of Artificial Stone

Abstract Introduction Clusters of silicosis cases related to the fabrication of quartz conglomerate products and accessories for the furnishing of kitchens and bathrooms are recently reported. The aim of this study was to evaluate the exposure to airborne respirable dust and crystalline silica (RCS) in a company specialized in the production of quartz conglomerates countertops and to investigate the effectiveness of introduced preventive measures (wet finishing, increasing of exhaust ventilation, closing in cabins some of the sanding and finishing operations). Materials and Methods The study was carried out on 51 workers involved in cutting and finishing operations in four facilities. Exposure to respirable dust was evaluated using GS3 cyclones positioned at the breathing zone level for the entire duration of the work shift. RCS content was measured by X-ray diffractometric analysis. Results and Discussion Respirable dust levels were in the range 0.046-1.154 mg/m3 (mean 0.160 mg/m3) with RCS levels within the range <0.003-0.098 mg/m3 (mean 0.022 mg/m3). All RCS levels were lower than the Italian OEL of 0.100 mg/m3 and the 22% above the more restrictive ACGIH-TLV of 0.025 mg/m3. Statistically higher levels were found in correspondence with finishing operations than in cut operations (p<0.05) and during dry operations than in wet (p=0.02). RCS levels were lower than those found in the past before the introduction of preventive technical measures where RCS levels were up to 0.744 mg/m3. Although there was a decisive reduction in exposure levels compared to what was observed in the past, the data still showed a risk condition for some activities. Board of the Italian Association of Industrial Hygienists (AIDII). Her scientific activity is documented by over 80 printed publications both as articles in Journals and contributions to National Congresses.

98 Novel Stoffenmanager® Algorithms for Quantitative Estimation of Exposure to Respirable Dust and Quartz in Construction, Formulating and Metal Manufacturing Industry

Abstract Stoffenmanager® is a well-established and widely accepted tool that is applied for regulatory risk assessments (e.g. REACH). This online-tool enables companies to identify hazardous chemicals, chemical risks and to control exposure to hazardous substances at the workplace. In the current version, however, Stoffenmanager® is not applicable to all areas of activity with solids in which dusty hazardous substances are used or may arise. Therefore, the aim of this project is to expand the applicability domain of Stoffenmanager® by developing three innovative algorithms: 1) respirable dust and quartz for tasks with dusty products, 2) respirable dust for metal-cutting manufacturing and 3) respirable dust and quartz for the mechanical processing of stone. To derive new quantitative regression models calibration and validation measurement datasets on hazardous substances are required. In this project, a total of approximately 6000 data points including comprehensive contextual information were extracted from the IFA Exposure database MEGA and MEGA variables were converted into Stoffenmanager® variables. Subsequently, the variables were divided into classes with scores on a logarithmic scale. Spearman correlation coefficients were calculated, and in case of significant positive relationship between the Stoffenmanager® scores and the measurements statistical regression analyses were performed to calculate the regression equations. After the development of the new algorithms, exposure models were validated against exposure data from the MEGA database. Scatter plots and regression equations will be presented. The new algorithms serve to improve workers’ health by reducing occupational exposure to respirable dust and quartz which are known to be human carcinogens.

101 Novel Stoffenmanager® Algorithms for Quantitative Estimation of Exposure to Respirable Dust and Quartz in Construction, Formulating and Metal Manufacturing Industry

Abstract Stoffenmanager® is a well-established and widely accepted tool that is applied for regulatory risk assessments (e.g. REACH). This online-tool enables companies to identify hazardous chemicals, chemical risks and to control exposure to hazardous substances at the workplace. In the current version, however, Stoffenmanager® is not applicable to all areas of activity with solids in which dusty hazardous substances are used or may arise. Therefore, the aim of this project is to expand the applicability domain of Stoffenmanager® by developing three innovative algorithms: 1) respirable dust and quartz for tasks with dusty products, 2) respirable dust for metal-cutting manufacturing and 3) respirable dust and quartz for the mechanical processing of stone. To derive new quantitative regression models calibration and validation measurement datasets on hazardous substances are required. In this project, a total of approximately 6000 data points including comprehensive contextual information were extracted from the IFA Exposure database MEGA and MEGA variables were converted into Stoffenmanager® variables. Subsequently, the variables were divided into classes with scores on a logarithmic scale. Spearman correlation coefficients were calculated, and in case of significant positive relationship between the Stoffenmanager® scores and the measurements statistical regression analyses were performed to calculate the regression equations. After the development of the new algorithms, exposure models were validated against exposure data from the MEGA database. Scatter plots and regression equations will be presented. The new algorithms serve to improve workers’ health by reducing occupational exposure to respirable dust and quartz which are known to be human carcinogens.

Mineralogical, pozzolanic and microscopic characterization of dolomite mine overburden

Waste generated during the cutting and processing of stones is a severe environmental problem. Using waste materials in civil engineering applications is beneficial for sustainable construction practices. The stone industry generates a very high quantity of overburden during mining processes. This overburden is discarded as its composition is not similar to that in the pure state. This study aims to characterize the dolomite mine overburden in its native state. This characterization is based on mineralogical, pozzolanic and microscopic characteristics of dolomite overburden. The mineralogical characterization was done using XRD and XRF analysis. XRD tests showed the presence of dolomite [CaMg(CO3)2] and Silica Oxide (SiO2) in significant compositions. The predominant presence of 30.54 % of Calcium Oxide (CaO), 18.71 % Silica Oxide (SiO2) and 7.6 % of (MgO) was determined by XRF analysis. Frattini and Strength Activity Index (SAI) tests were performed to check the presence of pozzolanic properties in the material. Frattini test results showed the non-pozzolanic/inert nature of overburden. The inert nature of dolomite overburden was confirmed by SAI test results. The modified mix failed to fulfill the criteria of 75 % and 85 % strength of the control mix after 7 and 28 days of curing. The microscopic analysis was carried out by SEM analysis. SEM images showed the irregular shape and rough surface texture of dolomite overburden. The pozzolanic characterization proves that the dolomite mine overburdened can't be used as a cementitious material. Its application can be tested for filler material or as a replacement for coarse/fine aggregates in concrete and mortar mixes. It can also be tested as filler material in bituminous mixes or stabilizing agent in soil stabilization.

Research on a Stone Processing Powder Recovery and Reuse Device

This article focuses on a recycling device for powder from stone processing. The device mainly includes three components: a filter device, a rolling device and a gathering device. It could not only perform the filtration, rolling and gathering of stone powder, but also effectively prevent the collected stone powder from accumulating in a single place, and greatly improve the filtration efficiency. The device can be applied in the concrete prepared by artificial sand with distinct advantages in production energy consumption, production cost, and also has a superiority in the development, utilization and application scope of by-products, and recycling of raw materials, At the same time, it can reduce pollution to living environment greatly. The device is simple in structure, practical in use and easy to promote.

Alkali-activation potential of stone wastes

The industrial processing of dimensional stones generates a significant amount of waste. According to the data released in 2020 by the nations with active dimensional stone industries, it is estimated that out of 316 million tons of dimensional stones extracted each year, 161.5 million tons end up as mining or quarry waste. These are dumped in open locations creating noxious conditions for mine workers, residents of nearby communities, and the environment. In the current work, an effort has been made to manufacture alkali-activated materials (AAM) using sandstone waste (SW) and marble stone waste (MW) obtained from Rajasthan (India). The primary precursor is SW, whereas MW is partially substituted as an admixture. The elemental composition of stone wastes was determined using X-ray fluorescence spectroscopy (XRF). Stone waste-based geopolymer composite was prepared using alkaline activating solutions sodium hydroxide (NH, NaOH) and sodium silicate (NS, Na2SiO3) and tested for mechanical and physical properties. Characterization and microstructural analysis of geopolymer composite was performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) fitted with energy dispersive X-ray spectroscopy (EDS). The findings suggest that the developed geopolymer composite can be employed as a construction material that will improve the re-utilization of stone wastes, offering a workable solution to the challenges associated with their disposal.