Rock Wool Fibers Research Articles

Influence of FexOy and Al2O3 Contents on the Thermal Stability of Iron Ore-Waste Fibers: Key Mechanisms and Control.

Traditional rock wool fibres are susceptible to crystallization and pulverization. To mitigate this, glass fibres were produced from iron ore waste (IOW). When the ratio of Fe2+ and Fe3+ is 1:3 and the Al2O3 content is 10 wt.%, increasing the FexOy content enhances the thermal stability.At an FexOy content of 17-19% and an Al2O3 content of 10-13%, the glass transition temperature (Tg) peaked. Increasing the FexOy content from 10% to 20% enhanced the stability of Si-O and Al-O bonds and increased bridged oxygen, stabilizing the structure. Here, Fe2+ balances structural charges, while Fe3+ replaces some Al atoms in the network. When the Al2O3 content is 10-13% and the FexOy content is 17-19%, the thermal stability of the IOW rock glass reaches its optimal level. At 20% FexOy content, the structure becomes three-dimensional and cyclic, increasing polymerization. Consequently, incorporating FexOy alongside a 10% Al2O3 content improves thermal stability, supporting the development of high-stability rock wool from IOW. This approach also enhances the refractory properties of rock wool fibres within the FexOy-Al2O3-SiO2-MgO-CaO system.

Nanosheet BiOBr Modified Rock Wool Composites for High Efficient Oil/Water Separation and Simultaneous Dye Degradation by Activating Peroxymonosulfate.

The development of superlyophobic materials in liquid systems, enabling synchronous oil/water separation and dye removal from water, is highly desirable. In this study, we employed a novel superwetting array-like BiOBr nanosheets anchored on waste rock wool (RW) fibers through a simple neutralization alcoholysis method. The resulting BiOBr/RW fibers exhibited superoleophilic and superhydrophilic properties in air but demonstrated underwater superoleophobic and underoil superhydrophobic characteristics. Utilizing its dual superlyophobicity, the fiber layer demonstrated high separation efficiencies and flux velocity for oil/water mixtures by prewetting under a gravity-driven mechanism. Additionally, the novel BiOBr/RW fibers also exhibited excellent dual superlyophobicity and effective separation for immiscible oil/oil systems. Furthermore, the BiOBr/RW fibers could serve as a filter to continuously separate oil/water mixtures with high flux velocity and removal rates (>93.9%) for water-soluble dye rhodamine B (RhB) simultaneously by directly activating peroxymonosulfate (PMS) in cyclic experiments. More importantly, the mechanism of simultaneous oil/water separation and RhB degradation was proposed based on the reactive oxygen species (ROS) quenching experiments and electron paramagnetic resonance (EPR) analysis. Considering the simple modified process and the waste RW as raw material, this work may open up innovative, economical, and environmentally friendly avenues for the effective treatment of wastewater contaminated with oil and water-soluble pollutants.

Structural properties and barrier performance of low-cost aerogel composites for building insulation

The high cost and weak mechanical properties of silica-based aerogel seriously affect its wide application in the field of building insulation. In this paper, low-cost SiO2 aerogel (WSA) was prepared based on water glass/water system, and the modulation of aerogel network structure was achieved under the dual effect of sodium methylsilicate (SMS) and pH. WSA exhibits extremely low density (∼88.5 kg/m3) and thermal conductivity (0.02114 W/(m·K)) as well as high hydrophobicity (150°). The cost of WSA is 53 % lower compared to atmospheric pressure drying and 21.5 % lower than commercial aerogel. On this basis, rock wool fiber felt (RWF) and ultrafine glass fiber wool felt (UGFW) were modified with WSA. The effect of fiber arrangement on the force-thermal coupling property of WSA@RWF was investigated. Meanwhile, the addition of WSA reduced the volumetric water absorption of RWF by 85.1 % and 91.4 %. Since the sandwich structure, the thermal conductivity of WSA@UGFW can be as low as 0.01168 W/(m·W), which is 44.7 % and 44.4 % lower than that of UGFW and WSA. It features a low density of 45.7 kg/m3 and a high hydrophobicity angle of 155.87°. In addition, the compressive strength of WSA@UGFW is increased by 16.5 times. Therefore, the aerogel materials prepared in this paper have great application potential as fire-proof building insulation materials.

Advantages of using a dual‐filler system with carbon black and rockwool fiber on Nitrile Rubber composites from a technical standpoint

AbstractThis study produced and characterized composites based on nitrile rubber reinforced with rockwool fiber (RW) and carbon black (CB). Ten formulations with dual‐filler loading amounts ranging from 0 to 40 phr of CB and RW were designed using a simplex‐centroid mixture. The composites were assessed regarding their rheometric, rheological, mechanical, and thermal properties. The use of the RW in the dual‐filler system contributed to overall improvements in Shore A hardness, tear strength, modulus at 50%, and resilience, as well as reducing the Payne effect. Instead of using 40 phr of CB alone, a dual‐filler system comprising 20 phr of CB and 20 phr of RW lowers the Payne effect by around 60%, improves resilience by 35%, modulus at 50% strain by 8%, and the residual stress at equilibrium (σ∞/σ0) by 7%. On the other hand, the tensile strength is reduced by 23%. The optimum cure time, crosslink density, and maximum decomposition rate temperature were not affected by the rockwool's presence in the dual‐filler system. In general, the use of RW in combination with CB is advantageous mainly because it reduces compressive stress relaxation, which is an important property for sealing applications.Highlights Dual‐filler systems based on carbon black (CB) and rockwool fiber (RW) offer advantages. RW‐rich dual‐filler systems reduce stress relaxation. RW‐rich dual‐filler systems reduce the Payne effect. CB‐rich dual‐filler systems increase tensile strength.

Energy efficiency of a house in Mediterranean region: insulation and glazing impact

The insulation of a building's envelope is critical for reducing energy consumption, enhancing indoor thermal comfort, and achieving sustainable development goals. This theoretical work focused on the energy and thermal aspect of insulators and glazing to determine the optimal thermal insulation and the best glazing for the building envelope in the Mediterranean region where the province of Ain Temouchent, Algeria, was taken in this study. This study evaluated the effectiveness of insulation materials, which are expanded polystyrene, glass wool, rock wool, and wood fiber of varying thicknesses, and glazing in the Algerian market. The TRNSYS 17 software is used to simulate the building's behavior. The study finds that wood fiber insulation with a 9 cm thickness provides the best thermal performance, resulting in a 26% reduction in energy costs compared to 3cm of expanded polystyrene. Furthermore, upgrading from single to double glazing can reduce heating and cooling costs by 23% and 10%, respectively, demonstrating the importance of proper insulation and glazing in achieving energy efficiency, and enhancing indoor thermal comfort for occupants. In conclusion, this study provides valuable findings for designing energy-efficient buildings with optimal thermal insulation and glazing. Future research should explore broader factors affecting building performance, such as the long-term performance and durability of materials in varying climates and building designs, as well as the impact of occupancy and building orientation. Although the study acknowledges its limited examination of factors and options, it still provides valuable insights into building performance with insulation and glazing.

Thermal insulation performance of rock wool reinforced kaolinite-based porous geopolymer

The development of thermal insulation materials with superior comprehensive properties is crucial to building energy conservation. This paper presents a kaolinite-based porous geopolymer type composite thermal insulation material through alkali activation, room temperature foaming technology, and the rock wool fiber reinforcement. The effects of rock wool fiber contents and heat treatment on the comprehensive properties of the kaolinite-based porous geopolymer were investigated. The addition of rock wool fiber can enhance the mechanical properties of kaolinite-based porous geopolymer, while heat treatment can generate a hierarchical porous structure, resulting in a dramatical improvement in thermal insulation performance. With a rock wool fiber content of 15 wt%, the sample exhibits a porosity of ∼90%, density of 0.118 g/cm3, thermal conductivity of 0.057 W/(m·K), and a maximum compressive strength of 0.66 MPa, increased by ∼22% compared to samples without addition of rock wool. Additionally, the optimized thermal insulation material followed waterproofing treatment exhibits excellent hydrophobicity with a contact angle of up to 98.5°. Therefore, this novel thermal insulation material not only has a simple manufacturing process and eco-friendly properties, but also showcases properties including lightweight construction, high strength, and low thermal conductivity. Consequently, it holds immense potential in the area of building energy conservation.

Rock Wool Fiber-Reinforced and Recycled Concrete Aggregate-Imbued Hot Asphalt Mixtures: Design and Moisture Susceptibility Evaluation

Designing asphalt mixtures for pavement construction by controlling the moisture-mediated damage remains challenging. With the progression of time, this type of damage can accelerate deterioration via fatigue cracking and rutting unless inhibited. In this study, two types of hot asphalt mixtures (HAMs) were made by incorporating recycled concrete aggregates (RCAs), which were reinforced with rock wool fibers (RWFs). The first specimen was a normal mixture with a completely virgin aggregate, and the second one was a sustainable mixture with 30% RCAs. The proposed mixes were thoroughly characterized to assess the impact of RWF incorporation at various contents (0.5, 1, 1.5, and 2%) on moisture resistance. The optimal asphalt concentration (OAC) and volumetric parameters of the mixes were determined using the Marshall technique. The moisture susceptibility of the obtained HAMs was evaluated in terms of the tensile strength ratio (TSR). The results revealed that the moisture resistance, Marshall stability, flow, and volumetric parameters of the HAMs were improved due to the reinforcement by RWFs, indicating a reduction in the moisture sensitivity and an increase in TSR%. In addition, the HAMs designed with 1.5% RWFs displayed the highest TSR% (11.37) and Marshall stability compared to the control mix. The observed improvement in the moisture resistance and Marshall attributes of the prepared HAMs was ascribed to the uniform distribution of the RWFs that caused a well-interconnected structure and tightening in the asphalt concrete matrix. It is asserted that the proposed HAMs can be nominated for the construction of durable high-performance pavements.

Contribution of Various Loads to the Convex Shape of Rock Wool Insulation Slabs during Production.

Rock wool insulation slabs are produced in special curing ovens, where molten rock wool fibres coated with binder are compressed between two slat conveyors and blown with hot air for vitrification. Often, the cross-section of the final slabs is slightly convex, which is undesirable. The degree of convexity depends on the deformation of the steel crossbars of the slat conveyors, which are subjected to combined pressure and nonlinear temperature loadings. Due to this complex loading state, it is difficult to determine the contribution of individual load to the total deformation. The main aim of the study was to determine these contributions. Temperature and stress measurements of the crossbars were performed during rock wool production. Upon collecting these measurements, a finite element (FE) model of a crossbar was established for the identification of the pressure loading acting on the crossbars, and finally for determination of their deformations. As a main result of the study, an inverse problem-based methodology for the identification of the deflection of a structure due to unknown temperature and pressure loadings was established and applied on the specific case. The deviations between the deformations of the FE crossbars and the final shape of the rock wool slabs were below 10%, which validates the novel methodology.

Effects of Hybrid Rockwool–Wood Fiber on the Performance of Asbestos-Free Brake Friction Composites

The present study explores the physical-mechanical and tribological properties of hybrid wood fiber and rockwool-reinforced asbestos-free resin-based friction materials. We developed asbestos-free brake friction composites with different contents of hybrid fiber (wood and rockwool fiber) at a total fixed fiber loading of 30%. Then, the developed composites were investigated on the physical, mechanical, and tribological properties according to the industry standards. The results show that, with the increase in wood fiber, the density, hardness, and strength decrease, and the water absorption increases. Meanwhile, rockwool fiber can improve the coefficient of friction and enhance friction stability, while wood fiber has a significant impact on wear resistance. The sample with 5% wood fiber and 25% rockwool fiber presented the best performance in terms of the coefficients of friction, wear rate, and fade–recovery behavior. It provides a new idea for the research of asbestos-free composites.

Industrial Rockwool Fiber Wastes as Reinforcement in Rigid Polyurethane Foam: Preparation and Characterization

Industrial Rockwool Fiber Wastes as Reinforcement in Rigid Polyurethane Foam: Preparation and Characterization

Exploring the Potential of Alternate Inorganic Fibers for Automotive Composites.

Composites are a promising material for high-specific strength applications; specifically, fiber-reinforced polymer composites (FRPCs) are in the limelight for their extraordinary mechanical properties. Amongst all FRPCs, carbon fiber reinforcements are dominant in the aerospace and automotive industry; however, their high cost poses a great obstacle in commercial-scale manufacturing. To this end, we explored alternate low-cost inorganic fibers such as basalt and rockwool as potential replacements for carbon fiber composites. In addition to fibrous inclusions to polymers, composites were also fabricated with inclusions of their respective particulates formed using ball milling of fibers. Considering automotive applications, composites' mechanical and thermo-mechanical properties were compared for all samples. Regarding mechanical properties, rockwool fiber and basalt fiber composites showed 30.95% and 20.77% higher impact strength than carbon fiber, respectively. In addition, rockwool and basalt fiber composites are less stiff than carbon and can be used in low-end applications in the automotive industry. Moreover, rockwool and basalt fiber composites are more thermally stable than carbon fiber. Thermogravimetric analysis of carbon fiber composites showed 10.10 % and 9.98 % higher weight loss than basalt and rockwool fiber composites, respectively. Apart from better impact and thermal properties, the low cost of rockwool and basalt fibers provides a key advantage to these alternate fibers at the commercial scale.

Prediction of Thermal Conductivity of a Rock Wool Board by Computer X-Ray Tomography Technique Scanning and Random Generation-Growth Model

Thermal conductivity of rock wool boards was investigated in this study. Although distribution of fibers in a realistic rock wool board is unclear, it can be simulated by computer X-ray tomography technique (CT) followed by rearrangement through the random generation-growth (RGG) model. An ideal CT-RGG structure model of rock wool boards (CT-random generation-growth model) was established by simplifying material properties based on the mesostructure parameters of the RGG model. Thermal conductivity of rock wool boards with different apparent densities and fiber diameters was studied, and the CT-RGG model was analyzed by explicit jump (EJ) diffusion equations solved by the fast Fourier transform method. We found that thermal conductivity of a single rock wool fiber can be successfully determined. Simulation and measurement results show that thermal conductivity increases consistently with the increase of apparent density and fiber diameter, particularly when the apparent density of rock wool board is greater than 140 kg m−3. Compared with the existing theoretical models, the proposed method does not depend on the empirical parameters; therefore, it is useful in designing and optimizing the thermal conductivity of rock wool boards.

Reclaimed rockwool fibers for thermally stable palm oil-based polyurethane foam

Reclaimed rockwool fibers for thermally stable palm oil-based polyurethane foam

Rock wool-reinforced concrete: Physico-mechanical properties and predictive modelling

Recent developments in lightweight concrete (LWC) have led to a renewed interest in incorporating fibers in concrete. However, research on the specific application of rock wool fiber in LWC is scarce. Hence, the present study aims to investigate the physical and mechanical characteristics of LWC with the inclusion of rock wool fibers (0%–15%) in different water-cement ratios (0.4, 0.5 and 0.6). The relationships between mix proportion and the density, permeable void, water absorption, compressive strength, splitting tensile strength and flexural strength of the composite were investigated. The results showed the density of the rock wool-incorporated specimen was highly reduced (up to 73% reduction) when the incorporation of rock wool fiber reached 15%. The oven-dry densities of the specimens for fiber contents from 2.5% to 10% are 800 kg/m3 to 2000 kg/m3, which can be classified as LWC. Permeable voids of the specimens were increased by 63% by volume with 15% of rock wool inclusion. Only a certain mix proportion fulfilled the requirement to be used as load-bearing internal walls. The correlation between compressive strength and splitting tensile strength was subsequently analyzed. Lastly, the empirical models for all properties were generated using the response surface method with R2 > 0.90. In conclusion, the selection of different mix ratios of rock wool and the water-cement ratio (w/c) for attaining better physical or mechanical properties of LWC will be presented, and hopefully serves as a sound basis for future related studies.

Friction Performance Improvement of Phenolic/Rockwool Fibre Composites: Influence of Fibre Morphology and Distribution

The size and morphology of reinforcing fibres have a great influence on organic brake friction composite material properties and performance. This research aims to establish the link between friction material microstructure heterogeneity induced by rockwool fibre morphology and distribution and the resulting tribological behaviour. The adopted approach is based on simplified formulations designed to limit synergistic effects by reducing the number and size distribution of constituents. Two simplified materials are developed with different rockwool fibre size and morphology. The first material is elaborated with calibrated fibre balls, and the second one is performed with separated fibres. Friction and wear behaviour are correlated with thermal phenomena in order to reveal wear mechanisms and thus understand the link between microstructural characteristics and the resulting tribological behaviour. It was found that a regular size and distribution of rockwool fibre balls induce better tribological behaviour and enhance wear resistance. Indeed, a homogeneously distributed porosity, which is induced by fibre balls, favours the development and preservation of the load-bearing plateaus in the contact. This, consequently guarantees a stable friction and a reduced wear rate. Consequently, reducing microstructural heterogeneity, resulting from rockwool fibre morphology and distribution, improves the performance of composite friction material.

Enhanced photocatalytic performance and persulfate activation properties by BiOBr supported waste rock wool fibers under LED blue light

An advanced oxidation process was developed under LED blue light (BL) photocatalysis in the presence of ammonium persulfate (APS) for effective degradation of tetracycline (TC) from contaminated water. Waste rock wool (RW) fibers modified with BiOBr nano-sheet (BiOBr/RW) using impregnation combined with hydrolysis process, was employed to activate APS to produce reactive radicals under LED BL irradiation (BiOBr/RW+APS+BL system). The influence factors on TC degradation were investigated. Besides, the radical scavengers such as methanol (MA), phenol (PN), tertbutanoland (TBA) and ethylene diamine tetraacetate (EDTA-2Na) combined electron spin paramagnetic resonance (EPR) analysis were used to confirm the reactive radical species. The developed BiOBr/RW+APS+BL system exhibited much higher TC removal efficiency compared with other reported oxidation systems. In addition, the BiOBr/RW could directly activate the APS leading to degrade TC in the darkness. A maximum TC removal of 84.3% was achieved under the optimal conditions such as initial concentration of APS 100 mg/L, BiOBr/RW dosage 0.1 g/L and pH 7 in 80 min. Results also ascertained that h+, •OH and •SO4- over surface of the BiOBr/RW were the primary active chemical species in the BiOBr/RW+APS+BL system. It was found that the •OH and •SO4- in solution play critical roles for degradation of TC on the BiOBr/RW+APS system in dark. Finally, the repeated experiments indicated the excellent stability, photocatalytic ability and cycling property of BiOBr/RW.

Wear Rate Behavior of Unsaturated Polyester Reinforced with (Glass and Rock Wool Fiber) under the Influence of Chemical Solutions

In this research, the adhesive wear of a composite material consisting of unsaturated polyester has been studied as a matrix material reinforced by glass fiber and rock wool fibers. The wear rate property is compared in the normal condition and after immersion in (NaOH) and (HCl) solutions at normality (0.3N) and the laboratory temperature (25 oC) for 30 (days) and with a fixed volume fraction of (20%). The results showed that the wear rate decreased with increasing number of reinforcement layers before and after immersion and for all samples. However, it is noted that immersion in chemical solutions leads to an increase in wear rate compared that of the normal condition and for all samples.

Effect of the type of reinforcing for Hardness properties for (Thermoset – fibers) composite .

This research included preparation of two types of fiber composites and the the basis as ato break the stereotypes and manual volumetric rate of 25% . The characterization of the fiber is divided into two types:Overlapping material composed of epoxy resin as a subsidized two layers and four layers , six layers of fiber glass basis of the type (E-Glass) is woven mat.Overlapping material composed of epoxy as supported by two layers and four layers , six layers of caors rock wool fibers basis . In this paper the hardness characteristic study of the above complexes in natural conditions and after immersion normal water for different time periods is (5,10,15) days at room temperature . The results showed the process that the value of surface hardness for both types of specimens in natural conditions increases with the number of layers of reinforcement and that the value of the complexes fiberglass higher than the value of the complex rock wool fibers , after immersion the samples with water usual noticed that the surface hardness decreases with increasing duration of water immersion and with increasing number of reinforcement layers and both types of complexes , but their value in the complexes, fiberglass largest of its value for the characterization of rock wool fibers .

Mechanical and sound absorption properties of open-cell polyurethane foams modified with rock wool fiber

The main objective of this paper was to evaluate the mechanical and sound absorption properties of open-cell flexible polyurethane foams (PUFs) synthesized with different contents of rock wool fiber (RWF) (0, 0.5, 1, and 1.5) after treating with Alkaline surface treatments at 5% concentration of sodium hydroxide (NaOH) solution. Characterizations were carried out using the sound absorption coefficient (SAC), Brunauer-Emmett-Teller (BET), Barret-Joiner-Halenda (BJH), a field emission scanning electron microscope (FESEM), and the 506-B1 universal testing machine (for measurement mechanical properties). The SAC of PUFs with various contents of the RWF filler was determined using the transfer function method with impedance tube meter in the frequency range between 63 and 6400 Hz. The meso-macroporosity of the carrier was confirmed by BJH analysis. BET analysis illustrated an increment in the free surface area for polyurethane composite foams prepared with 1 wt% of RWF (PUF-RWF1) and 1.5 wt% of RWF (PUF-RWF1.5). The cell and pore sizes and pore distribution in the polyurethane composite foams showed significant differences after adding filler contents. The highest efficiency of sound absorption was obtained for PUF-RWF1.5 in the range between 500 and 4800 Hz, while the SAC did not improve significantly at the frequency above 4800 Hz for PUF-RWF1 and PUF-RWF1.5. Depending on the reinforcement rates of fibers, the mechanical properties of composites, such as compression strength and stress relaxation, were investigated. Stress relaxation and compression strength showed superior results with adding the RWF fillers compared to pure PUFs, and it is mainly due to the enhanced interfacial contacts and compatibility between the polyurethane matrix and RWF filler surfaces. The results and conclusion obtained in the experiment support the application of composite foams for acoustic and noise reduction.

Visualization of Arabidopsis root system architecture in 3D by refraction-contrast X-ray micro-computed tomography.

Plant roots change their morphological traits in order to adapt themselves to different environmental conditions, resulting in the alteration of the root system architecture. To understand this mechanism, it is essential to visualize the morphology of the entire root system. To reveal effects of long-term alteration of gravity environment on root system development, we have performed an experiment in the International Space Station using Arabidopsis plants and obtained dried root systems grown in rockwool slabs. The X-ray computed tomography (CT) technique using industrial X-ray scanners has been introduced to visualize the root system architecture of crop species grown in soil in 3D non-invasively. In the case of the present study, however, the root system of Arabidopsis is composed of finer roots compared with typical crop plants and rockwool is also composed of fibers having similar dimension to that of the roots. A higher spatial resolution imaging method is required for distinguishing roots from rockwool. Therefore, in the present study, we tested refraction-contrast X-ray micro-CT using coherent X-ray optics available at the beamline of the synchrotron radiation facility SPring-8 for bio-imaging. We have found that a wide field of view but with low resolution obtained at the experimental Hutch 3 of this beamline provided an overview map of the root systems, while a narrow field of view but with high resolution obtained at the experimental Hutch 1 provided an extended architecture of the secondary roots, by a clear distinction between roots and individual rockwool fibers, resulting in the successful tracing of these roots from their basal regions.