Ferronickel Slag Research Articles

Characteristics of alkali-activated composites containing blast-furnace slag aggregate and ferronickel slag powder

The use of alkali-activated composites and alternative aggregates reduces the carbon dioxide emissions of the construction industry and mitigates the problem of aggregate depletion. However, published investigations into non-cement composites containing ferronickel slag powder (FSP) and blast-furnace slag fine aggregate (BSA) are limited. The aim of this study was thus to assess the mechanical properties and durability of non-cement composites containing FSP and BSA. The mix with 10% FSP and 25% BSA was found to have the highest 28-day compressive strength, of approximately 42.2 MPa. For the mixes with 5% FSP, the 28-day compressive strength increased with an increase in BSA content. Charge-passed tests revealed that, after 7 days, the sample with 5% FSP and 50% BSA exhibited a total charge of approximately 907 C, classifying it as ‘very low’ according to ASTM C1202. By 56 days, the total charge for this sample reached a value of approximately 120 C, close to ‘negligible’ as per ASTM C1202. It was thus concluded that an appropriate BSA content effectively enhances the mechanical properties and durability of non-cement composites.

Performance-Based Design of Ferronickel Slag Alkali-Activated Concrete for High Thermal Load Applications.

This study aimed to develop optimized alkali-activated concrete using ferronickel slag for high-temperature applications, focusing on minimizing environmental impact while maintaining high compressive strength and slump. A response surface methodology, specifically the mixture design of experiments, was employed to optimize five components: water, FNS-based alkali-activated binder, and three aggregate sizes. Twenty concrete mixes were tested for slump and compressive strength before and after exposure to 600 °C for two hours. The optimal mix achieved 88 MPa compressive strength before heat exposure and 34 MPa after, with a slump of 140 mm. An upscaled version with improved workability (210 mm slump) maintained similar unheated strength but showed reduced post-heating strength (23.5 MPa). Replacing limestone with olivine aggregates in the upscaled mix resulted in 65 MPa unheated and 32 MPa post-heating strengths. Life Cycle Analysis revealed that the optimized ferronickel slag alkali-activated concrete's CO2 emissions were 77% lower than those of ordinary Portland cement concrete of equivalent strength. This approach demonstrated the applicability of mixture design of experiments as an alternative design methodology for alkali activated concrete, providing a valuable performance-based design tool to advance the application of alkali-activated concrete in the construction industry, where no prescriptive standards for alkali-activated ferronickel concrete mix design exist. The study concluded that the developed ferronickel slag alkali-activated concrete, obtained through a performance-based mixture design methodology, offers a promising, environmentally friendly alternative for high-strength, high-temperature applications in construction.

Compressive Strength and Chloride Ion Penetration Resistance of GGBFS-Based Alkali-Activated Composites Containing Ferronickel Slag Aggregates

Various studies have reported the use of alkali-activated composites to enable sustainable development in the construction industry as these composites eliminate the need for cement. However, few studies have used ferronickel slag aggregates (FSAs) as an aggregate material for alkali-activated composites. Alkali-activated composites are environmentally friendly and sustainable construction materials that can reduce carbon dioxide emissions from cement production, which accounts for 7% of global carbon emissions. In the construction industry, various research was conducted to improve the performance of alkali-activated composites, such as changing the binder, alkali activator, or aggregate. However, research on the application of ferronickel slag aggregate as an aggregate in alkali-activated composites is still insufficient. In addition, the effect of ferronickel slag aggregate on the performance of alkali-activated composites when using calcium-based or sodium-based alkali activators has not been reported yet. Thus, this study prepared ground granulated blast-furnace slag-based alkali-activated composites with 0, 10, 20, and 30% FSA as natural fine aggregate substitutes. Then, the fluidity, micro-hydration heat, compressive strength properties, and resistance to chloride ion penetration of the alkali-activated composite were evaluated. The test results showed that the maximum temperature of the CF10, CF20, and CF30 samples with FSA was 35.4–36.4 °C, which is 3.8–6.7% higher than that of the CF00 sample. The 7 d compressive strength of the sample prepared with CaO was higher than that of the sample prepared with Na2SiO3. Nevertheless, the 28 d compressive strength of the NF20 sample with Na2SiO3 and 20% FSA was the highest, with a value of approximately 55.0 MPa. After 7 d, the total charge passing through the sample with Na2SiO3 was approximately 1.79–2.24 times higher than that of the sample with CaO. Moreover, the total charge decreased with increasing FSA content.

Feasibility of Using Ferronickel Slag as a Sustainable Alternative Aggregate in Hot Mix Asphalt

Ferronickel slag (FNS) is a byproduct produced during ferronickel alloy manufacturing, primarily used in the manufacturing of stainless steel and iron alloys. This material is produced by cooling molten slag with water or air, posing significant disposal challenges, as improper storage in industrial yards can lead to environmental contamination. This study investigates the chemical and mineralogical characteristics of reduction ferronickel slag (RFNS) and its potential use as an alternative aggregate in hot mix asphalt (HMA). The research is based on the practical application of HMA containing RFNS in an experimental area, specifically the parking lot used by buses transporting employees of Anglo American, located at the Codemin Industrial Unit in Niquelândia, Goiás, Central Brazil. Chemical analysis revealed that RFNS primarily consists of MgO, Fe2O3, and SiO2, which are elements with minimal environmental impact. The lack of significant calcium content minimizes concerns about expansion issues commonly associated with calcium-rich slags. The X-ray diffractogram indicates a predominantly crystalline structure with minerals like Laihunite and Magnetite, which enhances wear and abrasion resistance. HMA containing 40% RFNS was tested using the Marshall methodology, and a small experimental area was subsequently constructed. The HMA containing RFNS met regulatory specifications and technological controls, achieving an average resilient modulus value of 6323 MPa. Visual inspections conducted four years later confirmed that the pavement remained in excellent condition, validating RFNS as a durable and effective alternative aggregate for asphalt mixtures. The successful application of RFNS not only demonstrates its potential for local road paving near industrial areas but also underscores the importance of sustainable waste management solutions. This research highlights the value of academia–industry collaboration in advancing environmentally responsible practices and reinforces the contribution of RFNS to enhancing local infrastructure and promoting a more sustainable future.

Evaluation of MgO-rich materials obtained from Ferronickel slag for CO2 sequestration

Because it has a high magnesium content, ferronickel (FeNi) slag is a potential alternative material for CO2 sequestration. The slag can be pretreated by alkali fusion with NaOH to obtain MgO-rich materials. In this study, the potential of this MgO-rich material for CO2 sequestration was investigated using MgO from FeNi slag (MgO-FS) and MgNa2SiO4 from FeNi slag (MNA). A MgO reagent (MgO-R) and FeNi slag were used as reference materials. The carbonation process was carried out using a batch autoclave with various liquid-to-solid (L/S) ratios, initial pressures, times, and CO2 concentrations. The MgO-FS effectively captured CO2 and had a carbonation performance comparable to that of MgO-R. The degrees of carbonation for MgO-R, MgO-FS, and MNA were 68.43 %, 65.53 %, and 39.40 %, respectively, when carbonation was carried out at 423 K and 8 bar with an L/S ratio of 10 mL/g and pure CO2 for 9 h. Combination of the FeNi slag alkali fusion process (1:2 FeNi slag/NaOH mass ratio, 773 K, and 4 h) with water washing and carbonation (4 bar, 423 K, 10 mL/g L/S ratio, 3 h, and pure CO2) gave a CO2 uptake efficiency of 0.119 ± 0.004 g CO2/g FeNi slag. The results of the degree of carbonation (i.e. 65.53 %), X-Ray diffraction spectra (magnesite mineral peak), and scanning electron microscope observations (magnesite crystal appearance) provide evidence that MgO-FS is an effective alternative material for indirect CO2 sequestration.

Properties of mortar according to substitution rate of ferro-nickel slag powder

This study analyzes the properties of cement mortar according to the substitution of fine ferro-nickel slag powder in various types of fine aggregate, with the aim of recycling industrial waste. When using a ferro-nickel slag powder as the admixture of cement mortar, it is determined that substitution rates of 30% and higher are unsuitable for use as mortar. In order to solve this problem, it is believed that it is necessary to explore means to improve the initial strength degradation that results when fine ferro-nickel slag powder is mixed. Furthermore, the differences in carbon dioxide reduction according to fine ferro-nickel slag powder substitution rates were found to be minimal, and it is thought that additional performance analysis is necessary.

Economy, Energy, and Environment Impact on the Use of Ferronickel Slag Waste for Construction Project in Indonesia

This research intends to investigate the economic, energy and environmental aspects of mortar and concrete manufactured with ferronickel slag (FNS) as a substitute for cement and aggregate because many infrastructure projects in Indonesia use waste materials, particularly FNS, as one of the construction components. Results indicate that incorporating FNS powder as one material in construction projects also has indirect benefits such as generating employment, and fostering local community economic growth. The grinding of FNS will provide business opportunities for Micro, Small and Medium-sized Enterprises (MSMEs). The use of FNS as sand replacement affords an economy advantage in concrete production which also benefits in the construction sector. In addition, utilizing by-products (FNS 1 and FNS 2) in mortar production has a beneficial effect on lowering the LCC. However, adding FNS in place of sand does not reduce the LCC of concrete constructed with FNS. The usage of FNS in place of cement appears to help reduce mortar's energy consumption. However, using FNS in place of sand throughout the concrete-making process has minimal impact on energy usage. There is an environmental benefit to using FNS 1 and FNS 2 in the mortar production process. When concrete is built using FNS as a sand substitute, the CO<sub>2</sub> emission does not show the same favourable outcomes as mortar made with FNS powder. Although it doesn't significantly reduce carbon emissions, FNS sand significantly improves concrete's performance.

Case-based analysis of mechanically-assisted leaching for hydrometallurgical extraction of critical metals from ores and wastes: application in chalcopyrite, ferronickel slag, and Ni-MH black mass

Case-based analysis of mechanically-assisted leaching for hydrometallurgical extraction of critical metals from ores and wastes: application in chalcopyrite, ferronickel slag, and Ni-MH black mass

Experimental Study on the Mechanical Properties of Steel Fiber Ferronickel Slag Powder Concrete

The use of ferronickel slag powder (FNSP) as a cementitious additional material has been supported by numerous reports. FNSP concrete has the same shortcomings as ordinary concrete, including low hardness. In this study, in order to make FNSP concrete more durable, end-hooked type steel fibers were incorporated. To understand how various elements affect the mechanical properties of steel fibers, an experiment was carried out on the mechanical properties of steel FNSP concrete (SFNSPC). FNSP’s principal ingredients, with a particle size distribution ranging from 0.5 to 100 μm and a sheet-like powder shape, are CaO, SiO2, Al2O3, MgO, and others, according to tests conducted on the material’s microstructure and composition. Then, eighteen mix proportions were developed, comprising six distinct FNSP replacement rate types and three distinct steel fiber content types. Crucial metrics were evaluated and analyzed, including the relationship among the toughness, tensile strength, and compressive strength as well as slump, splitting tensile strength, compressive strength, and uniaxial compressive stress–strain curve of SFNSPC. The results showed that the slump of SFNSPC under different FNSP replacement rates decreased with increasing steel fiber volume. Steel fibers have a small but positive effect on SFNSPC’s compressive strength; nonetheless, as FNSP replacement rates increased, SFNSPC’s slump gradually decreased, though not by much. These results show that FNSP is a viable alternative cementitious material in terms of strength. Specifically, the splitting tensile strength of SFNSPC improves with an increase in steel fiber content, and the pace at which SFNSPC strength drops with an increase in the FNSP replacement rate. With varying mix proportions, the stress–strain curve trend of SFNSPC remains mostly constant, and steel fibers improve the compressive toughness of SFNSPC. After adding 0.5% and 1.0% steel fibers, the toughness index of concrete with different FNSP replacement rates increased by 8–30% and 12–43%, respectively.

Co-carbonation behaviors of blast furnace ferronickel slag-cement in aqueous conditions and the associated mechanisms

Blast furnace ferronickel slag (BFNS) has the potential to sequester CO2 for building materials. This study used cement to enhance reactivity of BFNS and found that cement can not only improve the CO2 capture ability of BFNS via stimulating the carbonation of Mg, but also stabilize the formed carbonation products. Co-carbonation of 70 % BFNS and 30 % cement (B70C30) shows higher CO2 uptake capacity (20.57 %) than the theoretical value (16.93 %). The main reason is the formation of the relatively more stable low-Mg calcite in the carbonated B70C30, compared to formed metastable monohydrocalcite in carbonated BFNS. Carbonation kinetics showed that pure BFNS and cement reached almost complete carbonation after 7 h, while B70C30 took 20 h to reach a stable state, resulting from the fact that Mg calcite forms in B70C30 at a low rate, due to incorporation of Mg and calcite crystal structure during growth. This study provides theoretical guidance for BFNS-cement CO2 capture to make building materials.

The carbon activation of electric furnace ferronickel slag and its utilization in cement-based materials

The high annual emissions and low utilization rate of electric furnace ferronickel slag (EFS) have brought enormous impacts on environment. This work intends to propose a methodology for the carbon activation of EFS to improve its resource utilization. To this end, the exfoliation-carbonation (i.e., hybrid aqueous carbonation) was developed and compared with CO2 bubbling carbonation (i.e., direct aqueous carbonation). The carbonation process of EFS and the hydration and mechanical strength of activated EFS blended cement-based materials was evaluated. Experimental results indicated that mechanical pre-treatment could disorder forsterite crystal and promote the dissolution of Mg to form Si enriched mineral surface. The direct aqueous carbonation led to the formation of passivation layer which could be striped by hybrid aqueous carbonation to facilitate further carbon mineralization. Increase in temperature significantly improved the decomposition of forsterite and accelerated the carbon mineralization kinetics. The activated EFS could accelerate the hydration and promote the mechanical strength of cement-based materials. Carbon mineralization is an effective method to strengthening the activity of EFS.

Experimental and Finite Element Analysis of Reinforced Concrete Beams Using Ferronickel Slag as Partial Replacement for Fine Aggregate under Semi-Cyclic Loading

Experimental and Finite Element Analysis of Reinforced Concrete Beams Using Ferronickel Slag as Partial Replacement for Fine Aggregate under Semi-Cyclic Loading

Preparation of enstatite-spinel based glass-ceramics from ferronickel slag and iron ore tailings by microwave-assisted one-step crystallization

A novel method to prepare high-quality enstatite-spinel based glass-ceramics by co-utilization of ferronickel slag (FNS) and iron ore tailings (IOT) via microwave-assisted one-step crystallization was proposed with an emphasis on the effect of IOT content on the preparation process. The thermodynamic analysis demonstrated that incorporating appropriate amounts of IOT into FNS can effectively transform olivine in FNS into enstatite. The experimental exploration revealed that the crystallization activation energy of the parent glass decreased from 564.6 kJ/mol to 351.93 kJ/mol when the IOT content increased from 30 wt% to 45 wt%. Meanwhile, the Avrami index of the parent glass increased from 3.88 to 4.81, indicating less depolymerization. In the subsequent crystallization process, with increasing content of IOT, the main phase was enstatite, accompanied by small amounts of spinel which acted as nucleation sites promoting the enstatite formation. Due to the decreased depolymerization degree that resulted in fewer nucleation sites, the average grain size of enstatite increased from 123 nm to 196 nm. By controlling crystallization of the melted mixture of 65 wt% FNS and 35 wt% IOT at 863 °C for 20 min, the resulting enstatite-spinel based glass-ceramics had excellent comprehensive properties, namely density of 3.13 g/cm3, bending strength of 153.53 MPa, Vickers microhardness of 9.22 GPa, acid resistance of 99.89%, and alkali resistance of 99.72%. With a much shorter crystallization time (1/6 of conventional one), the product obtained by microwave-assisted one-step crystallization had properties comparable to those derived from similar wastes.

Performance of Ferronickel Slag Powder Soil Cement under Freshwater Curing Conditions

Ferronickel slag is the solid waste slag produced by smelting nickel–iron alloy. After grinding ferronickel slag into powder, it has potential chemical activity. It can partially replace cement and reduce the amount of cement, and is conducive to environmental protection. The mechanical properties of soil cement were investigated through the compressive strength test and inter-split tensile test of ferronickel slag powder soil cement with different dosages. To further study the mechanism of ferronickel slag powder’s action on soil cement microscopically, the microstructure of soil cement was analyzed by using a scanning electron microscope and nuclear magnetic resonance equipment. The results of the study show that the incorporation of ferronickel slag powder can enhance the compressive and tensile strength of soil cement. The best performance enhancement of ferronickel slag powder was achieved when it was doped with 45% of its mass. The hydration products of soil cement increased with the increase in the doping amount, but the excessive doping of ferronickel slag powder would lead to a weakening of the hydration reaction and a decrease in the strength of the soil cement. At the same time, ferronickel slag powder plays the role of filling the void of soil cement. With the increase in ferronickel slag powder, the large pores inside the soil cement are reduced and the structure is denser.

Performance of Sustainable Green Concrete Incorporating Quarry Dust and Ferronickel Slag as Fine Aggregate.

This paper presents a study on the combined use of two by-products, namely quarry dust (QD) and ferronickel slag (FNS), as a full substitute for natural sand to improve the greenness of concrete production. Quarry dust was used in increments of 25% to a maximum of 75% substitution, where nickel slag was used as the remaining proportion of fine aggregate. All the combinations of quarry dust and nickel slag were found to be compliant with AS 2758.1 and they showed notably better grading than 100% sand. In this research, standard concrete tests, such as the slump test for fresh concrete, and compression, tensile and shrinkage tests for hardened concrete, were conducted. Scanning electron microscopy and X-ray diffraction analysis were also conducted for microstructural investigation. The results concluded that the combinations of quarry dust and nickel slag in concrete as a whole substitution of sand provide similar results for these properties. Specifically, 25% quarry dust with 75% nickel slag proved to be the most promising alternative to sand, with compressive and splitting tensile strengths of 62 and 4.29 MPa, respectively, which were 16% and 20% higher than those of the control mix. Also, lower drying shrinkage was observed for this combination compared to the control mix. The higher strength is attributed to the rough texture and angular shape of both quarry dust and nickel slag providing a better mechanical interlocking. The validity of this result has also been confirmed through image analysis of micrographs from various specimens. In microstructural investigations, specimens with QD and FNS exhibited fewer voids and a more compact surface compared to the control specimen. This shows the potential for further research into the use of quarry dust and nickel slag in the production of green concrete.

Research on Statistical Characteristics and Prediction Methods of Ferronickel Slag Pervious Concrete Performance with Different Sizes of Aggregate and Mixtures

In the exploration of sustainable construction materials, the application of ferronickel slag (FNS) in creating pervious concrete has been investigated, considering its potential to meet the dual requirements of mechanical strength and fluid permeability. To elucidate the statistical properties and models for predicting the performance of FNS-composited pervious concrete with different sizes of aggregates and mixtures, a series of experiments, including 54 kinds of mixtures and three kinds of aggregate, were conducted. The focus was on measuring the compressive strength and the permeability coefficient. The results indicate that the compressive strength of pervious concrete decreases with the increase in aggregate size, while the permeability coefficient increases with the increase in aggregate size. Through normalization, the variability of these properties was quantitatively analyzed, revealing coefficients of variation for the concrete’s overall compressive strength and the permeability coefficient at 0.166, 0.132, and 0.150, respectively. Predictive models were developed using machine learning techniques, such as Linear Regression, Support Vector Machines, Regression Trees, and Gaussian Process Regression. These models demonstrated proficiency in forecasting the concrete’s compressive strength and permeability coefficient.

Alkali-activated blast furnace ferronickel slag for Cr immobilization

Efficiently managing and utilizing Cr-containing slags and wastes is a global urgency. Alkali-activated materials offer a sustainable and cost-effective solution. This study investigated eco-friendly alkali-activated blast furnace ferronickel slag (AA-BFFS) for both self-stabilization/solidification (SS) of Cr-containing BFFS and immobilization of external Cr ions. Our investigation involved comprehensive analysis, including reaction characterization, pH-dependent leaching tests, and a novel thermodynamic modeling approach to reveal the reaction process and leaching behaviors. The results indicate that AA-BFFS forms a dual-layered self-S/S barrier: reaction products, AFm and C-(N)-A-S-H, constitute the first layer at the inner pH above ∼7, while Ca/Mg phases in BFFS form a secondary layer at the inner pH above ∼5. External Cr ion immobilization involves Cr(III) precipitation and sorption, while Cr(VI) is only partially sorbed, leaving 73.2 % soluble at 7 days at the high doping level. The research provides a scientific basis for the sustainable utilization of BFFS and other Cr-containing wastes.

Abrams’ Law Formulation for Blended Cement Paste Incorporated with Ground Ferronickel Slag

Ground ferronickel slag (GFS) is a form of an industrial waste by-product generated during the smelting process of nickel ore that has been crushed and ground into fine powder. GFS is a pozzolanic substance that may be employed as an environmentally beneficial binding agent when blended with Portland cement. This research aims to apply the Abrams Law formulation to blended cement combined with GFS. GFS was utilized as a Portland cement composite (PCC) replacement at varying percentages of 0, 10, 20, 30, 40, and 50 wt.%. The blended cement paste incorporated with GFS was tested at three water to cementitious material ratio (w/cm) levels of 0.4, 0.5, and 0.6. After samples have been made, a compressive strength test is carried out. The research results showed that at 28 days, the optimum amount of GFS was found in the percentage of 20 wt.% induced the compressive strength by 40.41 MPa with a w/cm of 0.4. The equations based on Abrams’ Law have been proposed for estimating the correlation of 28-day compressive strength with w/cm in the range from 0.4 to 0.6. In addition, the hardened densities of binary blended cement paste were investigated. It was found that the density decreased with an increase of w/cm. The proposed equations provide the beneficial interpretation for estimating the compressive strength of blended cement paste based on the w/cm..

Alkali-silica reaction of ferronickel slag fine aggregate in Portland cement and alkali-activated slag mortars: Pessimum effect investigation

Ferronickel slag (FNS) with dense and hard nature exhibits great potential to be utilized as recycled aggregate in concrete production. This study investigated the alkali-silica reaction (ASR) and the pessimum proportion of FNS fine aggregate in Portland cement (PC) and alkali-activated ground granulated bast furnace slag (AAS) mortars as a substitute for river sand. Over a 120-day period, the accelerated mortar bar test revealed that the addition of FNS fine aggregate in both cases resulted in harmless ASR expansion. In PC mortars, the ASR expansion consistently decreased from 0.569 % to 0.114 % as the FNS content increased. In comparison, AAS mortars with higher pore solution alkalinity had the pessimum proportion of 30 % FNS. The ASR expansion values initially increased from 0.472 % to 0.554 % with an increase in FNS content from 0 % to 30 %, but then decreased to 0.146 % as the FNS content was further raised to 100 %. The amorphous ASR gel was identified as a hydrated alkali silicate gel and present within the existing veins in the river sand grain. The ASR reaction of FNS fine aggregate exhibited a self-mitigating effect on the deleterious expansion through its pessimum behavior. Additionally, the addition of FNS fine aggregate yielded a beneficial outcome by reducing the cumulative pore volume in the mortars, and thus enhanced the compressive strengths.

Tailoring tactics for preparation of superior thermal insulation materials from blast furnace ferronickel slag: Control of sintering temperature

Blast furnace ferronickel slag (BFFS) was converted to thermal insulation materials by sintering of its mixture with 15 wt% fly ash cenosphere (FAC) from 1000 °C to 1200 °C. The influence of sintering temperature on the phase compositions, microstructures, and properties of the materials was investigated based on both thermodynamic and experimental analyses. It was demonstrated that increasing sintering temperature from 1000 °C to 1200 °C led to linear increases of contents of diopside (CaMgSi2O6; y = 0.039T – 21.5, where y and T denote the content and temperature, respectively), anorthite (CaAl2Si2O8; y = 0.0504T – 46.54), and magnesium aluminate spinel (MgAl2O4; y = 0.043T – 30.86) in the thermal insulation materials. Meanwhile, there existed linear decreases of contents of akermanite (Ca2MgSi2O7; y = -0.0352T + 66.18) and gehlenite (Ca2Al2SiO7; y = -0.0914T + 129.96), which could form a solid solution above 1100 °C, suppressing the expansion associated with the generation of magnesium aluminate spinel. Along with the phase transformation, the macroporous structure was also identified. By sintering at 1100 °C for 2 h, an optimal high-quality thermal insulation material with apparent porosity of 46.04%, water absorption of 42.12%, bulk density of 1.35 g/cm3, linear shrinkage of 0.82%, compressive strength of 6.83 MPa, thermal conductivity of 0.31 W/(m·K) at 25 °C and 0.42 W/(m·K) at 800 °C, and refractoriness of 1259 °C could be obtained.