Cupola Slag Research Articles

Effect of sintering temperature and binder addition on the properties of cupola slag glass–ceramic tiles

Effect of sintering temperature and binder addition on the properties of cupola slag glass–ceramic tiles

Cupola slag as partial replacement of fine aggregate in concrete – An experimental study

Cupola slag is one of the industrial by-products obtained from cupola furnace which is a device usually used in foundry industries for the melting of metals. Cupola slag is underutilized and very few studies are documented in literature wherein cupola slag has been utilized in concrete production. An attempt has been made to examine the effectiveness of cupola slag, as a partial substitute to fine aggregates, on the mechanical and durability properties of concrete. Fine aggregate was replaced by cupola slag at five different percentages (0%, 10%, 20%, 30% and 40%). In addition, the w/c ratios varied were 0.40, 0.45 and 0.50 at a fixed cement content of 380 kg/m3. Across all the concrete mixes and at all curing ages, an increase in the compressive strength was observed due to incorporation cupola slag up to 30% replacement level of fine aggregates after which a decrease in strength was observed on further addition of cupola slag. This increment in compressive strength was higher at lower w/c ratios. Similar trends were observed for split tensile strength. For all curing ages, a decrease in water penetration depth was observed with an increase in the percentage of cupola replacement (CR) from 0% to 40% and this decrease was most prominent at the w/c ratio of 0.4. Similarly, for all the aforesaid parameters a significant improvement of abrasion resistance in terms of reduction in wear depths was observed. Correlations were developed between strength and durability properties so as to validate the experimentally obtained results. To examine the ‘effect’ and ‘size of effect’ of CR percentage and w/c ratio on the concrete properties, two-way analysis of variance was carried out and statistically significant results were obtained. At all curing ages, quadratic relationships were developed for establishing the dependence of concrete properties on CR and w/c ratio. The results of this investigation indicate that cupola slag is a sustainable material which can be effectively used as partial substitute to natural sand.

Physical-Mechanical Properties of Cupola Slag Cement Paste

The high consumption of natural resources in the industrial sector makes it necessary to implement measures that enable the reuse of the waste generated, seeking to achieve circular economy. This work assesses the viability of an alternative to the use of CEM III B 32.5 R cement in mortars for the internal coating of centrifugally spun cast iron pipes for water piping. The proposal is to reuse the slag generated in the casting process after being finely ground, as an addition mixed with CEM I 52.5 R cement, which is basically Portland clinker. In order to analyse this possibility, an extensive experimental campaign was carried out, including the analysis of the cupola slag (micro-structural and chemical composition, leachates, setting time, vitrification, puzzolanicity and resistance to sulphate) and regarding the mortars (workability and mechanical properties). The experimental programme has shown that the optimum substitution is achieved with a replacement percentage of 20% of the cement, with which similar workability, superior mechanical properties and guaranteed resistance to sulphate attack are obtained. In addition, both economic and environmental savings are achieved by not having to transport or landfill the waste. In addition, the new cement is cheaper than the cement currently used.

Cupola slag reutilization for sustainable waste management: review and economic analysis

Cupola slag reutilization for sustainable waste management: review and economic analysis

Viability of Cupola Slag as an Alternative Eco-Binder and Filler in Concrete and Mortars

Obtaining new materials capable of meeting society’s demands motivates the search for new solutions that are capable of satisfying twofold requirements: respect for the environment and obtaining more durable and resistant materials. Cupola slag is a by-product generated in the process of obtaining ductile iron. When the slag undergoes rapid cooling, its vitrification is favored, leaving the silica in an amorphous structure and, thus, susceptible to reacting. Through reaction, the slag can develop cementing properties and cement can consequently be partially replaced with residue, providing savings in economic and environmental costs compared to traditional hydraulic binders. In this study, the physical and chemical properties of cupola slag and its recovery process are analyzed. Mortars that incorporate traditional admixtures (fly ash and limestone filler) have been manufactured and consistency and mechanical properties have been compared with mortars that incorporate cupola slag admixture. Mortars have also been manufactured with normalized sand and with Portland cement replacements (0, 10, 20, and 30% by weight) with cupola slag, and both the consistency and the mechanical properties have been compared at 7, 28, 60, and 90 days. The results obtained show the suitability of cupola slag as a binder and as an admixture, with respect to the traditional ones, and how the mechanical properties tend to converge for all of the replacement levels characterized, for ages close to 90 days of age.

On the development of sustainable and strong concrete

This paper presents the study on the development of sustainable, strong and durable concrete based on the cupola furnace slag (CFS). The CFS was divided into two parts: first part was pulverized and ball milled to achieved the powdered granulated cupola furnace slag (GCFS). X-Ray Diffraction (XRD) pattern of GCFS was obtained. The second part was crushed into size between 10 mm and 20 mm, which is used as coarse aggregate. Six different concrete mixes were prepared in this study; one natural aggregate concrete (NAC) and five concretes with CFS as a total replacement of coarse aggregate and partial replacement of cement from 2% to 10% in step of 2% respectively. Concrete samples prepared were cured for 7-d and 28-d respectively under ambient temperature of 27 ± 2 °C. The slump and compressive strength were carried out on the fresh and hardened concrete. It can be concluded that the cupola slag aggregate concrete (SAC) show a satisfactory development and consistency in strength as compared to NAC.

High Performance Self-Compacting Concrete with Electric Arc Furnace Slag Aggregate and Cupola Slag Powder

The development of self-compacting concretes with electric arc furnace slags is a novelty in the field of materials and the production of high-performance concretes with these characteristics is a further achievement. To obtain these high-strength, low-permeability concretes, steel slag aggregates and cupola slag powder are used. To prove the effectiveness of these concretes, they are compared with control concretes that use diabase aggregates, fly ash, and limestone supplementary cementitious materials (SCMs, also called fillers) and intermediate mix proportions. The high density SCMs give the fresh concrete self-compacting thixotropy using high-density aggregates with no segregation. Moreover, the temporal evolution of the mechanical properties of mortars and concretes shows pozzolanic reactions for the cupola slag. The fulfillment of the demands in terms of stability, flowability, and mechanical properties required for this type of concrete, and the savings of natural resources derived from the valorization of waste, make these sustainable concretes a viable option for countless applications in civil engineering.

Experimental Analysis on Cupola Slag Waste as a Partially Replacement in Coarse Aggregate in Concrete

Experimental Analysis on Cupola Slag Waste as a Partially Replacement in Coarse Aggregate in Concrete

Cupola Furnace Slag: Its Origin, Properties and Utilization

A cupola furnace is the most frequently used furnace aggregate for cast iron production. A by-product of the production of cast iron in cupola furnaces is cupola slag. Its amount is 40–80 kg per 1 tonne of the produced cast iron, and that is one of the reasons why this material is not as favoured as, for example, the blast-furnace slag. The purpose of this article is to provide the basic information on the formation of slag in a cupola furnace, and its chemical composition, structure and current potential applications. The greatest potential for the use of cupola slag is in the building industry; therefore, a section of the present article deals with the property that plays an important role particularly with regard to the use of slags in the building industry, i.e. the slag hydraulicity. The achieved results indicate that the hydraulicity of the cupola slag is incomparable with the hydraulicity of the blast-furnace slag; this may be associated with the problems that arise when the slag of this type is used in the building industry. The authors used the air-cooled as well as granulated slags from cupola furnaces in the production of concrete that was made from the slags alone. While the air-cooled slag may be used as a partial replacement for the blast-furnace slag in concrete mixtures, the use of granulated slag from cupola furnaces as a replacement for granulated blast-furnace slag in cement-free concrete has not proven to perform well.

One-year properties of concrete with partial substitution of natural aggregate by cupola foundry slag

Cupola foundry slag has almost no utilisation. There has been no long term experience with the application of foundry slag in concrete production. This paper analyses the potential utilisation of cupola foundry slag. It also presents a proposal for processing and utilising granulated cupola slag from cast iron production in concrete products and the long term (one-year period) verification of its properties as a base for industrial scale application. The wt. 25.5% substitution of 0/4 mm fine natural aggregate by 0/4 mm cupola foundry slag in concrete (CFSC) declares the same or very similar main civil engineering properties when compared to control concrete (CC). The CC and CFSC concrete are not frost resistant according to STN EN 206/NA: 2015 requirement. This lack could be removed by increasing the entrapped air levels from the current 2.0–2.4 volume percent to around 5–6 volume percent in fresh concrete mixture.

Application Approach and Prospects of the Foundry Waste Sand and Slag in Engineering

In the foundry industry, the main solid waste is the foundry waste sand, casting cupola dust and slag, which causes environmental pollution and becomes a bottleneck restricting the development of the foundry industry. The main components of the foundry waste sand and slag generated by casting are siliceous and calcareous granular materials, which meet the needs of engineering construction materials, they have a broad application prospect. In this paper, the investigation and analysis of the foundry waste sand and slag have been carried on about the research and application in the engineering construction, which provide reference and basis for the application of foundry waste sand and slag in the engineering.

Treatment of tannery wastewater in a pilot-scale hybrid constructed wetland system in Bangladesh

This paper reports the pollutant removal performances of a hybrid wetland system in Bangladesh for the treatment of a tannery wastewater. The system consisted of three treatment stages: a subsurface vertical flow (VF) wetland, followed by a horizontal flow (HF) and a VF wetland. The wetlands were planted with common reed (Phragmites australis), but employed different media, including organic coco-peat, cupola slag and pea gravel. In the first stage, experimental results demonstrated significant removal of ammonia (52%), nitrate (54%), BOD (78%), and COD (56%) under high organics loading rate (690gCODm−2d−1); simultaneous nitrification, denitrification, and organics degradation were attributed to the unique characteristics of the coco-peat media, which allowed greater atmospheric oxygen transfer for nitrification and organic degradation, and supply of organic carbon for denitrification. The second stage HF wetland produced an average PO4 removal of 61%, primarily due to adsorption by the iron-rich cupola slag media. In the third treatment stage, which was filled with gravel media, further BOD removal (78%) from the tannery wastewater depleted organic carbon, causing the accumulation of NO3 in the wastewater. Overall, the average percentage removals of NH3–N, NO3–N, BOD, COD, and PO4 were 86%, 50%, 98%, 98% and 87%, respectively, across the whole hybrid system. The results provided a strong evidence to support widespread research and application of the constructed wetland as a low-cost, energy-efficient, wastewater treatment technology in Bangladesh.

Cementitious Blends of Portland Cement with Calcium Sulphate, Fly Ash and Cupola Slag.

ABSTRACTThis investigation is on alternative cementitious materials of low cost, energy and environmental emissions. Portland cement (PC) was replaced by different types of calcium sulphate (hemihydrate HH, or anhydrite AN), fly ash (PFA) and cupola slag (CS) from an iron foundry. Pastes of blends of (HH or AN) – CS – PC and (HH or AN) – PFA – PC were characterized. The compositions varied within the ranges of 0 – 35% PC, 15 – 80% HH or AN, 10 – 80% CS and 10 – 80% PFA. The water/solids ratio was kept at 0.45 for HH blends and 0.37 for those of AN. The pastes were cured in dry and for some time under water. Selected blends of CS were repeated with blast furnace slag (BFS) for comparison. CS showed better results over PFA and less than BFS, perhaps as derived from its chemical composition, phase configuration and physical characteristics. These and other results of microstructural characterization will be discussed. This work is part of a broader research on the development of alternative environment friendly hydraulic composite cements of Portland cement highly replaced by calcium sulphate and industrial byproducts.

Effectiveness of recycled P products as P fertilizers, as evaluated in pot experiments

World phosphorus (P) resources are limited and may be exhausted within 70–175 years. Therefore recycling of P from waste materials by chemical or thermal processes is important. This study evaluated the effectiveness of recycled P products from sewage sludge and animal wastes as P fertilizer. Four products were obtained from chemical processes, three magnesium-ammonium-phosphates (MAP) of different sewage treatment plants and a Ca phosphate precipitated from wastewater (Ca-P) and four from thermal processes, an alkali sinter phosphate (Sinter-P), a heavy metal depleted sewage sludge ash (Sl-ash), a cupola furnace slag made from sewage sludge (Cupola slag) and a meat-and-bone meal ash (MB meal ash). The effectiveness of these products as P fertilizers compared with triple superphosphate (TSP) and phosphate rock (PR) was determined in a 2-year pot experiment with maize (Zea mays L., cv. Atletico) in two soils with contrasting pH (pH(CaCl2) 4.7 and 6.6). The parameters used to evaluate the effectiveness were P uptake, P concentration in soil solution (CLi) and isotopically exchangeable P (IEP). MAP products were as effective as TSP in both soils, while Ca-P was only effective in the acid soil. Sinter-P was as effective as TSP in the acid soil, while Cupola slag was in the neutral soil. The products Sl-ash and MB meal ash were of low effectiveness and were comparable to PR. The effect of the fertilizers on IEP, but not on CLi, described their effectiveness. Recycled P products obtained by chemical processes, especially MAP, could be directly applied as P fertilizers, while products such as Sl-ash and MB meal ash are potential raw materials for P fertilizer production.

Conventional hydrothermal synthesis of Na-A zeolite from cupola slag and aluminum sludge

Na-A type zeolites were prepared from two industrial wastes: the solid by-product of cupola slag and aluminum sludge from an aluminum plating plant. Two preparation methods using the same starting material compositions were carried out. In the first method, alkaline fusion was introduced, followed by the hydrothermal treatment to obtain sodium aluminosilicate which was then crystallized in NaOH solution under the condition of 90 ± 3 °C for 1–9 h with different H 2O/SiO 2 ratios. The result shows that higher H 2O/SiO 2 ratio increases the rate of crystallization. The largest amount of crystallinity for Na-A was found at 3 h. In the second method, alkaline hydrothermal treatment without fusion was carried out in the same condition as the first method. No Na-A zeolite was obtained by this method. The changes of the dissolved amounts of Si 4+ and Al 3+ in 3 M NaOH were investigated during the hydrothermal reaction.

Conventional and microwave hydrothermal synthesis of zeolite ZSM-5 from the cupola slag

ZSM-5 type zeolites have been prepared from cupola slag waste using both conventional hydrothermal and microwave syntheses at 130–200 °C. The ZSM-5 was synthesized by conventional heating by taking advantage of the high silica content of cupola slags. Microwave heating increased the rate of ZSM-5 formation by 4 times at 150 °C compared with conventional heating. The Si/Al ratio of the ZSM-5 produced by the conventional heating and the microwave crystallization were similar 28 and 29, respectively. The conventional-heating produced ZSM-5 particles 3 μm in diameter, while, microwave-heating produced smaller ZSM-5 particles only 0.3 μm in size.

Floor tiles fabricated from polymineral clays from mineral deposits of the republic of Belarus

Mixtures for fabricating floor tiles composed of a low-melting clay with high-melting clays and fluxing agents (nepheline concentrate, pearlite, glass cullet, and cupola slag) added are synthesized. The technological conditions are specified for obtaining high-quality products. The structural features and phase composition of the synthesized mixtures are discussed.

Devitrifying cupola slag for use in abrasive products

A value-added abrasive product can be obtained by devitrifying CaO-rich cupola slag glass. The treatment process forms a dense, intertwined, fibrous Mg-wollastonite microstructure that has improved chemical corrosion resistance and a two-fold increase in abrasion resistance (inverse grindability) over the original glass.

Devitrification hardening of cupola slag glass with CaO and SiO 2 additions

Slag from the cupola melting of pig and scrap iron was melted, air quenched into a glass and then devitrified forming an abrasion resistant fibrous microstructure. This crystallization behavior was further investigated by altering the composition of the major constituents of the slag, namely, CaO and SiO 2. The resulting structural and microstructural changes were measured with XRD, SEM, optical microscopy and DTA techniques. The first crystalline phase formed at ∼900°C was Mg-wollastonite, with a microstructure of finely interwined fibrous growth. Diopside was detected at ∼950°C, with a comparatively coarse fibrous microstructure. CaO addition enhanced the formation of Mg-wollastonite while SiO 2 addition resulted in enhanced diopside formation. After heat-treating the samples to 1000°C and holding for 60 min, the CaO-rich samples, having formed predominantly dense fibrous Mg-wollastonite, showed a hardness of 903±40 on the Vickers scale, an increase of a factor of 2 over amorphous samples. The maximum hardness in silica-rich samples after a suitable heat treatment was 771±69 kg/mm 2.

Crystallization behavior of cupola slag glass-ceramics

The slag formed from cast iron manufacture via a cupola furnace was found to form an X-ray diffraction amorphous mass after moderate quenching. The devitrification behavior and mechanical properties of cupola slag glass-ceramics were investigated as a function of thermal processing, utilizing XRD, SEM, TEM, DTA and dilatometry, interactively. The crystalline phase primarily responsible for superior mechanical properties was identified as a wollastonite structured solid solution, which appeared at 950°C, with a microstructure of intertwined fibrous growth. At higher temperatures (∼ 1120°C), diopside formed which resulted in a deterioration of mechanical properties. Hardness data indicated a 1.5- to 2-fold increase in the Vickers hardness values by suitable thermal processing.