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Showing 10 results for Slag

Rigaud M., Palco S., Paransky E.,
Volume 3, Issue 1 (6-2006)

Wear of various basic refractory materials to substitute to currently used magnesia chrome bricks has been studied, measuring matte and slag penetration and dissolution, through different cup and rotary slag tests. High magnesia with and without impregnation, magnesia graphite, magnesia-alumina spinel with and without impregnation, olivine-magnesia and olivine magnesia- graphite bricks, as well as magnesia-graphite and olivine magnesia castables, have been tested. It has been shown that carbon impregnation and graphite introduction into basic refractories are feasible ways to enhance their corrosion-dissolution and penetration resistance against fayalite as well as calcium-ferrite slags. Olivine-based refractories (castables or bricks) may be considered as viable candidates to use in copper-making furnaces. At this point, evaluation of the thermo-mechanical properties of this new class of materials is still missing.
M. Rezvani, B. Eftekhari Yekta, V. K. Marghussian,
Volume 5, Issue 1 (3-2008)

Abstract: The application of inexpensive materials such as copper, zinc, lead, iron and steel slag in manufacturing of glass and glass-ceramic products in construction industry, lining materials as anti-corrosion and anti-abrasion coatings in metals and etc, has led to considerable progress in glass technology in recent years. The composition of slag glass-ceramics is mainly located in the SiO2-Al2O3-CaO-MgO system, in which one of the most important problems is the lack of bulk crystallization. To resolve the above-mentioned problem, the crystallization behavior of various compositions containing different nucleating agents Cr2O3 , Fe2O3 and TiO2 in the single, double and triple forms were studied by differential thermal analysis (DTA).The precipitated crystalline phases was determined by the X-ray diffractometry and the micro-structural analysis was studies using the SEM micrographs. The three point bending strength, micro-hardness and the chemical resistance of the best composition were determined. According to the results, the resulted glassceramic had a better specification than the stoneware floor tiles and the porcelain one, which are considered as the two important competitors for it.
K. Ghanbari Ahari,
Volume 5, Issue 1 (3-2008)

Abstract: Thermodynamic computational packages MTDATA and FactSage have been used to carry out calculations on the variation with temperature of the phases precipitated on cooling in both oxidising and reducing conditions of a typical ladle slag composition, in the temperature range 1700 - 900°C. The current coverage of the databases associated with the computational packages is discussed in relation to their application to slag - refractory interaction and the validity of the results is compared with some relevant experimental data and phase equilibrium studies
A. Allahverdi, E. Najafi Kani, S. Esmaeilpoor,
Volume 5, Issue 2 (6-2008)

Abstract: The use of alkali-activated cementitious materials especially over the past decades has significantly been increased. The goal of this research is to investigate the effects of silica modulus and alkali concentration on alkali-activation of blast-furnace slag. In this research, the most important physical characteristics of cementitious systems, i.e. the 28-day compressive strength and final setting time, were studied by changing influencing parameters such as silica modulus, i.e. SiO2/Na2O, (0.44, 0.52, 0.60, and 0.68) and Na2O concentration (4, 6, 8 and 10% by weight of dry binder) at a constant water-to-dry binder ratio of 0.25. Final setting time of the studied systems varies in the range between 55-386 minutes. The obtained results show that systems cured at an atmosphere of more than 95% relative humidity at room temperature exhibit relatively high 28-day compressive strengths up to 107 MPa.
S. Ahmadi, H.r. Shahverdi, H. Arabi,
Volume 11, Issue 3 (9-2014)

This study is focused on the effects of electroslag remelting by prefused slag (CaO, Al2O3, and CaF2) on macrostructure and reduction of inclusions in the medical grad of 316LC (316LVM) stainless steel. Results showed that in order to obtain uniform ingot structures during electroslag remelting, the shape and depth of the molten pool should be carefully controlled. High melting rates lead to deeper pool depths and interior radial solidification characteristics. Furthermore, decrease in the melting rate caused more reduction of non-metallic inclusions. In practice, large shrinkage cavities formed during the conventional casting process in the primary ingots were the cause of the fluctuation in the melting rate, pool depth and extension of equiaxal crystals zone
A. R. Amini, A. R. Zakeri, H. Sarpoolaky,
Volume 12, Issue 3 (9-2015)

In this paper, the effect of MgO, BaO, Na 2 O and SrO addition to a pre-melted CaO-Al2O3 -Si 2 O synthetic slag on sulfur removal from plain carbon steel was studied under the same experimental conditions. The slags were pre-melted at 1400°C in an electric resistant furnace and desulfurization experiments were carried out in a high frequency induction furnace. The results showed that the optimum reaction time for desulfurization was 15 min. It was found that while SrO addition to the ternary slag enhances the sulfur removal capability, MgO, Na 2O and BaO additions reduce desulfurization efficiency of the ternary slag. Moreover, it was observed that restricting access to oxygen from the atmosphere by using a covered crucible, could increase desulfurization efficiency of the slag by more than two fold
A. Rashad,
Volume 15, Issue 2 (6-2018)

In the current work, the properties of cement pastes doped with high amounts of ground granulated blast-furnace slag (HVS) were investigated. Portland cement (PC) was substituted with ground granulated blast-furnace slag (donated as slag) at very high amounts of 85%, 90%, 95% and 100%, by weight. PC paste without any content of slag was used as a reference. Some fresh and hardened properties such as workability, density, compressive strength up to 56 days, pH value and drying shrinkage up to 200 days were measured. The various phases formed were identified using X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The microstructure of the formed hydration products was determined by scanning electron microscopy (SEM). The results indicated that HVS has higher workability and higher drying shrinkage beyond 60 days. On the other hand, HVS has lower pH, density and compressive strength.

A. Allahverdi, H. Hashemi, M. Mahinroosta,
Volume 17, Issue 1 (3-2020)

This work evaluates the resistance of alkali-activated slag (AAS) mortar against sodium sulfate attack. The effects of immersion in 5% sodium sulfate solution under room temperature and wetting-drying cycles on the compressive strength of mortar specimens were considered for evaluating the extent of degradation. Mortar specimens prepared from type II and V Portland cements (PC2 and PC5) in accordance with ASTM standard were also used as reference. To characterize the chemical products of the degradation process due to sodium sulfate attack, the specimens were also studied by X-ray diffractometry, scanning electron microscopy, and the elemental analysis by energy dispersive X-ray spectroscopy. After 360 days of exposure to the sodium sulfate solution, PC2, PC5 and AAS cements showed 71, 52 and 45% reduction in compressive strength, respectively. According to the obtained results, AAS cement exhibits a higher sulfate resistance compared to PC2 and PC5.

Mojtaba Hosseini, Ali Allahverdi, Mohammad Jaafar Soltanian Fard,
Volume 19, Issue 1 (3-2022)

The aim of the present research work is to evaluate the feasibility of processing and utilizing steel slag
in binary and ternary cement blends with limestone. The physical and microstructural properties of binary and
ternary composite cements produced by inter-grinding mixtures of ordinary Portland cement clinker, processed
steel slag and limestone in a laboratory ball mill with replacement levels varying from 0 wt.% to 30 wt.% were
studied. The effects of processed steel slag and limestone incorporation on density of dry cement mixes and water
consistency, setting time and volume stability of fresh and hardened cement pastes were investigated. Also,
density, water absorption, total open pore volume (%) and compressive strength of cement mortars were measured.
The mix with 15 wt.% limestone and 15 wt.% processed steel slag was selected as a typical ternary cement mix
for complementary studies including X-ray diffractometry, thermal gravimetry, Fourier-transform infrared
spectroscopy, and scanning electron microscopy analyses. The results show that removal of relatively high
metallic content of steel slag increases its grindability for mechanical activation and improves its hydraulic
properties effectively and makes it suitable for being recycled in cement industry. The results show that
mechanical activation of the cement mixes enhances the poor hydraulic activity of the processed steel slag and
compensates the strength loss to some extent. The physical and chemical properties of all studied composite
cement mixes comply with ASTM standard specifications, except the compressive strength of the cement mixes
at 28-days containing 20 wt.% or higher amounts of limestone ground to the relatively low Blaine specific surface
area of about 3000 cm2/g.

Davar Rezakhani, Abdol Hamid Jafari,
Volume 19, Issue 4 (12-2022)

In this work, the addition of a combination of Graphene Oxide Nanoplatelets (GONPs) and Ground Granulated Blast Furnace Slag (GGBFS) was studied as admixture in concrete. Tests on physical and mechanical properties and chloride permeability were conducted. GGBFS was replaced with Ordinary Portland Cement (OPC) and it was determined that GGBFS Up to 50% by weight improves the physical and mechanical properties of concrete. GONPs with an optimal amount of 50% by weight of GGBFS were added to the concrete and the physical and mechanical properties of the samples were determined. It was observed that the addition of GONPs was effective in improving the mechanical strength and physical properties of specimens. The results indicated that addition of 0.1 wt. % GO and 50 wt. % GGBFS would increase the compressive strength of the concrete sample up to 42.7 % during 28 days and 46 % during 90 days compared to OPC. Concrete with a combination of 0.1 wt. % GONPs and 50 wt. % GGBFS witnessed an increase in its flexural strength up to 58.5 % during 28 days and 59.2 % during 90 days.  The results indicated that by adding 0.1 wt. % GO and 50 wt. %, concrete chloride permeability decreased substantially 72 % for 90-day cured samples compared to OPC. GONPs as an alternative to cement up to 0.1% by weight can accelerate the formation of C-S-H gel, thereby increasing the strength and improving the resistance of water absorption and chloride permeability. The effects of pozolanic reaction in the concrete leading to the filling of the pores were significant factors in the proposed curtailment mechanism.

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