scholarly journals Chemical Composition, pH Value, and Points of Zero Charge of High Calcium and High Iron Electric Arc Furnace Slag

2018 ◽  
Vol 7 (3.23) ◽  
pp. 1 ◽  
Author(s):  
Siti Zu Nurain Ahmad ◽  
Hamdan R ◽  
Wan Afnizan Wan Mohamed ◽  
N Othman ◽  
Nur Shaylinda Mohd Zin

Electric arc furnace (EAF) slag as filter media has been extensively used nowadays for wastewater treatment technology. Steel slag was produced as byproduct from steelmaking processes. However, different batches of steel slag production produce different composition. Thus, this study determined the chemical composition, pH value and points of zero charge (PZC) of two different samples of electric arc furnace (EAF) slag; high iron EAF slag (Slag HFe) and high calcium EAF slag (Slag HCa). The steel slag were characterized using X-ray Fluorescence Spectroscopy (XRF) analysis for the chemical composition, extraction with boiling water for pH value, and salt addition method for PZC. Slag HFe was mainly consisted of 38.2% ferric oxide and 20.4% calcium oxide, 10.20 pH value and pH 10.55 for PZC. While for Slag HCa, they were composed of 1.64% ferric oxide and 49.5% calcium oxide of pH value of 11.11 and pH 11.75 for PZC. Therefore, Slag HCa was considered as a more basic species compared to Slag HFe. 

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1347 ◽  
Author(s):  
Pao Ter Teo ◽  
Siti Koriah Zakaria ◽  
Siti Zuliana Salleh ◽  
Mustaffa Ali Azhar Taib ◽  
Nurulakmal Mohd Sharif ◽  
...  

Steel slag is one of the most common waste products from the steelmaking industry. Conventional methods of slag disposal can cause negative impacts on humans and the environment. In this paper, the process of steel and steel slag production, physical and chemical properties, and potential options of slag recycling were reviewed. Since steel is mainly produced through an electric arc furnace (EAF) in Malaysia, most of the recycling options reviewed in this paper focused on EAF slag and the strengths and weaknesses of each recycle option were outlined. Based on the reports from previous studies, it was found that only a portion of EAF slag is recycled into more straightforward, but lower added value applications such as aggregates for the construction industry and filter/absorber for wastewater treatments. On the other hand, higher added value recycling options for EAF slag that are more complicated such as incorporated as raw material for Portland cement and ceramic building materials remain at the laboratory testing stage. The main hurdle preventing EAF slag from being incorporated as a raw material for higher added value industrial applications is its inconsistent chemical composition. The chemical composition of EAF slag can vary based on the scrap metal used for steel production. For this, mineral separation techniques can be introduced to classify the EAF slag base on its physical and chemical compositions. We concluded that future research on recycling EAF slag should focus on separation techniques that diversify the recycling options for EAF slag, thereby increasing the waste product’s recycling rate.


Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 706 ◽  
Author(s):  
Davide Mombelli ◽  
Andrea Gruttadauria ◽  
Silvia Barella ◽  
Carlo Mapelli

Studies conducted over the past 10 years have demonstrated the technical suitability of the electric arc furnace slag as an alternative to natural stone in several applications. Steel slag can be profitably used as a road surface layer, for foundations and embankments, or for concrete aggregates. However, a strong limitation to their use is due to the presence of toxic metals (Ba, Cr, V, Mo, etc.) that can be released into the environment in particular conditions, especially for unbound products in which the slag can come into contact with water. Recent studies have investigated the role of chemical composition and microstructure of slag on toxic metal leaching, allowing for the design of suitable stabilization treatments for hindering such leaching. In this work, four batches of electric arc furnace carbon steel slag underwent a stabilization treatment and the obtained results were compared. In two batches, the stabilizer was added directly in the slag pot and the slag was cooled down in the same pot. The other two batches were stabilized during the downfall from slag door to slag pit. Several slag samples were collected before and after the stabilization treatment and were characterized by means of ED-XRF, XRD, and SEM analysis. Leaching tests were carried out in agreement with EN 12457-2 standard on 4 mm granulated slag, and the leachate concentration was compared with the current Italian limits listed in D.M. 3 August 2005 N. 201 and D.M. 5 April 2006 N. 186. The results clearly indicated that the cooling in the slag pot improved the efficiency of the stabilization treatment, leading to a complete transformation of the microstructure by a full development of homogeneous gehlenite matrix and a coarsening of Cr-spinels, assuring better toxic metal retention behavior. On the contrary, stabilization in the slag-pit was rapid and reduced the interaction between slag and stabilizer, leading only to partial transformation of larnite into gehlenite, and also reducing the coarsening of Cr-spinel. In addition, a layering effect was observed, resulting in an inhomogeneous product from top to bottom in terms of chemical composition, microstructure, and leaching behavior.


2013 ◽  
Vol 275-277 ◽  
pp. 2206-2209
Author(s):  
Zhi Wei Liu ◽  
Yu Li ◽  
Da Qiang Cang ◽  
Yi Chen ◽  
Shuai Jiang ◽  
...  

Electric arc furnace (EAF) slag is the byproduct of electric arc furnace in the process of metallurgy. In this paper, a recovering iron process combined with an activating residual slag process for EAF slag has been put forward. Researches show that increasing fineness of EAF slag is adverse to recover iron from the slag and 21.27% of the EAF slag could be separated as recovered iron concentrate with grade of 64.34%. The residual slag after magnetic separation process could be activated through mixing activating agent. Hemihydrates gypsum was the best activating agent to improve reactivity of the residual slag, which could meet the requirement of the first grade of steel slag powder in national standard. Then residual slag cements had been successfully prepared with 30% of activated residual slag and a 28-day compressive strength of 44.46MPa.


Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 442
Author(s):  
Pao Ter Teo ◽  
Siti Koriah Zakaria ◽  
Nurulakmal Mohd Sharif ◽  
Anasyida Abu Seman ◽  
Mustaffa Ali Azhar Taib ◽  
...  

This study aims to optimize the composition (body formulation) and firing temperature of sustainable ceramic clay-based ceramics incorporated with electric arc furnace (EAF) steel slag waste using general full factorial design (GFFD). The optimization is necessary to minimize drawbacks of high iron oxide’s fluxing agent (originated from electric arc furnace, EAF steel slag waste), which led to severe surface defects and high closed porosity issue of the ceramics. Statistical analysis of GFFD including model adequacy checking, analysis of variance (ANOVA), interaction plots, regression model, contour plot and response optimizer were conducted in the study. The responses (final properties of ceramics) investigated were firing shrinkage, water absorption, apparent porosity, bulk density and modulus of rupture (MOR). Meanwhile, the factors employed in experimental parameters were weight percentage (wt.%) of EAF slag added and firing temperature. Upon statistical analysis, GFFD has deduced that wt.% amount of EAF slag added and firing temperatures are proven to significantly influence the final properties of the clay-based ceramic incorporated with EAF slag. The results of conducted statistical analysis were also highly significant and proven valid for the ceramics. Optimized properties (maximum MOR, minimum water absorption and apparent porosity) of the ceramic were attained at 50 wt.% of EAF slag added and firing temperature of 1180 °C.


2013 ◽  
Vol 652-654 ◽  
pp. 1628-1632 ◽  
Author(s):  
Kolawole Bankole Lateef ◽  
Abdul Rezan Sheikh ◽  
Mohd Sharif Nurulakmal ◽  
Norlia Baharun

This study investigates the leaching behavior of hexavalent chromium (Cr (VI)) from both industrial electric arc furnace steel slag and steel slag modified with up to 2% wt Cr2O3. The study was performed with European standard batch leaching test for 15 days and the lixiviant used were alkaline, de-ionized and rain water. The experimental work was also complimented with slag characterization using XRF, XRD and SEM/EDX analysis. After 15 days, Cr (VI) was found to be highest in rain water (0.016 mg/L) and lowest in de-ionized water (0.002 mg/L). With more Cr2O3 in EAF slag, more Cr will leach out based on the 2% wt Cr2O3 addition. Besides the lixiviant used, slag stirring speed and liquid to solid ratio also affect the dissolution of Cr (VI). With up to 2 wt % Cr2O3 in EAF slag, Cr (VI) dissolution was still lower than the threshold of 0.1 mg/L set by USEPA for public water systems. The analysis also indicated that the relative amounts of soluble basic and acidic oxides in the slag will affect the dissolution of Cr (VI).


2016 ◽  
Vol 102 ◽  
pp. 810-821 ◽  
Author(s):  
D. Mombelli ◽  
C. Mapelli ◽  
S. Barella ◽  
C. Di Cecca ◽  
G. Le Saout ◽  
...  

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