scholarly journals Recovery of Chromium from Slags Leachates by Electrocoagulation and Solid Product Characterization

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1593
Author(s):  
Lubomir Pikna ◽  
Maria Hezelova ◽  
Agnieszka Morillon ◽  
David Algermissen ◽  
Ondrej Milkovic ◽  
...  
Keyword(s):  
Steel Slag ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Arc Furnace ◽  
Low Carbon ◽  
Solid Product ◽  
Stainless Steel Slag ◽  
Carbon Ferrochrome ◽  
Ferrochrome Slag ◽  
Comparison Of The Results

Slags produced in the steelmaking industry could be a source of chromium. Slags contain, depending on different types of slags, between 2 to 5 wt.% of Cr. Roasting of slag with NaOH, followed by subsequent leaching can produce leachates which can be efficiently processed using electrocoagulation (EC). This paper provides results from the EC process optimization for Cr(VI) solutions with initial concentration 1000 mg/L of Cr(VI). Influence of pH, current intensity and NaCl concentration on the efficiency of chromium recovery, energy consumption as well as solid product composition is discussed in detail. Optimum of pH = 6 was chosen for EC processing of Cr leachates as well as current intensities of 0.1–0.5 A because of the higher Cr/Fe ratio in solid product compared to higher current intensities. Results of EC processing of four real leachates of electric arc furnace carbon steel slag (EAFC), electric arc furnace stainless steel slag (EAFS), low carbon ferrochrome slag (LC FeCr) and high carbon ferrochrome slag (HC FeCr) were evaluated. Comparison of the results of four real leachate samples is presented. Obtained final solid product was identified as (Fe0.6 Cr0.4)2O3 and with up to 20% of Cr could be used as source of chromium in the ferrochrome production.

scholarly journals The effect of microstructure on the leaching behaviour of electric arc furnace (EAF) carbon steel slag

2016 ◽  
Vol 102 ◽  
pp. 810-821 ◽  
Author(s):  
D. Mombelli ◽  
C. Mapelli ◽  
S. Barella ◽  
C. Di Cecca ◽  
G. Le Saout ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Steel Slag ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Arc Furnace ◽  
Leaching Behaviour ◽  
Effect Of Microstructure

Upgrading constructed wetlands phosphorus reduction from a dairy effluent using electric arc furnace steel slag filters

2007 ◽  
Vol 56 (3) ◽  
pp. 135-143 ◽  
Author(s):  
D. Weber ◽  
A. Drizo ◽  
E. Twohig ◽  
S. Bird ◽  
D. Ross
Keyword(s):  
Removal Efficiency ◽  
Constructed Wetlands ◽  
Steel Slag ◽  
Dairy Farm ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Management Approach ◽  
Arc Furnace ◽  
Treated Water ◽  
P Removal

In 2003, a subsurface flow constructed wetlands (SSF-CW) system was built at the University of Vermont (UVM) Paul Miller Dairy Farm as an alternative nutrient management approach for treating barnyard runoff and milk parlour waste. Given the increasing problem of phosphorus (P) pollution in the Lake Champlain region, a slag based P-removal filter technology (PFT) was established (2004) at the CW with two objectives: (i) to test the filters' efficiency as an upgrade unit for improving P removal performance via SSF-CW (ii) to investigate the capacity of filters technology to remove P as a “stand alone” unit. Six individual filters (F1–F6) were filled with electric arc furnace (EAF) steel slag, each containing 112.5 kg of material with a pore volume of 21 L. F1–F4, fed with CW treated water, received approximately 2.17 g DRP kg−1 EAF steel slag (0.25 kg DRP total) during the 259 day feeding period. F1–F4 retained 1.7 g DRP kg−1 EAF steel slag, resulting in an average P removal efficiency of 75%. The addition of filters improved CW DRP removal efficiency by 74%. F5 and F6, fed non-treated water, received 1.9 g DRP kg−1 EAF steel slag (0.22 kg DRP in total) and retained 1.5 g DRP kg−1 resulting in a P removal efficiency of 72%. The establishment of the EAF slag based PFT is the first in-field evaluation of this technology to reduce P from dairy farm effluent in Vermont.

scholarly journals The Influence of Slag Tapping Method on the Efficiency of Stabilization Treatment of Electric Arc Furnace Carbon Steel Slag (EAF-C)

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 706 ◽  
Author(s):  
Davide Mombelli ◽  
Andrea Gruttadauria ◽  
Silvia Barella ◽  
Carlo Mapelli
Keyword(s):  
Chemical Composition ◽  
Carbon Steel ◽  
Steel Slag ◽  
Toxic Metal ◽  
Electric Arc Furnace ◽  
Sem Analysis ◽  
Electric Arc ◽  
Arc Furnace ◽  
Stabilization Treatment ◽  
Electric Arc Furnace Slag

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.

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
Keyword(s):  
Chemical Composition ◽  
Calcium Oxide ◽  
Ferric Oxide ◽  
Ph Value ◽  
Steel Slag ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Arc Furnace ◽  
High Calcium ◽  
Eaf Slag

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. 

scholarly journals Assessment of Electric Arc Furnace (EAF) Steel Slag Waste’s Recycling Options into Value Added Green Products: A Review

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 ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Steel Slag ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Raw Material ◽  
Added Value ◽  
Arc Furnace ◽  
Separation Techniques ◽  
Eaf Slag ◽  
Physical And Chemical

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.

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