scholarly journals Valorization of Slags Produced by Smelting of Metallurgical Dusts and Lateritic Ore Fines in Manufacturing of Slag Cements

2020 ◽  
Vol 10 (13) ◽  
pp. 4670 ◽  
Author(s):  
Theofani Tzevelekou ◽  
Paraskevi Lampropoulou ◽  
Panagiota P. Giannakopoulou ◽  
Aikaterini Rogkala ◽  
Petros Koutsovitis ◽  
...  
Keyword(s):  
Raw Materials ◽  
Direct Reduction ◽  
Mineralogical Composition ◽  
Economic Benefits ◽  
Glassy Matrix ◽  
Strength Development ◽  
Arc Furnace ◽  
Reduction Smelting ◽  
Cooling Media ◽  
Cement Manufacturing

A pyrometallurgical process was developed for the recycling of Ni bearing dusts and laterite ore fines by direct reduction smelting in DC (direct current) arc furnace. In the course of the performed industrial trials, besides the Ni-recovery in the liquid bath, slag composition was deliberately adjusted in order to produce a series of metallurgical slags with different chemical and mineralogical composition. The aim of this study was to investigate their suitability as clinker substitute in cement manufacturing. Examined parameters were slag FeOx content, basicity and applied cooling media (air, water cooling). A series of composite Portland and slag cements were manufactured in laboratory scale incorporating 20% and 40% of each slag, respectively; the rest being clinker of OPC (ordinary Portland cement) and 5% gypsum. The extended mineralogical analysis and microstructural properties of the produced slags were examined and correlated with the properties of the produced cements. The physical and mechanical characteristics of all examined cement products were found to meet the requirements of the regulation set for cements. The present research revealed that the most critical parameter in the compressive strength development of the slag cements is the mineralogical composition of the slag. Even in cases where rapid cooling to obtain glassy matrix is not feasible, adjustment of slag analysis to obtain mineralogical phases similar to those met in clinker of OPC, even at higher FeO contents (up to ~21wt.%), can result in production of slag with considerable latent hydraulic properties. These results indicate that there is potentially space for adjustments in conventional EAF (electric arc furnace) steel slags composition to allow for their wider use in cement manufacturing with significant environmental and economic benefits resulting from the reduction of energy requirements, CO2 emissions and natural raw materials consumption.

scholarly journals State of the direct reduction and reduction smelting processes

2002 ◽  
Vol 38 (3-4) ◽  
pp. 123-141 ◽  
Author(s):  
A. Markotic ◽  
N. Dolic ◽  
V. Trujic
Keyword(s):  
Blast Furnace ◽  
Direct Reduction ◽  
Electric Arc ◽  
High Price ◽  
Manufacturing Processes ◽  
Arc Furnace ◽  
Process Metallurgy ◽  
Modern Process ◽  
Long Time ◽  
Reduction Smelting

For quite a long time efforts have been made to develop processes for producing iron i.e. steel without employing conventional procedures - from ore, coke, blast furnace, iron, electric arc furnace, converter to steel. The insufficient availability and the high price of the coking coals have forced many countries to research and adopt the non-coke-consuming reduction and metal manufacturing processes (non-coke metallurgy, direct reduction, direct processes). This paper represents a survey of the most relevant processes from this domain by the end of 2000, which display a constant increase in the modern process metallurgy.

ON THE PROCESSING OF HEMATITE RAW MATERIALS AT THE KRYVOROZHSK MINING AND PROCESSING PLANT OF OXIDIZED ORE ON TECHNOLOGY OF DIRECT RECOVERY ITmk3

2018 ◽  
pp. 32-37
Author(s):  
P.I. Loboda ◽  
Younes Razaz ◽  
S. Grishchenko
Keyword(s):  
Magnetic Properties ◽  
Cast Iron ◽  
Iron Content ◽  
Raw Materials ◽  
Direct Reduction ◽  
Processing Plant ◽  
High Iron Content ◽  
High Iron ◽  
Direct Restoration ◽  
First Time

Purpose. To substantiate the efficiency of processing hematite raw materials at the Krivoy Rog Mining and Processing Plant of Oxidized Ores using the direct reduction technology itmk3®. Metodology. Analysis of the results of the itmk3® direct restoration technology developed by Kobe Steel Ltd., Japan and Hares Engineering GmbX, Austria, with a view to using it to process Krivbass hematite ores into granulated iron (so-called “nuggets”). Findings. The involvement in the production of hematite ores (oxidized quartzite) of Krivbass with high iron content, but with low magnetic properties for their processing into granular cast iron is grounded. Originality. The use of itmk3® direct reduction technology from Kobe Steel Ltd., Japan and Hares Engineering GmbH, Austria for the processing of Krivbass hematite ores into granular cast iron is justified for the first time. Practical value. The efficiency of the use of hematite ores (oxidized quartzite) has been substantiated, which can significantly reduce the costs in the mining cycle for the economical production of metallurgical products.

scholarly journals Strength Development and Elemental Distribution of Dolomite/Fly Ash Geopolymer Composite under Elevated Temperature

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 1015 ◽  
Author(s):  
Emy Aizat Azimi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Petrica Vizureanu ◽  
Mohd Arif Anuar Mohd Salleh ◽  
Andrei Victor Sandu ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Fly Ash ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Raw Materials ◽  
Liquid Sodium ◽  
Strength Development ◽  
Elemental Distribution ◽  
Distribution Analysis ◽  
Geopolymer Composites

A geopolymer has been reckoned as a rising technology with huge potential for application across the globe. Dolomite refers to a material that can be used raw in producing geopolymers. Nevertheless, dolomite has slow strength development due to its low reactivity as a geopolymer. In this study, dolomite/fly ash (DFA) geopolymer composites were produced with dolomite, fly ash, sodium hydroxide, and liquid sodium silicate. A compression test was carried out on DFA geopolymers to determine the strength of the composite, while a synchrotron Micro-Xray Fluorescence (Micro-XRF) test was performed to assess the elemental distribution in the geopolymer composite. The temperature applied in this study generated promising properties of DFA geopolymers, especially in strength, which displayed increments up to 74.48 MPa as the optimum value. Heat seemed to enhance the strength development of DFA geopolymer composites. The elemental distribution analysis revealed exceptional outcomes for the composites, particularly exposure up to 400 °C, which signified the homogeneity of the DFA composites. Temperatures exceeding 400 °C accelerated the strength development, thus increasing the strength of the DFA composites. This appears to be unique because the strength of ordinary Portland Cement (OPC) and other geopolymers composed of other raw materials is typically either maintained or decreases due to increased heat.

The Effect on Cement Mortar and Concrete by Admixture of Spray Drying Absorption Products

1989 ◽  
Vol 178 ◽  
Author(s):  
Kirsten G. Jeppesen
Keyword(s):  
Grain Size ◽  
Fly Ash ◽  
Cement Mortar ◽  
Setting Time ◽  
Mineralogical Composition ◽  
Cement Clinker ◽  
Strength Development ◽  
Fall Meeting ◽  
Freeze Thaw ◽  
Spray Dried

AbstractSpray dried absorption products (SDA) having special characteristics are used as substitutes for cement in the preparation of mortars; the qualities of the resulting mixed mortars are described. Conditions are described for mortar mixes, data for which were presented at the MRS Fall Meeting 1987.The influence of the composition of the SDA on water requirement and setting time has been studied. A full scale project involving 3 precast, reinforced concrete front-elements containing 20 and 30 wt.% SDA is described. Strength development, mineralogical composition and corrosion were monitored for two years.A non-standard freeze-thaw experiment was performed which compares mortars containing SDA and fly ash (FA) and also shows the effect of superplasticizer.The possibility of improving the SDA by grinding has been tested and a limited improvement has been found. The strength of the mixed mortars seems slightly influenced by the grain size of SDAGypsum (CaSO4·2H2O), synthetic calcium-sulphite (CaSO3·½H2O) and 2 SDAs have been used as retarders for cement clinker. Mortar test prisms have been cast and comparative strengths after curing for 3 years are reported

Conversion of Red Muds into Pozzolans

1991 ◽  
Vol 245 ◽  
Author(s):  
Jean Pera
Keyword(s):  
Red Mud ◽  
Mineralogical Composition ◽  
Waste Materials ◽  
Strength Development ◽  
Blended Cements ◽  
Temperature Range ◽  
Lime Consumption ◽  
Red Muds ◽  
Mineralogical Compositions

ABSTRACTRed muds are waste materials obtained from the aluminium extraction industry. They consist mainly of clays, aluminium and iron hydrated oxides. Three muds were studied; they differed in chemical and mineralogical compositions. They were converted into reactive pozzolans by calcination in the temperature range 600–800°C for five hours. Pozzolanicity was investigated on calcined red mud-OPC mixes studying strength development and lime consumption as evaluated by DTA. The nature of hydrates formed during hardening was also identified.The mineralogical composition of the mud is the most important factor affecting its pozzolanicity. Blended cements containing 30% calcined red mud develop significant strengths.

scholarly journals Physicochemical Properties of Handere Clays and Their Use as a Building Material

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yasin Erdoğan
Keyword(s):  
Physicochemical Properties ◽  
Building Materials ◽  
Raw Materials ◽  
Organic Matter Content ◽  
Volcanic Glass ◽  
Mineralogical Composition ◽  
Matter Content ◽  
Loss On Ignition ◽  
X Ray Diffraction ◽  
Clay Deposits

Handere clay deposits were discovered at Adana in Turkey. These clay units primarily consist of uncoloured claystone, pebbly sandstone, sandstone, siltstone, and mudstone marl and include gypsum lenses and clay levels of various thicknesses in places. The physicochemical properties of these clays have been investigated by different techniques including Scanning Electron and Elemental Analysis (SEM and EDS), mineralogical analyses, chemical and physical analyses, X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), and Atterberg (Consistency) Limits Test. The mineralogical composition deduced from XRD is wide (smectite + palygorskite + illite ± feldspar ± chlorite ± quartz ± calcite ± serpentine) due to the high smectite contents (≈85%). SEM studies reveal that smectite minerals are composed of irregular platy leaves and show honeycomb pattern in the form of wavy leaves in places. The leaves presenting an array with surface edge contact are usually concentrated in the dissolution voids and fractures of volcanic glass. Organic matter content and loss on ignition analysis of raw materials are good for all the studied samples. In summary, Handere clays can be used as building materials in bricks, roof tiles, and cement and as a binder.

Characterization of Ceramic Tiles Added with EAF Slag Waste

2014 ◽  
Vol 1024 ◽  
pp. 211-214 ◽  
Author(s):  
Pao Ter Teo ◽  
Abu Seman Anasyida ◽  
Mohd Sharif Nurulakmal
Keyword(s):  
Flexural Strength ◽  
Raw Materials ◽  
Solid Wastes ◽  
Arc Furnace ◽  
Ceramic Tiles ◽  
Total Percentage ◽  
Eaf Slag ◽  
Ball Clay ◽  
Slag Waste

The increasing production of steel leads to an increment of solid wastes generated especially Electric Arc Furnace (EAF) slag. This becomes a serious concern as the slag has to be disposed in a proper manner in order to avoid dumping in landfills which will eventually occupy available land and may cause permanent damage to the flora and fauna. In this project, an attempt was made to utilize the EAF slag as one of the raw materials in ceramic tiles. Results obtained showed that as percentage of EAF slag added was increased up to 60%, percentage of apparent porosity and water absorption were found to increase, accompanied by reduction in flexural strength due to more severe porosity was observed in the tiles. On the other hand, reducing the percentage of EAF slag up to 40% while increasing percentage of ball clay added led to formation of higher total percentage of anortite and wollastonite minerals. This would contribute to higher flexural strength of tiles. In addition, by adding silica and feldspar, the flexural strength of tile produced was further improved due to optimization of densification process. Highest flexural strength of EAF slag based tiles was attained at composition of 40% EAF slag 30% ball clay 10% feldspar 20% silica. It was observed that properties of ceramic tiles added with EAF slag, especially flexural strength are comparable with commercial ceramic tiles. Therefore, the EAF slag ceramic tiles have great potential to be made into high flexural strength or wear resistant floor tiles.

scholarly journals Reduction Properties of Raw Materials for Direct Reduction Shaft Furnace

1977 ◽  
Vol 63 (14) ◽  
pp. 2269-2277
Author(s):  
Dentaro KANEKO ◽  
Yoshio KIMURA ◽  
Mamoru ONODA ◽  
Isao FUJITA
Keyword(s):  
Raw Materials ◽  
Shaft Furnace ◽  
Direct Reduction
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