Hydration of dicalcium silicate and diffusion through neo-formed calcium-silicate-hydrates at weathered surfaces control the long-term leaching behaviour of basic oxygen furnace (BOF) steelmaking slag

The article presents the findings of the research concerning the usage of slowly cooled crystallized steelmaking slags, taken from slag disposal area, in the raw mix for autoclaved silicate materials. By means of dry milling and with the use of this slag the slag-containing binders of various compositions and basicity were prepared. The application of steelmaking slags in the raw mix allows intensifying the process of new formations synthesis and increasing the amount and crystallization degree of low-basic calcium silicate hydrates of the tobermorite group, which provides more than twofold increase of strength characteristics of the obtained materials as compared to the control sample.

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Precipitation Behavior of V-Enrichment Mineral in Steelmaking Slag Bearing Vanadium Modified by SiO2

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.295-298.1729 ◽

2013 ◽

Vol 295-298 ◽

pp. 1729-1734

Author(s):

Liu Shun Wu ◽

Yun Zhou ◽

Yuan Chi Dong

Keyword(s):

Calcium Silicate ◽

Converter Slag ◽

Dicalcium Silicate ◽

Experimental Results ◽

Steelmaking Slag ◽

Precipitation Behavior ◽

Silicate Phase ◽

Rich Phase ◽

Addition Amount

In order to concentrate vanadium in converter slag bearing vanadium, the effect of SiO2 on behavior of vanadium in the process of enriching was studied. Experimental results show that, during cooling, dicalcium silicate containing vanadium and phosphorus precipitate first from original slag. For original with 7% SiO2, most of vanadium dissolves in calcium silicate phase. However, the proportion of dicalcium silicate is big. For slag modified by 12% SiO2, during cooling, two vanadium-rich minerals precipitate firstly, i.e. Ca3(V,P)2O8(30-33%V2O5) and Ca3(V,P)2O8•nCa2SiO4 (14-31%V2O5), then 3CaO•2SiO2 (2-4%V2O5) generates. With addition amount of SiO2 increasing, the proportion of 3CaO•2SiO2 decreases gradually, and the content of vanadium in vanadium-rich phase increases gradually. So appropriate SiO2 addition can suppress the precipitation of Ca2SiO4 and Ca3•Si2O7, and promote the generation of vanadium-rich phase.

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A comparison between fly ash- and basic oxygen furnace slag-modified gold mine tailings geopolymers

International Journal of Energy and Environmental Engineering ◽

10.1007/s40095-019-00328-x ◽

2019 ◽

Vol 11 (2) ◽

pp. 207-217 ◽

Cited By ~ 2

Author(s):

Thabo Falayi

Keyword(s):

Fly Ash ◽

Mine Tailings ◽

Basic Oxygen Furnace ◽

Gold Mine ◽

Basic Oxygen ◽

Gold Mine Tailings ◽

Bof Slag ◽

Lower Temperature ◽

The One

AbstractFly ash (FA) and Basic oxygen furnace (BOF) slag were used to as additives in the geopolymerisation of gold mine tailings (GMT).The aim of the research was to determine the effects of the two additives on the strength formation and mechanism of metal immobilisation by modified GMT geopolymers. GMT, FA and BOF were mixed, respectively, and made into a paste with the addition of potassium hydroxide (KOH) before curing at various conditions. 50% replacement of GMT in the starting materials gave the highest unconfined compressive strength (UCS). The UCS for BOF-based geopolymer was 21.44 Mega Pascals (MPa), whilst the one for FA-based geopolymer was 12.98 MPa. The BOF-based geopolymer cured at lower temperature (70 °C) as compared to the FA-based geopolymer (90 °C). The optimum KOH concentration was 10 and 15 M for BOF- and FA-based geopolymers, respectively. BOF-based geopolymers resulted in the formation of calcium silicate hydrate (CSH) phases which contributed to higher strength; whereas in FA-based geopolymers, no new structures were formed. BOF-based geopolymers resulted in over 94% iron (Fe) immobilisation, whereas FA-based geopolymers had 76% Fe immobilisation. Fe immobilisation was via incorporation into the CSH or geopolymer structure, whilst other metal immobilisations were thought to be via encapsulation. 12-month static leaching tests showed that the synthesised geopolymers posed insignificant environmental pollution threat for long-term use.

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Package Characterization by Laboratory Leaching and Diffusion Experiments using Radionuclides

MRS Proceedings ◽

10.1557/proc-127-519 ◽

1988 ◽

Vol 127 ◽

Author(s):

H. A. Das

Keyword(s):

Steady State ◽

Saturated Solution ◽

Outward Diffusion ◽

Leaching Behaviour ◽

Inorganic Waste ◽

And Diffusion

ABSTRACTThe leaching of solid inorganic waste from loaded concrete or cement by Incoming water can be described in terms of a “steady-state” outward diffusion of the saturated solution, formed inside the pores. The derived equations permit the prediction of long-term leaching behaviour. Radiotracer experiments enahle the determination of the parameters involved.

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Evaluation of Long-term Skid Resistance of Asphalt Mixture with Multi-content Basic Oxygen Furnace (BOF) Steel Slag Using the Circular Vehicle Simulator (CVS)

E3S Web of Conferences ◽

10.1051/e3sconf/202124801044 ◽

2021 ◽

Vol 248 ◽

pp. 01044

Author(s):

Liqun Hu ◽

Shouke Wang ◽

Qiang Zhang

Keyword(s):

Steel Slag ◽

Asphalt Mixture ◽

Basic Oxygen Furnace ◽

Vital Role ◽

Driving Safety ◽

Basic Oxygen ◽

The Road ◽

Vehicle Simulator ◽

On The Road

Long-term anti-skid performance plays a vital role on the road life cycle and driving safety. Therefore, the CVS was proposed, which can perform full-size polishing on the rutting slabs. The CVS system was used to simulate the long-term anti-skid attenuation law of five kinds of asphalt mixture with different BOF steel slag contents, and the influence of different BOF steel slag contents on the road anti-skid performance was comprehensively analyzed by using pendulum friction value. With the increase of BOF steel slag volume, the long-term anti-skid performance of asphalt mixture increases first and then decreases. Especially, the asphalt mixture with 50% BOF steel slag content has the best long-term anti-skid performance.

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Phosphorus speciation in dicalcium silicate phases: Application to the basic oxygen furnace (BOF) slag

Cement and Concrete Research ◽

10.1016/j.cemconres.2015.03.012 ◽

2015 ◽

Vol 73 ◽

pp. 207-214 ◽

Cited By ~ 10

Author(s):

Cédric Duée ◽

Christine Bourgel ◽

Emmanuel Véron ◽

Mathieu Allix ◽

Franck Fayon ◽

...

Keyword(s):

Basic Oxygen Furnace ◽

Dicalcium Silicate ◽

Phosphorus Speciation ◽

Basic Oxygen ◽

Bof Slag

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Creep of a C-S-H gel: a micromechanical approach

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652010000100004 ◽

2010 ◽

Vol 82 (1) ◽

pp. 25-41 ◽

Cited By ~ 15

Author(s):

Julien Sanahuja ◽

Luc Dormieux

Keyword(s):

Strain Rate ◽

Creep Behavior ◽

Calcium Silicate ◽

Elastic Strain ◽

Hydration Products ◽

Microscopic Mechanism ◽

Calcium Silicate Hydrates ◽

Micromechanical Approach ◽

Short And Long Term

Both clays and calcium silicate hydrates(the main hydration products of Portland cements) exhibit a microstructure made up of lamellar particles. The microscopic mechanism responsible for the macroscopic creep of such materials is often described as the relative sliding of the sheets. This paper proposes a micromechanical approach to estimate the macroscopic creep behavior rising from this microscopic mechanism. The asymptotic evolution of creep at both short- and long-term is especially investigated. More precisely, a non-vanishing initial elastic strain is retrieved. At long-term, a threshold on porosity appears. At lower porosities, the creep evolution admits an asymptotic strain. At higher porosities, it admits an asymptotic strain rate.

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Mineral Sequestration of CO2 Using Basic Oxygen Furnace (BOF) Steelmaking Slag

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.194-196.2140 ◽

2011 ◽

Vol 194-196 ◽

pp. 2140-2144 ◽

Cited By ~ 2

Author(s):

Guo Jun Ma ◽

Hui Tang ◽

Yi Biao Jin

Keyword(s):

Raw Materials ◽

Ambient Pressure ◽

Basic Oxygen Furnace ◽

Steelmaking Slag ◽

Solid Waste Disposal ◽

Basic Oxygen ◽

Leaching Process ◽

Carbonation Process ◽

Long Term Storage ◽

Leaching Solution

A promising option for long-term storage of CO2 is to fix CO2 by industrial solid wastes, such as basic oxygen furnace (BOF) steelmaking slag. It is advantage to use BOF steelmaking slag to fix CO2, such as large volume of BOF steelmaking slag, low price of raw materials, close to the CO2 emission sources, and no secondary pollution. It is of great significance to the CO2 emissions reduction and solid waste disposal in the ironmaking and steelmaking plant. In this paper, the leaching process, impurities removing and carbonation of steelmaking plant waste slag were studied at ambient pressure. The results show that Ca2+ leaching mainly occurs at the beginning 60min in the leaching process. The Ca2+ leaching ratio can reach about 45% with the leachant of 2mol/L HAc, leaching temperature of 30°C and solid-liquid ratio of 1:20. Moreover, it can effectively remove Mg2+, Al3+ and Fe3+ by adding small amounts of NaOH and triethanolamine in the leaching solution, and thereafter, high purity CaCO3 products can be obtained through the carbonation process.

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