ALTERNATIVE BINDERS TO BENTONITE FOR IRON ORE PELLETIZING: PART I: EFFECTS ON PHYSICAL AND MECHANICAL PROPERTIES

2014-7-3
Sivrikaya, Osman
Arol, A. I.
<jats:p>The use of conventional bentonite binder is favorable in terms of mechanical and metallurgical pellet properties, however, because of its acid constituents bentonite is considered as impurity especially for iron ores with high acidic content. Therefore, alternative binders to bentonite have been tested. Organic binders are the most studied binders and they yield pellets with good wet strength; they fail in terms of preheated and fired pellet strengths. This study was conducted to investigate how insufficient pellet strengths can be improved when organic binders are used as binder. The addition of a low-melting temperature and slag bonding/strength increasing constituent (free in acidic contents) into pellet feed was proposed. Addition of boron compounds such as colemanite, tincal, borax pentahydrate, boric acid together with organic binders such as CMC, starch, dextrin and some organic based binders, into iron oxide pellet was tested. Wet and thermally treated pellet physical-mechanical qualities (balling - moisture content - size - shape - drop number - compressive strengths - porosity - dustiness) were determined. The results showed that good quality wet, dry, preheated and fired pellets can be produced with combined binders (an organic binder plus a boron compound) when compared with bentonite-bonded pellets. While organic binders provided sufficient wet and dry pellet strengths, the boron compounds provided the required preheated and fired pellet strengths at even lower firing temperature. Especially, the contribution of boron compound addition is most pronounced for hematite pellets which do not have strengthening mechanism through oxidation like magnetite pellets during firing. Therefore, addition of boron compound is beneficial to recover the low physical-mechanical qualities of pellets produced with organic binders through slag bonding mechanism. Furthermore, lowering the firing temperature thanks to low-melting boron compounds will be cost-effective for firing part of the pelletizing plants.</jats:p>

Suggestions

Use of boron compounds as binders in iron ore pelletization
Sivrikaya, Osman; Arol, Ali İhsan (2010-05-01)
Low grade iron ores with impurity gangue minerals containing silica and alumina must be upgraded to an acceptable level of iron content. Concentrates, due to their fine sizes, are not suitable to be directly charged to the iron-making processes such as the blast furnace or the DR-plant. Hence, an agglomeration technique should be applied to fine concentrate. The most commonly employed one is pelletizing in iron ore industry. In pelletizing, iron ore, water and a binder are balled in a mechanical disc or dru...
ALTERNATIVE BINDERS TO BENTONITE FOR IRON ORE PELLETIZING : PART II : EFFECTS ON METALLURGICAL AND CHEMICAL PROPERTIES
Sivrikaya, Osman; Arol, A. I. (Instituto Federal de Educacao, Ciencia e Tecnologia do Rio Grande do Norte (IFRN), 2014-7-3)
<jats:p>This study was started to find alternative binders to bentonite and to recover the low preheated and fired pellet mechanical strengths of organic binders-bonded pellets. Bentonite is considered as a chemical impurity for pellet chemistry due to acid constituents (SiO2 and Al2O3). Especially addition of silica-alumina bearing binders is detrimental for iron ore concentrate with high acidic content. Organic binders are the most studied binders since they are free in silica. Although they yield pellets...
The bonding/strengthening mechanism of colemanite added organic binders in iron ore pelletization
SİVRİKAYA, OSMAN; Arol, Ali İhsan (2012-07-18)
The addition of boron compounds into pellet mix is proposed as a potential solution to overcome the insufficient compressive strengths of preheated and fired pellets produced with organic binders. Colemanite was tested as an alternative binder to bentonite either alone or in combination with some organic binders on magnetite pellets. The performances of the tested binders on pellet qualities: balling, wet pellet moisture content, drop number, compressive strengths and microstructure of pellets have been com...
The Effect of Calcined Colemanite Addition on the Mechanical Strength of Magnetite Pellets Produced with Organic Binders
SİVRİKAYA, OSMAN; Arol, Ali İhsan; Eisele, Timothy; Kawatra, S. Komar (2013-06-01)
Iron ore pellets must have sufficient mechanical strengths against degradation in all stages of pellet production. Low strength is also a problem for product pellets since they abrade during transportation to the reduction furnaces. The use of a binder is necessary to provide sufficient strength to the pellets and for better operation and handling of pellets. Bentonite is the standard binder in the industry; however, it is considered an impurity due to its acid oxide contents. Organic binders have been test...
Novel conversion of thiols into disulfides, via S-nitrosothiol intermediates using trichloronitromethane
Demir, Ayhan Sıtkı; Igdir, AC; Mahasneh, AS (1999-10-15)
An efficient oxidative coupling of thiols to give disulfides via thionitrite (S-nitrosothiol) intermediate is described using trichloronitromethane as an efficient reagent in organic solvents and water. Cysteine and glutathione are converted into the corresponding disulfides in water in high yields.
Citation Formats
O. Sivrikaya and A. I. Arol, “ALTERNATIVE BINDERS TO BENTONITE FOR IRON ORE PELLETIZING: PART I: EFFECTS ON PHYSICAL AND MECHANICAL PROPERTIES,” HOLOS, 2014, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/51471.