Distribution of As within Magnetic and Non-Magnetic Fractions of Fluidized-Bed Coal Combustion Ash

Separation of coal ash into magnetic and non-magnetic fractions facilitates their utilization when processed separately. Due to desulphurization additives added to coal during the fluidised-bed combustion, non-magnetic fractions often contain elevated CaO levels (while magnetic concentrates are typically rich in Fe2O3). Both CaO and Fe2O3 are known for their ability to bind As during the combustion, whose distribution is a crucial parameter in terms of proper utilization of these fractions. Therefore, the study deals with the As partitioning within magnetic and non-magnetic fractions of fluidized-bed coal combustion ashes. Two different (successive) procedures of dry magnetic separation were used to separate each ash into strongly magnetic, less magnetic, and a non-magnetic fraction. Due to their optimal utilization, the concentrations of As and other target elements in these fractions were evaluated and compared. Magnetic concentrates from the first separation step (in vibrofluidized state) contained 60–70% Fe2O3, magnetic concentrates separated manually out of the residues after the first separation contained 26–41% Fe2O3, and the non-magnetic residues contained 2.4–3.5% Fe2O3. Arsenic levels were the highest in the non-magnetic residues and gradually decreased with the increasing Fe2O3 content in the magnetic fractions. The dominant As association in the studied samples was to CaO (r = +0.909) and with SO3 (r = +0.906) whereas its joint occurrence with Fe2O3 was improbable (r = −0.834).

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Recovery of magnetic fraction from coal combustion waste by high-gradient magnetic separation

Gornyi Zhurnal ◽

10.17580/gzh.2015.12.01 ◽

2015 ◽

pp. 4-8 ◽

Cited By ~ 1

Author(s):

T. N. Aleksandrova ◽

◽

V. V. Lvov ◽

K. V. Prokhorov ◽

◽

...

Keyword(s):

Magnetic Separation ◽

Coal Combustion ◽

Magnetic Fraction ◽

High Gradient Magnetic Separation ◽

Coal Combustion Waste ◽

High Gradient

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Study of a possibility of enrichment of fine-crushed magnetite ore by dry magnetic separation

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2019-5-564-571 ◽

2019 ◽

Vol 75 (5) ◽

pp. 564-571

Author(s):

N. V. Sedinkina ◽

O. E. Gorlova ◽

N. V. Gmyzina ◽

E. Yu. Degodya

Keyword(s):

Magnetic Separation ◽

High Efficiency ◽

Magnetic Fraction ◽

Magnetite Ore ◽

Ore Processing ◽

Initial Stage ◽

Specific Magnetic Susceptibility ◽

Dry Magnetic Separation ◽

Lower Limits ◽

And Storage

Dry magnetic separation (DMS) enables to separate the non-magnetic fraction of iron ores at the initial stage of their concentration and therefore to decrease cost of their further processing. However, a considerable amount of metal is lost in DMS tails at that. The efficiency of DMS considerably depends on difference between the upper and lower limits of the ore coarseness) ore coarseness range), delivered for concentration. At the Magnitogorsk steel-works crushing and concentration plant No. 5 this range is from 50 mm up to 15 mm. To determine the optimal ore size, delivered to DMS, studies accomplished to determine the specific magnetic susceptibility of the magnetite and the burden for the magnetite ore of Maly Kuibas deposit. After the study of different size iron ore separation, a reasonability of the DMS feed size decreasing down to 30–7 mm shown. A possibility to obtain additional product of 7–0 mm size determined, suitable for sintering. It will enable to decrease the amount of material, delivered for crushing and wet magnetic separation, as well as to decrease expenses for transporting and storage of wet separation tails. Peculiarities of fine magnetite ore processing by DMS in a suspended state considered, optimal parameters of the separator determined and its high efficiency for magnetite ore of 7–0 mm size concentration shown.

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Improvement of the technology for processing siderite ore from the Bakal deposit

Transbaikal State University Journal ◽

10.21209/2227-9245-2021-27-4-6-12 ◽

2021 ◽

Vol 27 (4) ◽

pp. 6-12

Author(s):

Е. Degodya ◽

◽

N. Sedinkina ◽

О. Shavakuleva ◽

N. Gmyzina ◽

...

Keyword(s):

Magnetic Field ◽

Magnesium Oxide ◽

Magnetic Separation ◽

Mass Fraction ◽

Iron Ore ◽

Raw Material ◽

Magnetic Fraction ◽

Suspended State ◽

Dry Magnetic Separation ◽

Siderite Ore

The Urals is one of the unique iron ore provinces of the world, including all the variety of iron ores. Siderite ores are represented by the Bakal group of deposits, in which siderite in mineralogical terms is not a chemically pure iron carbonate, but has an isomorphic admixture of magnesium and calcium, forming sideroplesite and pistomesite. The main iron ore mineral of the siderite ore of this deposit is an isomorphic mixture of iron, magnesium and manganese carbonates, which occur in different quantitative ratios. A scheme for ore dressing is proposed, which includes crushing to a size of 10-0 mm and dry magnetic separation in a suspended state at a magnetic field strength of 52 k/m. The study of dry magnetic separation of siderite ore was carried out on a suspended separator with a constant magnetic field and on an electromagnetic separator 138T-SEM. The resulting magnetic fraction is sent to the baking, subsequent crushing to a size of 2-0 mm and dry magnetic separation in the suspended state. To increase the mass fraction of iron and reduce the mass fraction of magnesium oxide, the magnetic fraction is sent for grinding and wet magnetic separation. The results of the experiments have showed that the enrichment using high-intensity dry magnetic separation of siderite ore from various sections of the deposit, the mass fraction of MgO decreased from 9.4-12.3% to 8.0-10.1%, and the mass fraction of iron increased from 28.8-33.4% to 31.4-40.8%. As a result, a product with a mass fraction of iron 59.3-60.1% and magnesium oxide 10.0-11.3% has been obtained. The developed enrichment technology allows us to obtain conditioned raw materials, which can serve as a promising raw material for PJSC Magnitogorsk Iron and Steel Works (PJSC MMK)

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Research of the influence of material composition and size of iron quartzites of the Olenegorsk deposit on the results of dry magnetic separation

Obogashchenie Rud ◽

10.17580/or.2020.06.03 ◽

2020 ◽

pp. 15-20

Author(s):

S. V. Tereshchenko ◽

◽

D. N. Shibaeva ◽

S. A. Alekseeva ◽

A. A. Kompanchenko ◽

...

Keyword(s):

Magnetic Separation ◽

Structural Features ◽

Magnetic Fraction ◽

Magnetic Separator ◽

Mass Fractions ◽

Dry Magnetic Separation ◽

Iron Quartzites ◽

Increased Strength ◽

Grinding Efficiency ◽

Ferruginous Quartzites

On the example of a sample of ferruginous quartzites from the Olenegorskoye deposit, the possibility of preliminary concentration by dry magnetic separation (DMS) has been established. The mineralogical and petrographic studies have shown that, in terms of their textural and structural features and mineral composition, ferruginous quartzites may be divided into two types, differing in the amount of hematite included in their composition, which indicates the possibility of using DMS to generate the following three separation products: magnetite, hematite-magnetite, and rock. DMS with the use of a laboratory drum magnetic separator allowed selecting the upper size limit of 80 mm for lumps entering the separation. At the same time, 24.7 to 26.0 % of all waste and low-mineralized rocks with the mass fraction of Fetot of 4.51 to 6.07 % are transferred to the non-magnetic fraction during the separation of classes of –80+50 and –50+25 mm. For the size class of –25+10 mm, the yield and Fetot values are within the same limits. It has been shown that sulfidecontaining rocks and rocks of increased strength (with the strength coefficient of at least 23) are separated into the non-magnetic fraction. The strength of ferruginous quartzites does not exceed 20. This rock strength ratio confirms improved crushing and grinding efficiency. The possibility of separation of the magnetic fraction with the particle size of –80+25 mm into the following products has been established: the magnetite-hematite product (MF-1 + MF-2) with the mass fractions of Femagn 43.3% and Fehem 14.9 %, and the predominantly hematite product (MF-3 + MF-4) with the mass fractions of Femagn 1.1 % and Fehem 67.9 %.

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Possibilities of Utilizing Solid Residues from Pressured Fluidized Bed Coal Combustion (PSBC) for the Production of Blended Cements

Cement and Concrete Research ◽

10.1016/s0008-8846(97)00258-5 ◽

1998 ◽

Vol 28 (2) ◽

pp. 299-307 ◽

Cited By ~ 36

Author(s):

J Havlica ◽

J Brandstetr ◽

I Odler

Keyword(s):

Fluidized Bed ◽

Coal Combustion ◽

Blended Cements

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NOx process inhibition and energy efficiency improvement in new swirl modification device for steel slag based on coal combustion

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2018-0007 ◽

2018 ◽

Vol 16 (7) ◽

Author(s):

Junxiang Guo ◽

Lingling Zhang ◽

Daqiang Cang ◽

Liying Qi ◽

Wenbin Dai ◽

...

Keyword(s):

Energy Efficiency ◽

Flue Gas ◽

Coal Combustion ◽

Steel Slag ◽

Coal Ash ◽

Combustion Efficiency ◽

Gas Temperature ◽

Staged Combustion ◽

Energy Efficiency Improvement ◽

Swirl Combustion

Abstract In this study, a novel swirl combustion modified device for steel slag was designed and enhanced with the objective of achieving highly efficient and clean coal combustion and also for achieving the whole elements utilization of coal. Coal ash and steel slag were melted in the combustion chamber and subsequently entered the slag chamber. The detrimental substances solidified and formed crystals, which allowed for the comprehensive utilization of the ash and slag. Our experiments mainly aimed to mitigate the formation of NOx, while using the heat and slag simultaneously during the coal combustion without a combustion efficiency penalty. The increase in the device’s energy efficiency and reduction in the NOx emissions are important requirements for industrialization. The experiments were carried out in an optimized swirling combustion device, which had a different structure and various coal feeding conditions in comparison to previously reported devices. The fuel-staged and non-staged combustion experiments were compared under different coal ratios (bitumite:anthracite). For the fuel-staged combustion experiments, the NOx concentration in the flue gas was observed to decrease significantly when the coal ratio of 1:1, an excess air coefficient of 1.2, and a fuel-staged ratio of 15:85 were used. Under these conditions, the flue gas temperature was as high as 1,620°C, while the NOx concentration was as low as 320 mg/m3 at 6 % O2. The air-surrounding-fuel structure that formed in the furnace was very beneficial in reducing the formation of NOx. In comparison to other types of coal burners, the experimental combustion device designed in this study achieved a significant reduction of NOx emissions (approximately 80 %).

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