Ore Furnace Research Articles

Buildup of Fault Protection for High-Current Single-Phase Transformers in Ore Furnaces

Buildup of Fault Protection for High-Current Single-Phase Transformers in Ore Furnaces

Arc Fault Protection of the High-Current Busbar Assembly of an Ore Furnace

The design features of high-power ore furnaces are the transformer’s secondary winding made of 4–8 isolated splits and a busbar assembly made of the same number of paired bifilar bus tubes, spaced 20–40 mm apart. Only an arc fault (AF) can occur between paired bus tubes in such an assembly, during which the assembly with currents of 35–150 kA can be completely destructed. To protect against AFs, these bus tubes are wrapped in several layers of gluey fiberglass cloth. However, such cloth is abraded under the impact of airborne abrasive dust particles during furnace operation, and coal dust in the air creates the conditions for an AF. A new current protection with a magnetic current transformer (MCT), which prevents busbar assembly destruction, is suggested. Its design is based on the analysis of the distribution of busbar assembly magnetic fields. The choice of MCT position is justified, and parameters of its windings are determined; MCT construction and fastening are described, and a technique for reliable MCT output signal transmission under strong magnetic fields and with a specified protection threshold is suggested. These protections are currently the simplest and cheapest tool for preventing the complete destruction of an expensive busbar assembly in events of AFs during it.

Alloy Production from High-Silica Manganese Ore and High-Ash Kazakhstan Coal

Engineering principles are outlined for the production of silicon–aluminum–manganese alloy from high-silica manganese ore and high-ash Kazakhstan coal (from the Borly and Saryadyr fields in the Karaganda and Teniz-Korzhunkol coal basins), Tekturmas quartzite, and Shubarkol long-flame coal. By thermodynamic diagram analysis of the four-component Fe–Si–Al–Mn system on the basis of handbook data (and calculated thermodynamic data where no handbook data are available), a mathematical model of the phase structure may be developed. The aluminum–silicon–manganese composition obtained from the Karaganda and Teniz-Korzhunkol coal, in contrast to the aluminum–silicon–manganese alloy from Ekibastuz coal, is shifted on the thermodynamic diagrams toward tetrahedra with relatively large volume. This indicates increased stability and technological predictability. The results of tests in an ore furnace show that aluminum–silicon–manganese alloy of regular composition may be obtained by a continuous slag-free method from high-ash Borly and Saryadyr coal and unconditioned high-silica manganese ore from the Western Kamys field if Shubarkol long-flame coal and Tekturmas quartzite are added to the batch. The alloy composition may be regulated by adding manganese ore to the weighed batch materials. An alloy with the following composition is obtained: 32–53 wt % Si, 15.5–25.0 wt % Al, 12–32 wt % Mn, 8–20 wt % Fe, 0.02–0.05 wt % P, and 0.2–0.5 wt % C. The resulting alloy does not crumble to powder on storage, thanks to the low phosphorus content and high aluminum content (>10%). The phase components of the experimental alloy are determined. The cost of the alloy is low, since it is produced from high-ash tailings coal and unconditioned high-silica manganese ore, with absolutely no coke. The alloy may be used for the reduction and alloying of steel and also as a reducing agent in the production of refined ferromanganese.

Application of stochastic programming for iron ore quality control

Stockpiling and blending play a major role in maintaining the quantity and quality of the raw materials fed into processing plants, especially the cement, iron ore and steel making, and coal-fired power generation industries that usually require a much uniformed feed. Due to the variable nature of such materials, they even come from the same source and the produced ores or concentrates are seldom homogeneous enough to be directly fed to the processing plant ore furnaces. Processing plants in iron ore mines need uniform feed properties in terms of each variable (in this work, iron phosphorous ratio and Fe content in magnetite phase) grade of ore, and therefore, homogenization of iron ore from different benches of an open pit or ore dumps has become an essential part of modern mine scheduling. When ore dumps are considered as an ore source, the final grade of the material leaving the dump to the blending bed cannot be easily determined. This difficulty contributes to mixing the materials of different grades in a dump. In this work, the ore dump elements were treated as normally distributed random variables. Then a stochastic programming model was formulated in an iron ore mine in order to determine the optimum amount of ore dispatched from different bench levels in open pit and also four ore dumps to a windrow-type blending bed in order to provide a mixed material of homogenous composition. The chance-constrained programming technique was used to obtain the equivalent deterministic non-linear programming problem of the primary model. The resulting non-linear model was then solved using LINGO. The results obtained showed a better feed grade for the processing plant with a higher probability of grade blending constraint satisfaction.

История исследования производственных комплексов хунну

Last years in Xiongnu archaelogical investigations emerged a new branch, which is investigation of pottery ovens and iron ore furnaces. The works started in 1999 with the detailed research of a pottery oven in the historical area of Khustyn Bulag located in the valley of the small Zuun Baidlag River. This river is a branch of the Kherlen River, which is located in Mongonmorit Soum of the Töv Province. These works were executed by a combined Mongolian and Korean expedition. Later the works were continued by annual combined Mongolian and Japanese expeditions within the 2011—2013 Project of Mongolian Iron Age History and 2014—2018 Project of Ancient Mongolian Manufacture History. The 2016 combined Mongolian and Japanese expedition performed archaeological excavation of the iron ore furnace in the area of Bulgijn of Mandal Soum of the Selenge Province. Heads of the project are Ch. Amartuvshin on the Mongolian party and T. Sasada on the Japanese party, respectively. Originally the pottery oven remnants in the area of Khustyn Bulag have been revealed by geologist P. Khosbayar.

KARAKTERISTIK BETON ASPAL DENGAN SUBSTITUSI AGREGAT LIMBAH INDUSTRI PENGOLAHAN BIJI BESI (STEEL SLAG)

Hot mix asphalt concrete with substitution of waste metal processing ( steel slag ) aggregate is the result of residual waste processing or a crust of iron ore furnace , visually shaped as hard lumps and irregularly shaped rock , has a specific gravity > 2.9, steel slag considered as a heavy aggregate. According to the sii 0052-80, steel slag that had less than 27% destroyed sections through a 1.7 mm sieve when tested with los angeles engines, can be used as aggregate. A 50% substitution variation of steel slag aggregate provides characteristics of asphalt concrete mixtures that is eligible to the bina marga 1998 requirement, with the optimum value at the variation of 50 % steel slag to coarse aggregate, with the stability value of 1016.00 kgf, melting value ( flow ) has the lowest value of 3:32 mm , marshall quetion optimum at 306.30 , cavities in aggregate > 16 % , the cavity filled with asphalt > 65 % , the cavity in a mixture of 3 % - 5 % .
 Keywords : steel slag , filler , marshall test , temperature , asphalt concrete

Silicon-carbide production from steel-plant wastes

Global silicon-carbide production and consumption is assessed. It is expedient to produce silicon carbide from industrial microsilica by furnace synthesis and plasma metallurgy. The balance of silicon-monoxide formation is considered on the basis of the physicochemical interactions in ore furnaces during the melting of silicon and ferroalloys, and the processes responsible for microsilica formation are analyzed. The synthesis of silicon carbide by furnace heating with carbon and its plasma-metallurgical production are discussed.

Constant component of the phase voltage when smelting zirconium electrocorundum

When smelting zirconium electrocorundum in an ore furnace, the furnace performance is related to the constant component of the phase voltage. The possibility of selecting optimal technological parameters on the basis of the constant phase voltage is considered.

Electrochemical processes in an ore-furnace bath

When an alternating current passes through an ore furnace, the surface where electrochemical reactions occur moves through the electrically conducting layer. These reactions occur over the whole conducting volume. In this period, the voltage drop at the furnace bath remains constant. This behavior may be employed to assess the parameters of the process: the quantity of conducting material in the furnace bath; and the melt composition.

Processing of zinc-bearing dust and slurry to obtain crude zinc and iron

Methods for the processing of zinc-bearing dust from steel smelting are briefly reviewed. The system developed at Energoterm-Sistema Development Center is described. This system produces iron and crude zinc by processing dust briquets with carbon reducing agent in a sealed ore furnace. The products are hot metal, zinc and lead captured in the cooling systems, and hot gas that may be used for drying and reduction of the briquets.

Control of arc development in an ore furnace

The influence of voltage and current variation on the power distribution in an ore furnace between the arc, the shunting resistance, and the melt is considered, for the example of a phosphorus furnace.

Processes in melts of solid-phase reduction products of ilmenite concentrates

South Ural titanomagnetites are a promising source of iron ore. Their reserves are estimated at tens of millions of tons, but traditional processing is impos� sible on account of the high content of titanium oxides. In the enrichment of such ore, ferrovanadium and ilmenite concentrates are obtained. Ilmenite concentrates may be used to obtain high� titanium slag in ore furnaces [1]. Disadvantages of smelting powdered ilmenite concentrate in ore fur� naces include high power consumption and consider� able entrainment of material. Therefore, it is expedi�

Increasing the wear resistance of linings of ore furnaces for melting normal electrocorundum

The use of air-cooled linings on ore furnaces for melting normal electrocorundum has made it possible to increase their wear resistance by an order of magnitude. This is explained by the formation of a steady solid-phase skull due to a higher temperature gradient with a total decrease in the thermodynamic levels of the ambient and the refractory lining.

Magnetism in Copper Slags

ON examining the magnetic properties of some ores and minerals, I observed that a specimen of ore furnace slag from copper smelting was strongly polar magnetic.