Use Of Sintering Research Articles

Studies to determine the influence of the basicity modulus on the qualitative and quantitative indicators of production technology and the material composition of the sintere

In recent years, the increase in the efficiency of the blast furnace process is largely associated with the use of sinter with improved metallurgical properties. In the blast furnace charge of PJSC NLMK, the share of sinter is 60–75% with a change in basicity from 1.3 to 1.8. Studying the material composition of agglomerates of different basicity and their characteristics allows us to adjust the technological process and determine the optimal modulus of basicity depending on specific conditions. Agglomerates with a basicity index of: 1.3; 1.4; 1.5; 1.6; 1.7 and 1.8. As a result of the research, it was established that the maximum vertical sintering speed and specific productivity of the sintering process correspond to the basicity of the sinter of 1.7. The influence of the basicity of the agglomerate on its strength is extreme, with a basicity of 1.4 the minimum strength of the agglomerate was obtained. Increasing the basicity of the agglomerate by more than 1.4 monotonically increases its strength. The nature of the change in the strength of the ag-glomerate with a change in basicity is determined by the mineral composition of the binder and is associated with a decrease in the proportion of glass in the structure of the agglomerate and an increase in the proportion of the crystalline silicate-ferrite binder. When studying the material composition, it was established that the samples of agglomerates have an identical phase composition, but differ in the phase ratio. Crystallization of calcium ferrites in contact with iron oxides contributes to the strengthening of the agglomerate, and the presence of impurities (Al, Si, Mg) in them increases the melting point. As a result of mineralogical and analytical studies, it was established that the highest metallurgical properties are found in agglomerates with a basicity modulus of 1.6–1.8.

Synthetic space bricks from lunar and Martian regolith via sintering

The prospect of establishing extra-terrestrial habitats using in situ resource utilization (ISRU) constitutes a long-term goal of multiple space agencies around the world. In this work, we investigate furnace sintering as a potential route for making building blocks—termed synthetic space bricks—using in situ regolith material. By systematically evaluating sintering parameters using a numerical lattice model, coupled with experimental observations and post-sintering characterization, we propose a process protocol for two lunar simulants (lunar highland simulant (LHS-1) and lunar mare dust simulant (LMS-1)) and one Martian simulant (mars global simulant, MGS-1). The resulting bricks demonstrate compressive strengths of up to 45 MPa under uniaxial loading, depending on the simulant used. These strengths are much greater than those typically mandated for structural applications under reduced gravity. Taking recourse to classical ceramic sintering studies, we infer particle-level sintering mechanisms indirectly by measuring temporal evolution exponents of sample dimensions. For all three simulants, volume diffusion appears to be the primary mechanism for particle coalescence. Our results clearly make a strong case for the use of sintering as a potentially scalable method for consolidating regolith into brick-like structures for construction and load-bearing applications in extra-terrestrial settings.

Research of the production of iron ore sinter from bauxite processing waste

This article presents the results of a study of the agglomeration of waste alumina ferrous sands and the use of sinter as a substitute for metal charge in steelmaking. At this time, in the process of processing bauxite, JSC "Aluminium of Kazakhstan" produces a large number of fines, which is of great interest to ferrous metallurgy. Wastes from alumina production include a variety of waste sludge, including red, gray sludge, and ferrous sands. According to the chemical composition, ferrous sands can be attributed to iron ore material with a high content of alumina. Most of these problems are eliminated by preliminary agglomeration of fines. In this work, agglomeration studies made it possible to establish the optimal parameters for sintering ferrous sands. When using 10% fuel, the best sintering performance is achieved. The optimal parameters for sintering ferrous sands mixed with other metallurgical wastes are such as productivity - 0.92 t / m2 h, mechanical strength - 80.0%, sintering speed - 19.3 mm/min, yield - 82.0%, the maximum temperature in the layer is 1340 °С. The results of laboratory melt carried out in an induction melting furnace indicate the possibility of using a sinter as a substitute for metal charge in iron and steel smelting. The conducted melting confirms the fundamental possibility of using a sinter, made from waste products of alumina production of ferrous sands, is a man-made charge material that is suitable for use as a 5% additive to the metal charge in the smelting of iron-carbon alloys similar in composition to cast irons.

Life cycle assessment of blast furnace ironmaking processes: A comparison of fossil fuels and biomass hydrochar applications

The impact of the iron and steel production process on the ecological environment cannot be ignored. This study aims to assess the impact of life cycle assessment on the traditional fossil fuel blast furnace ironmaking process and the biomass hydrochar blast furnace ironmaking process. The Simapro v9.0 software is used to comprehensively evaluate the life cycle impacts of biomass hydrochar in the blast furnace ironmaking process. The results show that the life cycle impact categories of the blast furnace ironmaking process mainly include global warming, non-renewable energy and respiratory inorganics. The global warming impact of the ironmaking process using hydrochar is 2054.00 kg CO2 eq, which is 420.61 kg CO2 eq less than that of traditional blast furnace ironmaking process. The global warming impact is mainly reflected in the emission of CO2 gas, and the main source is the generation of blast furnace gas and the use of sinter. The respiratory inorganics impact is mainly manifested in the emission of nitrogen oxides, sulfur oxides and particulates, which mainly comes from the mining of iron ore and the production of sinter. The non-renewable energy impact mainly comes from the coal resources, and the use of other renewable energy such as biomass energy is an important way to reduce the impact. Therefore, biomass hydrochar used in the metallurgical process is more suitable for sustainable development of the ecological environment.

SHS of highly dispersed powder compositions of nitrides with silicon carbide Review

The application of the process of self-propagating high-temperature synthesis (SHS) to prepare highly dispersed powder nitride-carbide compositions from the most common refractory nitride (Si3N4, AlN, TiN) and carbide (SiC) compounds with a particle size of less than 1 μm is considered. The advantages of composite ceramics over single-phase ceramic materials and such trends of its development as the transition to nanostructured ceramics and the application of in situ processes of direct chemical synthesis of nanoparticles of components in the composite body are described. The attractiveness of the SHS process as one of the promising in situ processes characterized by simplicity and cost-effectiveness, the possibility of obtaining highly dispersed ceramic powders by burning mixtures of inexpensive reagents is shown. Considerable attention is paid to the consideration of the results of the application of azide SHS, based on the use of sodium azide and gasified halide salts as part of mixtures of initial powders of nitrided and carbidized elements during their combustion in nitrogen gas. The review of publications devoted to the application of SHS to obtain highly dispersed composite powders Si3N4–SiC, AlN–SiC and TiN–SiC, promising for use in sintering of the corresponding composite ceramic materials of submicron and nano-sized structure with improved properties, lower brittleness, good machinability, lower sintering temperatures compared with single-phase ceramic materials made of nitrides or carbides as well as for other applications, is presented. The results of the application of azide SHS are presented in detail both in the form of the results of thermodynamic calculations and the results of experimental research of combustion parameters, combustion product structure and composition. The advantages and disadvantages of using the combustion process for the synthesis of nitride compositions with silicon carbide, the causes of the disadvantages and the directions of further research to eliminate them are discussed.

Model of an iron ore sinter plant with selective waste gas recirculation

The use of sinter influences hot metal production substantially and significantly affects an integrated steel mill’s total emissions. Sintering of iron ores is an enormous energy-intensive and resources consuming process. Introducing a selective waste gas recirculation (SWGR) to the sintering process reduces the energy consumption, stack gas volume flow, and sulfur dioxide emissions of an iron sinter production. Simulating this complex process in flowsheet simulations of integrated iron and steelworks is a fast and cost-effective opportunity to validate new operation settings. The implementation of a sinter plant in gPROMS ModelBuilder®characterizes the sintering processes by three main sub-models. A burner model describes the gas combustion, a black-box model consider the main sintering processes, and a wind box model divides the total off-gas into a recycle gas and a stack gas. A specific temperature polynomial represents the temperature distribution across the wind boxes to allow detailed investigations on SWGR in complex flowsheet simulations. Implementing SWGR to the sintering process, the model shows a reduction of coke consumption, stack gas flow rate, and sulfur dioxide emissions by 11%, 27%, and 27%, respectively. In the SWGR scenario, the utilization rate of carbon monoxide increases and less coke is consumed. The chlorine emissions of the sintering process differ with and without SWGR insignificantly.

Use of sintering to immobilize toxic metals present in galvanic sludge into a stabile glass-ceramic structure

Galvanization process requires the use a large amount of water and produces wastewaters that are usually purified by conventional cost-effective procedure. This kind of treatment generates waste sludge which becomes a hazardous if is not properly stabilized. Hence, the aim of this paper is to investigate the characteristics of galvanic sludge through the inspection of its physicochemical parameters and consider stabilization of waste materials, including waste glass and aluminum slag by their conversion into an eco-designed material referred to as glass ceramics. The obtained products have been studied by X-ray diffraction (XRD). XRD analyses confirmed occurrence of chemical and phase transformations in treated galvanic sludge and binding of toxic metals (Al3+, Cr3+, Cu2+, Cd2+, Ni2+, Pb2+, Zn2+) into crystalline phases and very sTab. structure.

Sintering of solid waste generated in iron and steel manufacturing process in Shougang Jingtang

It is important to make full use of waste generated in the iron and steel manufacturing process for energy saving, emission reduction, low carbon production and a circular economy. Based on research on different kinds of industrial solid wastes from Shougang Jingtang, wastes have been optimized for use in sintering. At first, basic tests for all kinds of solid wastes that may be used in sintering were carried out, including chemical composition, calorific value of a fuel, holding time at high temperatures, the sintering pot test, etc. The results show that the appropriate solid waste ratios for current sintering conditions are: steel slag <5%, scale 2.0%, environmental ash 2.0%, and cyclone ash 1.0%; blast furnace dry ash, sintering electric field ash, and steelmaking ash should not be circulated in sintering. As for the fuel structure, both coking ash and nut coke should be below 15%. By optimizing the addition of solid wastes, the damage of harmful elements to sintering and blast furnaces has been significantly reduced, which satisfies the demands for blast furnace materials and earns benefits. The utilization of solid wastes has made a contribution to the circular economy and sustainable development.

Improving the Technology for the Blow-In of Blast Furnaces After Class-I and Class-II overhauls

This article describes the blow-in of a large blast furnace with the use of sinter prepared especially for this purpose. It is shown that use of the “blow-in” sinter makes operation of the furnace more reliable during the blow-in period which follows an overhaul and reduces the time required to restore the furnace to its normal operating regime while also minimizing fuel consumption.

Development of fluxed micropellets for sintering utilising iron oxide waste fines

Ultrafine iron oxide wastes such as slime, blue dust and Linz–Donawitz (LD) converter sludge have very limited use in sintering of iron ore due to their excessive fineness (−50 μm). Pelletisation of these ultrafine materials for use in blast furnace involves high temperature curing, which is a highly energy intensive process. Briquetting of LD sludge requires costly binders and contains high moisture, which creates problem at high temperature of the downstream process. In order to alleviate these problems, the current study has developed a process for preparing micropellets of waste iron oxide fines (2–6 mm size) without using any binder. The strength of the micropellet has been increased by a novel CO2 treatment process at room temperature. Developed micropellets exhibit very suitable drop strength (125 Nos), tumbler properties and cold compressive strength (∼9 kg/pellet) to withstand cold handling. Low lime containing micropellets have the possibility of being used as a mixed material in usual sinter making, and high lime containing micropellets may be exploited for making super fluxed sinter that can be used as synthetic flux in the basic oxygen furnace process towards the formation of low melting oxidising slag at the early stage of blow.

Preparation of iron-bearing wastes for industrial use

To permit the industrial use of sintering and steel-smelting slurries at OAO MMK, laboratory research is undertaken on the formulation of briquets with specified chemical composition and mechanical strength. In the batch for slurry briquetting, it proves expedient to add rolling scale; a binder consisting of ligno-sulfonate powder and portland cement provides the optimum briquet strength.

Producing high-basicity sinter from low-silica ore

Experience at OAO MK Azovstal in the production and blast-furnace use of sinter of basicity 1.74 is described. The sinter is produced using unique low-silica ore (∼1% SiO2) in quantities of 195.0–352.6 kg/t of sinter. In appropriate market conditions, this ore may be used to increase hot-metal supplies, to stabilize furnace operation, or to compensate for the losses of hot metal due to furnace shutdown.

SPANISH COLONIAL AND INDIGENOUS PLATINUM: A HISTORICAL ACCOUNT OF TECHNOLOGY AND FABRICATION

The pre-Columbian Indians of Ecuador and Colombia were the first people to make use of native platinum. The dating of this metallurgy is difficult but it probably goes back to the early centuries Be and continues at least until ad 800. The Indians made use of sintering in the production of their platinum-gold alloys, some of which are plated with platinum over gold by the process of diffusion bonding of small platinum grains to the gold surface. This pre-Hispanic platinum metallurgy has no parallel in the Old World, where platinum remained unknown and unused in any quantity until the scientists of the seventeenth and eighteenth centuries began to investigate its properties. The Spanish platinum industry and the attempts of French and Spanish scientists to make use of the metal are briefly discussed.

Spanish colonial and indigenous platinum: a historical account of technology and fabrication

The pre-Columbian Indians of Ecuador and Colombia were the first people to make use of native platinum. The dating of this metallurgy is difficult but it probably goes back to the early centuries Be and continues at least until AD 800. The Indians made use of sintering in the production of their platinum-gold alloys, some of which are plated with platinum over gold by the process of diffusion bonding of small platinum grains to the gold surface. This pre-Hispanic platinum metallurgy has no parallel in the Old World, where platinum remained unknown and unused in any quantity until the scientists of the seventeenth and eighteenth centuries began to investigate its properties. The Spanish platinum industry and the attempts of French and Spanish scientists to make use of the metal are briefly discussed.