Ferrosilicon Alloy Research Articles

The Influence of Electro-Deposition Time to the Distribution of Silicon in Ferrosilicon Alloy

As soft magnetic alloy, Si steel has been brought to the attention of the people. When the content of Si is about 6.5%, the magnetic induction intensity is highest, and the wastage of the iron is lowest, with good magnetic energy. Due to the brittleness and poor process-ability of the 6.5% Si silicon, the traditional production process is very difficult to be used for the production. With traditional production process, the content of Si in silicon steel is commonly 0.1% ~ 4.0%, which makes the property of the silicon steel limited. Use molten salt electro-position method to product silicon steel on the basis of silicon steel surface, to lay the foundation for producing 6.5% Si silicon steel. The influence of the process parameters of molten salt electro-position method to the deposit surface morphology and the silicon content distribution from surface to inside shows that along with the increase of the electro-position time, the size of sediment particle on the deposit surface gradually increases. The sedimentary thickness is proportional to the electro-deposition time.

The Study of Ferrosilicon Alloy Sediment Horizon Metallographic Etchant

It is the precondition of material microstructure test to show the metallographic specimen microstructure clearly. Chemical etching method is most often used to display the metallographic microstructure, which is to put the sample into the proportioned etchant, the structure will be revealed because of the electrochemical effect between the surface of each structure unit and the etchant. According to the characteristics of ferrosilicon alloy material, configure several kinds of etchant, and by comparing the changes in the microstructure determine the best etchant of ferrosilicon alloy sediment.

Electro-Deposition Methods Influence to Ferrosilicon Organization

Combining ferrosilicon alloy with electro-deposition method, the main phase in the deposit layer is Fe3Si, and the substrate texture is mainly distributed in γ orientation line, {111}<110> and {111}<110> is the key component. The sample is mainly the cubic texture of {100}<001> and {111}<112> in γ orientation line, with a small amount of Goss texture. {111} texture share in the sample decreases.

Reaction sintered Fe–Sialon ceramic composite: Processing, characterization and high temperature erosion wear behavior

Fe–Sialon ceramic matrix composite has been newly developed from ferro-silicon alloy and commercial-grade industrial alumina powders by reaction sintering under a nitrogen atmosphere. The phase composition, mechanical properties and impact erosion wear behavior were investigated. The solid particle erosion tests have been conducted at elevated temperatures ranging from 25 °C to 1200 °C. Sharp SiC particles between 325 and 830 μm in diameter were employed as impact abrasives. The results showed that Fe–Sialon ceramic consisted of β-Sialon and Fe3Si phases. The Z value of the as-formed β-Sialon varied from 0 to 3.2 with increasing the alumina content in the starting powders. The bending strength and Rockwell hardness gradually increased with raising the alumina addition. The erosion rate of Fe–Sialon ceramic is highly dependent on the testing temperature. The minor erosion took place at room temperature or 1200 °C, while the major erosion occurred at 600–1000 °C. Fe–Sialon composites showed better erosion wear resistance than the control material of alumina ceramic at 1200 °C, although having much lower density and slightly lower bending strength.

Trends and developments in green cement and concrete technology

The cement industry faces a number of challenges that include depleting fossil fuel reserves, scarcity of raw materials, perpetually increasing demand for cements and concretes, growing environmental concerns linked to climate change and an ailing world economy. Every tonne of Ordinary Portland Cement (OPC) that is produced releases on average a similar amount of CO 2 into the atmosphere, or in total roughly 6% of all man-made carbon emissions. Improved production methods and formulations that reduce or eliminate CO 2 emissions from the cement manufacturing process are thus high on the agenda. Emission reduction is also needed to counter the impacts on product cost of new regulations, green taxes and escalating fuel prices. In this regard, locally available minerals, recycled materials and (industry, agriculture and domestic) waste may be suitable for blending with OPC as substitute, or in some cases replacement, binders. Fly ash, Blast furnace slag and silica fumes are three well known examples of cement replacement materials that are in use today that, like OPC, have been documented and validated both in laboratory tests and in practice. The first is a by-product of coal combustion, the second of iron smelting and the third of electric arc furnace production of elemental silicon or ferro silicon alloys. This paper presents a concise review of the current state-of-the-art and standards underpinning the production and use of OPC-based cements and concretes. It outlines some of the emerging green alternatives and the benefits they offer. Many of these alternatives rely on technological advances that include energy-efficient, low carbon production methods, novel cement formulations, geopolymers, carbon negative cements and novel concrete products. Finally, the economics of cement production and the trends in the UK, US and the Gulf Cooperation Council (GCC) Region are presented, to help guide and inform future developments in cement production based on maximizing the value of carbon reduction.

Green binding material using alkali activated blast furnace slag with silica fume

Recently million tons of cement is produced in Egypt accompanied with million tons of CO2 emission which causes annually negative impact on the environment. Granulated blast furnace slag and silica fume are produced as by-product from iron and chemical industries with limited recycling facility. This paper represents an experimental study aimed to safe ferrosilicon alloy of slag and silica fume to produce cementless binding material using both of Sodium Hydroxide and water glass liquid (Sodium Silicate) as alkaline activator. Experimental program was designed to study silica/slag ratio, percentage of alkali activator, water/binding ratio, incorporation of superplasticizer, and curing condition on the properties of the produced binding material. Compressive strength and mineralogical analysis were conducted on the polymeric binding material to asses the effectiveness of the main variables. The tests were divided into two stages; in the first stage compressive strength was conducted for all mixes while X-ray, microscopic scan (SEM), and infrared analysis (IR) were carried out for the most pronounced promising mixes. The results showed that ratio of 25% of silica/slag is the most effective ratio and 5% of each of Sodium Hydroxide and Sodium Silicate was the optimum percentage of the alkaline activator. Additionally the use of superplasticizer is essential as it positively reduces the mixing water and maintains the binding material with acceptable workability.

Simultaneous Decarburization and Oxidation Reactions Occurring in Silicon and Ferrosilicon Alloys at 1823 K

AbstractWe present high temperature investigations on ferrosilicon alloys (Si: 24.7, 74, and 98.5%); silicon oxidation and decarburization studies in steelmaking have generally been limited to Fe‐based alloys containing up to 3.5 wt% Si. The effect of alloy composition, oxygen partial pressure and gas flow rate on interactions at 1823 K is evaluated. Decarburization and silicon oxidation reactions were found to occur simultaneously with significant differences observed in the weight gain and carbon loss. The net weight gain in these alloys was found to be due to the combined influence of decarburization (weight loss due to the generation of a gaseous product) and silicon oxidation (weight gain due to silica formation on the sample surface). There was a clear evidence for two rate regimes: the rate of decarburization was found to be much higher during the initial 2 min and a much slower rate was observed in later stages for all specimens. These rate regimes are explained in terms of the extent of surface coverage with the reaction product silica. No significant effect was found on the decarburization rates when the proportion of oxidizing gas (CO2) was increased from 20 to 100%. The outcomes of this investigation will assist with the development of mechanisms governing the reactions of molten ferrosilicon and silicon alloys during their interactions with gaseous phases in the cupola process.

Human health risk assessment of ferrosilicon alloys under REACH

Human health risk assessment of ferrosilicon alloys under REACH

Preparation Vermicular Graphite in Thin and Thick Wall Iron Castings

The results of studies on the use of magnesium alloy in modern Tundish for production of vermicular graphite cast irons were described. This paper describes the results of using a low-magnesium ferrosilicon alloy for the production of vermicular graphite cast irons. The paper presents a vermicular (and nodular) graphite in different walled castings. The results of trials have shown that the magnesium Tundish process can produce high quality vermicular graphite irons under the specific industrial conditions of Foundries Odlewnie Polskie S.A. in Starachowice. In this work describes too preliminary studies on the oxygen state in cast iron and their effect on graphite crystallization.

The Structure and Mechanical Properties of Pearlitic-Ferritic Vermicular Cast Iron

The results of studies on the use of magnesium alloy in modern Tundish + Cored Wire injection method for production of vermicular graphite cast irons were described. The injection of Mg Cored Wire length is a treatment method which can be used to process iron melted in an electric induction furnace. This paper describes the results of using a high-magnesium ferrosilicon alloy in cored wire for the production of vermicular graphite cast irons at the; Tundish + Cored Wire to be injected methods (PE) for pearlitic-ferritic matrix GJV with about 25 %ferrite content. The results of calculations and experiments have indicated the length of the Cored Wire to be injected basing on the initial sulfur content and weight of the treated melt. The paper presents a microstructure matrix and vermicular graphite in standard sample and different walled castings. The results of numerous trials have shown that the magnesium Tundish + PE Method process can produce high quality vermicular graphite irons under the specific industrial conditions of the above mentioned foundries.

Adsorption and Removal of a Xanthene Dye from Aqueous Solution Using Two Solid Wastes as Adsorbents

This study aims to explore the possibility of utilizing silica fume (SF) and coal fly ash (CFA), both of which are solid wastes and collected from producing silicon metal or ferrosilicon alloys and electric power station, respectively, as cost-effective adsorbents. Laboratory-scale experiments were carried out to investigate the adsorption equilibrium and adsorption kinetics of a xanthene dye Rhodamine B (RhB) on SF and CFA. Batch experiments were conducted to evaluate the effects of various parameters including contact time, temperature, adsorbent dosage, ionic strength, and solution pH on the adsorption capacity of the two selected adsorbents. Experimental result showed that the adsorption equilibrium was achieved within 150 min for each adsorbent and both of the adsorption isotherms could be well fitted to the Freundlich model. However, the adsorption capacity and removal efficiency of SF is nearly 4 times higher than that of CFA under the same conditions. Electrostatic interaction and cation exchange reaction play an important role on the adsorption process of RhB on SF and CFA. Desorption studies showed that 50% ethanol could be used as an effective extractant for the reuse of the adsorbents and recovery of the adsorbate. The two selected adsorbents have a potential in the application of the dye wastewater treatment.

Study on High Performance Fe<sub>3</sub>Si-Si<sub>3</sub>N<sub>4</sub>-SiC Composite Preparation and its Application in Blast Furnace

Excellent Fe3Si-Si3N4-SiC composites were successfully prepared with FeSi75 and SiC as main starting materials by nitridation reaction(at 1300°C for 8Hrs). The effect of ferrosilicon alloy addition amount on material properties was studied; the ferrosilicon nitridation mechanism was analyzed through chemical thermodynamics; phase composition, microstructure, alkali resistance of products were also investigated. The results show that when ferrosilicon addition amount is 12wt%, the comprehensive property of Fe3Si-Si3N4-SiC is the best. The nitridation products are fiber-like α-Si3N4 and rod-like β-Si3N4, which makes better mechanical behavior due to fiber reinforcement; a great deal of Fe3Si intermetallic compounds uniformly distribute in matrix, which is one of the products of Fe-Si nitridation and as a plastic phase forming in grain boundary optimizes the performance of products. Chemical thermodynamic analysis shows that the fiber-like α-Si3N4 is formed by SiO(g) and N2(g) reaction which also increases the rate of nitridation. Fe3Si-Si3N4-SiC material has good performance. Now it has been successfully applied to one 2000M3 domestic steel plant, the blast furnace operation goes well.

Effect of Rare Earth on 30CrMnSi Steel Investment Castings Cracking

Through adding different amounts of rare earth into the crack sensitive 30CrMnSi steel samples used in investment casting, the cracking tendency of the steel was evaluated and the optimum amount of rare earth addition was obtained. The results show that the cracking susceptibility decreases with the increase of the amount of rare earth added. The cracking susceptibility was lowest at the addition amount of rare earth ferrosilicon alloy being 450g per 50kg of 30CrMnSi steel, while increasing again thereafter with the addition amount up to 600g. It was revealed that the addition of rare earth with an appropriate amount can refine grains, reduce sulfur content, change the volume fraction and size of inclusions as well as improve their distribution, reduce or eliminate ferrite network in castings, and improve the hardness of the matrix, thus finally reduce the cracking susceptibility of the steel.

Synthesis of Silicon Carbide Nanopowder Using Silica Fume

Silica fume is a byproduct of producing silicon metal and ferrosilicon alloys, and contains 94–97 wt% SiO2. This study demonstrates, for the first time, that silica fume can be converted to nano‐SiC powder at 1500°C via carbothermic reduction with the aid of high‐energy ball milling of the silica fume plus graphite mixture at room temperature. The nano‐SiC synthesized has particle sizes as small as 30 nm. The effects of the carbothermic reduction temperature and the graphite concentration in the starting SiO2+C mixture on the conversion of SiO2to SiC have been investigated. The reaction pathways of carbothermic reduction have been identified. A carbon elimination treatment using H2to remove the free carbon in the nano‐SiC powder has also been proven effective and the extent of carbon elimination depends on the reaction temperature, reaction duration, and quantity of the free carbon present before the carbon elimination treatment.

Dust Exposure Assessed by a Job Exposure Matrix Is Associated with Increased Annual Decline in FEV1

The relationship between dust exposure and annual decline in lung function among employees in the smelting industry is unknown. The aim of the study was to investigate the relationship between annual change in lung function and occupational dust exposure among workers in 15 Norwegian smelters. All employees (n = 2,620) were examined annually for 5 years (11,335 health examinations). At each examination spirometry was performed and a respiratory questionnaire was completed. The smelters were grouped as follows: (1) ferrosilicon alloys (FeSi) and silicon metal (Si-metal); and (2) silicon manganese (SiMn), ferromanganese (FeMn), and ferrochromium (FeCr). A job exposure matrix was available on the basis of 2,619 personal dust exposure measurements. The association between lung function expressed as FEV(1) and FVC per squared height (height(2)) and dust exposure was investigated using multivariate linear mixed model analyses. The annual change in FEV(1)/height(2) (deltaFEV(1)) related to dust exposure in the FeSi/Si-metal and SiMn/FeMn/FeCr smelters was -0.42 (95% confidence interval, -0.95 to 0.11) and -1.1 (-2.1 to -0.12) (ml/m(2)) x (mg/m(3))(-1) x year(-1), respectively. The annual decline in FEV(1)/height(2) was 1.6 ml/m(2) (0.15 to 3.1) steeper in smokers than in nonsmokers. The median geometric mean of the time-weighted dust exposure concentration levels of the employees was 2.3 mg/m(3) in the FeSi/Si-metal smelters and 1.6 mg/m(3) in the SiMn/FeMn/FeCr smelters. Among nonsmokers, deltaFEV(1) was -0.86 (-1.6 to -0.10) and -1.1 (-2.5 to 0.25) (ml/m(2)) x (mg/m(3))(-1) x year(-1) in the FeSi/Si-metal and SiMn/FeMn/FeCr smelters, respectively. Thus, for a 1.80 m tall employee the annual decline in FEV(1) associated with average dust exposure was 5.7 ml/year in the SiMn/FeMn/FeCr smelters, and 6.4 ml/year for a nonsmoker in the FeSi/Si-metal smelters. In all smelters combined, the annual change in FEV(1) was negatively associated with increasing dust exposure. This association was also significant among workers in SiMn/FeMn/FeCr smelters and among nonsmokers in the FeSi/Si-metal smelters.

Utilization potential of silica fume in fired clay bricks

Silica fume (SF) is an inorganic waste material which is generated during the elemental silicon and ferro-silicon alloy production. Due to the unique properties, it is utilized in several industries. However, very little information is available on the utilization potential of SF in traditional clay brick industry. In this study, the effect of different quantities of SF addition on the properties of fired clay brick was investigated. Test samples were produced by uniaxial pressing and fired at 800, 900, 1000 and 1100 degrees C. The microstructures of the samples were investigated by Scanning Electron Microscopy (SEM). The strength of the fired samples at 1000 and 1100 degrees C were significantly improved with SF addition. It was concluded that the reactive amorphous nature of SF particles enhances the sintering action locally and this gives better strength behaviour. SF addition also improved the efflorescence behaviour of the bricks. It was concluded that the effect of SF addition on the fired clay brick mainly depends on the firing temperature. At low firing temperatures, SF addition has a tendency to decrease the bulk density. However at higher firing temperatures, SF addition allows better sintering action with a drastic increase in bulk density.

Cement-Slurry Performance and Set-Cement Properties vs. Microsilica Densification

Summary Microsilica is the extremely fine noncrystalline silica obtained in electric furnaces as a byproduct in the manufacture of elemental silicon and ferrosilicon alloys. This waste material, also improperly called silica fume, is available in different grades of various handling characteristics. It has been used for years as cement admixture both in the oil field and in construction and civil engineering industries. Because of its extremely fine nature and high reactivity as a pozzolanic material, microsilica has been used to improve slurry stability and the mechanical properties of the hardened material. This paper reviews typical uses of microsilica in oilfield cements. Particular attention is given to the influence of material grade in terms of degree of densification, on slurry behavior, and set cement properties. The physical properties of the tested micro-silica include specific gravity, loose and compacted bulk densities, and particle-size distribution before and after being submitted to an ultrasonic treatment. Slurry behavior is evaluated in terms of rheology and stability. The observation of set microsilica cement microstructure with a scanning electron microscope, coupled with an energy dispersive spectrometer, clarifies the question concerning the dispersability of densified microsilica in cement slurry. An unambiguous correlation between physical properties of microsilica, slurry performance, and set cement stability and morphology is also established, leading the way to correctly specifying the quality of microsilica to be used in oilfield applications. This work demonstrates that, contrary to common belief, not all grades of microsilica are equal and that densified microsilica does not redisperse into small particles when mixed in a cement slurry. Therefore, densified grades, which are popular for their ease of handling, do not provide the performance required for adequate zonal isolation as is normally expected from microsilica slurry. In particular, densified material improves neither the slurry stability nor the set cement mechanical properties. Only moderately compacted microsilica with a bulk density of approximately 300 kg/m3 have been found to offer the adequate compromise between proper handling characteristics and good slurry and set cement performance.

Carbon Dissolution Occurring during Graphite–Ferrosilicon Interactions at 1550°C

The carburisation reaction is a key reaction for the cupola process, since the metallic liquid droplets interact with coke at high temperatures. The kinetic mechanism of carbon dissolution in liquid iron had been extensively investigated. However, there is little knowledge about the kinetics of carbon dissolution when the silicon contents are over 10%, since the silicon content during the iron and steel making processes are usually well below this limit.Carbon dissolution phenomenon and associated mechanisms are established for ferrosilicon alloys and silicon at 1550°C in this study. The overall-rate constants at 1550°C for Si 98.5%, FeSi 74% and FeSi 24.7% were 3.8, 3 and 3.9×10−3 (s−1) respectively. The appearance of SiC as an interfacial product was found during the metal–graphite interactions and its role as a retarding agent during the carbon pickup was established.The kinetics of carbon dissolution from graphite is controlled by a mixed-control mechanism and this includes the diffusion of carbon and carbon transfer from the SiC interfacial layer.

Quantitative and Qualitative Assessment of Exposure among Employees in Norwegian Smelters

To generate a job exposure matrix (JEM) for dust exposure in Norwegian smelters to be used in an epidemiologic study of respiratory diseases and to identify determinants of exposure. The arithmetic mean and geometric mean (GM) of 2619 personal dust exposure measurements were applied in constructing the JEM, which was assigned to 2620 employees participating in a respiratory survey including yearly spirometry and a respiratory questionnaire. A qualitative exposure classification was constructed: (i) line operators were those employed full time in the production line, (ii) non-exposed employees were those who did not work in production and (iii) the remainder were classified as non-line operators. In the ferrosilicon alloy and silicon metal production group (FeSi/Si-metal), the median GM of dust exposure was 2.3 mg m(-3) (0.04-5.6) (10-90% percentiles) compared with 1.6 mg m(-3) (0.02-2.3) in the silicomanganese, ferromanganese and ferrochromium production group (SiMn/FeMn/FeCr). Multivariate analyses showed that dust exposure concentration levels decreased significantly with increasing age (FeSi/Si-metal), was significantly lower in females than in males and was significantly higher in current smokers than in never-smokers. Dust exposure concentration levels were also higher in employees reporting previous exposure to dust, fumes and gases than in employees without such previous exposure, though, significant only in the FeSi/Si-metal production group. The dust exposure levels of the employees were higher in the FeSi/Si-metal production group than in the SiMn/FeMn/FeCr production group. Age, gender, smoking status and previous exposure were significant determinants of dust exposure and should be evaluated in future analyses of the relationship between health outcomes and dust exposure in this industry.

Effect of ferrosilicon addition on the composition of inclusions in 16Cr-14Ni-Si stainless steel melts

The silicon deoxidation equilibrium between the 16Cr-14Ni-1.5Mn-Si melts and the CaO-SiO2-8MgO-5CaF2 (basicity=1.8) slag at 1743 K was investigated to understand the effect of aluminum and silicon contents on the composition of inclusions. Therefore, the ferrosilicon alloys with different aluminum content were chosen based on the preceding objective. In addition, the phase stability diagram of the inclusions was computed using commercial thermodynamic software based on the Gibbs energy minimization principles. The content of MnO in the inclusions sharply decreases with increasing silicon content when the steel melts were deoxidized by the ferrosilicon alloys containing high aluminum (FeSi-H). The content of SiO2 in the inclusions slightly increases with increasing silicon content when the FeSi-L is used, while a maximum value is shown at [Si]=1.5 pct when the FeSi-H is used. The content of MgO in the inclusions increases by increasing the content of silicon, regardless of the kinds of ferrosilicon alloys. The use of the FeSi-L as a deoxidizer could suppress the formation of Al2O3 in the inclusions, while the content of Al2O3 increases with increasing silicon content when the FeSi-H is used. When the FeSi-H is used as a deoxidizer, the inclusions are the glassy type with the composition of Mn-silicates at [Si]≤1.3 pct, while the Mg(Ca)-silicates with the composition of the forsterite phase are observed in the steel composition of [Si]=3.3 pct. When the steel melts were deoxidized by the FeSi-L alloys, the inclusions are the glassy-type Mn-silicates at [Si]=0.8 pct, while the Mn-silicates containing the cristobalite phase are observed at [Si]=1.5 to 2.4 pct. In the composition of [Si]=3.3 pct, the Mg-silicates with the composition of the rhodonite phase are observed. The log(X SiO2/X MnO) of the inclusions linearly increases by increasing the log [a Si · a O / a Mn] with the slope close to unity when the FeSi-L is used as a deoxidizer, while the slope of the line is about 2 times greater than that of the expected value when FeSi-H is used. The log (X MgO/X MnO) of the inclusions linearly increases by increasing the log [a Mg/a Mn] with slopes greater than the expected value of unity.