High-chromium vanadium-titanium magnetite all-pellet integrated burden optimization and softening-melting behavior based on flux pellets

High-chromium vanadium-titanium magnetite(HVTM)is a crucial polymetallic-associated resource to be developed.The allpellet operation is a blast furnace trend that aims to reduce carbon dioxide emissions in the future.By referencing the production data of vanadium-titanium magnetite blast furnaces,this study explored the softening-melting behavior of high-chromium vanadium-titanium magnetite and obtained the optimal integrated burden based on flux pellets.The results show that the burden with a composition of 70wt%flux pellets and 30wt%acid pellets exhibits the best softening-melting properties.In comparison to that of the single burden,the softening-melting characteristic temperature of this burden composition was higher.The melting interval first increased from 307 to 362℃and then decreased to 282℃.The maximum pressure drop(ΔPmax)decreased from 26.76 to 19.01 kPa.The permeability index(S)dropped from 4643.5 to 2446.8 kPa·℃.The softening-melting properties of the integrated burden were apparently improved.The acid pellets played a role in withstanding load during the softening process.The flux pellets in the integrated burden exhibited a higher slag melting point,which increased the melting temperature during the melting process.The slag homogeneity and the TiC produced by over-reduction led to the gas permeability deterioration of the single burden.The segregation of the flux and acid pellets in the HVTM proportion and basicity mainly led to the better softening-melting properties of the integrated burden.

Simulation of deuterium pellet ablation and deposition in the EAST tokamak with HPI2 code

Pellet injection is a primary method for fueling the plasma in magnetic confinement devices.For that goal the knowledges of pellet ablation and deposition profiles are critical.In the present study,the pellet fueling code HPI2 was used to predict the ablation and deposition profiles of deuterium pellets injected into a typical H-mode discharge on the EAST tokamak.Pellet ablation and deposition profiles were evaluated for various pellet injection locations,with the aim at optimizing the pellet injection to obtain a deep fueling depth.In this study,we investigate the effect of the injection angle on the deposition depth of the pellet at different velocities and sizes.The ablation and deposition of the injected pellet are mainly studied at each injection position for three different injection angles:0°,45°,and 60°.The pellet injection on the high field side(HFS)can achieve a more ideal deposition depth than on the low field side(LFS).Among these angles,horizontal injection on the middle plane is relatively better on either the HFS or the LFS.When the injection location is 0.468 m below the middle plane on the HFS or 0.40 m above the middle plane of the LFS,it can achieve a similar deposition depth to the one of its corresponding side.When the pre-cooling effect is taken into account,the deposition depth is predicted to increase only slightly when the pellet is launched from the HFS.The findings of this study will serve as a reference for the update of pellet injection systems for the EAST tokamak.

Pelleting and particle size reduction of corn increase net energy and digestibility of fiber,protein,and fat in corn-soybean meal diets fed to group-housed pigs

Background Reduction of the particle size of corn increases energy digestibility and concentrations of digestible and metabolizable energy.Pelleting may also reduce particle size of grain,but it is not known if there are interactions between particle size reduction and pelleting.The objective of this experiment was to test the hypothesis that particle size reduction and pelleting,separately or in combination,increase N balance,apparent total tract digestibility(ATTD)of fiber and fat,and net energy(NE)in corn-soybean meal diets fed to group-housed pigs.Methods Six corn-soybean meal-based diets were used in a 3×2 factorial design with 3 particle sizes of corn(i.e.,700,500,or 300μm)and 2 diet forms(i.e.,meal or pelleted).Pigs were allowed ad libitum access to feed and water.Twenty-four castrated male pigs(initial weight:29.52 kg;standard diviation:1.40)were allotted to the 6 diets using a 6×6 Latin square design with 6 calorimeter chambers(i.e.,4 pigs/chamber)and 6 periods.Oxygen consumption and CO_(2)and CH_(4)productions were measured during fed and fasting states and fecal and urine samples were collected.Results Regardless of particle size of corn,the ATTD of gross energy(GE),N,and acid-hydrolyzed ether extract(AEE),and the concentration of NE were greater(P<0.05)in pelleted diets than in meal diets.Regardless of diet form,the ATTD of GE,N,and AEE,and the concentration of NE were increased(linear;P<0.05)by reducing the particle size of corn,but the increase was greater in meal diets than in pelleted diets(interaction;P<0.05).Conclusions Both pelleting and reduction of corn particle size increased nutrient digestibility and NE,but increases were greater in meal diets than in pelleted diets.

Effect of titanium on the sticking of pellets based on hydrogen metallurgy shaft furnace:Behavior analysis and mechanism evolution

Direct reduction based on hydrogen metallurgical gas-based shaft furnace is a promising technology for the efficient and low-carbon smelting of vanadium-titanium magnetite.However,in this process,the sticking of pellets occurs due to the aggregation of metal-lic iron between the contact surfaces of adjacent pellets and has a serious negative effect on the continuous operation.This paper presents a detailed experimental study of the effect of TiO2 on the sticking behavior of pellets during direct reduction under different conditions.Results showed that the sticking index(SI)decreased linearly with the increasing TiO2 addition.This phenomenon can be attributed to the increase in unreduced FeTiO3 during reduction,leading to a decrease in the number and strength of metallic iron interconnections at the sticking interface.When the TiO2 addition amount was raised from 0 to 15wt%at 1100°C,the SI also increased from 0.71%to 59.91%.The connection of the slag phase could be attributed to the sticking at a low reduction temperature,corresponding to the low sticking strength.Moreover,the interconnection of metallic iron became the dominant factor,and the SI increased sharply with the increase in re-duction temperature.TiO2 had a greater effect on SI at a high reduction temperature than at a low reduction temperature.

Diffusion and reaction mechanism of limestone and quartz in fluxed iron ore pellet roasting process

The increase to the proportion of fluxed pellets in the blast furnace burden is a useful way to reduce the carbon emissions in the ironmaking process.In this study,the interaction between calcium carbonate and iron ore powder and the mineralization mechanism of fluxed iron ore pellet in the roasting process were investigated through diffusion couple experiments.Scanning electron microscopy with energy dispersive spectroscopy was used to study the elements’diffusion and phase transformation during the roasting process.The results indicated that limestone decomposed into calcium oxide,and magnetite was oxidized to hematite at the early stage of preheating.With the increase in roasting temperature,the diffusion rate of Fe and Ca was obviously accelerated,while the diffusion rate of Si was relatively slow.The order of magnitude of interdiffusion coefficient of Fe_(2)O_(3)-CaO diffusion couple was 10^(−10) m^(2)·s^(−1) at a roasting temperature of 1200℃for 9 h.Ca_(2)Fe_(2)O_(5) was the initial product in the Fe_(2)O_(3)-CaO-SiO_(2) diffusion interface,and then Ca_(2)Fe_(2)O_(5) continued to react with Fe_(2)O_(3) to form CaFe_(2)O_(4).With the expansion of the diffusion region,the sillico-ferrite of calcium liquid phase was produced due to the melting of SiO_(2) into CaFe_(2)O_(4),which can strengthen the consolidation of fluxed pellets.Furthermore,andradite would be formed around a small part of quartz particles,which is also conducive to the consolidation of fluxed pellets.In addition,the principle diagram of limestone and quartz diffusion reaction in the process of fluxed pellet roasting was discussed.

Persicaria lanigera (Polygonaceae) leaf extract exhibits antiulcerogenic and antiproliferative activities against acetic acid-induced ulcerative colitis and cotton pellet-induced granuloma tissue in rats

Objective:To assess the effect of leaf extract of Persicaria lanigera on cotton pellet-induced granuloma tissue formation and acetic acid-induced ulcerative colitis.Methods:Rats were randomly divided into six groups:normal control,negative control,positive control(dexamethasone or sulfasalazine)as well as Persicaria lanigera(100-600 mg/kg)-treated groups.The effects of the extracts on body weight,antioxidant,and hematological parameters,as well as mast cell proliferation,were assessed.In addition,a histological evaluation was conducted.Results:Persicaria lanigera extract significantly decreased the mean exudate amount and suppressed granuloma tissue formation in a concentration-dependent manner in rats(P<0.05).Additionally,the extract significantly increased body weight,improved hematological profile,reduced the disease activity index score and malondialdehyde level,as well as enhanced catalase and superoxide dismutase activities(P<0.05).Histological evaluation showed Persicaria lanigera extract alleviated acetic acid-induced colonic damages,as evidenced by decreased cell necrosis,edema,and inflammatory cell infiltration.Conclusions:Persicaria lanigera extract possesses antiproliferative,antioxidative,and anti-colitis activities.However,its underlying mechanisms of action need further investigation.

Industrial utilization of arsenic-containing gold dressing tailings as pellet prepared by straight grate process

The utilization of arsenic-containing gold dressing tailings is an urgent issue faced by gold production companies worldwide.The thermodynamic analysis results indicate that ferrous arsenate(FeAsO_(4)),pyrite(FeS_(2))and sodium cyanide(NaCN)in the arsenic-containing gold metallurgical tailings can be effectively removed using straight grate process,and the removal of pyrite and sodium cyanide is basically completed during the preheating stage,while the removal of ferrous arsenate requires the roasting stage.The pellets undergo a transformation from magnetite to hematite during the preheating process,and are solidified through micro-crystalline bonding and high-temperature recrystallization of hematite(Fe_(2)O_(3))during the roasting process.Ultimately,pellets with removal rates of 80.77% for arsenic,88.78% for sulfur,and 99.88% for cyanide are obtained,as well as the iron content is 61.1% and the compressive strength is 3071 N,meeting the requirements for blast furnace burden.This study provides an industrially feasible method for treating arsenic-containing gold smelting tailings,benefiting gold production enterprises.

Effect of pyroxenite and olivine minerals as source of MgO in hematite pellet on improvement of metallurgical properties

Pelletization of hematite ore requires high fineness and very high induration temperature（~1325 ℃） owing to its poor diffusion bonding unlike magnetite ore. Further, high-alumina hematite pellets show very high reduction degradation index（RDI） during low temperature（500-650 ℃） reduction due to their volume expansion and lattice distortion. Noamundi（India） hematite ore contains very high Al2O3（2.3%） with adverse ratio of alumina to silica（~2） for which, it shows very high RDI. In this work, the acid pellets prepared from Noamundi ore fines of optimum Blaine fineness show good cold crushing strength（CCS）. However, it shows very high RDI（77%）. In order to reduce RDI, Mg O in form of two different gangue-containing fluxes, such as pyroxenite and olivine in varying quantities has been added. The optimum requirement and performance of these fluxes has been examined and compared. Both pyroxenite and olivine fluxed pellets show significant lowering of RDI（26% and 23%, respectively） and improvement of other properties, viz CCS, swelling indices etc with good reducibility（70%-77%）. Finally, a good quality acidic hematite pellet was developed from high-alumina ore without using any lime which is very important charge material in combination of basic sinter in blast furnace.

Probing deactivation by coking in catalyst pellets for dry reforming of methane using a pore network model

Dry reforming of methane(DRM) is an attractive technology for utilizing the greenhouse gases(CO_(2) and CH_(4)) to produce syngas. However, the catalyst pellets for DRM are heavily plagued by deactivation by coking, which prevents this technology from commercialization. In this work, a pore network model is developed to probe the catalyst deactivation by coking in a Ni/Al_(2)O_(3) catalyst pellet for DRM. The reaction conditions can significantly change the coking rate and then affect the catalyst deactivation. The catalyst lifetime is higher under lower temperature, pressure, and CH_(4)/CO_(2) molar ratio, but the maximum coke content in a catalyst pellet is independent of these reaction conditions. The catalyst pellet with larger pore diameter, narrower pore size distribution and higher pore connectivity is more robust against catalyst deactivation by coking, as the pores in this pellet are more difficult to be plugged or inaccessible.The maximum coke content is also higher for narrower pore size distribution and higher pore connectivity, as the number of inaccessible pores is lower. Besides, the catalyst pellet radius only slightly affects the coke content, although the diffusion limitation increases with the pellet radius. These results should serve to guide the rational design of robust DRM catalyst pellets against deactivation by coking.

Effect mechanism of aluminum occurrence and content on the induration characteristics of iron ore pellets

With the intensified depletion of high-grade iron ores,the increased aluminum content in iron ore concentrates has become unavoidable,which is detrimental to the pelletization process.Therefore,the effect mechanism of aluminum on pellet quality must be identified.In this study,the influence of aluminum occurrence and content on the induration of hematite(H)and magnetite(M)pellets was investigated through the addition of corresponding Al-containing additives,including alumina,alumogoethite,gibbsite,and kaolinite.Systematic mineralogical analysis,combined with the thermodynamic properties of different aluminum occurrences and the quantitative characterization of consolidation behaviors,were conducted to determine the related mechanism.The results showed that the alumina from various aluminum occurrences adversely affected the induration characteristics of pellets,especially at an aluminum content of more than 2.0wt%.The thermal decomposition of gibbsite and kaolinite tends to generate internal stress and fine cracks,which hinder the respective microcrystalline bonding and recrystallization between Fe2O3particles.The adverse effect on the induration characteristics of fired pellets with different aluminum occurrences can be relieved to varying degrees through the formation of liquid phase bonds between the hematite particles.Kaolinite is more beneficial to the induration process than the other three aluminum occurrences because of the formation of more liquid phase,which improves pellet consolidation.The research results can further provide insights into the effect of aluminum occurrence and content in iron ore concentrates on downstream processing and serve as a guide for the utilization of high-alumina iron ore concentrates in pelletization.

Elucidating the suppression of lithium dendrite growth with a void-reduced anti-perovskite solid-state electrolyte pellet for stable lithium metal anodes

Solid-state lithium-metal batteries,with their high theoretical energy density and safety,are highly promising as a next-generation battery contender.Among the alternatives proposed as solid-state electrolyte,lithium-rich anti-perovskite(Li RAP)materials have drawn the most interest because of high theoretical Li^(+)conductivity,low cost and easy processing.Although solid-state electrolytes are believed to have the potential to physically inhibit the lithium dendrite growth,lithium-metal batteries still suffer from the lithium dendrite growth and thereafter the short circuiting.The voids in practical Li RAP pellets are considered as the root cause.Herein,we show that reducing the voids can effectively suppress the lithium dendrite growth.The voids in the pellet resulted in an irregular Li^(+)flux distribution and a poor interfacial contact with lithium metal anode;and hence the ununiform lithium dendrites.Consequently,the lithium-metal symmetric cell with void-reduced Li_(2)OHCl-HT pellet was able to display excellent cycling performance(750 h at 0.4 m A cm^(-2))and stability at high current density(0.8 m A cm^(-2)for 120 h).This study provides not only experimental evidence for the impact of the voids in Li RAP pellets on the lithium dendrite growth,but also a rational pellet fabrication approach to suppress the lithium dendrite growth.

Hydrochar Pelletization towards Solid Biofuel from Biowaste Hydrothermal Carbonization

Hydrothermal carbonization is highly applicable to high moisture biomass upgrading due to the fact that moist-ure involved can be directly used as reaction media under the subcritical-water region.With this,value-added utilization of hydrochar as solid fuel with high carbon and energy density is one of the important pathways for biomass conversion.In this review,the dewatering properties of hydrochar after the hydrothermal carbonization of biowaste,coalification degree with elemental composition and evolution,pelletization of hydrochar to enhance the mechanical properties and density,coupled with the combustion properties of hydrochar biofuel were discussed with various biomass and carbonization parameters.Potential applications for the co-combustion with coal,cleaner properties and energy balance for biowaste hydrothermal carbonization were presented as well as the challenges.

The Logistics of Production and Supply of Ag Pellets for Industrial Applications in Canada

In this work we analyze the supply of biomass from field to an in-land or port destination. The biomass is pelletized to increase its bulk density to extend its storage period and for ease of its transport. The pellet may be used for conversion to chemicals and animal bedding or for straight combustion. We analyzed supply chain in Saskatchewan where there are plenty of crop residues but widely dispersed and harvest seasons are short. We envisioned that the farmer collects bales from field and transports the bales to farmstead during the harvest season. The bales are then processed into pellets using small scale pellet equipment. A custom operator with expertise in pelletization may engage in handling and densifying the biomass. The business case for the mobile mill will be similar to the well established custom grain and forage harvesting operations. The pellets are stored in hopper bottom grain bins at the farmstead. From this point, the handling of pellets would be similar to the handling and marketing of grain. The farmer trucks a specified volume of pellets from farmstead to the nearest elevator where the pellets are transferred to larger bins or silos. Pellets are extracted from silos and loaded onto the rail cars. The Canadian freight rail companies (mainly CN) currently transport over 3 million dry tonne (dt) of wood pellets in rail cars. The pellets are hauled to marine ports on the West Coast or East Coast for export. The cost of delivering ag pellets to biorefinery or to the shipping port is $86.09/dt. This cost does not include the equivalent value of removing biomass from the farm (e.g. fertilizer replacement) and return on investment. The GHG emissions to produce and transport ag pellets add up to 185.9 kg of CO2 per dt of biomass. The cost of producing pellets without drying feedstock is $35.05/dt and the corresponding GHG for palletization amounts $146.30/dt.

The Application of Electron-Beam Welding in Pellet Mold Preparation

This paper provides insight into the application of electron-beam welding in pellet mold preparation,highlighting the importance of the combination of electron-beam welding and pellet mold preparation in the fields of microstructure joining and micro-and nanostructure preparation.Precise material joining and microstructure fabrication can be achieved by the precise control of electron-beam welding and the shape adjustment of pellet molds.These applications hold significant potential in the modern industrial field,providing robust support for the development of new materials and the growth of the petrochemical industry.This paper asserts that in the future,the ongoing development of electron-beam welding and pelletizing template technology will unlock new possibilities in the field of petrochemicals,fostering progress in science and technology.

Effect of Na_2CO_3 on reduction and melting separation of ludwigite/coal composite pellet and property of boron-rich slag

The effects of Na_2CO_3 on the reduction and melting separation behavior of ludwigite/coal composite pellet, the desulfurization ratio and the property of the separated boron-rich slag were investigated at laboratory scale in the present work. Na_2CO_3 could improve the reduction rate of the composite pellet to some extent. The melting separation of the composite pellet became increasingly difficult with the increase of Na_2CO_3 in the pellet due to the sharply increasing of the melting point of slag. The sulfur content of the iron nugget gradually decreased from 0.27% to 0.084%（mass fraction） with the Na_2CO_3 content in the pellet increasing from 0 to 6%. The efficiency of extraction of boron（EEB） of the slow cooled boron-rich slag decreased from 86.46% to 59.52% synchronously. Na_2CO_3 had obviously negative effect on melting separation of the composite pellet and boron extraction of the boron-rich slag.

基于特征选择与PSO-XGBoost的球团矿抗压强度预测

链篦机-回转窑工艺是生产球团矿的一套工艺,由于链篦机-回转窑生产工艺的复杂性,成品球的质量与各个工序生产参数和工艺参数相互耦合,很难建立精确的机理模型。在实际生产过程中对成品球团矿质量的检测存在较大的滞后,不能及时反馈调整工艺生产参数。针对此问题,基于Spearman相关系数和Pearson相关系数对参数进行特征处理,并结合XGBoost算法、粒子群优化算法建立了球团矿抗压强度预测模型,用实际生产数据完成模型的训练。结果表明,该模型有较高的预测效果,命中率可达94%,满足现场实际生产需求,可实现对球团矿质量的快速精准预测,为现场生产及工艺参数的调整提供参考。

激活的富血小板血浆促进Pellet培养的脂肪间充质干细胞成软骨样分化

目的探讨激活的富血小板血浆(PRP)对Pellet培养的人脂肪来源间充质干细胞向软骨样细胞分化及相关信号通路的影响。方法添加不同比例(5%、10%和15%)的激活PRP,检测不同培养时间(1、3、5、7、9、11 d)脂肪干细胞的增殖能力。将采用Pellet培养的P3代的h ADSCs分为3组,对照组、激活PRP组和含TGF-β3的软骨诱导组,持续培养21 d后,阿利新蓝和苏木精-伊红染色进行软骨分化鉴定,real-time PCR测定Sox-9、Aggrecan和II型胶原的基因表达,DMMB法测定胞外基质中GAG含量,Western blot进一步检测对照组和激活PRP组中Sox-9、Gli-1和BMP-2蛋白的表达。结果 MTT实验结果显示,在10%激活PRP培养条件下,11 d的生长时间内hADSCs的增殖率最适宜。阿利新蓝和苏木精-伊红染色显示,激活PRP组和软骨诱导组中软骨表达呈阳性。Real-time PCR结果表明软骨诱导组其Sox-9、Aggrecan和II型胶原mRNA表达的能力高于激活PRP组(P<0.05)。GAG实验结果显示,软骨诱导组促GAG分泌的能力优于激活PRP组(P<0.05)。Western blot结果显示,相比对照组,激活PRP组中伴随Gli-1和BMP-2的蛋白表达升高,而Sox-9蛋白表达随之升高。结论激活PRP刺激hADSCs的最适增殖能力的浓度比例为10%。激活PRP和软骨诱导剂对脂肪干细胞成软骨分化中的诱导表达具有相似的能力,激活PRP对h ADSCs诱导成软骨作用与Hedgehog和BMP信号通路有关。

Mixed plastics waste valorization to high-added value products via thermally induced phase separation and spin-casting

Plastic waste is an underutilized resource that has the potential to be transformed into value-added materials.However,its chemical diversity leads to cost-intensive sorting techniques,limiting recycling and upcycling opportunities.Herein,we report an open-loop recycling method to produce graded feedstock from mixed polyolefins waste,which makes up 60%of total plastic waste.The method uses heat flow scanning to quantify the composition of plastic waste and resolves its compatibility through controlled dissolution.The resulting feedstock is then used to synthesize blended pellets,porous sorbents,and superhydrophobic coatings via thermally induced phase separation and spin-casting.The hybrid approach broadens the opportunities for reusing plastic waste,which is a step towards creating a more circular economy and better waste management practices.

Influence of flux additives on iron ore oxidized pellets

Six additives,i.e.,limestone,lime,magnesite,magnesia,dolomite and light-burned-dolomite,were added for investigating their influences on the pellet quality.For green balls,adding lime and light-burned-dolomite makes the wet drop strength decrease firstly,and then increase with further increase of additive dosage.Ca(OH)2 affects the bentonite properties at the beginning,but the binding property of Ca(OH)2 will be main when the dosage is higher.The other four additives decrease the drop strength for their disadvantageous physical properties.For preheated pellets,no mater what kind of additive is added,the compressive strength will be decreased because of unmineralized additives.For roasted pellets,calcium additives can form binding phase of calcium-ferrite,and suitable liquid phase will improve recrystallization of hematite,but excessive liquid will destroy the structure of pellets,so the compressive strength of pellet increases firstly and then drops.When adding magnesium additives,the strength will be decreased because of the oxidation of magnetite retarded by MgO.

An Innovative Process for Direct Reduction of Cold bound Pellets from Iron Concentrate with a Coal-based Rotary Kiln

Successfully developed an innovative process of direct reduction of cold bound pellets from iron ore concentrate with a coal based rotary kiln, in comparison with the traditional direct reduction of fired oxide pellets in coal based rotary kilns , possesses such advantages as: shorter flowsheet, lower capital investment, greater economic profit, good quality of direct reduced iron. The key technologies , such as the composite binder and corresponding feasible techniques were employed in practice. A mill utilizing this process and with an annual capacity of 50 thousand ton DRI has been put into operation.