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By V. P. Bystrov

Vanyukov process has been developed and investigated in Russia over the last 25 years. It has been established that various kind of material could be treated in Vanyukov process. The results of the pilot plant trials as well as industrial experience are presented in this paper.

Jan 1, 1993

By Wan Entong, Xie Junlin, Jiann YangHwang, Yang Chengwei, Chen Junfu, Zhang Jianjun, Cao Tongyou, He Feng, Peng Zhugang, Fang De

During the solidification process of peritectic steel (PS), the peritectic reaction often causes volume contraction which associated with surface longitudinal cracks, and using mould flux with low heat flux density help for alleviating surface longitudinal cracks. New peritectic steel mold flux with Co2O3 doping reduced the heat flux density, and the optimal content was found to be 2.0 wt %. Furthermore, basicity and Na2O addition were designed, and the minimum heat flux density required basicity of 1.4 and 10.0 wt %. Na2O content. As a result, the optimal peritectic composition was CaO(35.67wt% ), SiO2(25.48 wt %)，Al2O3(3.7 wt %)， MgO(2.53 wt %)，Na2O(10 wt %)，CaF2(14 wt %)，Co2O3(2 wt %).

Jan 1, 2015

By Wagner Aldeia, Duclerc Fernandes Parra, Danae Lopes Francisco, Ademar B. Lugão, Lucilene Betega de Paiva

The inorganic nanotube halloysite (HNT) is a promising type of natural occurring filler for polymers. Its characteristics, such as high aspect ratio (10–50), small size, and high strength (elasticmodulus—140GPa) suggest that HNT shave a potential use in high-performance polymer nanocomposites. Compared to other nanoclays and nanosilica the relatively low content of hydroxyl groups on their surfaces makes HNTs relatively hydrophobic, although, sometimes, this is not sufficient for guaranty a good interfacial adhesion in composite systems. Further hydrophobic treatment is required to improve HNTs compatibility with polymer matrixes, maximizing interfacial interactions. In the present study, different percentages of EPB (2,2-(1,2-ethene diyldi-4,1-phenylene) bisbenzoxazole) was used to perform anon-covalent functionalization of halloysite, based on electron transfer interactions. The functionalization is characterized by specific surface area (BET), thermogravimetric analysis (TG) and water/toluene extraction experiment.

Mar 1, 2018

By Mingming Zhang, Udaya Bhaskar Kodukula, Marcelo Andrade

The physical and chemical properties of sinter feed are important factors that determine the productivity and quality of sinter product. In this study the feasibility of treating sinter feed by high pressure grinding rolls (HPGR) is investigated for selective cracks generation exploiting weak zones along grain boundaries of poor quality iron ores without generating much fines. The pre-treated sinter feed was characterized for size distribution, surface area, contact angle, and SEM analyses. The characterization results indicated that surface area of the pre-treated sinter feed sample increased about 20%. Pot-grate sintering tests results also indicated improvement on cold permeability, sintering yield and productivity, sinter Tumbler index, and low temperature degradation index (LTD) after HPGR pre-treatment.

Mar 1, 2018

By Neng-Wen Yu, Miao Wang, Ji-He Wei

The mass transfer characteristic between powder particles and liquid steel in the RH-PTB (Powder Top Blowing) refining has been investigated in a water model of 1/5 scale for a 90t RH degasser. The sodium chloride powder with analytical purity has been used as the flux for blowing. The mass transfer coefficient of the liquid side has been determined under the conditions of RH-PTB process. The influences of the main technological and structural parameters on the mass transfer rate have been examined. The results indicated that under the conditions of the present work, the mass transfer coefficient on the liquid side increases with raising the lifting gas blowing rate, inner diameter of the up-snorkel, circulation rate of the liquid and particle size of powder flux. And it decreases with an increase in the inner diameter of the down-snorkel. It is in the range of (l.36-7.30) x 10·4 mis, the appropriate dimensionless relationships have been obtained as follows:

Jan 1, 2000

By James C. Barker

Near Rainbow Mountain in the east-central Alaska Range an ultramafic complex forms a sill-like intrusion composed of dismembered bodies exposed along the south side of the Denali Fault and Broxson Gulch Thrust. The complex comprises dunite and peridotite with lesser gabbro, which together exhibit poorly defined, steeply-dipping compositional layering. The complex hosts four types of copper-nickel occurrences which have characteristic platinum-group elements (PGE), gold, and cobalt distributions. Three of the occurrence-types are considered to have formed as a result of primary mineral segregations which developed during intrusion of the complex. The fourth type of copper-nickel occurrence formed as a result of post-magmatic hydrothermal fluids at intrusive contacts. Scanning electron microscope examination indicates that PGE occur as micron-size telluride and arsenide minerals.

Jan 1, 1987

By Peter K. Liaw, Niann-i Yu, Wei Zhao

"For a plain-weave Nicalon ™ fiber fabric-reinforced silicon carbide (SiC) ceramic composite, little attentation has been paid to the effect of fabric stacking sequence on its mechanical behavior. In this paper, fiber-fabric stacking sequence effects on the elastic stress distributions, ceramic matrix-cracking stress, effective elastic moduli, and flexural strengths of laminated flexural test bars are quantified. A quantification model is established based on the combination of classical laminated plate theories and a fiber undulation model developed by Chou et al. A FORTRAN program is compiled to implement the modeling, which can be run in a SUN work station. The mechanical performance of a continuous fiber-reinforced ceramic-matrix composite (CFCC) with a [0/30/60] lay-up was analyzed and predicted. The variation in the fiber-fabric stacking sequence can vary the elastic stress distributions along the thickness direction of specimens, magnitude of ceramic matrix-cracking stress, effective elastic moduli of the laminate, and crack initiation sites as well as fracture modes. Moreover, all these factors contribute to scatter in flexural strengths of the CFCC.I. IntroductionWith enhanced fracture toughness and the ability of non-catastrophic (graceful) failure behavior, CFCCs are currently under evaluation for high-temperature structural applications in heat exchangers, combustors, hot-gas filters, boilers components, first walls and high-heat flux surfaces gas turbines, space vehicles and nuclear reactors.[1-8] Extensive applications of CFCCs by industry are still hampered by an insufficient understanding of the mechanical behavior, and sometimes, the lack of a well-developed and widely accepted design philosophy, in addition to the high-production costs."

Jan 1, 1998

Based on experimental and computer simulation results from our group, we report a systematic, atomic level analysis of carbon dissolution from carbonaceous materials in molten iron. Experimental results on graphite / Fe-C-S system were obtained using carbon dissolution studies, XRD and FESEM investigations and were supplemented with Monte Carlo simulations. Three basic mechanisms, namely carbon atom dissociation rate, interfacial phenomena and mass transfer in the melt were found to be responsible for the overall dissolution process. While mass transfer in the melt is governed by the concentration gradients, melt composition and temperature; impurities present in ash play a significant role in the interfacial phenomena. For less ordered forms of carbonaceous materials, carbon atom dissociation rate depends strongly on the degree of long-range order and is an important rate controlling mechanism in the overall dissolution process. A systematic comparison of dissolution rates for a variety of coal-chars, natural and synthetic graphites has been carried out in an attempt to identify rate-controlling mechanisms. The structure of the carbonaceous material appears to be an important underlying factor in the carbon dissolution process.

Jan 1, 2003

By N. J. Themelis

In the last two decades, the Outokumpu flash smelting process has become the dominant new technology for copper smelting and has? also been applied to the smelting of other metal sulfides. The application of oxygen enrichment and improvements in concentrate burner and furnace design have resulted in ever increasing smelting rates per unit volume of the reaction shaft. This paper examines the. rate phenomena taking place in the reaction shaft of the Outokumpu furnace and compares information obtained from a mathematical model of heat and mass transfer rates to results obtained in pi1ot tests conducted at Pori, Finland, and to actual performance of a number of flash smelters around the world. 2?

Jan 1, 1985

By Nickolas J. Themelis

Nearly thirty two million tons of municipal solid wastes (MSW) are combusted annually in over one hundred U.S. Waste-to-Energy (WTE) power plants, thus reducing the use of fuel oil by about 1.6 billion gallons of fuel oil. One of the advanced WTE processes is the 0.9-million ton/y SEMASS facility at Rochester. Mass. Most of the combustion in the three giant combustion chambers occurs while the injected shredded wastes are in suspension, i.e .? in flash combustion mode. The velocity. temperature, and concentration profiles in the SEMASS combustion chamber were simulated by representing the combustible fraction of MSW by the simplified formula C6HIO04 and using the CFD program Fluent to solve the turbulent energy and mass transport equations. After validation against plant data. this model will be used to examine options for increasing the productivity of WTE combustion chambers, such as optimum distribution of primary and secondary air and oxygen enrichment.

Jan 1, 2003

By Xia Lou, Hossein Dashti

Gas hydrates technology has been considered as an alternative method for carbon dioxide (CO2) separation. A wide range of studies have been reported in the past decade on the improvement of the separation efficiency by using chemical additives. While most of these studies have shown improved kinetics, thermodynamics and/or separation efficiency at the laboratory scale, there has been no quantitative analysis of the energy consumption for viable industrial applications. Comparison of the effectiveness of the chemical additives from separate studies or groups also is impossible. The present work is focused on the modelling of the hydrate-based CO2 separation process and provides a quantitative approach that is new in its analysis of the effectiveness of chemical additives in relation to the energy required and the kinetic parameters involved in the process.

Mar 1, 2018

Numerical simulation of the fluid flow and heat transfer has been carried out for a waste-heat boiler in an Outokumpu type copper flash smelter. In this boiler, SO2-containing off-gas flows into the waste-heat boiler radiation section at about 1350°C. A fraction of cooler off-gas from the electrostatic precipitator at about 200°C was recirculated into the radiation section, and a small amount of ambient air was leaked into the boiler from the bottom. The computational results show that the flow is strongly recirculating and distinctly three dimensional in most of the boiler, particularly in the radiation section. The hot off-gas cooled down rapidly after entering the radiation section due to radiation. The predicted flow pattern and temperature distribution were in a good agreement with laboratory models and industrial measurements.

Jan 1, 1995

By Ramiro Escudero G.

Since the introduction of column flotation almost forty years ago the column technology has grown into several non-mineral applications such as among others the effluent treatment, soils recovery and de-inking of recycled paper. Recent studies have demonstrated that particular characteristics of the dispersion (bubble size, gas holdup, bubble surface area flux) are needed for a given flotation column duty. In this work, two kind of spargers were tested (i.e., internal and external) using a 4 inch column lab in a two phase system. Results show that the external sparger provides a dispersion with characteristics that include those produced by the two internal spargers.

Jan 1, 2003

By Chen-Ming Kuo, Esher Hsu

"The importers and manufacturers who import or produce products with packaging containers are charged a recycling fee in Taiwan. The amount of waste packaging containers used for calculating the recycling charge is based upon the amount declared by importers and manufacturers which might be underestimated. This study aims to estimate the amount of waste packaging containers generated by households in Taiwan and also explores its distribution. The sampling survey and ratio estimation are conducted for estimating the recycled amount; while the refuse sampling method for municipal solid waste composition is employed to estimate the un-recycled waste packaging containers. The estimated total amount of waste packaging containers in 2011 generated by households in Taiwan is 696,511 m.t., of which, 79.49% of the waste packaging containers were recycled and 20.51 % were landfilled or incinerated. This study shows that the amount of waste packaging containers declared by importers and producers is underestimated around 20%.IntroductionWaste packaging containers including iron cans, aluminum cans, glass bottles, plastic containers, paper containers, aluminum foiled paper packs are officially announced to be recycled in Taiwan. In order to create the economic incentive for raising recycling performance, associated manufacturers and importers are charged a recycling fee to subsidize recyclers. The amount of packaging containers declared by importers and manufacturers is used for calculating the recycling charge and recycling rate. The importers and manufacturers might underreport their producing (importing) amount to pay less recycling fees. Therefore, the estimated waste packaging containers based upon the amount declared by importers and manufacturers is usually underestimated. Related previous studies about waste packaging containers recycling in Taiwan are done by Hsu and co-workers [1-4]. Hsu and Kuo [1] estimated total production values of recycling and evaluated the performance of recycling performance based upon the estimated production values. Hsu and Liu [5] provided a cost analysis of recycling for waste packaging containers in Taiwan. Bor, Chien, and Hsu [2] presented a market-incentive recycling system for waste packaging containers in Taiwan. Hsu and Kuo [4] provided an amending mechanism for product charge and recycling subsidy in response to the social economic changes for waste packaging containers recycling. Lee and Hsu [ 6, 7] explored the distribution, fee rates, and collection rate of waste containers. This study aims to estimate the amount of waste packaging containers generated by households in Taiwan and also explore its distribution."

Jan 1, 2014

By Andrew B. Suttie

The lead-acid battery recycling industry was seriously affected during the 1980s by increasing environmental protection costs and poor lead prices. The process is now being repeated in the 1990s causing further difficulties, for recyclers. In Europe, many lead-acid battery recycling plants use rotary furnaces. The Darley Dale smelter, redeveloped between 1984-87, uses only rotary furnaces. A review of options for this plant has been completed and 'concluded in favour of further investment to exploit more fully the benefits of rotary furnace technology.

Jan 1, 1995

By Dan Wang, Qian Xu, Guangshi Li, Xionggang Lu, Xingli Zou, Zhongfu Zhou, Hongwei Cheng, Changyuan Lu

The preoxidation of the ore has a profound significance to the concentration, separation and purification of nickel and copper from the lean complex ore. In this paper, the natural Ni-Cu sulfide mineral samples under the elevated temperature condition in air were investigated, as well as under isothermal condition at 600 oC in air. The mineralogical characterization was studied using XRF, ICP and the Rietveld method. The oxidation behavior and the element migration of the Ni-Cu sulfide ore were studied by XRD, SEM-EDS and TG. The XRD Rietveld method was successfully developed in the phase identification and quantification of this complex ore powder sample. The oxidative intermediates (Cu/Ni-ferrite) were detected by XRD, and the process of the element migration was obviously revealed by the line scans using SEM-EDS. It is the preoxidation of this mineral that provides guidance for the extraction of valuable metals from low-grade Ni-Cu sulfide ores in the future.

Jan 1, 2015

By Aichun Zhao, Rui Wang, Yihong Li, Yanping Bao, Yafeng Ji, Jiansheng Liu, Xiao Hu, Qingxue Huang

The slag entrapment under different conditions of 80t blowing argon ladle furnace was investigated by physical simulation. The water was used to simulate liquid steel and liquid paraffin was for slag. The processing of slag entrapment under different blowing structures was analyzed and the critical velocity and critical droplets diameter of describing it was obtained. Based on the experiments, the relationship between the interface flow velocity and the critical blowing rate CBR was deduced. In the real process, it is suggested that the bottom blowing rate is from 40 L/min to 180L/min when the interface tension is 0.12~1.2 N/m during the soft argon blowing.

Jan 1, 2016

By Marcos Aurélio S. Costa, Nilton F. Nagem, Andreia B. Henriques, Herman S. Mansur, Alexandra A. P. Mansur, Antonio E. C. Peres, Valeria G. Silva

The superfine material generated in the Bayer process was used in one innovatively way as a precursor to geopolymerization techniques because of the presence of Gibbsite. Gibbsite can play a role in system adjustment because of the SiO2/Al2O3 ratio. Furthermore in the geopolymeric system it was studied the influenceof the additives such as kaolin, metakaolin and sodium trisilicate in an alkaline media. Others conditions to form the geopolymer were also evaluated such as solid/liquid ratio, SiO2/Al2O3 ratio and total alkaline. The raw materials and geopolymeric products were characterized by several techniques e.g. XRD, DSC, FTIR and SEM. Through the FTIR technique it was observed an increase in intensity and bandwidth in the region centered at 1010 cm-1, which is related to the asymmetric vibration Si(Al)-O, this is an indicating of the possible geopolymer formation This broadening of the band promotes a relative disappearance (overlapping) peaks at 965 and 935 cm-1 associated with raw material (ESPDust).

Jan 1, 2015

By Petr Dvorak, Jana Selucka, Hong Vu, Petra Starkova, Tomas Frydl

Waste, generated during high pressure leaching of lateritic nickel ores, contains about 50% of iron in form of magnetite but high chromium content ( *3%) does not allow its extensive utilization as the raw material for pig iron production in blast furnace. The chromium removal from the waste was carried out by two methods: (1) oxidative alkali roasting with NaOH and/or Na2CO3, followed by water leaching and (2) oxidative leaching in KOH sub-molten salts solutions. The results show that about 90.1% of Cr was removed when the waste was roasted at 900 °C for 3 h with 33.1 wt% of NaOH. The removal of 88.2% of Cr was achieved if the waste was roasted at 900 °C for 3 h with 40 wt% of Na2CO3. The sodium content in the water-leached residues was reduced from 5% to about 0.5% by reaction with CaO in aqueous solutions at 80 °C for 2 h. About 70% of Cr was removed if the waste was leached at 190 °C in 73 wt% KOH for 8 h.

Mar 1, 2017

By Lixin Qian, Tiejun Chun, Yifan Wang, Huan Wang, Hongming Long, Zhengwei Yu

To solve the problem that the sintered liquid phase fluidity characteristic of low silica (w(SiO2) < 3 wt%) and high silica (w(SiO2) > 7 wt%)) iron ores were different from actual sintering production with using the common method based on w(CaO)/w(SiO2), a new improved method based on n(Fe2O3)/n(CaO) was proposed. The differences between two methods for iron ore fluidity detection were studied. The results show that when the common method is used to detect the liquid phase fluidity, as the content of SiO2 increased from 2.12 to 11.68 wt%, the amount of CaO addition augmented from 7.88 to 32.65 wt% and the corresponding fluidity index changed from 0 to 5.68. The fluidity index has a linearly positive correlation with the content of SiO2. The improved method could significantly reduce the effect of the change of CaO addition on the fluidity characteristic of iron ore which caused by the difference of SiO2.

Mar 1, 2018