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By Chen Tian, Tingfeng Wu, Qinghai Pang, Junhong Zhang, Zhijun He

Microwave technology as new aided tool has been applied on waste water treatment and metallurgical fields. This paper explores the affected factors such as microwave power, microwave irradiation time, polyaluminium chloride (PAC) amount and addition of phosphoric acid on treatment of Blast Furnace gas washing water by utilization of coagulation associated with microwave. Through the orthogonal experiment, the optimum experimental parameters were obtained in the course of treatment of 300 ml Blast Furnace gas washing wastewater: 396 W microwave power, 2 min of microwave irradiation time, 0.12 ml Added PAC and 0.8 ml added phosphoric acid. It indicates the affected factors in descending order on removal of SS in BF gas’s washing water: Added PAC level, added phosphoric acid level, time of microwave irradiation, and microwave power while those parameters that can affect suspended solids(SS)’s hardness reduction in descending order are added phosphoric acid level, added PAC level, time of microwave irradiation, and microwave power. Also, it demonstrates those parameters that can affect washing water’s turbidity in descending order: Added PAC level, time of microwave irradiation, added phosphoric acid level, and microwave power. The results showed that PAC coagulation associated with microwave on treatment of Blast Furnace gas washing wastewater has several benefits: short treatment time, strong sedimentation velocity and other excellent characteristics, it can effectively remove suspended solids in wastewater, the SS hardness and turbidity can be reduced.

Mar 1, 2017

By Pan Gu, Zhen Zhang, Wen-Feng Tan, Jiang Diao, Bing Xie, Wang Zhou

In order to recover the chromium resource in chromium-containing vanadium extraction residue, a promising method is to prepare ferrochromium with the residue. The synthetic residue has been reduced under 1300, 1350 and 1400 °C at the reduction time of 1, 2 and 3 h respectively. The reduced samples have been smelted and separated by an induction furnace. The contents of chromium and iron in metallic phase have been determined by an inductively-coupled plasma spectrometer. The results indicate that chromium iron carbide (Cr, Fe)3C7 is the intermediate phase and titanium oxides have been reduced during the reduction process. While the sample has been reduced under 1400 °C for 3 h, metallic phase becomes the dominate phase and reduction reactions almost complete. Moreover, the chromium content in the metal phase reaches 10.19%.

Mar 1, 2017

By Mohammed A. Tayeb, Narottam Behera, Raja Mathu

With the struggling steel market nowadays, steel producers are under intense pressure to reduce their operational cost. Therefore optimization in the melt shops becomes not only preferable, but mandatory. A continuous dynamic process model for scrap-DRI EAF process was developed. The model was then used to propose a new carbon profile, implemented successfully to decrease (%FeO) in the slag and improve the yield. While this work is continued at HADEED, this article reviews the basics of the model and presents a summary of the preliminary plant findings.

Mar 1, 2017

By Wen-long Zhan, Zhe Ning, Jun-hong Zhang, Ji-hui Liu, Zhi-jun He, Qing-hai Pang

The influence of microwave irradiation and ultrasonic vibration on granularity of 0.074 mm pulverized coal was investigated in this research. It is indicated in the results that the granularity of coal decreased after microwave treatment, which led to the increased in specific area of pulverized coal in combustion reaction and consequently optimized the kinetic condition of combustion reaction. Higher ultrasonic power may lead to better performance of PC in combustion. The optimum condition for ultrasonic treatment is 10 min under 350 W microwave power.

Mar 1, 2017

By Jian-guang Yang, Lei Jie, Si-yao Peng, Jian-ying Yang

A new membrane electrolysis process for bismuth recovery from bismuthinite concentrate was introduced. Under the conditions of temperature 70 degrees C, acidity 3 mol/L, solid liquid ratio 1:4 and 1.1 times stoichiometry sodium chlorate dosage for 1.5 h oxidation leaching, more than 98.5% bismuth can be leached from bismuthinite concentrate. The resultant leach solution was subjected to membrane electrolysis. Under the conditions of NaCl concentration 300 g/L and pH 7 in anolyte, bismuth ions concentration 80 g/L and HCl concentration 3 mol/L in catholyte, heteropole distance 6 cm, temperature 40 degrees C and current density 200 A/m2, a flat deposited bismuth plate can be obtained after 24 h electrolysis, and the bismuth purity was more than 99%. The current efficiency of cathode was 97.88%. Chemical component analysis results showed that the average convert efficiency of the sodium chlorate was 52.77% and the average oxidizing efficiency of chloride ion was 69.78%, and the resultant anolyte generated in anode compartment could be fully reused as oxidant for leaching bismuthinite concentrate again.

Mar 1, 2017

By Jian Pan, Deqing Zhu, Benjing Shi, Yuxiao Xue

COREX smelting reduction process which is freed of metallurgical coke provides a sustainable developing way for ironmaking industry. However, the shortage and high cost of pellets limit its development in China. Meanwhile, iron ore sinter has a great output in China. This work studied the reduction behaviors of sinter made from magnetite concentrates during the reducing process of COREX shaft furnace and compared the RI and RDI of sinter with BF process. The results showed that the reduction degree of sinter increased obviously during the temperature zone from 600 to 850 °C, while the reduction degradation presented rapidly aggravate in the temperature zone from 425 to 550 °C in COREX shaft furnace, and the increase of metallic iron content leads to the degradation of sinter got decreased slightly during the stage of temperature above 650 °C. Sinter got higher RI than BFprocess but also got higher RDI in low reduction temperature of 550 °C, which means sinter would have heavier disintegration in COREX shaft furnace.

Mar 1, 2017

By İbrahim Göksel Hizli, Selim Ertürk, Ayşegül Bilen, Raşit Sezer, Cüneyt Arslan

Turkish celestite ore was roasted in a lab scale rotary kiln furnace with metallurgical coke. Coke and celestite were mixed; the product contained 32% coke which is more than the stoichiometric requirement.100 g of the mixed product was fed to a rotary furnace at 35 g/min. Temperature (1000 and 1100 °C), rotation speed (2.5, 5 and 10 rpm) and the slope of the furnace (2,3 and 5°) were among the investigated parameters. Phase and chemical analyses were carried out by XRD and XRF techniques, respectively. The maximum solubility of the roasted product in water was 48% under the roasting conditions of 1100 °C, 2.5 rpm and 2° slope.

Mar 1, 2017

By Ademar B. Lugão, Sandra R. Scagliusi, Elizabeth C. L. Cardoso

When butyl rubbers are subjected to high energy radiation, they form easy free radicals that initiate various chemical reactions. These reactions alter the molecular distribution of irradiated rubbers by crosslinking or scission affect their physical and mechanical properties. This work aims to the analysis of effect induced by γ-exposure on the crosslinking density in butyl rubbers by swelling measurements accomplished before and after irradiation at 25, 50, 100 and 200 kGy, with further evaluation of crosslinking density accomplished by Flory-Rehner equation; this is a proper procedure for the qualification of radiation resistance. It can be noticed that changes in material structure was due to build-up of new three-dimensional network in studied rubbers. Changes in crosslinking density of butyl rubber compounds emphasize that degradation mechanism is strongly influenced by gamma-radiation doses higher than 50 kGy, since chain scission process predominates over crosslinking reaction.

Mar 1, 2017

By S. Chama, K. Nyirenda, J. Machona, P. W. Chishimba, S. Parirenyatwa, G. Kaluba, Y. R. S. Hara, D. M. Musowoya

Our study focuses on upgrading of copper and cobalt from the Democratic Republic of Congo tailings, containing 2 wt% Cu and 0.5 wt% Co. Cobalt is in the complex iron silicate matrix such that its recovery by direct leaching is not possible. Two concentrating methods were employed in order to obtain copper and cobalt concentrates. Copper was concentrated via flotation and, at the optimal conditions its grade in the concentrate was 31.9 wt%. Cobalt was concentrated to 8.6 wt% b ycarbothermically reducing the flotation tailings with coal in a temperature range of 800–1050 °C and followed by magnetic separation. The reaction products were analysed by atomic absorption spectrometer (AAS) and scanning electron microscopy (SEM) techniques. The best carbothermic reduction temperature was found to be 950 °C due to maximum metallisation and less sintering between gangue and metallic/alloy phases.

Mar 1, 2017

By Yuanbo Zhang, Zijian Su, Bingbing Liu, Guanghui Li, Tao Jiang

With the depletion of rich manganese ores, high-Fe content manganese ores are becoming the mainstream resources for manganese extraction. Reduction roasting-magnetic separation process is reported as a relatively effective route to realize the separation of manganese and iron. This study investigated the phase transformation of MnO2 and Fe2O3 briquettes (molar ratio 1:1) roasted under various temperatures and CO–CO2 atmospheres. Results showed that when the CO content was in the range of 0–10 vol%, MnxFe3−xO4 (x = 0−1) phase was formed and its content increased with the rising of temperature. The formation of ferromagnetic MnxFe3−xO4 with strong magnetism resulted in an inferior separation of manganese and iron by magnetization roasting-magnetic separation process. With the increase of CO content to over 25 vol%, the MnxFe3−xO4 content decreased while the content of feebly magnetic substance (MnO)y(FeO)1−y(y = 0−1) increased. Further increasing the CO content to over 80 vol%, (MnO)y(FeO)1−y was reduced to MnO and metallic iron.

Mar 1, 2017

By Joseph Hamuyuni, Fiseha Tesfaye, Daniel Lindberg

E-waste management through traditional methods such as disposing in landfills, burning in incinerators or exporting abroad for disposal are no longer options due to the strict environmental regulations. Fortunately, the presence of valuable metals in the e-waste and increasing demand for the metals as well as complexities of the currently available primary raw materials make recycling an attractive and viable option both environmentally and economically. Moreover, it is efficient in terms of resource management by closing the loop of metals. Consequently, urban mining such as the recovery of precious metals from e-waste streams through sustainable recycling processes have emerged. The sustainable recycling practices address the scarcity of primary resources and reduce consumption of energy for metals production while managing environmental issues related to hazardous materials from the e-waste streams. In this paper, valuable metals recoveries from e-waste streams through pyrometallurgical and hydrometallurgical processes are critically reviewed. And, innovative ideas for different steps of the thermochemical processes in the valuable metals and energy recovery from the e-waste streams are discussed.

Mar 1, 2017

By Wei-Tong Du, Yu Wang, Peng-cheng Li, Shu-Chao Wang

CaCO3 thermal decomposition produces CO2 and CaO, and CO2 can be used as a weak oxidant in vanadium extraction. CaO will also affect the vanadium extraction process. This experiment, taking self-blowing and temperature acquisition experiment system, through adding different quality CaCO3, studies the molten iron in the oxidation behavior of C, V and P and its impact, and analysis of CaCO3 decomposition of the heating effect of the molten pool. The result indicates that adding CaCO3 in the vanadium extraction process had no obvious effect on the oxidation of carbon, but partly increased vanadium oxidation which reached more than 90%. Increased CaCO3 additions also increased cooling the molten pool, with a maximum decrease in temperature of 20 K. In addition, the oxidation of P also increased, reaching 40%. The research has proved that CaCO3 can serve to oxidize V and P is effective in vanadium extraction.

Mar 1, 2017

By Weizhi Zeng, Michael L. Free, Shijie Wang

Copper electrorefining is an old technique that is generally performed in electrolytic cells with a bottom inlet and top outlet that are convenient for electrolyte flow control. Nevertheless, this configuration cannot effectively direct electrolyte flow to the regions between electrodes, which results in weak convection and inadequate delivery of chemical species and additives. In this article, we discuss the innovations in electrore fining cell design to improve electrolyte flow for better cathode quality and simulation of fluid flow field and particle movements based on finite element modeling method. The resulting fluid flows in cells can transport suspended slime particles to the cathode, where they can be incorporated as impurities. The concentration of suspended slime particles is inversely related to slime adhesion, which is strongly influenced by slime particle sintering, and sintering is dependent on temperature and slime particle composition. Thus, the combination of innovative fluid flow and slime particle sintering can play important roles in improving cathode quality.

Mar 1, 2017

By Coida D. S. Renata, Gerald Okwuchi Onyedika, Moura E. B. Esperidiana, Graca Valenzuela-Diaz, Martin Chidozie Ogwuegbu, Francisco R. Valenzuela-Diaz, Amauche Cyprian Achusim-Udenko

This work aims to incorporate Mgbee clay, vegetal fibre (Costus afer) in recycled low density polyethylene (rLDPE). The incorporation of clay and vegetal fibre in rLDPE was carried out using a twin screw extruder machine and the nanocomposites were obtained. The nano composites were characterized by the Young’s modules test, tensile tests, bending test, XRD, SEM, DSC, and TG and other properties evaluated. The results of morphological and thermal properties showed a good interaction between the clay, and rLDPE as compared to neat rLDPE.

Mar 1, 2017

By Ruixuan Zhang, Yan Li, Shusen Cheng

The measurement of raceway temperature in the blast furnace is a critical issue, which is very significant for judgment of, prediction and diagnosis of the racewa yburning state. This paper deals with mathematical models by Monte Carlo method to approximately simulate the radiation heat transfer in the race-way and establish matrix equations using CCD cameras, which are solved to obtain the three-dimensional temperature field. Due to the existence of fluctuation error, CCD camera measurement error and others,this is analyzed and random error is added in the measurement data to demonstrate the effectiveness and stability of the reconstructed temperature field. The results show that the reconstructed three-dimensional temperature field of the raceway is very close to the exact temperature.

Mar 1, 2017

By Qingguo Xue, Jingsong Wang, Yingli Liu, Guang Wang

In the dropping zone of blast furnace (BF), primary slag absorbing ash of pulverized coal and coke become to be intermediate slag. Due to viscosity and surface tension of slag and the pore between cokes, some slag remained in coke layer and affected the permeability of blast furnace. The flow behavior of slag with different basicity (0.55–1.10) and Al/Si (0.35–0.50) were studied. Meanwhile, the viscosity and surface tension of slag were calculated. The results showed that, with the increasing basicity of slag, surface tension increased and viscosity decreased. With the Al/Si increase, surface tension and viscosity increased. The smallest pore that all slag can pass through was 4.5 mm. However, the height between slag droplets and the bottom of crucible indicated that the ability of slag to pass through pore were weakened with the increasing basicity and Al/Si. Thus, slag which absorbed ash from fuel become difficult to pass through coke layer.

Mar 1, 2017

By Daniel K. Lindberg, Fiseha Tesfaye

To reduce the use of fossil fuels and increase self-sufficiency in energy, nowadays, there is an increasing interest to produce heat, power and transportation fuels from renewable resources. Solid biomass is one of the most important renewable energy sources for meeting this target. However, fouling, slagging, and corrosion threaten long-term operation availability and costs of biomass power plants. Slags accumulated on the surfaces of superheaters, which decrease thermal efficiency, often constitute a considerable percentage of complex inorganic phases. However, thermodynamic properties of the complex inorganic phases and their combined effect, which will help to deal with the slag related problems during high-temperature biomass combustion processes, are not well known. In the present paper, thermodynamic properties of K-, Ca-, and Na-based inorganic phases and their mixtures under different gas conditions are both critically reviewed and experimentally studied. The obtained results are presented and discussed.

Mar 1, 2017

By Jorge Alberto Soares Tenório, Denise Crocce Romano Espinosa, Solange Kazue Utimura, Amilton Barbosa Botelho, Carlos Gonzalo Alvarez Rosario

In this study, the recycling of waste materials is interesting in the environmental aspect to reduce the amount of waste in land fill and attenuate the pollution of groundwater, air and soil due to the liberation of dangerous elements. Recycling materials is an important issue once it represents a potential source of valuable metals. Waste printed wired boards (PWBs) as a principal part of Waste Electrical and Electronic Equipment (WEEE) and it is a fast growing stream with complex composition. The composite materials from PWBs are ceramic, polymers and metals. Biohydrometallurgical route may offer possibilities to recycle PWBs from discarded computers with the order to recover copper. The extraction of copper from PWBs by bioleaching processeswas studied using a mixed culture of acidophilic bacteria fromacid mine drainage (AMD) and the bacteria Acidithiobacillus ferrooxidans (A. ferrooxidans). The bioleaching experiments were performed in shaker flasks at temperature 30 °C and 170 rpmwith 10% (v/v) inoculum and pulp density of 35 g/L. Themetals concentration was determined by energy dispersiveX-ray Fluorescence (XRF). The results showed that the maximum copper recovery from PWBs using A. ferrooxidans was approximately 89% and with a mixed culture of bacteria from AMD the copper recovery was 92%.

Mar 1, 2017

By Hong Li, Chenxiao Li, Wenwen Mao, Hua Lu

Directly charging limestone into slag in BOF is a newly emerging technique which broke through the traditional BOF slagging principle. It is necessary to study the decomposition behavior of limestone in converter slag during BOF steelmaking. FeOx, SiO2, MnOx and pre-melting slags were mixed with limestone according to different quality proportion to simulate the environment of limestone in converter slag. TG-DTA results indicated that slag with individual component, including FeOx, SiO2 and MnOx, all had obvious effects on reducing the decomposition temperature of limestone. Pre-melting slags with multiple components had further reducing effects than individual component. XRD results showed converter slag component would react with decomposition product of CaCO3 and generate solid solution or oxide, reducing the activity of CaO and the decomposition temperature of CaCO3.

Mar 1, 2017

By Bingguo Liu, PENG LIU, Haigang Dong, Jinhui Peng, Libo Zhang

Parameters of technique to decarburize from spent petrochemical catalysts via microwave oxidation roasting were investigated. Decarburization process was performed on a microwave heating system. The results showed that the decarburization percentage of spent petrochemical catalysts was significantly affected by roasting temperature and sample thickness in the range studied. The decarburization percentage was 99.5% in microwave fields under the optimized conditions, roasting temperature 600 °C, roasting time 40 min and sample thickness 2 cm respectively. The residuum after microwave decarburization was characterized by field emission scanning electron microscopy (FE-SEM) which showed that the deposit carbon had been removed effectively.

Mar 1, 2017