scholarly journals Enhanced Leaching of Zinc from Zinc-Containing Metallurgical Residues via Microwave Calcium Activation Pretreatment

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1922
Author(s):  
Aiyuan Ma ◽  
Xuemei Zheng ◽  
Lei Gao ◽  
Kangqiang Li ◽  
Mamdouh Omran ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Mineral Inclusion ◽  
Calcium Activation ◽  
Activation Temperature ◽  
Selective Heating ◽  
Zinc Oxides ◽  
Mineral Phases ◽  
Pretreatment Conditions ◽  
Utilisation Efficiency ◽  
Leaching Reaction

Given the shortage of zinc resource, the low utilisation efficiency of secondary zinc resource, and the crucial problem that the synchronous dissolution of zinc from different mineral phases, an activation pretreatment method merged with calcium activation and microwave heating approach was proposed to enhance the zinc leaching from complex encapsulated zinc-containing metallurgical residues (ZMR). Results indicated that under the optimal pretreatment conditions, including microwave activation temperature of 400 °C, CaO addition of 25% and activation time of 20 min, the zinc leaching rate reached 91.67%, which was 3.9% higher than that by conventional roasting pretreatment. Meanwhile, microwave heating presents excellent treatment effects, manifested by the zinc leaching rates, all exceeding that of conventional roasting under the same conditions, while the process temperature is decreased by 200 °C. In addition, XRD and SEM-EDS analysis denoted that microwave calcification pretreatment can effectively promote the transformation of the refractory zinc minerals like Zn2SiO4 and ZnFe2O4 into the easily leachable zinc oxides. The distinctive selective heating characteristics of microwave heating strengthened the dissociation of mineral inclusion, and the generated cracks increased the interfacial reaction area and further enhancing the leaching reaction of zinc from ZMR.

Preparation of Eupatorium Adenophorum Based Porous Carbon with Microwave Heating using Response Surface Methodology

2014 ◽  
Vol 33 (5) ◽  
pp. 427-437
Author(s):  
Zhao-qiang Zheng ◽  
Hong-ying Xia ◽  
C. Srinivasakannan ◽  
Jin-hui Peng ◽  
Li-bo Zhang
Keyword(s):  
Activated Carbon ◽  
Microwave Heating ◽  
Process Parameters ◽  
Flow Rate ◽  
Porous Carbon ◽  
Steam Flow ◽  
Process Conditions ◽  
Eupatorium Adenophorum ◽  
Activation Temperature ◽  
Steam Flow Rate

AbstractEupatorium adenophorum was utilized as raw materials for the preparation of activated carbon via microwave assisted steam activation. Influences of the three vital process parameters – activation temperature, activation duration and steam flow rate – have been assessed on the adsorption capacity and yield of Eupatorium adenophorum activated carbon (EAAC). The process parameters were optimized utilizing the Design Expert software and were identified to be an activation duration of 45 min, an activation temperature of 950 °C and a steam flow rate of 0.7 ml/min, with the resultant iodine number and yield being 1,010 mg/g and 20.13% respectively. The validity of process model to optimize the process parameters was verified using the analysis of variance (ANOVA). The key parameters that characterize quality of the porous carbon such as the BET surface area, total pore volume and average pore diameter were estimated to be 1,142 m2/g, 0.84 ml/g and 3.3 nm respectively, for the sample corresponding to the optimized process conditions. Additionally the pore structure is characterized using Scanning Electron Microscope (SEM). The present work strongly supports utilization of Eupatorium adenophorum as a potential precursor through microwave heating.

Investigation on drying characteristics of high titanium slag using microwave heating

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Xuefeng Liao ◽  
Guo Chen ◽  
Qianqian Liu ◽  
Jin Chen ◽  
Jinhui Peng
Keyword(s):  
Moisture Content ◽  
Microwave Heating ◽  
Raw Materials ◽  
Adsorbed Water ◽  
Scientific Basis ◽  
Microwave Drying ◽  
Optimum Conditions ◽  
Drying Time ◽  
Titanium Slag ◽  
Selective Heating

AbstractIn the present study, the moisture of high titanium slag was chosen as the research object. Taking advantage of selective heating of microwave and the specific inductive capacity of water, the drying experiment of high titanium slag using microwave heating have been carried out. The results revealed that the presence of moisture in the form of high titanium slag was adsorbed water, and the wet sample possesses excellent wave-adsorbing performance; the bed depth preferred was no larger than 10 mm, with moisture content at around 3%. The microwave drying process was divided into two stages: the constant-stage and the deceleration-stage. The optimum conditions were identified to be microwave power of 700 W, sample mass of 200 g, bed depth of 10 mm and drying time of 50 s. The dehydration extent can reach 90% and moisture content remains at 0.3% under the optimum conditions. The demonstration of microwave drying techniques can be applied effectively and efficiently into the treatment processing of drying of the raw materials of metallurgy and chemical industry with the theoretical and scientific basis.

Microwave Energy Application for Materials' Processing and Environmental Technology

2014 ◽  
Vol 88 ◽  
pp. 21-30
Author(s):  
Noboru Yoshikawa
Keyword(s):  
Microwave Heating ◽  
Rapid Heating ◽  
Wave Interaction ◽  
Functional Materials ◽  
Industrial Wastes ◽  
Materials Processing ◽  
Internal Heating ◽  
Environmental Technology ◽  
Selective Heating ◽  
Environmental Technologies

Microwave heating was discovered more than 60 years ago. And nowadays, it became popular for the use as domestic ovens. Microwave has also been utilized for the industrial processes, such as drying and roasting. On the other hand, there have been many applications of microwave, being investigated for materials' processing and environmental technologies. They are attempted to take advantage of some specific characteristics in microwave heating, which differs from that of the conventional one. Rapid heating, internal heating, selective heating are the features to be taken into consideration. Moreover, so-called "non-thermal effect" is the additional feature in which researchers are particularly interested. In this article, it is intended to describe fundamental aspects in microwave heating and introduce some selected topics of research projects performed in our research group. They include researches on fabrication of some functional materials and on handling industrial wastes etc. In this article, it is also intended to interpret the phenomena observed in these applications from the fundamental view points of electromagnetic wave interaction with materials.

Leaching reaction and kinetics of zinc from indium-bearing zinc ferrite under microwave heating

2016 ◽  
Vol 57 (4) ◽  
pp. 301-307 ◽  
Author(s):  
Linye Zhang ◽  
Jiamei Mo ◽  
Xuanhai Li ◽  
Liuping Pan ◽  
Guangtao Wei
Keyword(s):  
Microwave Heating ◽  
Zinc Ferrite ◽  
Leaching Reaction ◽  
Kinetics Of

scholarly journals Enhanced ‘in situ’ catalysis via microwave selective heating: catalytic chain transfer polymerisation

RSC Advances ◽  
2014 ◽  
Vol 4 (31) ◽  
pp. 16172-16180 ◽  
Author(s):  
Kevin Adlington ◽  
Robert McSweeney ◽  
Georgios Dimitrakis ◽  
Samuel W. Kingman ◽  
John P. Robinson ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Chain Transfer ◽  
Active Catalyst ◽  
Selective Heating ◽  
Catalytic Chain Transfer ◽  
Synthesis Methodology ◽  
In Situ Catalysis

The formation of a CCTP active catalyst, which is promoted by adopting microwave heating and an “in situ” synthesis methodology.

Application of Microwave Heating in Aerospace Composite Processing

2014 ◽  
Vol 564 ◽  
pp. 310-314 ◽  
Author(s):  
Mohd Roshdi Hassan ◽  
Babak Ganjeh
Keyword(s):  
Microwave Heating ◽  
Interaction Mechanism ◽  
Attractive Alternative ◽  
Selective Heating ◽  
Concise Review ◽  
Energy Consuming ◽  
Industrial Level ◽  
Time And Energy ◽  
Materials Behavior ◽  
Heating Technology

Microwave heating technology regarded as a highly time and energy efficient heating technique which recently has acquired attention in aerospace composite manufacturing. Capability of offering exceptional advantages including volumetric and selective heating makes the microwave heating attractive alternative over the conventional highly time and energy consuming autoclave processing. However due to the complexity of interaction mechanism of electromagnetic field and composite materials, applying microwave ovens on an industrial level requires comprehensive experimental and numerical investigation to determine and predict the materials behavior during the curing process. On laboratory scales great potentials of microwave heating in terms of time and energy saving have been proven through several studies, a concise review over these studies is presented in this paper.

scholarly journals Local microwave heating of sand molds as a means to overcome design limitations in sand mold casting

2014 ◽  
Vol 12 ◽  
pp. 21-28 ◽  
Author(s):  
O. Wiedenmann ◽  
R. Ramakrishnan ◽  
P. Saal ◽  
E. Kılıç ◽  
U. Siart ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Microwave Heating ◽  
Casting Process ◽  
Sand Mold ◽  
Metal Casting ◽  
Temperature Dependent ◽  
Selective Heating ◽  
Thermodynamic Simulations ◽  
Mold Casting ◽  
Absorbing Materials

Abstract. Microwave induced selective heating outmatches conventional mold heating by convective heat transfer in means of energy efficiency and cycle time. Moreover, it provides the opportunity of a local manipulation of solidification and cooling processes within the sand casting mold. In this paper, we investigate the suitability of different highly absorbing materials to indirectly heat up the mostly microwave transparent sand mold. The temperature-dependent permittivity of the involved materials is determined by resonator experiments and subsequently used to simulate the electromagnetic field and the thermodynamic response of the sand mold prior to a metal casting process. Experimental results are presented and compared with the outcome of the coupled electromagnetic-thermodynamic simulations and the influence of local microwave heating on the solidification and cooling of the cast is studied.

Applications of microwave energy in gas production and tar removal during biomass gasification

2020 ◽  
Vol 4 (12) ◽  
pp. 5927-5946
Author(s):  
Feiqiang Guo ◽  
Yichen Dong ◽  
Beile Tian ◽  
Shilin Du ◽  
Shuang Liang ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Rapid Heating ◽  
Biomass Gasification ◽  
Microwave Energy ◽  
Gas Production ◽  
Biomass Pyrolysis ◽  
Selective Heating ◽  
Tar Removal

Microwave heating has the potential to promote gas production and tar removal during biomass pyrolysis or gasification based on its advantageous characteristics such as rapid heating and selective heating.

The Development of New Microwave Heating Applications at Ontario Hydro'S Research Division

1990 ◽  
Vol 189 ◽  
Author(s):  
Steven J. Oda ◽  
Ibrahim S. Balbaa ◽  
Bruce T. Barber
Keyword(s):  
Microwave Heating ◽  
Energy Savings ◽  
Ceramic Materials ◽  
Industrial Processes ◽  
Test Results ◽  
Selective Heating ◽  
New Device ◽  
Research Division ◽  
Significant Process ◽  
Time And Energy

ABSTRACTThis paper reviews the results from two relatively new microwave heating studies under development at Ontario Hydro's Research Division. The first study involves the development of a hybrid kiln to process advanced ceramics at high temperatures. Using a combination of resistive heating elements and microwave heating, this new device has been operated to show significant process advantages in terms of time and energy savings. A description of the hybrid kiln is presented together with the test results for calcining and sintering a variety of ceramic materials.The second investigation involves the use of microwave heating for the treatment of hazardous wastes. The selective heating ability of microwaves has been applied to reduce the environmental impact of wastes generated from industrial processes. An example is provided to illustrate the advantages and difficulties of applying this technology.

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