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By V. Reiter, K. Reinharter, C. Wenzl, D. Gregurek, A. Spanring

The refractory linings in lead furnaces are exposed to several stresses rather complex in their interaction. In the present study the magnesia-chromite brick out of a lead recycling furnace suffered from a high chemical attack by the process slag. The high CaO, BaO and sulfur bearing silicate slag, as well as a high NaO2 supply from soda resulted both in a deep-reaching infiltration of the brick microstructure and a severe corrosion of the brick components. Both the sintered magnesia and chromite were attacked chemically. The FactSage calculations showed the formation of high amounts of liquid phase in the infiltrated microstructure. Further phenomena affecting the refractory performance such as iron oxide attack, redox effects, and boron attack are also discussed in the paper. The obtained information and insights serve as a basis for improving refractory materials (i.e., choice of refractories for individual process and new developments) and consequently furnace operations.

Mar 1, 2017

By Shijie Wang

Lifetime achievements of Professor Reddy ’s teaching, research and scholarship in the field of chemical and materials science and engineering are briefly described. He has devoted his entire career in the introduction and application of process engineering principles to the quantitative description of materials processing reactions, and industrial operations. He has formulated quantitative methodologies based on first principles of thermodynamics, phase equilibria and kinetics to: design of slags and fluxes for production and purification of metals and alloys; development of Reddy-Blander model for a priori prediction of impurities capacities of melts; development of novel ionic liquid electrolytes for materials processing; development of new theories for alloys and molten salts; design materials for fuel cells and capacitors; use of thermodynamic approaches to predict physical properties of materials; industrial energy waste separation and remediation; and thermal energy storage. He is a scholar and mentor, and has made numerous scientific and service contributions to the society and metallurgical and materials engineering education.

Mar 1, 2017

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

This research investigated how gamma-radiation affected PP/HMSPP structural foams filled with biodegradable synthetic polyester PLA in terms of thermal properties, biodegradability and infrared spectrum. Polymers are used in various applications providing enormous quantities of wastes in environment and contributing with 20–30% of total volume of solid residues. Besides, shortage of plastics resins obtained from fossil base is addressing research and development toward alternative materials; environmental concerning in litter reduction is being directed to renewable polymers for manufacturing of polymeric foams. Biodegradable polymers, a new generation of polymers produced from various natural resources, environmentally safe and friendly, can contribute for pollution reduction. PLA (poly(lactic) acid)) was chosen to be blended with PP/HMSPP. Blends thereof were subjected to gamma radiation at 50, 100, 150, 200 and 500 kGydoses.Soilburialtestpointedtowardapartialbiodegradationofirradiated PLA-PP/HMSPP foams; other characterizations involved TG/DTG technique and FTIR assessments.

Mar 1, 2017

By Haibin Wang, Kaile Tang, Chenn Q. Zhou, Guangwu Tang, Zhixiang Cui, Ping Zhou, Armin K. Silaen, Hongjie Yan, Zhi Wang

The submerged lance smelting furnace (SLS) for copper smelting has been developed and used by Dongying Fangyuan Nonferrous Metals Co., Ltd. The technology has shown advantages such as high oxygen enrichment, good feed adaptability, short processing time, high SO2 concentration for acid plant, and auto-thermal operation. In this study, computational fluid dynamics (CFD) was used to investigate the gas/matte two-phase flow characteristics and the chemical reactions in the SLS during typical operational conditions. The Eulerian-Eulerian approach was employed to model the phase interactions. The chemical reactions were modeled by calculating the mass transfer coef ficients and using the eddy-dissipation model. The simulation was conducted using the commercial software ANSYS Fluent®. The developed CFD model is able to predict the flow, temperature, and species distributions inside the SLS under various operating conditions.

Mar 1, 2018

By Christoph Czettl, Christian Storf, Gregor Kücher, Stefan Luidold

The purpose of this investigation is to provide a basis for the semidirect recycling of hard metals. The present investigation focuses on revealing the fundamental chemical kinetic aspects during cemented carbide leaching in hydrochloric acid media. The kinetic relations of cobalt binder leaching from WC-Co cemented carbide are studied using a central composite face-centered design of experiments with temperature, acid concentration, and hydrogen peroxide as variables.

Mar 1, 2017

By M. A. Usman, E. I. Akpan, S. O. Adeosun

Preliminary studies on the extraction and characterisation of biodegradable lignin from palm oil fruitbunch (POFB) for carbon fibre production has been conducted. Centra lComposite Design was used to determine the optimum operating conditions for maximum yield and properties of the extracted lignin. Soda concentration (1–3 wt/vol%), temperature (50–90 °C) and reaction time (20–30 min) were analysed using Rcore software. Experimental results show that using reaction temperature of 90 °C, time of 30 min and 3 wt/vol% soda concentration yields 3.3 g of lignin from 30 g of the POFB. The path of steepest ascent from ridge analysis shows that with temperature of 130 °C, time of 40 min. and soda concentration of 3. wt/vol%, 8.7 g of lignin can be extracted from 30 g of POFB. Analysis of FTIR and SEM show that the lignin has the same structure in all cases with minimal impurities.

Mar 1, 2017

By Qingyun Huang, Wei Lv, Junyi Xiang, Xuewei Lv, Chenguang Bai

The roasting is the key step for the extraction of vanadium from vanadium slag by calcification roasting–acid leaching process. In this study, thermogravimetric analysis and kinetic study of vanadium slag in the presence of calcium oxide was investigated. The maximum oxidation degree was slightly increased by increasing temperature from 700 to 900 °C then almost unchanged further increasing temperature to 1000 °C. The reaction mechanism was analyzed through both Sharp method and ln-ln method. Results showed that the mechanism the reaction in the a range of 0.1–0.8 corresponded to the random nucleation and subsequent growth, as represented as (G( a)=[ −ln(1−a)] 1/3 = kt. The apparent activation energy was calculated to be 3.5 kJ/mol according to Arrhenius equation.

Mar 1, 2018

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