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A series of reduction experiments of iron ore pellets with hydrogen, carbon monoxide and their mixture were carried out in a laboratory scale shaft furnace. The sticking behavior accompanying reduction of iron ore pellets was investigated. And morphology of the sticking interface forming during reduction was analyzed by SEM equipped with EDS. In order to evaluate the effects of the temperature and gas composition on sticking properties, reduction of iron ore pellets were conducted at 800–1000 °C. The results show that the sticking strength of the pellets increases with temperature, however, decreases with hydrogen content in reducing gas. For an efficient shaft furnace operation in direct reduction (DR), relative prevention of sticking such as coating of pellets was also developed to solve sticking problem. The results show that CaO is a suitable material for the coating method.

A new iron-making process using carburized pre-reduced iron ore pellets and microwave heating is investigated. The pre-reduced pellets, with a porous structure, and fine particles are carburized homogeneously at 400–650 °C in a CO atmosphere. The carburized carbon not only acts reaction as a reduction agent, but also absorbs microwave in the reduction process. Hence, the carburized pre-reduced pellets can be rapidly reduced by microwave heating. There are three procedures involved in the process, namely, gas-based pre-reduction, low-temperature carburization and deep reduction by microwave heating. Carburized pre-reduced iron ore pellets show a rapid temperature rise that is twice as fast as the results for pre-reduced pellets in the laboratory. This not only improves the efficiency of the microwave heating, but also accelerates the reduction of iron oxides. The temperature of the pre-reduced pellets rises to 1050 °C in 45 min when the carburization rate is 2.02%, and the metallization rate and compressive strength reach 94.24% and 1725 N/pellet, respectively.

At present coal gas with high calorific value is used in ignition (CGI) of iron ore sintering, which brings about problems of high energy consumption and environmental pollution. In this paper, the ignition model using microwave heating (MHI) was developed. Took raw materials of a domestic sintering plant as sample, model calculations showed that the minimum ignition temperature was 638.54°C and the energy consumption was 42.03 MJ/m 2 for MHI process in ignition time of 1.5 min. According to the sintering experiments, with ignition at 660°C for 1.5 min the main indexes of sinter qualities and production in MHI were better than those of CGI (1 050°C) process. And the ignition energy consumption (IEC) in MHI was 43.77 MJ/m 2 , which was far less than 185.13 MJ/m 2 of CGI. Results also show other advantages of suffi

The quench sensitivity of 6082 aluminum alloy was investigated by time–temperature–property (TTP) curves. The sensitive temperature of quenching ranges from 250 °C to 440 °C in 6082 Al-alloy, and the nose temperature is about 360 °C. During isothermal treatment process, the Mg 2 Si particles precipitate from the supersaturated solid solution, and the precipitation rate is the highest at the nose temperature. A number of rod-shaped β′ and β particles precipitate in the early stage of isothermal treatment at 360 °C. Prolonging the holding time leads to more and coarser β particles in the matrix. Both the precipitation of β′ and β particles results in loss of solute and decreasing of the subsequent age hardening effect. Also, the important coefficients k 2 – k 5 and critical cooling rate for 6082 Al-alloy are identified, and the properties after different rates of cooling were predicted using quench factor analysis.