HUANG Zhu-cheng
,
WU Kai
,
HU Bing
,
PENG Hu
,
JIANG Tao
钢铁研究学报(英文版)
The microwave heating characteristics of the mixture with oxidized pellet and coal was studied, and the non-isothermal reduction dynamics is discussed. The results show that, the slow-heating stage of the temperature rising process can be segmented into two heating temperature curves approximately that have good linear relationship. They can be seen as temperature programming. In the first stage, between 827 and 1073 K, the reaction mechanism obeys diffusion controlled model. In the second stage, between 1093 and 1323 K, the reaction mechanism also obeys diffusion controlled model. The apparent activation energies are found to be 7513 kJ/mol for the first stage and 5317 kJ/mol for the second stage. That is lower than the apparent activation energy under conventional heating. The microstructure of the reduced pellets shows that microwave can improve the kinetics of the reduction. Microwave has anxo-action to the reaction obviously.
关键词:
microwave
,
oxidized pellet
,
non-isothermal kinetics
LONG Hongming
,
FAN Xiaohui
,
JIANG Tao
,
DAI Linqing
钢铁研究学报(英文版)
An expert system skeleton tool of sintering process was constructed using objectoriented method, which can actualize two functions, ie, the shell function and the program function. The skeleton tool offered a platform to build a prototype system, to program class code, and to develop the expert system. Four branch expert systems were developed using the skeleton tool including the control of chemical composition, the control of sintering process state, the control of expended energy, and the diagnosis of abnormity. It is found that the performance of all systems is satisfactory in practice.
关键词:
sintering process;expert system;skeleton tool;knowledge base;illation engine
FAN Jian-jun
,
QIU Guan-zhou
,
JIANG Tao
,
GUO Yu-feng
,
CAI Mei-xia
钢铁研究学报(英文版)
Investigation was conducted on roasting properties of pellets with an iron concentrate of complex mineral composition. The results indicated that the pellets of complex mineral composition concentrate required higher preheating temperature and longer preheating time than that of single magnetite concentrate. Therefore, it is difficult for preheated pellets to withstand the mechanical collision in the roasting process in rotary kiln. It was found that after the iron concentrate being subjected to high pressure roll grinding, the specific surface area reached 2029.1 cm2/g. Consequently, the preheating and roasting temperature of pellets were decreased by 70 and 50 ℃ and preheating and roasting time were decreased by 2 and 4 min, respectively. Meanwhile, the compression strength of preheated and roasted pellets were increased by 200 N for a pellet and 220 N for a pellet, respectively. The mechanism lied in that the increase of specific surface area activated thermal reaction and promoted formation of iter-grain bridge.
关键词:
pellet
,
iron concentrate
,
high pressure roll grinding (HPRG)
,
specific surface area
HAN Gui-hong
,
JIANG Tao
,
ZHANG Yuan-bo
,
HUANG Yan-fang
,
LI Guang-hui
钢铁研究学报(英文版)
By means of isothermal oxidation and chemical analysis, great importance was attached to the parameters that made effects on the oxidation degree of vanadium, titanium-bearing magnetite pellet in high-temperature processing (1073-1323 K). Based on the experimental data, oxidation kinetics of pellet was analyzed according to shrinking unreacted-core model subsequently. Experiment results display that the oxidation degree of pellet increases with increasing of oxidation time, oxidation temperature and oxygen content, as well as shrinking of pellet diameter. Under the condition of oxidation time 20 min, oxidation temperature 1223 K, oxygen content 15%, and pellet diameter 12 mm, oxidation degree of pellet reaches 92.92%. The analysis of oxidation kinetics indicates that oxidation process of pellet is controlled by chemical reaction with activation energy 68.64 kJ/mol at a relatively lower temperature (1073-1173 K). Oxidation process of pellet is mixed-controlled by chemistry reaction and diffusion with activation energy 39.66 kJ/mol in the temperature range of 1173-1273 K. When oxidation temperature is higher than 1273 K, the limited link of oxidation reaction is the diffusion control with the activation energy 20.85 kJ/mol. These results can serve as a reference to the production of vanadium, titanium-bearing magnetite pellet.
关键词:
vanadium
,
titanium-bearing magnetite
,
oxidation degree
,
pellet
,
shrinking unreacted-core model
,
oxidation kinetics
