To achieve the green and low-carbon transformation of the ironmaking system, in response to the special thermal behavior issues of Ansteel's self-produced ultra-fine magnetite-hematite mixed concentrate, such as extremely fine particle size, poor pelletizing property, strong oxidation heat release, narrow roasting window, and easy overheating and cracking, a systematic study was carried out on the characterization of raw material physical and chemical properties, optimization of pelletizing parameters and ore blending structure, design of the straight-grate system, and evaluation of metallurgical properties, and a complete set of key technologies for the preparation of fluxed pellets was formed. On this basis, the 4 million t/a fluxed pellet production line with the straight-grate system in Donganshan Sintering Plant of Ansteel Group Mining Co., Ltd. achieved stable operation. The TFe of the fluxed pellets was approximately 64.0%, the SiO2 was about 3.8%, and the basicity was stable at 1.0. Compressive strength was ≥ 2 800 N per piece, drum strength was >92%, reduction degree was >78%, reduction expansion rate was <12%, low-temperature reduction pulverization rate (RDI+3.15 mm) was > 90%. According to the "Guidelines for Accounting and Reporting of Carbon Emissions in the Iron and Steel Industry (for Trial Implementation) ", after the pelletizing process replaced the original 360 m2 sintering machine, the carbon emission intensity of the product decreased from 199.02 kgCO2/t sintered ore to 40.64 kgCO2/t pelletized ore, representing a 79.58% emission reduction. This study provides an engineering example for the preparation of fluxed pellets from ultra-fine mixed iron concentrate resources and their low-carbon application.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |