Measurement and Characterisation of Metallic Iron Particles on Coal-Based Reduction and Magnetic Separation of Refractor
- PDF / 1,793,046 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 112 Downloads / 190 Views
Measurement and Characterisation of Metallic Iron Particles on Coal-Based Reduction and Magnetic Separation of Refractory Titanomagnetite Yongqiang Zhao 1 & Tichang Sun 1 & Zhengyao Li 1 & Zhe Wang 2 Received: 4 June 2020 / Accepted: 11 September 2020 # Society for Mining, Metallurgy & Exploration Inc. 2020
Abstract Coal-based reduction followed by magnetic separation is a promising technology for processing refractory iron ores. Analysis of the size distribution of metallic iron particles is an effective approach for exploring the mechanisms of coal-based reduction. As metallic iron particles exhibit very complex shapes compared with nature ores, approaches for measuring and characterising metallic iron particles still remain unclear. In this study, the size of metallic iron particles was measured and characterised using manual point-counting by optical microscopy technics and image analysis. The effects of CaF2 as an additive on behaviour of the particle size distribution (i.e. mean size and cumulative frequency distribution) were also determined. Results indicate that CaF2 had a significant effect on the growth of metallic iron particles. When the CaF2 dosage increased from 0 to 8%, the mean size according to the area method increased from 9.03 to 16.28 μm, while the promotion effect gradually weakened and generated many fine metallic iron particles when the CaF2 dosage exceeded 8%. An increase in CaF2 dosage also led to cumulative distribution curves gradually shifting to the right mainly because F− can break the crystal structure of each phase during the carbothermic reduction of titanomagnetite and reduce the stability of the lattice structure, thus reducing the melting point and accelerating the growth of metallic iron grains. Compared to different measuring methods, the area method is a more suitable approach for measuring and characterising the size of metallic iron particles. Keywords Coal-based reduction . Titanomagnetite . Magnetic separation . Metallic iron particles
1 Introduction A decline in the discovery of new, large, high-grade ore deposits has driven attention towards low-grade and refractory ores to meet the global resource demand [1, 2]. Beach titanomagnetite (TTM) is extensively distributed in the coastal areas of Indonesia and New Zealand. It can provide an alternative to conventional iron ores [3, 4]. However, the conventional smelting route for smelting refractory TTM with carbon requires a blast furnace to produce pig iron, which has many disadvantages [5]. Therefore, most of the studies focus on developing an alternative route.
* Zhengyao Li [email protected] 1
School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
2
State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
Recent research showed that coal-based reduction followed by magnetic separation, which is a promising iron-making process, provides a feasible way of using refractory iron ores. In this process, iro
Data Loading...
