Micromorphology and safety properties of meager and meager-lean coal for blast furnace injection

Four types of meager and meager-lean coal and one type of high-quality anthracite were selected based on the safety requirements for blast furnace coal injection and domestic coal quality to conduct microstructure and component analyses. The analyses of the organic and inorganic macerals and the chemical compositions of the selected coal samples indicate that the four types of meager and meager-lean coal have low volatilization, low ash content, and low sulfur content; these qualities are suitable for blast furnace injection. Grindability test was conducted on the four types of meager and meager-lean coal and the anthracite mixed coal samples. Results indicate that the mixture of meager and meager-lean coal and anthracite is beneficial to improve the grindability of pulverized coal. The explosive tests reveal that the selected coal samples are non-explosive or weakly explosive. When the proportion of meager and meager-lean coal is less than 40wt%, the mixed coal powder would not explode during the blowing process. The minimum ignition temperature test determines that the minimum ignition temperatures of the four types of meager and meager-lean coal and anthracite are 326, 313, 310, 315, and 393°C, respectively. This study provides a guiding research idea for the safety of meager and meager-lean coal used in blast furnace injection.