Blast furnace coal injection is a vital part of modern ironmaking, reducing the amount of coke reductant required in the process and increasing its efficiency. However the injection of different coals or their blends, into the raceway formed by the hot blast, has technical issues due to the very short particle residence times and the limited availability of oxygen in this region. This makes complete burnout difficult and limits the range of coals suitable for this application, leading to partially burnt chars being carried out of the raceway into the blast furnace shaft and potentially into the off-gas system.

This paper explores the fate of these chars, from a range of different coals, looking at how this influences the selection for injection and the implication of these on the blast furnace. In particular, we have looked beyond the limitations of selecting coals based on proximate analysis alone by examining in more detail other physical and chemical properties and their potential effect on the process. A drop tube furnace (DTF) has been used to synthesise chars in a high heating rate environment, and although burnout and volatile loss values suggest suitability of some coals for blast furnace injection, additional problematic effects have been identified and measured such as char swelling and agglomeration which may impact the gas permeability of the furnace. A TGA/DSC has been used to measure the gasification of chars by the Boudouard reaction and compare the thermal impact of more reactive samples.

While other studies have concentrated on the combustion of injection coals to determine their suitability, this one focuses on the implications of the partially burnt chars formed by incomplete reaction in the raceway.

高炉喷煤是现代炼铁的重要组成部分，可减少该过程中所需的焦炭还原剂数量并提高其效率。然而，由于该区域中非常短的颗粒停留时间和有限的氧气可利用性，将不同的煤或其混合物注入由热风形成的管道中存在技术问题。这使得完全燃尽困难，并限制了适用于该应用的煤的范围，导致部分燃烧的焦炭从滚道带入高炉竖井，并有可能进入废气系统。

本文探讨了来自多种不同煤种的这些炭的去向，探讨了这些炭如何影响进样的选择以及这些炭在高炉中的含义。特别是，我们通过仅详细研究其他物理和化学特性及其对工艺的潜在影响，超越了仅基于近距离分析选择煤炭的局限性。滴管式炉（DTF）已用于在高加热速率环境中合成焦炭，尽管燃尽和挥发性损失值表明某些煤适合于高炉喷吹，但已发现并测量了其他问题，例如焦炭溶胀和烧焦。结块可能会影响炉子的气体渗透性。

虽然其他研究集中在注入煤的燃烧以确定它们的适用性上，但这一研究着重研究了由滚道中不完全反应形成的部分燃烧的焦炭的含义。