Utilizing locally based and renewable biomass resources are challenging. This work aims to understand the role of the utilization of solid byproduct of Indonesian mill scale, formed during the cold rolling process, and abundant local resources of coconut coir wastes. Mill scale has a fairly high total iron content with the dominant phase being hematite, while pure Fe content is insignificant. In this study, we utilized coconut coir-based carbon (CCC) for direct reduction of mill scale via a carbothermic process to enhance its metallic Fe content. The reduction was carried out by mixing mill scale/CCC at 6:1 wt% ratio in high energy milling for 2 min. The mixture was pressed (100 MPa for 1 min) into pellets and sintered at 900 °C for 1 h and 1000 °C for 1 and 2 h under inert gas atmosphere. After cooling, the sintered pellets were crushed into powder and separated from impurities by magnetic separation. The results show that the reduction process is dominated by carbon gasification–diffusion from CCC. The improved metallization and better reducing process was more pronounced at 1000 °C for 2 h than that for 1 h with over 80 wt% being separated into metallic Fe and lesser CO₂ trapped within the sample. X-ray diffractometry revealed that the intimate contact of mill scale/CCC was more increased in solid than that in powder state and indicated that the obtained phases are Fe, Fe₃O₄, and CO₂. The presence of CO₂ can be expected due to incomplete evacuation within the sample. These results suggest that mill scale/CCC has some promising potential on certain technical-industrial-scale applications, which might enhance their economic value after further research investigation and evaluation.

中文翻译：

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生物质碳减排的工厂规模工业垃圾的制备与表征

利用本地和可再生的生物质资源具有挑战性。这项工作的目的是了解利用冷轧过程中形成的印尼工厂规模的固体副产品的利用以及椰子椰汁废料丰富的本地资源的作用。轧机氧化皮具有较高的总铁含量，主要相为赤铁矿，而纯铁含量微不足道。在这项研究中，我们利用了基于椰壳椰皮的碳（CCC）通过碳热法直接减少了轧机氧化皮，以提高其金属铁含量。还原是通过在高能研磨中以6：1 wt％的比例混合氧化皮/ CCC 2分钟来进行的。将混合物压制成粒（100 MPa，1分钟），并在惰性气体气氛下于900°C烧结1 h和1000°C烧结1和2 h。冷却后 将烧结后的颗粒粉碎成粉末，并通过磁选与杂质分离。结果表明，还原过程主要由CCC的碳气化扩散引起。改进的金属化和更好的还原过程在1000°C下2 h比1 h更明显，超过80 wt％的金属被分离为金属Fe和较少的CO₂被困在样品中。X射线衍射法显示，与固体相比，粉末状/ CCC在固体中的紧密接触比粉末状中的紧密接触增加，并且表明获得的相为Fe，Fe ₃ O ₄和CO ₂。由于样品中的不完全排空，可以预期到CO ₂的存在。这些结果表明，工厂规模/ CCC在某些工业技术规模的应用上具有一定的发展潜力，经过进一步的研究调查和评估，可能会提高其经济价值。