Chemical Engineering Department, Visvesvaraya National Institute of Technology, South Ambazari Road, Nagpur, 440010, India.
National Chemical Laboratory, Pune, India.
Environ Sci Pollut Res Int. 2019 Jan;26(1):492-500. doi: 10.1007/s11356-018-3648-9. Epub 2018 Nov 7.
India is one of the major rice-producing countries. Rice husk is a major agricultural by-product from rice production, which is used as a fuel in boilers. Its use as fuel produces huge amounts of silica-rich rice husk ash (RHA). This paper aims at providing an overall assessment of environmental impacts associated with the extraction of silica from RHA-a process developed by our study group. The functional unit used in this study is production of 100 kg of silica. The analysis included the extraction and transportation of other raw materials; RHA was assumed to be processed at the site. The study was conducted in accordance with the international ISO 14040 procedural framework. LCA is performed using GaBi Education software, and five midpoint indicators are chosen to assess the environmental impacts of silica extraction. The overall climate change (CC) of the extraction process is 7.26 kg CO equivalent per kg of silica produced. A high contribution of calcination to CC is attributed to the use of electricity. The comprehensive environmental impacts of silica-rich RHA resulting from processing of RHA and improvement options to achieve sustainable production are presented. The negative impacts that can be avoided during silica extraction are also discussed. It is observed that calcination is a major contributor to the overall environmental indicators. The work also stresses on the use of renewable energy for electricity generation, which would help in decreasing the overall greenhouse gas emissions during extraction while ensuring waste utilization.
印度是主要的稻米生产国之一。稻壳是稻米生产的主要农业副产品，可用作锅炉燃料。作为燃料使用会产生大量富含硅的稻壳灰（RHA）。本文旨在对从 RHA 中提取硅的过程（本研究小组开发的工艺）所产生的环境影响进行全面评估。本研究中的功能单位是生产 100 公斤的硅。该分析包括其他原材料的提取和运输；假设 RHA 在现场进行加工。该研究符合国际 ISO 14040 程序框架。使用 GaBi Education 软件进行 LCA，选择了五个中点指标来评估硅提取的环境影响。提取过程的整体气候变化（CC）为每公斤生产的硅 7.26 公斤 CO 当量。煅烧对 CC 的高贡献归因于电力的使用。介绍了加工 RHA 产生的富含硅的 RHA 的综合环境影响和实现可持续生产的改进方案。还讨论了在硅提取过程中可以避免的负面影响。可以观察到煅烧是整体环境指标的主要贡献者。这项工作还强调了使用可再生能源发电，这有助于在提取过程中减少温室气体排放总量，同时确保废物利用。
