Abstract
Kraft pulp mills produce the main raw material for paper, while several waste products are generated in large quantities in the process. This review study addresses four of the main inorganic wastes formed by this industry, namely green liquor dregs (GLD), slaker grits (SG), lime mud (LM) and boiler fly ash (BFA), which are still mostly discarded in landfills. A brief overview of a typical industrial process was included to outline the waste generation points. The main chemical and physical properties are indicated for highlighting the most relevant characteristics to determine which applications may be considered in each case. An in-depth literature review allowed the identification of the main applications that have been tested mainly at the laboratory scale and some at an industrial scale. The applications are grouped into construction materials, geotechnical, environmental, agricultural and others. This assessment shows that the circular economy and the sustainable development goals of the UN are important issues for organizations in general, and the pulp mill in particular. In fact, this industry has managed to close the chemicals loops, recover energy and reduce water consumption in the process. However, the current situation of inorganic waste can still be improved if industrial applications are developed to avoid landfill.
Highlights
IntroductionAccording to the Confederation of European Paper Industries (CEPI), which represents nearly
According to the Confederation of European Paper Industries (CEPI), which represents nearly151 pulp mills from Europe, in 2018, about 154.9 Mt of wood (42.8 Mt of hardwood and 112.1 Mt of softwood) was consumed and 38.3 Mt of pulp was produced [1]
Circular Economy Action Plan in 2015 [2], there is potential for more recycling of paper, with both environmental and economic benefits, including less wood utilization for pulp production
Summary
According to the Confederation of European Paper Industries (CEPI), which represents nearly. Sci. 2020, 10, 2317 grits (SG), lime mud (LM) and boiler fly ash (BFA) These wastes have been produced in high quantities, and landfill has been the main disposal method [4,5]. 90 references were considered in this study, with 75% of those sources published from 2010 onwards In this context, the main objective of this review is to summarize the properties of the main inorganic wastes generated in kraft pulp mills, highlighting which resources can be recovered and the applications which can be implemented on an industrial scale to reduce or eliminate the current disposal in landfills. For each waste (GLD, SG, LM, and BFA) the main applications tested/used at the laboratory or industrial scale were identified. The study ends with future perspectives for the use of these resources, emphasizing the main factors for selecting the best paths for an emerging circular economy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
