Simultaneous Material Flow Analysis of Nickel, Chromium, and Molybdenum Used in Alloy Steel by Means of Input–Output Analysis

Abstract

Steel is not elemental iron but rather a group of iron-based alloys containing many elements, especially chromium, nickel, and molybdenum. Steel recycling is expected to promote efficient resource use. However, open-loop recycling of steel could result in quality loss of nickel and molybdenum and/or material loss of chromium. Knowledge about alloying element substance flow is needed to avoid such losses. Material flow analyses (MFAs) indicate the importance of steel recycling to recovery of alloying elements. Flows of nickel, chromium, and molybdenum are interconnected, but MFAs have paid little attention to the interconnected flow of materials/substances in supply chains. This study combined a waste input-output material flow model and physical unit input-output analysis to perform a simultaneous MFA for nickel, chromium, and molybdenum in the Japanese economy in 2000. Results indicated the importance of recovery of these elements in recycling policies for end-of-life (EoL) vehicles and constructions. Improvement in EoL sorting technologies and implementation of designs for recycling/disassembly at the manufacturing phase are needed. Possible solutions include development of sorting processes for steel scrap and introduction of easier methods for identifying the composition of secondary resources. Recovery of steel scrap with a high alloy content will reduce primary inputs of alloying elements and contribute to more efficient resource use.

A review and comparative assessment of existing approaches to calculate material footprints

“…indicators that integrate all types of biotic and abiotic materials and cover a country's economy. Apart from this macro level, a large body of litera-ture exists on approaches to calculate materials embodied in international trade or required for certain technologies on the level of single substances, using various methodologies including material flow models, input-output analysis and life cycle assessment (for example, Elshkaki and Graedel, 2013;Moran et al, 2014;Nakajima et al, 2013;Nakamura et al, 2009;Nansai et al, 2014;Wiedmann et al, 2014). In order to keep a clear focus for this paper, these publications oriented at single substances were not considered in our review.…”

Assessing circularity interventions: a review of EEIOA-based studies

“…The waste input-output material flow analysis (WIO-MFA) was used to trace the final destination of materials and their specific elements through the supply chain (Nakamura and Nakajima 2005;Nakajima et al 2013;Ohno et al 2014). For example, in an analysis of metal industry, Ohno et al (2016) applied the WIO-MFA to assess the material network of metals and alloying elements.…”

Material Flow Analysis and Waste Management

“…Some studies discuss alloying elements in metal recycling (Nakajima et al 2011(Nakajima et al , 2013Nakamura et al 2012 ;Ohno et al 2014 ). For example, Ohno et al ( 2014 ) showed that considerable amounts of alloying elements, which correspond to 7-8 % of the annual consumption in electric arc furnace (EAF) steelmaking, are unintentionally introduced into EAFs.…”