Life Cycle Inventory Analysis of the Recycling of Electric Arc Furnace Dust to the Zinc Metal

Abstract

CO 2 emission from the zinc production by recycling of the Electric Arc Furnace dust (EAF dust) was quantitatively evaluated using Life Cycle Assessment (LCA) technique. EAF dust is used as one of the raw materials in pyrolytic zinc for the smelter. So, inventories for this study such as fuel consumption of unit process and inhouse electricity were established based on literatures and the public statistical data. The analysis of Life Cycle Inventory (LCI) has been conducted and as a result, the followings have been observed.(1)̙The amount of CO 2 emission from the pyrolytic zinc production is about 3.4 kg / kg-zinc. 40 % of the whole CO 2 emission is originated by the coke combustion in the smelting furnace. And, 20 % of the whole CO 2 emission is attributable to the separation process of EAF dust. (2)̙If recycling of EAF dust to pyrolytic zinc is accelerated, the amount of CO 2 emission from zinc production is increased under the assumption that the energy consumption in the stabilization process of EAF dust is negligible. This is attributable to the difference of the energy consumption to convert to the roasted ore from the raw materials. As a result, the present zinc recycling system from EAF dust has disadvantage from the viewpoint of the CO 2 emission. Hence, the projected recycling systems of metal recovery in the steel industry are expected to reduce the energy consumption. However, the recycling of the EAF dust must be evaluated from not only the CO 2 emission, but also impact assessment based on the resources exhaustion, the global warming, the land use and so on. Impact assessment methodology must be developed to evaluate the validity of the recycling of EAF dust.

Development of a Dynamic Substance Flow Model of Zinc in Japan

“…Narita et al indicate that "other raw materials" of "distilled zinc" in production statistics means zinc recycled from EAF dust, which corresponds to outflow from the waste management stage in this study. 30) Therefore, we compare these statistics 29) with our estimate in Fig. 6.…”

New EAF Dust Treatment Process with the Aid of Strong Magnetic Field

“…However, some problems are pointed out from environmental aspects. 2,3,27) The objective of the present work is to establish the basic principle of the new EAF dust treatment process which enables to recover crude zinc oxide from the dust without carbothermic reduction.…”

Substance Flow Analysis of Zinc Associated with Iron and Steel Cycle in Japan, and Environmental Assessment of EAF Dust Recycling Process

“…22) With regard to category (b), zinc waste is mostly in the form of steelmaking dust. The dust generation ratio in the EAF steelmaking process, which is defined as (amount of EAF dust generation)/(crude steel production), and the average zinc content in the dust were obtained from the report by Narita et al 23) The present work assumed that approximately 65 % of EAF dust is routed to an intermediate process for zinc recovery, according to the report of Furukawa. 20) The yield of zinc in the zinc recovery process was estimated from the report by Nishizeki and Ogawa 24) together with results obtained in our own field work.…”

“…(1) and other process information. 11,12,23) The energy inputs of heavy oil (0.027 kg) and electricity (0.110 kW h) and the CO 2 emission by the production and combustion per ton of each fuel were calculated from literature.…”