Millions of canned drinks are consumed everyday globally and their wastes create an enviromental issue. Fortunately, the cans are made from aluminium (Al) so that it can be recycled. There are two main keypoints existing during the recycling process of Al cans, i.e. the aluminium loss or low Al-yield and low recycling yield. This work outlines the strategies to improve the recycling perfomance for Al beverage cans, i.e. by adding drossing flux, applying improved melting strategy, and cans decoating prior to melting. Drossing flux was added to assist the detachment of Al from the slag. Another improved melting strategy was worked out by decreasing exposure time cans to the furnace atmosphere during melting. All those above strategies result in an increase of recycle yield in a range of 4 % to 5 %.
During stainless steelmaking in the electric arc furnace at Deutsche Edelstahlwerke GmbH, oxygen is injected to oxidize unwanted tramp elements mainly carbon and silicon. Unfortunately the injected oxygen also oxidizes valuable elements such as chromium and iron, which causes an economical loss and has a negative environmental effect. Since the temperature and dilution techniques to minimise chromium oxidation are seldom applied in the electric arc furnace, a new strategy to minimise chromium oxidation has to be developed. This paper proposes a new strategy which involves the use of a continuous off‐gas analysing system to minimise chromium oxidation by monitoring the oxidation products in the off‐gas, i.e. CO and CO2. During stainless steelmaking in the electric arc furnace, for which initial carbon and silicon input cannot be precisely known due to imprecise scrap analysis, the installed off‐gas analysing system should provide precise information concerning an efficient oxygen injection. This would then directly prevents excess chromium and iron oxidation. A continuous off‐gas analysing system installed at Deutsche Edelstahlwerke GmbH delivers a promising result for future applications. During the plant trial, the efficiency of oxygen injection as well as the chromium and iron yields were increased.
A356.0 aluminum-silicon alloy is a base material for car rims application. Car rims are critical components for a vehicle as they carry the load of the passengers, goods, and the weight of the vehicle itself, therefore they should be sufficiently strong to withstand the vertical load, fatigue load, impact load, the side load and the braking force. Car rims are made by gravity die casting process. During the casting process, the inclusion of iron-content parts entering the molten Al can take place which leads to higher iron (Fe) concentration. High Fe con concentration lowers the toughness and the ductility of car rims. This study investigates the maximum value of Fe concentration that can be tolerated for acceptable mechanical properties of Al-Si alloy A356.0 for car rims application. The Fe concentration studied was 0.12 %wt, 0.16 %wt, and 0.20 %wt. Evaluation was performed on tensile and impact properties of the specimens. The test results show that increased Fe concentration decreases elongation, yield strength and ultimate tensile strength (UTS). Furthermore, there is a quite large decrease in UTS (by 34 MPa) when Fe concentration increases only by 0.06 %wt. Impact strength decreases significantly from 15.47 to 2.91J/cm 2 as Fe concentration content increases from 0.12 %wt. to 0.16 %wt. The porosity present in the casting is predicted to contribute to the ductility decrease. In addition, the decreasing value of UTS is predicted due to grain growth and dendrites formation. It is recommended that the maximum allowable Fe concentration for car rims application is 0.12 %wt.
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