How to Design the Utilization of Larger Scrap Share in Aluminum Production

The production of Al-alloys is mainly based on electrolytic pure Al alloyed with the necessary other elements, which are added in high purity into the melt pool during smelting processes. This fact is responsible for high costs and emissions during aluminum production. The usage of aluminum scrap in its downstream production processes provides multiple benefits since it reduces the overall cost of aluminum production by preserving raw materials through the utilization of scrap streams. This work provides some indicative examples with the aim to propose and demonstrate alternative ways to exploit aluminum waste for the production of aluminum alloys.

Shaping the Microstructure of High-Aluminum Cast Iron in Terms of the Phenomenon of Spontaneous Decomposition Generated by the Presence of Aluminum Carbide

A suitable aluminum additive in cast iron makes it resistant to heat in a variety of environments and increases the abrasion resistance of the cast iron. It should be noted that high-aluminum cast iron has the potential to become an important eco-material. The basic elements from which it is made—iron, aluminum and a small amount of carbon—are inexpensive components. This material can be made from contaminated aluminum scrap, which is increasingly found in metallurgical scrap. The idea is to produce iron castings with the highest possible proportion of aluminum. Such castings are heat-resistant and have good abrasive properties. The only problem to be solved is to prevent the activation of the phenomenon of spontaneous decomposition. This phenomenon is related to the Al4C3 hygroscopic aluminum carbide present in the structure of cast iron. Previous attempts to determine the causes of spontaneous disintegration by various researchers do not describe them comprehensively. In this article, the mechanism of the spontaneous disintegration of high-aluminum cast iron castings is defined. The main factor is the large relative geometric dimensions of Al4C3 carbide. In addition, methods for counteracting the phenomenon of spontaneous decay are developed, which is the main goal of the research. It is found that a reduction in the size of the Al4C3 carbide or its removal lead to the disappearance of the self-disintegration effect of high-aluminum cast iron. For this purpose, an increased cooling rate of the casting is used, as well as the addition of elements (Ti, B and Bi) to cast iron, supported in some cases by heat treatment. The tests are conducted on the cast iron with the addition of 34–36% mass aluminum. The molten metal is superheated to 1540 °C and then the cast iron samples are cast at 1420 °C. A molding sand with bentonite is used to produce casting molds.

Effect of Various Forms of Aluminum 6082 on the Mechanical Properties, Microstructure and Surface Modification of the Profile after Extrusion Process

This article presents a method of reusing aluminum scrap from alloy 6082 using the hot extrusion process. Aluminum chips from milling and turning processes, having different sizes and morphologies, were cold pressed into briquettes prior to hot pressing at 400 °C at a ram speed of 2 mm/s. The study of mechanical properties combined with observations of the microstructures, as well as tests of density, hardness and electrical conductivity were carried out. On the basis of the results, the possibility of using the plastic consolidation method and obtaining materials with similar to a solid ingot mechanical properties, density and electrical conductivity was proven. The possibility of modifying the surface of consolidated aluminum scrap was tested in processes examples: polishing, anodizing and coloring. For this purpose, a number of analyses and tests were carried out: comparison of colors on color histograms, roughness determination, SEM and chemical composition analysis. It has been proven there are differences in the surface treatment of the solid material and that of scrap consolidation, and as such, these differences may significantly affect the final quality.

INVESTIGATION OF LIGHTWEIGHT STRUCTURAL MATERIALS PRODUCED USING ALUMINUM SCRAPS WITH CEMENT MORTAR

A lot of environmental concerns are increasing day after day result in the raise of solid waste in large quantities in the world resulting from the demolition of buildings and various industrial and commercial activities. This research provides the possibility of reusing one of these wastes solid aluminum scrap (Als) by using it to produce a modified type of cement mortar. The research focuses on the mechanical behavior of the new cement mortar type obtained by adding aluminum scrap by different percentages (1%, 2%, 3%, 4%, and 5%) as a replacement ratio from the weight of sand mixed with Ordinary Portland Cement (OPC). The findings of this research indicated the possibility of using aluminum waste material in certain limits where the compressive strength significantly reduced by increasing the percentage of Als. The most interesting observation was to increase the volume of the mixture by increasing the ratio of Als. According to the results, it is possible to use this type of cement mortar to produce lightweight structural members such as slabs, bricks, etc. Finally, the general formulation was proposed based on the regression analysis and experimental measurements to give a capture of the compressive strength of mortar under any variables alter (age of specimen and/or quantity of aluminum replacement).

Analisis Sifat Mekanik dan Struktur Mikro Aluminium Scrap (ADC12) Menggunakan Tungku Listrik

Knowing the mechanical and microstructural properties of aluminum scrap materials found in casting using an electric furnace. The research procedure included temperature data (750oC, 800oC, 850oC) and smelting time for 120 minutes. Hardness testing procedure is carried out to get the hardness value from some casting result areas. Microstructure is characterized by a comparison of the grain size of the metal that has undergone casting, to measure the grain size in this study using the image J program. The highest hardness value shows the melting temperature of 800oC with a temperature holding time of 120 minutes of 63.8HB. The longer the temperature holding time, the hardness value will increase. The smallest grain size occurs at a melting temperature of 800oC with a temperature holding time of 120 minutes of 21µm.

The use of supercritical water for the catalyst-free oxidation of coarse aluminum for hydrogen production

Supercritical water is used to oxidize aluminum scrap and 3 mm aluminum slugs without employing catalysts, milling or specialized alloys.