Synthesis and Performance of PAFS Coagulant Derived from Aluminium Dross

Polymerised aluminium ferric sulphate (PAFS) was prepared from aluminium dross as a coagulant in wastewater treatment. The effects of leaching time, leaching temperature, and sulfuric acid concentrations on the turbidity removal of the wastewater were investigated, and the optimum conditions were determined using response surface methodology. The results showed that the optimum PAFS preparation conditions were at a leaching time of 60 minutes, a leaching temperature of 65°C, and a sulfuric acid concentration of 1 mol/L. Furthermore, experiments were performed to investigate the effect of coagulant dosages using the PAFS prepared under the optimum leaching conditions, settling time and initial pH of the wastewater on the turbidity removal efficiency. As a result, it was found that the optimum coagulation conditions for PAFS coagulants were at a settling time of 15 minutes, coagulant dosage of 0.5g, and raw water pH 8. Under these optimum conditions, the turbidity removal efficiency of the wastewater was 91.45%. The purpose of this study was to investigate the possibility of aluminium dross utilisation as a coagulant agent for wastewater treatment. Therefore, it can be concluded that PAFS prepared by leaching metal oxides from aluminium dross is an effective wastewater coagulant.

Waste-to-Reuse Foam Glasses Produced from Soda-Lime-Silicate Glass, Cathode Ray Tube Glass, and Aluminium Dross

Aluminium dross is a hazardous industrial waste generated during aluminium production. It contains metallic oxides of aluminium and magnesium, other phases (aluminum nitride), and residues of fluxes and salts from the melting process of aluminium. Discarding this by-product is considered an environmental and economic challenge due to the high reactivity of dross with water or even air humidity. After removing the hazardous components from the as-received dross, one of the optional approaches is to incorporate the treated dross into construction materials. Dross is applied in several types of research as a secondary raw material source for alumina, clinker, cement or glass-ceramic production, but only a few papers focus on the usage of dross as a foaming agent for foams. Even fewer research are reported where dross was applied as a basic component of foam glasses. In this work, foam glasses were produced completely from waste materials: Aluminium dross, container (SLS) glass, and cathode ray tube (CRT) glass. The research holds several specificities, i.e., combining two industrial waste materials (CRT glass and dross), and adding an increased amount from the wastes. The physical and mechanical characteristics were examined with a special focus on the effect of the foam glass components on the microstructure, density, thermal conductivity, and compressive strength.

Effect of Aluminium Dross on Workability and Setting Time of Cement and Concrete

Aluminium dross is generated when resmelting process is done in an aluminium industry to recover residual aluminium, wherein primary dross is taken as a raw material. It is completely a waste product and hazardous to dispose it into landfills. This is rich in aluminium oxide and having traces of few heavy metals. It is necessary to check the eco-friendly methods of solidification of this material. One of the feasible methods of solidifying the industrial wastes is using them in production of cement concrete. In this study, behaviour of aluminium dross as a partial replacement for Ordinary Portland Cement is evaluated. Aluminium dross is replaced at 5, 10, 15 and 20% of Ordinary Portland Cement. Consistency and setting time of cement paste samples were determined which shows a lag in setting time of paste. Workability and setting time of concrete mixes with 5, 10, 15 and 20% of Aluminium dross as a binder, were evaluated. Retardation of setting time and increase in the workability are the main observations of this study. As the percentage of aluminium dross increases, the setting time also increases. This may be considered as a reason to utilize such concrete mixes in hot weather conditions wherein delayed setting time is an added advantage. Therefore, retardation of setting time is the positive impact of aluminium dross. Keeping in view of the fact that there can be a reduction in strength with increased binder replacement and the workability requirements, only up to 20% of aluminium dross was replaced in the present study.

Studies on the Formation and Processing of Aluminium Dross with Particular Focus on Special Metals

In terms of production volume, aluminium is the leading metal in non-ferrous metallurgy. In particular, the recycling of aluminium-containing residues has strongly increased in recent years and will continue to gain importance in the future. Due to the high affinity of aluminium to oxygen, the oxidation of the molten bath is unavoidable, which leads to the formation of dross on the surface. This has a high content of metallic aluminium and therefore represents a valuable residual material that must be further processed. In the presented work, a study is conducted on the formation and possible further processing of aluminium dross. Within the scope of this experimental work, the pyrometallurgical treatment of Al-dross in the salt drum furnace was evaluated on the basis of an experiment in a TBRC (top blown rotary converter) by adding a salt mixture. In addition, the behaviour of special metals, in particular the rare earth elements (REEs), was investigated during such a melting process. This knowledge will be particularly important in the future, as inadequate scrap processing leads to more of these partially valuable contaminants entering the aluminium scrap cycle. The result of the experimental study was that the metal yield of the dross used in the melting experiment at the Chair of Nonferrous Metallurgy was higher than that achieved by external reprocessing. Regarding the distribution of the rare earths, there was a direct transition of these from the dross into the emerging salt slag phase.

Characterization of train brake-blocks composite reinforced with aluminum-dross

Brake blocks are usually made from asbestos, metals and ceramics. It has been realised that asbestos discharges dangerous gases which can be harmful. This problem necessitated the search for human-friendly materials. Therefore, this paper studies the production and characterization of train brake blocks produced from clay reinforced with aluminum dross. This was done by producing samples of composite using clay from a deposit at Osiele and aluminum dross from Tower Rolling Mill Otta, both in Ogun state. The percentage composition of aluminum dross was varied from 0% to 25% to produce brake samples. Their wear rate, tensile strength, compressive strength, hardness, thermal conductivity and microstructure were analysed. The results from this project such as Ultimate tensile strength (UTS) of 7.4Mpa, Impact energy 6.92J, Hardness 28.8 HV, wear rate 0.0071g/sec and thermal conductivity of 0.01075 indicate that, with 5% aluminium dross it is possible to develop brake block that exhibits property recommended by Rail Industry Safety and Standard Board (RISSB). Keywords: Train, Brake blocks, Clay composite, Aluminum Dross, Mechanical properties.