Zero‐Waste Progress for the Synthesis of High‐Purity β‐Sialon Ceramics from Secondary Aluminum Dross

Abstract

Aluminum dross (AD) is a solid waste and the main byproduct that is formed in the process of smelting, consumption, and utilization of aluminum. The volume of the solid waste from aluminum industries is large, and most of these wastes are in the form of waste residues that are meant for accumulation or landfill treatment. [1][2][3] The treatment and reuse of AD is the last link in the production chain in the aluminum industry, and it poses a global challenge. AD can be classified into primary aluminum dross (PAD) and secondary aluminum dross (SAD). The composition of AD is complex; it contains metal aluminum, alumina, carbide, nitride, salt, and other metal oxides. [4] However, SAD has a low metal content of %5-10 wt%, whereas PAD contains a high metal fraction of %80 wt%. [5,6] SAD is an industrial waste with comprehensive utilization value that has been utilized for various purposes including preparing aluminum oxide, producing aluminum sulfate, and synthesizing brown corundum. [1,7] Although some progress has been made in the comprehensive utilization of SAD, the overall resource utilization level of this industrial solid waste still has to be improved.Generally, the utilization of industrial solid waste such as SAD is still at a low level; therefore, it becomes imperative to speed up the research and development of high value-added resource technology to further improve the comprehensive utilization efficiency of this industrial solid waste. [5] To achieve high-value recycling of solid wastes such as SAD, it can be used as a raw material for the production of Sialon ceramics, which will reduce the production cost and the impact of industrial wastes on the environment. Sialon materials are new types of ceramic materials, which are composed of Si, Al, O, and N. These materials are considered as one of the most promising high-temperature structural ceramics because of their excellent mechanical and thermal properties as well as their chemical stability. [8][9][10] However, Sialon materials are highly pure materials, and they are expensive; therefore, it is not economically sustainable to use these materials as highperformance ceramic materials for large-scale industrial production. [11] Presently, most of the raw materials used for the preparation of Sialon are industrially purified materials that are expensive. At the same time, Sialon phase composition is relatively complex, and the microstructure changes in a wide range. Therefore, the synthesis of Sialon is mostly controlled at the initial stage, which limits the progress of Sialon-related research, especially the industrialization of low-cost synthesis of Sialon materials. Lee [12] first prepared Sialon materials with clay minerals by carbothermal reduction desalination method, and their method unlocked a new technical way for the production of cheap Sialon materials. Further studies on the preparation of Sialon materials using industrial solid wastes, such as clay, zeolite, slag, fly dross, and AD, were conducted. The utilization of SAD as the raw material...

Preparation of Self-Coating Al2O3 Bonded SiAlON Porous Ceramics Using Aluminum Dross and Silicon Solid Waste under Ambient Air Atmosphere

“…The reaction Many studies have reported the formation of SiAlON whiskers using Si and Al-based compounds as starting materials under nitrogen atmosphere, and the vapor-solid (VS) and used vapor-liquid-solid (VLS) growth mechanisms to explain the growth of SiAlON whiskers [44,45]. The composition of synthesis gas (containing SiO and Al 2 O) makes it an important intermediate phase, which significantly influences the preparation and growth mechanism of the whiskers [46]. However, in this study, uniform granules were found in the porous samples instead of whiskers, which may indicate that the gas phase was less involved during the growth process of the SiAlON phase.…”

Friction and wear characteristics of β‐Sialon prepared from secondary aluminum dross

“…The synthesis temperature of 1450 • C, holding time of 4 h, and Si-Al ratio of 1:2.5 resulted in β-Sialon powder with a purity exceeding 95 %. 25 Preparation of dense sintered bodies: To ensure homogeneity and eliminate agglomerates in the β-Sialon powder, the prepared powder was subjected to grinding using a planetary ball mill (FP400) for 1 h. The ground powder was then pressed into a mold with a diameter of 10 mm. Subsequently, sintering was performed in a discharge plasma sintering furnace (SPS-211HLABOX 650F) under a pressure of 40 MPa.…”

“…Si powder was added to adjust the Si‐Al ratio. The synthesis temperature of 1450°C, holding time of 4 h, and Si‐Al ratio of 1:2.5 resulted in β‐Sialon powder with a purity exceeding 95 % 25 …”

“…24 In our previous research, we successfully synthesized high-purity β-Sialon powders using SAD as the raw material. 25 However, the investigation of the friction and wear characteristics of the prepared β-Sialon has not been explored extensively.…”

“…In contrast, Abdulhakim achieved a hardness of 13.8 GPa and a fracture toughness ranging from 3.5 MPa to 4.6 MPa when utilizing SPS at temperatures between 1600°C and 1700°C to produce β‐Sialon, showcasing mechanical performance on par with fully dense β‐Sialon 24 . In our previous research, we successfully synthesized high‐purity β‐Sialon powders using SAD as the raw material 25 . However, the investigation of the friction and wear characteristics of the prepared β‐Sialon has not been explored extensively.…”