Powders

This study presents an approach to synthesizing LTA-type zeolite from spodumene residue generated during a lithium extraction process. A residue was obtained after leaching β-spodumene with 2 mol/L phosphoric acid. After solid–liquid separation, the delithiated residue was first treated with 2 mol/L sodium hydroxide and then subjected to hydrothermal synthesis using sodium aluminate as an additional aluminum source. The resulting material was characterized by XRD, SEM-EDS, XPS, and FTIR, which collectively confirmed the formation of a crystalline material exhibiting the structural features, elemental composition, and morphological characteristics consistent with LTA-type zeolite. Additional analyses, including BET surface area, particle size distribution, and zeta potential measurements, were performed to further evaluate the physicochemical properties of the synthesized zeolite. The spodumene leach residue (SLR)-derived zeolite was further tested for its adsorption performance in heavy metal ions removal from a mixed ion solution containing Pb²⁺, Cu²⁺, Zn²⁺, and Ni²⁺ ions. The zeolite demonstrated a high selectivity for Pb²⁺, followed by moderate uptake of Cu²⁺, while Zn²⁺ and Ni²⁺ adsorption was minimal. These findings demonstrate that spodumene residue, a waste by-product of lithium processing, can be effectively upcycled into LTA zeolite suitable for heavy metal remediation in water treatment applications.

The growing regulatory scrutiny and the emerging trends towards natural products and clean labels have led to a particular focus on food supplements’ composition, including excipients. The objective of this study is to establish a methodological approach combining conventional techniques, i.e., tapped density and flowability testers, with more objective and quantitative ones to identify alternative powder excipients that can replace conventional ones in the development of solid-dose formulations without affecting their processing, workability, and mechanical properties. In the first phase, the alternative powder excipients were characterized in terms of cohesiveness, compressibility, and flow function coefficient. We then evaluated the possibility of using selected excipient combinations to totally and/or partially replace the conventional excipients within three nutraceutical formulations. Glyceryl behenate at 1–3% w/w could be considered as a viable alternative lubricant to magnesium stearate without compromising the rheological properties of the mixtures. Fructo-oligosaccharides showed a free-flowing behavior comparable to calcium phosphate and microcrystalline cellulose, improving the flowability and compressibility of the formulations. The study of powder rheology could be advantageous to formulate new products or reformulate existing ones in a time- and money-saving way, leading to high-quality products that can appeal to consumers in terms of health-functional effectiveness.

In recent years, sustainable recycling approaches for chicken eggshell waste have increased significantly worldwide due to environmental and circular economy benefits. This work aimed to synthesize and characterize a new calcium aluminate powder using chicken eggshell waste as an alternative source of calcium carbonate through mechanical activation and subsequent calcination. The starting formulation consisting of the eggshell waste (CaCO₃):Al₂O₃ (1:1) ratio was subjected to a high-energy milling process for 0 h, 15 h and 30 h and subsequent calcination at 1200 °C for 4 h. The resulting calcium aluminate powders have been investigated using X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscopy (SEM), and photoluminescence techniques. After calcination, a calcium aluminate-based composite powder with an average crystallite size between 46.45 nm and 52.27 nm and a predominance of the CaAl₂O₄ phase was found. The calcium aluminate powders produced (milled for 15 h and 30 h and calcined at 1200 °C) showed a luminescent behavior, emitting characteristic violet light with a wavelength between 380 and 418 nm. Our findings may provide a novel technical pathway for recycling chicken eggshell waste into calcium aluminate powder with luminescent properties.