Objective To address the challenges of insufficient standardization in the processing of Orpiment (arsenic disulfide, As₂S₂) and the difficulty in controlling its toxicity, this study elucidated the interactions among “particle size-morphology-porosity-crystal defects-arsenic (As) release”. It analyzed the effects of different processing methods on elemental composition and microstructure, and established a rapid identification model based on multimodal spectral fusion. Methods A multi-dimensional “element-morphology-spectrum” data matrix was constructed. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine elemental content. Scanning electron microscopy (SEM) was employed to observe morphology and analyze surface porosity, combined with dissolution experiments to quantify As release. Furthermore, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy (RS) data were integrated. Partial least squares-discriminant analysis (PLS-DA) and support vector machine (SVM) discrimination models were built using both low-level and mid-level data fusion strategies. Results The zirconia-ball water-grinding method reduced As content and increased sulfur (S) content in Orpiment. SEM analysis revealed that particles processed by this method exhibited a more concentrated size distribution, their morphology became more rounded and blunt, and surface porosity significantly increased, forming a hierarchical pore structure. In simulated gastric and intestinal fluids, As dissolution decreased by 72.8% and 81.4%, respectively, compared to dry crushing (P < 0.001). The SVM model based on mid-level spectral fusion achieved 100% classification accuracy. Conclusion The water-grinding method achieves detoxification by removing As³⁺ from Orpiment, regulating the particle morphology and pore structure of Orpiment particles, and enhancing the stability of Orpiment crystals. It establishes a multidimensional data matrix integrating elemental composition, microscopic morphology, pore structure, and spectral characteristics, providing efficient and reliable technical support for quality control of the mineral drug Orpiment.

Orpiment  /  processing  /  zirconia ball-assisted water-grinding  /  detoxification mechanism  /  spectral fusion  /  chemometrics  /  multimodal data fusion  /  support vector machine