Secondary aluminum dross (SAD) is a hazardous waste produced in the electrolytic aluminum, aluminum processing, and aluminum recycling industries. The SAD produced from different processes has the characteristics of complex mineral phases and large discrepancy in chemical composition, which leads to a large difference in the effect of treatment technology for various SAD and a low resource utilization rate. Clarifying the morphology, distribution and formation of the nitride and fluoride in the SAD from the typical aluminum alloy production process is conducive to the development of a highly adaptable SAD treatment technology to realize the efficient separation of the toxic and valuable components of the SAD and solve the problem of resource utilization effectively. In this paper, Chemical and instrumental analysis are combined by using X-ray diffraction and X-ray fluorescence spectroscopy to quantitatively study the content of fluoride, nitride, and other phases in the samples of SAD from different processes. X-ray photoelectron spectroscopy and scanning electron microscope are used to analyze fluoride and nitride's combined form and distribution characteristics. The results show that the quantitative results of nitrides and fluorides in SAD using spectral and chemical analysis methods are consistent. The content of nitrides in different samples of SAD from the aluminum alloys production of Al-Si, Al-Mg, and Al-Mg-Si is 4. 30%similar to 5. 48%. The nitride phases are mainly in the form of AlN, which is generated by the reaction of aluminum melt and nitrogen. The particles of AlN are spherical-end strip and prismatic, which are separate particles connected with aluminum-containing particles. The content of fluorides in different samples of SAD is 1. 04% similar to 2. 29%, and the SAD generated in the Al-Si alloy production are mainly NaF, CaF2, MgF2, Na3AlF6, while those from the Al-Mg and Al-Mg-Si alloy production are CaF2, MgF2, and KF. The fluorides are used as additives to enter the SAD during the production process of aluminum products, and no other phase formation occurs during the SAD generation process. In the samples of these three series, the fluorides are concentrated on the surface, in the forms of flocculent or irregular lumps, attaching to or covering the large particles, existing in joint with other components, or as separated free particles. This study would provide a fundamental basis for removing fluorides and nitrides from SAD.
