Recycled acrylonitrile–butadiene–styrene (rABS) and recycled high impact polystyrene (rHIPS) are vital components of waste electrical and electronic equipment (WEEE) plastics, playing crucial roles in the recycling process. This paper utilized sodium chlorite (NaClO 2 ) to modify the surfaces of rABS and rHIPS, followed by flotation to separate the two types of plastics. X-ray photoelectron spectroscopy (XPS) test confirmed that the number of hydrophilic groups introduced on the rABS surface was more than that of rHIPS after surface modification. Through contact angle measurements, scanning electron microscope (SEM), and atomic force microscopy (AFM), it was confirmed that the modification on the rABS sample surface altered its microstructure and enhanced its surface wettability. The sodium chlorite concentration, modification temperature, and modification time significantly affected the floating percentage of rABS and rHIPS. The optimal surface modification conditions were determined to be a sodium chlorite concentration of 0.08 mol L -1 , a modification temperature of 70 °C, and a modification time of 60 min. Under these conditions, efficient separation of rABS and rHIPS was achieved, with floating percentage of 3.62 and 96.39%, respectively. Therefore, surface modification using sodium chlorite can be utilized to facilitate the flotation separation of rABS and rHIPS.
The slow leaching rate of molybdenite (MoS 2 ), due to its inert nature, and low recovery hinders the application of traditional hydrometallurgical processing. This study investigated the effects of grinding speed and time, molar ratio of sodium chlorate (NaClO 3 , oxidant) to MoS 2 , leaching time and temperature on the leaching efficiency of molybdenum (Mo). Grinding at low speeds via mechanical activation decreased particle size. However, at speeds over 450 rpm for 1.0 h, or at lower speeds but with longer time, it triggers a solid-state reaction (mechanochemistry) producing soluble Na 2 Mo 2 O 7 . This may be due to the existence of an energy threshold for the solid-state reaction. The most suitable activating conditions were 600 rpm for 0.5 h, with a molar ratio of NaClO 3 : MoS 2 = 5, leached in 0.1 M NaOH solution for 2.0 h at 348 K, giving rise to a Mo recovery of 74.8%. The initial acid leaching stage of the ground mixture is dominated by the dissolution of Na 2 Mo 2 O 7 , giving rise to elevated Mo recovery. The later stage is controlled by the dissolution of MoS 2 , slowing down the increase in Mo extraction. As compared to alkaline conditions, acidic leaching of MoS 2 ground at low speeds (non solid-state reaction) gives greater Mo recovery, due to the greater activity of NaClO 3 to MoS 2 under acidic conditions. However, the greatest Mo recovery is achieved in alkaline solution for MoS 2 ground at high speed (solid-state reaction) due to the occurrence of mechanochemical reaction.
危险品化学品经营许可证（带存储）