A value-added multistage utilization process for the gradient-recovery tin, iron and preparing composite phase change materials (C-PCMs) from tailings

Abstract

Tin-, iron-bearing tailing is a typically hazardous solid waste in China, which contains plenty of valuable tin, iron elements and is not utilized effectively. In this study, a multistage utilization process was put forward to get the utmost out of the valuable elements (tin and iron) from the tailings, and a gradient-recovery method with three procedures was demonstrated: (1) An activated roasting followed by magnetic separation process was conducted under CO-CO2 atmosphere, tin and iron were efficiently separated during magnetic separation process, and 90.8 wt% iron was enriched in magnetic materials while tin entered into non-magnetic materials; (2) The tin-enriched non-magnetic materials were briquetted with CaCl2 and anthracite and roasted, then tin-rich dusts were collected during the chloridizing roasting process; (3) The roasted briquettes were infiltrated in melting NaNO3 to prepare NaNO3/C-PCMs by a infiltration method. Three kinds of products were obtained from the tailings by the novel process: magnetic concentrates containing 64.53 wt.% TFe, tin-rich dusts containg 52.4 wt.% TSn and NaNO3/C-PCMs for high temperature heat storage. Such a comprehensive and clean utilization method for tin-, iron-bearing tailings produced no secondary hazardous solid wastes, and had great potential for practical application.

Ternary metal oxide nanocomposite for room temperature H2S and SO2 gas removal in wet conditions

“…The PXRD pattern of MFZO nanocomposite has diffraction peaks for β-MnO 2 (purple circle) 23 , ZnO (pink circle) 24 , ferrites (green square) 25 , and NaNO 3 (blue square) 26 , which confirmed a poly-oxide nature of the composite (Fig. 2 a).…”

Mapping Recyclability of Industrial Waste for Anthropogenic Circularity: A Circular Economy Approach

“…Mining dumps (comprising unconsolidated waste rock, parent material, tailings, or mixtures) are globally generated at approximately 20–25 billion t per year and deposited into pond piles on-land or underwater. − The pyro-metallurgical slag is considered hazardous waste with a low economic value and intricate use. − Copper slag, for example, is a byproduct produced through matte smelting and copper processing. Producing 1 ton of copper generally generates around 2.2–3.0 t of copper slag. , Since the use and recovery of the metal are mainly relied on its physical–chemical form, the slag of 0.8% copper is either tossed out for waste purposes or sold as products with similar characteristics to natural basalt (crystalline) or obsidian (amorphous).…”