Innovative methodology for comprehensive utilization of high iron bearing zinc calcine

Zhang

et al. 2017

Sci Rep

Self Cite

The mechanism of ZnO sulfidation with sulfur and iron oxide at high temperatures was studied. The thermodynamic analysis, sulfidation behavior of zinc, phase transformations, morphology changes, and surface properties were investigated by HSC 5.0 combined with FactSage 7.0, ICP, XRD, optical microscopy coupled with SEM-EDS, and XPS. The results indicate that increasing temperature and adding iron oxide can not only improve the sulfidation of ZnO but also promote the formation and growth of ZnS crystals. Fe2O3 captured the sulfur in the initial sulfidation process as iron sulfides, which then acted as the sulfurizing agent in the late period, thus reducing sulfur escape at high temperatures. The addition of carbon can not only enhance the sulfidation but increase sulfur utilization rate and eliminate the generation of SO2. The surfaces of marmatite and synthetic zinc sulfides contain high oxygen due to oxidation and oxygen adsorption. Hydroxyl easily absorbs on the surface of iron-bearing zinc sulfide (Zn1−xFexS). The oxidation of synthetic Zn1−xFexS is easier than marmatite in air.

Section: Resultsmentioning

confidence: 99%

Mechanism study on the sulfidation of ZnO with sulfur and iron oxide at high temperature

Zhang

et al. 2017

Sci Rep

Self Cite

“…The leaching results were evaluated by chemically determining the original materials and leach products using ICP, XRD and SEM-EDS. The element concentrations of both solid and solution samples were determined by ICP (ICAP7400 Radial, Intrepid II XSP, Waltham, MA, USA), and each sample was measured at least three times [26][27][28]. 1 mL of leachate was diluted with 500 mL 10% HNO 3 medium to provide a sample with the appropriate concentration.…”

Section: Methodsmentioning

confidence: 99%

Selective Separation of Arsenic from Lead Smelter Flue Dust by Alkaline Pressure Oxidative Leaching

et al. 2019

Minerals

Self Cite

This study investigated the feasibility of using an alkaline pressure oxidative leaching process to treat lead smelter flue dust containing extremely high levels of arsenic with the aim of achieving the selective separation of arsenic. The effects of different parameters including NaOH concentration, oxygen partial pressure, liquid-to-solid ratio, temperature, and time for the extraction of arsenic were investigated based on thermodynamic calculation. The results indicated that the leaching efficiency of arsenic reached 95.6% under the optimized leaching conditions: 80 g/L of NaOH concentration, 1.0 MPa of oxygen partial pressure, 8 mL/g of liquid-to-solid ratio, 120 °C of temperature, 2.0 h of time. Meanwhile, the leaching efficiencies of antimony, cadmium, indium and lead were less than 4.0%, basically achieving the selective separation of arsenic from lead smelter flue dust. More than 99.0% of arsenic was converted into calcium arsenate product and thus separated from the leach solution by a causticization process with CaO after other metal impurities were removed from the solution with the addition of Na2S. The optimized causticization conditions were established as: 4.0 of the mole ratio of calcium to arsenic, temperature of 80 °C, reaction time of 2.0 h. The resulting product of calcium arsenate may be used for producing metallic arsenic.

“…Figure 7b reveals that leaching temperature has a positive effect on the leaching efficiency of tin. The value increases significantly when the temperature increases from 25 to 85 • C, which is attributed to the fact that the increase of leaching temperature results in the increase of the ion diffusion coefficient and decrease of the activation energy of the dissolution reaction [43]. Thereafter, it remains nearly constant.…”

Section: Alkaline Leaching Of Tinmentioning

confidence: 96%

Preparation of Calcium Stannate from Lead Refining Dross by Roast–Leach–Precipitation Process

et al. 2019

Minerals

Self Cite

Lead refining dross containing plenty of tin and other heavy metals, such as lead and antimony, is considered a hazardous waste generated in large quantities in lead smelter plants. In this study, calcium stannate was synthesized from lead refining dross using sodium carbonate roasting and alkaline leaching followed by precipitation with CaO. The effect of roasting and leaching parameters on the extraction efficiency of tin was investigated. The leaching efficiency of tin reached 94% under the optimized conditions: roasting with 60% Na2CO3 at 1000 °C for 45 min, and leaching using 2 mol/L NaOH solution for 90 min at 85 °C and 8 cm3/g liquid/solid ratio. Furthermore, more than 99% of tin in the leaching solution was precipitated using CaO. Finally, XRD, SEM, and ICP-OES analyses indicated that the final CaSnO3 product had a purity of 95.75% and its average grain size was smaller than 5 μm. The results indicated that the developed method is feasible to produce calcium stannate from lead refining dross.