Analysis for Optimum Conditions for Recovery of Valuable Metals from E-waste Through Black Copper Smelting

Author(s):  
M. A. H. Shuva ◽  
M. A. Rhamdhani ◽  
G. A. Brooks ◽  
S. Masood ◽  
M. A. Reuter ◽  
...  
2020 ◽  
Vol 38 (11) ◽  
pp. 1214-1221
Author(s):  
Yuhui Zhang ◽  
Xiaoyan Feng ◽  
Bingjie Jin

Separation of arsenic and valuable metals (Pb, Zn, Cu, Bi, Sn, In, Ag, Sb, etc.) is a core problem for effective utilization of high arsenic-containing copper smelting ashes (HACSA). This study developed an effective separation process of arsenic, lead, and zinc from HACSA via alkali leaching followed by sulfide precipitation. The separation behaviors and optimum conditions for alkali leaching of arsenic and sulfide precipitation of lead and zinc were established respectively as follows: NaOH concentration 3.81 M; temperature 80°C; time 90 minutes; liquid-to-solid ratio 4:1; agitation speed 450 revolutions/minute (r/min) and 2.0 times of theoretical quantity of sodium sulfide (Na2S); temperature 70°C; and time 60 minutes. The results indicated that the leaching rates of As, Pb, and Zn were 92.4%, 36.9% and 13.4%, respectively. More than 99% of lead and zinc were precipitated from the alkali leachate. The scanning electron microscopy/energy dispersive X-ray spectroscopy study confirmed that arsenic was dissolved from HACSA into the alkali leachate. Furthermore, lead and zinc were precipitated as sulfides from the alkali leachate. The proposed process was a good technique for separation of arsenic and enrichment of valuable metals for further centralized treatment separately. It provided high separation efficiency of arsenic and valuable metals, as well as low environmental pollution.


2016 ◽  
Vol 74 (10) ◽  
pp. 2454-2461
Author(s):  
Qiang Bi ◽  
Juanqin Xue ◽  
Yingjuan Guo ◽  
Guoping Li ◽  
Haibin Cui

The recycling of copper and nickel from metallurgical wastewater using emulsion liquid membrane (ELM) was studied. P507 (2-ethylhexyl phosphonic acid-2-ethylhexyl ester) and TBP (tributyl phosphate) were used as carriers for the extraction of copper and nickel by ELMs, respectively. The influence of four emulsion composition variables, namely, the internal phase volume fraction (ϕ), surfactant concentration (Wsurf), internal phase stripping acid concentration (Cio) and the carrier concentration (Cc), and the process variable treat ratio on the extraction efficiencies of copper or nickel were studied. Under the optimum conditions, 98% copper and nickel were recycled by using ELM. The results indicated that ELM extraction is a promising industrial application technology to retrieve valuable metals in low concentration metallurgical wastewater.


2019 ◽  
Vol 62 (1) ◽  
pp. 8-14 ◽  
Author(s):  
V. A. Martirosyan ◽  
M. E. Sasuntsyan

In connection with the development of copper and molybdenum production in Armenia, it becomes necessary to develop a technology for processing the slags of the functioning metallurgical plants to extract valuable metals from these slags. It concerns the copper slags of Alaverdi Copper-Smelting Plant with a content of FeO ~50  % and the molybdenum slags of Yerevan “Pure Iron” Plant with a content of SiO2 ~80  %. These slags are obtained at high temperatures (with FeO·SiO2 , CaO·SiO2 , Fe3 O4 ) and, therefore, they are less active to be used later. Meanwhile, the mentioned slags are rich in iron and silicon oxides and can serve as a cheap raw material for producing iron silicides. The iron silicides can be used in micro- and nanoelectronics, as well as in metallurgy as an alloying additive in the production of steels of special physical and chemical properties. The production of such valuable silicides from an inexpensive raw material is important for Republic of Armenia and is of not only economic, but also ecological significance. To obtain iron silicides, a method of combined aluminothermal reduction of primarily mechanoactivated copper and molybdenum slags is proposed. The preliminary mechanoactivation allows to purposefully affect the structure of the reaction mixture and parameters of the self-propagating high-temperature synthesis (SHS), thus ensuring the possibility of regulating the structure and phase composition of the synthesized silicides. This work considers issues on the impact of transformation and phase formation on the morphology of slags of copper and molybdenum production in the functioning Armenian metallurgical plants at mechanochemical activation by the method of fine grinding in a vibromill. It is shown that at fine grinding (up to 10  mcm), the slags, containing small-reactivity complex compounds of iron and silicon (fayalite, magnetite, quarzite) undergo profound chemical changes, transforming into amorphous oxides. The obtained activated oxides can serve as a raw material for producing iron- and silicon-containing alloys – iron silicides.


Author(s):  
Wei Gao ◽  
Bin Xu ◽  
Junkui Yang ◽  
Yongbin Yang ◽  
Qian Li ◽  
...  

2014 ◽  
Vol 881-883 ◽  
pp. 564-569
Author(s):  
Da Chao Zhang ◽  
Xiao Lai Liu ◽  
Da Ming Guan ◽  
Xiao Yi Xu ◽  
Su Ying Wu

Copper smelting gas producing sulfuric acid process produces contaminated acid which contains high concentration of fluorine, chlorine, arsenic and copper, zinc, lead, cadmium and other metals. The sulfide precipitation and lime neutralization methods have been used at present. Those methods have some deficiencies as which produces a lot of hazardous and unwieldy solid wastes, spends huge processing cost, reuse difficultly the water after treatment. In this paper, according to characteristics of this kind of smelting contaminated acid, evaporation condensing process and the feasibility of recycling arsenic, sulfuric acid and valuable metals were studied. Under the condition of atmospheric heating evaporation, this study explored the distribution characteristics of fluorine, chlorine, sulfate radical, arsenic in condensate and in concentrate and the crystallization removal rates of arsenic trioxide in concentrate at different temperatures and different enrichment ratios. The results show arsenic, fluorine and chloride have good removal rates from contaminated acid by evaporation condensing process. Temperature at 130°C, enrichment multiple in 6~7, the removal rate of arsenic, fluorine and chlorine reached 62%, 88%, 77%. The results also show evaporation condensing process has good application prospects to treat smelting contaminated acid.


2015 ◽  
Vol 737 ◽  
pp. 642-645 ◽  
Author(s):  
Zhong Guang Ji ◽  
Zheng Xu ◽  
Wei Wang ◽  
Li Mei Yang

Valuable metals in smelting sludge from smelting industry have a recovery value. In this work, for realizing waste recycling effectively, selective and multi-step leaching of valuable metals was investigated with scrap copper-smelting sludge as research object. The effect of the concentration of sulphuric acid on leaching rates of valuable metals was investigated first. The results showed that the leaching rates of Cu, Zn and Ni were 6.1%, 59.4% and 63.3% at the acid concentration of 65g/L. Then, the results of the selective and multi-step leaching indicated that the leaching rates of Cu, Zn and Ni were over 90% after two-step leaching. In third step, the content of Cu in leached residue was 6.68%, which was higher than origin sludge. Repeat three-step leaching process above, Zn and Ni were leached selectively and Cu was accumulated in leached residue continually.


Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1822 ◽  
Author(s):  
Behrouz Sabzezari ◽  
Seyed Mohammad Javad Koleini ◽  
Sina Ghassa ◽  
Behzad Shahbazi ◽  
Saeed Chehreh Chelgani

Industrial wastes may contain high concentrations of valuable metals. Extraction and recovery of these metals have several economic and environmental advantages. Various studies showed positive effects of microwaves as a pretreatment method before the leaching of minerals. However, there are empty rooms for exploring simultaneous microwave and leaching (microwave-leaching) of industrial waste material for the production of valuable metals. This investigation examined the microwave-leaching method to extract copper and zinc from a copper-smelter dust (CSD). The results of microwave-leaching mechanism were compared with conventional heating leaching based on kinetics modelling. The final Cu recovery in the conventional heating and microwave irradiation was 80.88% and 69.83%, respectively. Kinetic studies indicated that the leaching reactions follow diffusion across the product layer. Based on X-ray powder diffraction (XRD) analyses, during conventional experiments sulfate; components formed with high intensity as an ash layer which prevents reagent access to the solid surface and decreases the Cu dissolution. While the sulfate components did not detect in the microwave-leaching residuals which means that microwave irradiation helped to decrease the ash layer formation. Taking all mentioned results into consider it can be concluded that microwave-leaching can be considered as an efficient method for extraction of valuable metals from waste materials.


2011 ◽  
Vol 391-392 ◽  
pp. 1138-1142 ◽  
Author(s):  
Dian Kun Lu ◽  
Li Fang Shi ◽  
Zhe Nan Jin

Mineralogical examinations of Asheler copper mine flotation tailings have been carried out. Results show that the major metal sulphide minerals are pyrite and the main gangue constituents are quartz, chlorite-serpentine and muscovite. The main valuable metals are Cu, Zn and Ag. Basic mineral compositions of copper and zinc have been identified through chemical phase analysis. On the basis of mineralogical examinations, leaching test has been carried out in about 240g/l NaCl solution. The optimum conditions for leaching are found as follows: temperature at 86°C, pulp concentration is 24.19%wt, [Cu2+] =19.22g/l, [HCl] initial =0.17mol/L. Under these conditions, chloride leaching can extract 83.35%Cu, 92.10%Zn, and 85.26%Ag after 8 hours leaching.


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