Recovery of valuable metals from copper smelting open-circuit dust and its arsenic safe disposal

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.

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SLAGS OF THE METALLURGICAL PLANTS OF ARMENIA AT FINE GRINDING

Izvestiya Ferrous Metallurgy ◽

10.17073/0368-0797-2019-1-8-14 ◽

2019 ◽

Vol 62 (1) ◽

pp. 8-14 ◽

Cited By ~ 1

Author(s):

V. A. Martirosyan ◽

M. E. Sasuntsyan

Keyword(s):

Chemical Properties ◽

Complex Compounds ◽

Raw Material ◽

Copper Smelting ◽

Iron Silicides ◽

Fine Grinding ◽

High Temperature Synthesis ◽

Valuable Metals ◽

Physical And Chemical ◽

The Impact

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.

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Study on Treatment of Smelting Contaminated Acid by Evaporation Condensing Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.881-883.564 ◽

2014 ◽

Vol 881-883 ◽

pp. 564-569

Author(s):

Da Chao Zhang ◽

Xiao Lai Liu ◽

Da Ming Guan ◽

Xiao Yi Xu ◽

Su Ying Wu

Keyword(s):

Sulfuric Acid ◽

Removal Rate ◽

Solid Wastes ◽

Copper Smelting ◽

High Concentration ◽

Removal Rates ◽

Processing Cost ◽

Valuable Metals ◽

Different Temperatures ◽

Copper Zinc

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.

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Selective and Multi-Step Leaching of Valuable Metals from Scrap Copper-Smelting Sludge

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.737.642 ◽

2015 ◽

Vol 737 ◽

pp. 642-645 ◽

Cited By ~ 1

Author(s):

Zhong Guang Ji ◽

Zheng Xu ◽

Wei Wang ◽

Li Mei Yang

Keyword(s):

Sulphuric Acid ◽

Acid Concentration ◽

Waste Recycling ◽

Copper Smelting ◽

Leaching Process ◽

Valuable Metals

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.

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Research on Recovery of Valuable Metals in Waste Acid from Copper Smelting Flue Gas Acid-Making and Reduction and Harmless Treatment of Solid Wastes

The Minerals, Metals & Materials Series - Extraction 2018 ◽

10.1007/978-3-319-95022-8_24 ◽

2018 ◽

pp. 303-312

Author(s):

Yan Wen ◽

Zhen Bao ◽

Xinmin Wu

Keyword(s):

Flue Gas ◽

Solid Wastes ◽

Copper Smelting ◽

Valuable Metals ◽

Waste Acid

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Microwave-Leaching of Copper Smelting Dust for Cu and Zn Extraction

Materials ◽

10.3390/ma12111822 ◽

2019 ◽

Vol 12 (11) ◽

pp. 1822 ◽

Cited By ~ 5

Author(s):

Behrouz Sabzezari ◽

Seyed Mohammad Javad Koleini ◽

Sina Ghassa ◽

Behzad Shahbazi ◽

Saeed Chehreh Chelgani

Keyword(s):

Microwave Irradiation ◽

Kinetic Studies ◽

Copper Smelter ◽

Product Layer ◽

Industrial Wastes ◽

Copper Smelting ◽

Conventional Heating ◽

Positive Effects ◽

Ash Layer ◽

Valuable Metals

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.

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Electrochemical Mechanism of Recovery of Nickel Metal from Waste Lithium Ion Batteries by Molten Salt Electrolysis

Materials ◽

10.3390/ma14226875 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6875

Author(s):

Hui Li ◽

Yutian Fu ◽

Jinglong Liang ◽

Chenxiao Li ◽

Jing Wang ◽

...

Keyword(s):

Molten Salt ◽

Lithium Ion Batteries ◽

Electrochemical Reduction ◽

Reduction Process ◽

Lithium Ion ◽

Open Circuit ◽

Nickel Metal ◽

Molten Salt Electrolysis ◽

Reduction Behavior ◽

Valuable Metals

With the widespread use of lithium-ion batteries, the cumulative amount of used lithium-ion batteries is also increasing year by year. Since waste lithium-ion batteries contain a large amount of valuable metals, the recovery of valuable metals has become one of the current research hotspots. The research uses electrometallurgical technology, and the main methods used are cyclic voltammetry, square wave voltammetry, chronoamperometry and open circuit potential. The electrochemical reduction behavior of Ni3+ in NaCl-CaCl2 molten salt was studied, and the electrochemical reduction behavior was further verified by using a Mo cavity electrode. It is determined that the reduction process of Ni3+ in LiNiO2 is mainly divided into two steps: LiNiO2 → NiO → Ni. Through the analysis of electrolysis products under different conditions, when the current value of LiNiO2 is not less than 0.03 A, the electrolysis product after 10 h is metallic Ni. When the current reaches 0.07 A, the current efficiency is 77.9%, while the Li+ in LiNiO2 is enriched in NaCl-CaCl2 molten salt. The method realizes the separation and extraction of the valuable metal Ni in the waste lithium-ion battery.

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