Hydrometallurgical processing of waste integrated circuits (ICs) to recover Ag and generate mix concentrate of Au, Pd and Pt

Panda, Rekha; Dinkar, Om Shankar; Kumari, Archana; Gupta, Rajesh; Jha, Manis Kumar; Pathak, Devendra Deo

doi:10.1016/j.jiec.2020.10.007

Cited by 18 publications

(6 citation statements)

References 19 publications

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“…Pyrolysis and manual separation effectively enriched Ta values from 34 to 74% in the sintered core, while Ag values increased from 0.94% to 2.45% in the minus 212 μm fraction. Subsequently, the sink product can be hydro metallurgically treated using HNO 3 leaching and precipitation (KCl, NaCl) to recover Ag values (Panda et al 2021). The process utilises citric acid ∼ 1.12 L, NaOH (for precipitation) ∼ 715 ml, and H 2 O 2 ∼ 7.6 ml.…”

Section: Resultsmentioning

confidence: 99%

Recycling of metallic values from discarded tantalum capacitors

Mir

Dhawan

2023

Mineral Processing and Extractive Metallurgy

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The generation of electronic waste generation has led to significant attention towards metal recovery from urban sources. Due to scarcity, finite resources, and geopolitical constraints, tantalum recycling from capacitors is essential. In this study, sequential separation involving the removal of tightly bound epoxy resin and metallic impurities is carried out. Pyrolysis as a pre-treatment and its response on phase transformation, resin decomposition and metal enrichment are investigated. Pyrolysis effectively liberates the tantalum-rich sintered core from outer resin which is followed by mild organic acid leaching. The manganese impurity was removed from the core to obtain Ta recovery of ∼94.8% with ∼96% purity in the leach residue. The separated resin component was subjected to conventional sink-float separation for the recovery of metallic values (silver, tantalum). It is found that 100 g (666 units) of Ta capacitors can yield 34 g of Ta, equivalent to 0.28 tons of primary ore.

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Section: Resultsmentioning

confidence: 99%

Recycling of metallic values from discarded tantalum capacitors

Mir

Dhawan

2023

Mineral Processing and Extractive Metallurgy

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“…On average, the contents of precious metals in ECs ranged from the highest level of silver (992 mg/kg) > gold (303 mg/ kg) > palladium (88 mg/kg) > platinum (3 mg/kg). Due to their excellent electrical conductivity, high corrosion resistance, the demand for precious metals in the manufacture of electronic products is increasing (Panda et al, 2021). Ag was detected in 11 groups of ECs, ranging 15-5290 mg/kg, which is much higher than the other three precious metals, because of its high conduction (Li et al, 2019a).…”

Section: Precious Metalsmentioning

confidence: 99%

“…Slurry electrolysis was applied to recover copper and gold from CPU sockets (Li et al, 2019b). Ag, Au, Pd and Pt are recovered from waste integrated circuits (ICs) with a process that combined physical beneficiation and hydrometallurgy (Panda et al, 2021). There are also few studies on the toxicity of ECs constituents.…”

Section: Introductionmentioning

confidence: 99%

Toxic footprint and materials profile of electronic components in printed circuit boards

et al. 2022

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“…The discipline basis of hydrometallurgy mainly includes physical chemistry of metallurgy, chemical reaction principles, and mechanical engineering . The leaching process is the key process of hydrometallurgy, which determines the extraction efficiency of target products and the difficulty of slag recovery . Gold leaching process is a chemical process in which sodium cyanide solution reacts with gold in the ore.…”

Section: Introductionmentioning

confidence: 99%

“… 4 The leaching process is the key process of hydrometallurgy, which determines the extraction efficiency of target products and the difficulty of slag recovery. 5 Gold leaching process is a chemical process in which sodium cyanide solution reacts with gold in the ore. Through the thickening washing process, the cyanide leaching liquid containing sodium gold cyanide can be preliminary separated from the slag.…”

Section: Introductionmentioning

confidence: 99%

Model-Free Adaptive Control of Hydrometallurgy Cascade Gold Leaching Process with Input Constraints

et al. 2023

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Hydrometallurgy technology can directly deal with low grade and complex materials, improve the comprehensive utilization rate of resources, and effectively adapt to the demand of low carbon and cleaner production. A series of cascade continuous stirred tank reactors are usually applied in the gold leaching industrial process. The equations of leaching process mechanism model are mainly composed of gold conservation, cyanide ion conservation, and kinetic reaction rate equations. The derivation of the theoretical model involves many unknown parameters and some ideal assumptions, which leads to difficulty and imprecision in establishing the accurate mechanism model of the leaching process. Imprecise mechanism models limit the application of model-based control algorithms in the leaching process. Due to the constraints and limitations of the input variables in the cascade leaching process, a novel model-free adaptive control algorithm based on compact form dynamic linearization with integration (ICFDL-MFAC) control factor is first constructed. The constraints between input variables is realized by setting the initial value of the input to the pseudo-gradient and the weight of the integral coefficient. The proposed pure data-driven ICFDL-MFAC algorithm has anti-integral saturation ability and can achieve faster control rate and higher control precision. This control strategy can effectively improve the utilization efficiency of sodium cyanide and reduce environmental pollution. The consistent stability of the proposed control algorithm is also analyzed and proved. Compared with the existing model-free control algorithms, the merit and practicability of the control algorithm are verified by the practical leaching industrial process test. The proposed model-free control strategy has advantages of strong adaptive ability, robustness, and practicability. The MFAC algorithm can also be easily applied to control the multi-input multi-output of other industrial processes.

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Hydrometallurgical processing of waste integrated circuits (ICs) to recover Ag and generate mix concentrate of Au, Pd and Pt

Cited by 18 publications

References 19 publications

Recycling of metallic values from discarded tantalum capacitors

Recycling of metallic values from discarded tantalum capacitors

Toxic footprint and materials profile of electronic components in printed circuit boards

Model-Free Adaptive Control of Hydrometallurgy Cascade Gold Leaching Process with Input Constraints

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