Leaching of lead from solder material of waste printed circuit boards (PCBs)

Jha, Manis Kumar; Kumari, Archana; Choubey, Pankaj Kumar; Lee, Jae-chun; Kumar, Vinay; Jeong, Jaeseung

doi:10.1016/j.hydromet.2012.04.010

Cited by 117 publications

(52 citation statements)

References 12 publications

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“…The purpose of the first nitric acid pretreatment is the recovery of Sn and Pb from waste PCBs. The first nitric acid pretreatment of waste PCBs was conducted according to previous reports (Yang et al, 2011;Jha et al, 2012). In a typical experiment, waste PCBs pieces with different sizes were immersed in 8.1 wt.% dilute nitric acid solution for 20 min at 90°C in the presence of agitation in a closed chamber.…”

Section: Methodsmentioning

confidence: 99%

“…In this Sn-Pb recovery stage, soldering tin reacts with nitric acid to form insoluble metastannic acid and soluble lead nitrate, while Cu almost cannot be leached out due to that Cu exists in the middle layer of the waste PCBs and it does not expose to nitric acid. Tin partially dissolved at low concentration HNO 3 , while it formed a protective b-SnO 2 oxide film which led to the reduction in the overall rate of dissolution of tin, and insoluble metastannic acid was formed at higher concentrations acid (Jha et al, 2012). The insoluble metastannic acid formed from the reaction between soldering tin and nitric acid may hinder the further reaction of Pb leaching, leading to a negative influence on the Pb removal.…”

Section: Methodsmentioning

confidence: 99%

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A novel recovery method of copper from waste printed circuit boards by supercritical methanol process: Preparation of ultrafine copper materials

Xiu

Weng

et al. 2017

Waste Management

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a b s t r a c tIn this study, supercritical methanol (SCM) process was successfully used for the preparation of ultrafine copper materials from waste printed circuit boards (PCBs) after nitric acid pretreatment. Waste PCBs were pretreated twice in nitric acid. Sn and Pb were recovered by the first nitric acid pretreatment. The leach liquor with a high concentration of copper ions after the second nitric acid leaching was subjected to SCM process. The mixture of Cu and Cu 2 O with poor uniformity of particle size was formed due to the effect of ferric iron contained in the leach liquor of waste PCBs, while more uniform and spherical Cu particles with high monodispersity and smaller size could be prepared after the removal of Fe. The size of Cu particles increased obviously with the decline of SCM temperature, and particles became highly aggregated when the reaction temperature decreased to 300°C. The size of Cu particles decreased markedly with the decrease of initial concentration of copper ion in the leach liquor of waste PCBs. It is believed that the process developed in this study is simple and practical for the preparation of ultrafine copper materials from waste PCBs with the aim of recycling these waste resources as a high value-added product.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

A novel recovery method of copper from waste printed circuit boards by supercritical methanol process: Preparation of ultrafine copper materials

Xiu

Weng

et al. 2017

Waste Management

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show abstract

“…2) The recovery of valuable metals (e.g., Sn and Ag) from waste solder can be achieved using nitric acid 3,4) or electrochemical leaching. 5) However, since some Pb-free solders still contain traces of Pb, this Pb should be removed prior to the extraction of the more valuable metals to prevent it remaining as an impurity in the end product.…”

Section: Introductionmentioning

confidence: 99%

Lead Trace Removal from Waste Electronic Scraps by Organic Acids

et al. 2014

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The removal of Pb traces from Pb-free solder is an important process in the recycling of solder. Pb must be removed before the more valuable metals are extracted, otherwise the recycling becomes less efficient and the end product impure. Pb removal by three organic acids is investigated here. Acetic acid was shown to dissolve Pb selectively from waste solder better than citric acid or oxalic acid could. Leaching for 72 h in 0.01 M acetic acid removed approximately 137 mg/L Pb from the solder at 30°C, 220 rpm; in addition, no Sn was leached. Higher concentrations of acetic acid (0.05 and 0.1 M) led to increased Sn leaching and decreased Pb leaching, similar to the results observed in citric acid. A total of 0.01 M citric acid leached 7 mg/L Pb and 1831 mg/L Sn; 0.01 M oxalic acid leached 8 mg/L Pb and 1318 mg/L Sn. A comparison using pure Pb and Sn powders showed that the leaching of both metals increased with increasing concentrations of acetic acid and citric acid, contrary to the results observed using solder.

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“…Currently, metallurgical techniques, including pyrometallurgical process Moltó et al, 2011) and hydrometallurgical process (Oishi et al, 2007;Jha et al, 2012;Tuncuk et al, 2012) are the two traditional approaches for the recovery of metals from waste PCBs. Hydrometallurgical processes with relatively low capital costs, no gas/dust formation, operational selectivity and suitability for small scale applications are propitious alternatives for the treatment of waste PCBs (Havlik et al, 2010;Pant et al, 2012;Tuncuk et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Recovery of metals from waste printed circuit boards by supercritical water pre-treatment combined with acid leaching process

2013

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a b s t r a c tWaste printed circuit boards (PCBs) contain a large number of metals such as Cu, Sn, Pb, Cd, Cr, Zn, and Mn. In this work, an efficient and environmentally friendly process for metals recovery from waste PCBs by supercritical water (SCW) pre-treatment combined with acid leaching was developed. In the proposed process, waste PCBs were pre-treated by SCW, then the separated solid phase product with concentrated metals was subjected to an acid leaching process for metals recovery. The effect of SCW pre-treatment on the recovery of different metals from waste PCBs was investigated. Two methods of SCW pre-treatment were studied: supercritical water oxidation (SCWO) and supercritical water depolymerization (SCWD). Experimental results indicated that SCWO and SCWD pre-treatment had significant effect on the recovery of different metals. SCWO pre-treatment was highly efficient for enhancing the recovery of Cu and Pb, and the recovery efficiency increased significantly with increasing pre-treatment temperature. The recovery efficiency of Cu and Pb for SCWO pre-treatment at 420°C was 99.8% and 80%, respectively, whereas most of the Sn and Cr were immobilized in the residue. The recovery of all studied metals was enhanced by SCWD pre-treatment and increased along with pre-treatment temperature. Up to 90% of Sn, Zn, Cr, Cd, and Mn could be recovered for SCWD pre-treatment at 440°C.

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Leaching of lead from solder material of waste printed circuit boards (PCBs)

Cited by 117 publications

References 12 publications

A novel recovery method of copper from waste printed circuit boards by supercritical methanol process: Preparation of ultrafine copper materials

A novel recovery method of copper from waste printed circuit boards by supercritical methanol process: Preparation of ultrafine copper materials

Lead Trace Removal from Waste Electronic Scraps by Organic Acids

Recovery of metals from waste printed circuit boards by supercritical water pre-treatment combined with acid leaching process

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