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Lead sulfate, lead oxides and lead metal are the main component of lead paste in spent lead acid battery. When lead sulfate was desulfurized and transformed into lead carbonate by sodium carbonate, lead metal and lead oxides remained unchanged. Lead carbonate is easily decomposed to lead oxide and carbon dioxide under high temperature. Namely, vacuum thermal process is the reduction reaction of lead oxides. A compatible environmental process consisted of hydrometallurgical desulfurization and vacuum thermal reduction to recycle lead was investigated in this research. Lead paste was firstly desulfurized with sodium carbonate, by which, the content of sulfur declined from 7.87% to 0.26%. Then, the desulfurized lead paste was reduced by charcoal under vacuum. Under the optimized reaction conditions, i.e., vacuum thermal reduction at temperature 850 °C under 20 Pa for 45 min, a 22.11 × 10 −2 g cm −2 min −1 reduction rate, and a 98.13% direct recovery ratio of fine lead (99.77%) had been achieved, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Spent lithium-ion batteries containing lots of strategic resources such as cobalt and lithium are considered as an attractive secondary resource. In this work, an environmentally compatible process based on vacuum pyrolysis, oxalate leaching and precipitation is applied to recover cobalt and lithium from spent lithium-ion batteries. Oxalate is introduced as leaching reagent meanwhile as precipitant which leaches and precipitates cobalt from LiCoO2 and CoO directly as CoC2O4·2H2O with 1.0M oxalate solution at 80°C and solid/liquid ratio of 50gL−1 for 120min. The reaction efficiency of more than 98% of LiCoO2 can be achieved and cobalt and lithium can also be separated efficiently during the hydrometallurgical process. The combined process is simple and adequate for the recovery of valuable metals from spent lithium-ion batteries. [Copyright &y& Elsevier]

Abstract: Waste lead storage battery is the most important recyclable lead material not only in various European and other OECD countries but also in China. Pollution control of lead has become the focus of people’s attention in the world. A vacuum process for recycling waste lead storage battery was developed in this work. The experimental results showed that all the valuable materials in waste lead storage battery could be satisfactorily recycled by vacuum technologies. The vacuum melting of lead grids and the vacuum reduction of lead pastes produce the lead bullion with the direct recovery ratio of 96.29% and 98.98%, respectively. The vacuum pyrolysis of plastics can produce pyrolysis oil with yield of more than 93 wt.%. These vacuum recycling technologies offer improvements in metallurgical and environmental performance. [Copyright &y& Elsevier]

• A novel technology, for atomic economic recovery of lead paste, is proposed. • Direct recovery ratio of Pb reaches 99.29%, which means that Pb-loss is very little. • Sb-content in crude Pb-Sb alloy decreased from 46% to 0.98%. • The technology has advantages of lower cost and less pollution, etc. Until today, there are still many problems that must be solved through innovative research to make the recycling of spent lead-acid batteries and the separation of Pb-Sb alloy more environmentally friendly and energy-saving. In this paper, a novel method for regenerating lead paste, by vacuum reduction reaction coupling with separation of Pb-Sb alloy, was developed. In this process, antimony from Pb-Sb alloy is used to reduce desulfurized lead paste into lead under vacuum, while it is oxidized into volatile Sb 2 O 3 as by-product. The results showed that direct recovery ratio of Pb from desulfurized lead paste reached 99.29% and Sb-content in Pb-Sb alloy decreased from 46% to 0.98% under following conditions: the mass ratio of desulfurized lead paste to Pb-Sb alloy of 1.50, residual gas pressure of 30 Pa, reduction temperature of 810 °C for 50 min. By this method, not only the lead paste can be recovered with high atom economy, but also the Pb-Sb alloy can be separated efficiently at zero cost and without "three wastes" generation. Therefore, this method is very useful for the recycling of spent lead-acid battery and the separation of Pb-Sb alloy. [ABSTRACT FROM AUTHOR]

Abstract: Here, we focused on the recycling of waste printed circuit boards (WPCBs) using vacuum pyrolysis-centrifugation coupling technology (VPCT) aiming to obtain valuable feedstock and resolve environmental pollution. The two types of WPCBs were pyrolysed at 600°C for 30min under vacuum condition. During the pyrolysis process, the solder of WPCBs was separated and recovered when the temperature range was 400–600°C, and the rotating drum was rotated at 1000rpm for 10min. The type-A of WPCBs pyrolysed to form an average of 67.91wt.% residue, 27.84wt.% oil, and 4.25wt.% gas; and pyrolysis of the type-B of WPCBs led to an average mass balance of 72.22wt.% residue, 21.57wt.% oil, and 6.21wt.% gas. The GC–MS and FT-IR analyses showed that the two pyrolysis oils consisted mainly of phenols and substituted phenols. The pyrolysis oil can be used for fuel or chemical feedstock for further processing. The recovered solder can be recycled directly and it can also be a good resource of lead and tin for refining. The pyrolysis residues contained various metals, glass fibers and other inorganic materials, which could be recovered after further treatment. The pyrolysis gases consisted mainly of CO, CO2, CH4, and H2, which could be collected and recycled. [Copyright &y& Elsevier]

Abstract: In this research, a two-step process consisting of vacuum pyrolysis and vacuum centrifugal separation was employed to treat waste printed circuit boards (WPCBs). Firstly, WPCBs were pyrolysed under vacuum condition at 600°C for 30min in a lab-scale reactor. Then, the obtained pyrolysis residue was heated under vacuum until the solder was melted, and then the molten solder was separated from the pyrolysis residue by the centrifugal force. The results of vacuum pyrolysis showed that the type-A of WPCBs (the base plates of which was made from cellulose paper reinforced phenolic resin) pyrolysed to form an average of 67.97 wt.% residue, 27.73 wt.% oil, and 4.30 wt.% gas; and pyrolysis of the type-B of WPCBs (the base plates of which was made from glass fiber reinforced epoxy resin) led to an average mass balance of 72.20 wt.% residue, 21.45 wt.% oil, and 6.35 wt.% gas. The results of vacuum centrifugal separation showed that the separation of solder was complete when the pyrolysis residue was heated at 400°C, and the rotating drum was rotated at 1200rpm for 10min. The pyrolysis oil and gas can be used as fuel or chemical feedstock after treatment. The pyrolysis residue after solder separation contained various metals, glass fibers and other inorganic materials, which could be recycled for further processing. The recovered solder can be reused directly and it can also be a good resource of lead and tin for refining. [ABSTRACT FROM AUTHOR]