Assessment of the effects of the Japanese shift to lead-free solders and its impact on material substitution and environmental emissions by a dynamic material flow analysis

Lead-free electronics has been extensively studied, whereas their adoption by society and their impact on material substitution and environmental emissions are not well understood. Through a material flow analysis (MFA), this paper explores the life cycle flows for solder-containing metals in Japan, which leads the world in the shift to lead-free solders in electronics. The results indicate that the shift has been progressing rapidly for a decade, and that substitutes for lead in solders, which include silver and copper, are still in the early life cycle stages. The results also show, however, that such substitution slows down during the late life cycle stages owing to long electronic product lifespans. This deceleration of material substitution in the solder life cycle may not only preclude a reduction in lead emissions to air but also accelerate an increase in silver emissions to air and water. As an effective measure against ongoing lead emissions, our scenario analysis suggests an aggressive recycling program for printed circuit boards that utilizes an existing recycling scheme.


Science of the Total Environment
Volume 438, 1 November 2012, Pages 49-58



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Leaching studies for tin recovery from waste e-scrap

Scopus: Printed circuit boards (PCBs) are the most essential components of all electrical and electronic equipments, which contain noteworthy quantity of metals, some of which are toxic to life and all of which are valuable resources.

Therefore, recycling of PCBs is necessary for the safe disposal/utilization of these metals. Present paper is a part of developing Indo-Korean recycling technique consists of organic swelling pre-treatment technique for the liberation of thin layer of metallic sheet and the treatment of epoxy resin to remove/recover toxic soldering material. To optimize the parameters required for recovery of tin from waste PCBs, initially the bench scale studies were carried out using fresh solder (containing 52.6% Sn and 47.3% Pb) varying the acid concentration, temperature, mixing time and pulp density. The experimental data indicate that 95.79% of tin was leached out from solder material using 5.5 M HCl at fixed pulp density 50 g/L and temperature 90 °C in mixing time 165 min. Kinetic studies followed the chemical reaction controlled dense constant size cylindrical particles with activation energy of 117.68 kJ/mol. However, 97.79% of tin was found to be leached out from solder materials of liberated swelled epoxy resin using 4.5 M HCl at 90 °C, mixing time 60 min and pulp density 50 g/L. From the leach liquor of solder materials of epoxy resin, the precipitate of sodium stannate as value added product was obtained at pH 1.9. The Pb from the leach residue was removed by using 0.1 M nitric acid at 90 °C in mixing time 45 min and pulp density 10 g/L. The metal free epoxy resin could be disposed-of safely/used as filling material without affecting the environment.


Waste Management
2012
Leaching studies for tin recovery from waste e-scrap  ( Articles not published yet, but available online Article in press About articles in press (opens in a new window) )

Jha, M.K.a , Choubey, P.K.a, Jha, A.K.a, Kumari, A.a, Lee, J.-c.b , Kumar, V.a, Jeong, J.b 

a  Metal Extraction and Forming Division, National Metallurgical Laboratory (NML), Jamshedpur 831 007, India
b  Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources, Daejeon 305-350, Republic of Korea

Seika Machinery’s SPR Produces Pure Solder Ingots

Seika Machinery said an independent lab has confirmed its Solder Paste Recycling machine is capable of producing pure solder ingots from solder paste.

The ingots produced by the SPR Unit are reportedly 100% pure, with no additives or impurities added to the solder paste during the recycling process. The system removes the flux from the metal and produces a flux-free ingot. There are no voids inside the solder ingots, says Seika.

A number of analyses were performed, including Fourier Transform Infrared Spectroscopy, Inductively Coupled Plasma technique, and Scanning Electron Microscopy.

The machine enables 100% of the metal content of waste solder paste to be recovered as solder bar, the firm says.

US WEEE recycling statistics

Factiva According to the International Data Corporation (IDC), a global market research provider, growth in the U. S. electronics recycling industry in the past decade shows a bright spot in an otherwise sluggish economy.

"Approximately 3.5 million tons of electronics were recycled by the recycling industry in the United States in 2010, employing more than 30, 000 workers with estimated revenue of over $5 billion," said David Daoud, IDC research director.

A recent IDC survey "shows a booming electronics recycling industry and prescribes a clear path for even more growth," said Robin Wiener, president of the Institute of Scrap Recycling Industries Inc.

"Electronics recyclers are creating American jobs, adopting an industry standard that will help sustain growth, and are recycling electronics here at home." McKernan, who has been in the electronics industry more than 40 years and with the Victor company for 12, said he is proud to be part of a positive movement.

Recycling "is our biggest environmental defense," he said.

Electronic Products and Technology - Unit recycles 90% solder paste

EP&T : "SEIKA USA Solder Paste Recycling Unit enables approximately 90 percent of waste solder paste to be recovered as solder bar. System provides a major decrease in disposal costs for factory waste, a reduction in CO2 emissions and reduced costs for solder bar as a result of recycling waste. As an additional benefit. Unit is fully automated with the use of a touch screen panel."

European Metal Recycling and Summit Solders

European Metal Recycling: "EMR has a wholly owned subsidiary, Summit Solder Products, who are the leading UK manufacturer of tin based solder products. Our expertise has been developed through understanding each industry and knowing exactly what different customers require. Our reputation has been built through supplying consistently high quality solder products with exceptional levels of customer service.

Using highly efficient technology, we are able to enhance the purity of any alloy, which not only reduces waste for the end user, but also saves on cost."

Method for Removing Solder Oxides Floating on Molten Solder

Factiva: "'There are disclosed a soldering apparatus comprising a solder wave shape forming means for melting solder and forming solder wave shape, and a separating agent dusting means for dusting solder oxides with a separating agent which separates solder and solder oxides, wherein said separating agent is any one selected from the group consisting of offal, cereal grain or flour, bean flour, seed grain or flour, soybean-cake flour, and peanut hull flour, or a combination thereof, as well as an agent and a method for separating solder and solder oxides.'"

Solder Prices High as LME Tin over 19,000 per ton | AWA Refiners News

AWA Refiners News: "AWA Refiners offer a FREE collection service throughout the Uk, so please contact us if you have any Sn bearing material you would like to offer."

Hydrometallurgical treatment of used printed circuit boards after thermal treatment

Scopus: "The hydrometallurgical route of copper and tin extraction from printed circuit boards (PCB) of used personal computers after thermal pretreatment is discussed."

The PCB fractions crushed and sorted into -8 + 0, -8 + 3 and -3 + 0 mm were used for the experiments. The samples were thermally pretreated at temperatures of 300, 500, 700 and 900 °C during 15, 30 and 60 min with the presence of air (burning) before the leaching process. The leaching solution of 1 M HCl and temperature of 80 °C was used for the leaching. The original as well as thermally pretreated samples were leached under these conditions. The weight losses within the range from 5% to 35% were achieved by burning depending on the burning temperature. The increase of burning temperature causes the copper extraction into solution up to 98%, while copper extraction into solution from non-burned samples was up to 6%. The opposite effect was observed in the case of the tin leaching, where the highest extraction was achieved when the original sample was leached. The increase of the burning temperature caused the lowering of the copper extraction

Havlik, T., Orac, D., Petranikova, M., Miskufova, A.

Technical University of Kosice, Faculty of Metallurgy, Centre of Waste Processing, Letna 9, 042 00 Kosice, Slovakia

Top recycler in Tuscon receives OHSAS 18001 certification

EMSNow: "Sims Recycling Solutions, the world's largest electronics recycler is pleased to announce that their facility in Tucson, AZ has become the seventh Sims Recycling Solutions facility in North America to achieve OHSAS 18001 certification."

P. KAY Metal Granted Broad Dross Elimination Coverage in New US Patent

ThomasNet: "P. KAY Metal has been granted United States Patent No. 7,861,915 providing broad coverage for its chemical dross elimination and reduction technology as used in the soldering process. The patent comes into force on January 4th 2011."

Waste electronics in developing countries to grow dramatically

Electronics Recycling: "Harris pointed to a newly released study in the March 22, 2010, issue of the journal, Environmental Science and Technology. In the report, author Eric Williams of Arizona State University writes, 'Trade bans will become increasingly irrelevant in solving the problem' and argues that a complete ban on export of used and end-of-life electronics to developing counties fails to solve the problem because the developing world will generate more used and end-of-life electronics than developed countries as early as 2017. Additionally, by 2025, the developing world will generate twice the amount of electronic scrap as what will come from developed nations."

Managing Dross in Soldering Processes

EMS007s: "Wave, selective and related soldering processes involve relatively large volumes of molten solder that are exposed to the atmosphere. Turbulence, oxygen exposure, temperature and other factors affect dross formation in wave soldering processes. Keith Sweatman and Keith Howell, both of Nihon Superior, advise operators on how to reduce dross."

Recovery of materials from waste printed circuit boards by vacuum pyrolysis and vacuum centrifugal separation

Scopus: "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 30 min 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 1200 rpm for 10 min. 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.

Zhou, Y., Wu, W., Qiu, K.

School of Chemistry and Chemical Engineering, Central South University, Changsha Hunan 410083, China

A novel cyclic process involving zinc for separating silver from lead-free solder residue

Scopus: "In this study, a novel cyclic process to separate silver from the lead-free solder residues using a metal solvent has been developed. The process uses zinc as a metal solvent which selectively forms intermetallic compounds with silver, followed by the volatilization separation step to recover zinc which can be reused as the metal solvent. Based on the results obtained, up to 90% of the silver in a lead-free solder residue was calculated to be separated into the dross phase through the sixth silver separation stage using the proposed process"

Solder dross recycling system finds success

Dataweek: "The world price of solder is at an all time high, so reducing solder consumption – and therefore costs – should be on every electronics manufacturer’s wish list.

On average, it is estimated that companies throw away 75% of their solder as dross, but by automating solder dross recovery from the wave soldering process, a company can actually reduce de-drossing time by up to 80% and solder purchases by up to 50%. This article looks at how one company worked with its equipment supplier to automate this process in-house."

Managing Dross in Soldering Processes

EMS007: "Phosphorus, typically added at a level of about 100 ppm, has long been used to control drossing in tin/lead solder. It is presumed to work as an oxygen scavenger, migrating to the surface of the solder, reacting preferentially with it, and preventing it from oxidizing the solder. The phosphorus is consumed in that process, so if anti-drossing action is to be maintained, more phosphorus must be added to the solder bath regularly, typically as pellets of phosphor/tin."

Use of nickel turns the otherwise unusable tin/0.7% copper (SnCu) alloy into a highly efficient and user-friendly solder.* Extensive research revealed that effective oxidation control without the negative effects experienced with phosphorus could be achieved by adding less than 100 ppm germanium. That combination of tin-copper-nickel-germanium has a dross rate typically half that of SAC alloys and can be used in untreated stainless steel solder pots.

A novel process for separating silver from waste lead-free solder

Scopus: "Significant amounts of waste lead-free solder have been generated from electric and electronic industry as the environmental regulation becomes to be strictly in Europe. In general, the waste lead-free solder is generated from the step to affix components to printed circuit boards, which contains 2 - 4 % of silver and 90 - 93 % of tin. In this work, a novel process to separate silver from waste lead-free solder using a metal solvent has been developed.

The process uses zinc as the metal solvent which selectively forms intermetallic compounds with silver, and zinc is also recovered through the volatilization separation step to reuse as the metal solvent. Up to 90% of the silver in the waste lead-free solder was separated in the dross phase from the proposed process."

Japan Recovered Rare Metal Drops by 37% in F2009

Factiva: "Japanese recovered rare metal volume from electronic materials decreased by 37% to 2,041 tonnes in fiscal 2009 ended March 2010 from fiscal 2008, according to Japan Catalyst Recovering Association. Japanese scrap generation, from which rare metal is recovered, decreased due to slower economy. The precious metal recovery from catalyst, electronic materials, dental alloy and jewelry was 395 tonnes as fiscal 2008.

The rare metal includes gallium, indium and selenium from electronic materials. The recovered gallium decreased by 12% in fiscal 2009 from fiscal 2008 while the volume reached 10 tonnes for 2 years in a row. The recovered indium from indium tin oxide increased by 11% to 250 tonnes. The recovered volume from solder decreased by 50% for lead and by 34% for tin while the recovered selenium from photoreceptor of copy machine increased by 50%."

Seika Machinery Updates Solder Paste Recycling Unit

Circuits Assembly "Solder Paste Recycling unit reportedly is able to reduce the amount of waste material to less than 10% of current volumes. Now enables the separation of flux and solder, using a solder pot mechanism that inverts during each cycle. Turns wasted solder paste into solder bar in approx. 34 to 45 min. Max. volume per cycle is approx. 5.5 lb."