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Eco-friendly Urban Mining

By CTimes
Published: May 29,2015


Figure 1 :  Cities contain mineral vein waiting for us to mine.
Figure 1 : Cities contain mineral vein waiting for us to mine.

In cities, people shuttle back and forth day and night, and their bustling steps tread on one section of the pulse. There are strings of high-rise buildings on the roads that interweave with a night zone which is even more dazzling than the moon and rapidly expanding.

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Under the growth of this firm and dazzling night zone, a mineral deposit that is as shiny as copper is waiting to be mined by us. This mineral vein is fed by people and it can, in turn, feed people. We call it urban mining.


Urban mining means recycling precious metals and other materials which have reuse value, including construction waste materials, waste paper, and plastic from large quantities of e-waste, such as cellphones and computers. Furthermore, the materials with the greatest economic value is Gold.


Gold has an unshakeable status as an economic resource that is used internationally. Even in this era where currency is universal, gold still maintains its importance and is the good with the most universal value. On the other hand, due to its distinctive ductility and its electrical conductivity, it has become an important electronic and industrial material, and it is an essential key material that is indispensable to the technology industry.


The Questionable Benefits of Traditional Mining

Because it has value and is useful, people’s enthusiasm for gold is timeless, and in this unabated boom, gold mining is always an important enterprise that all nations invest in.


Compared to the past, today’s methods of gold mining are a major change, and the main difference is the use of heavy machinery and electronic equipment.


Figure 2 :  Mechanization has greatly increased the speed of mining; however, the rendering rate has not improved significantly.
Figure 2 : Mechanization has greatly increased the speed of mining; however, the rendering rate has not improved significantly.

In the mining market, modernized heavy machinery and electronic equipment have replaced traditional digging using explosions and manpower. Large amounts of ore and minerals can be quickly extracted, which not only increases the global amount of gold mined each year, but also makes the mining process safer and more efficient. Although mechanization greatly increases the mining speed, it does not lead to a significant improvement in the purity of the extracted gold. Moreover, the huge cost of machinery and equipment make it difficult to justify in terms of profits and loses from mining a particular mineral deposit.


Currently, the amount of gold content in gold minerals varies from region to region; however, the global average is approximately 5-10 grams per ton, meaning that only 5-10 grams of gold can be refined from one ton of mined gold ore.


From another standpoint, although heavy machinery and electronics have improved the degree of difficulty in the procedures for mining on the front end, on the back end, refining the gold causes severe environmental pollution problems. Mercury and cyanide are used in the current refinement procedures, and they are very harmful to both the environment and human health.


Eco-friendly Urban mining is the best choice

In order to provide a better environment for the mining industry and to have a more efficient gold refining environment, Taiwan’s environmental gold-stripper supplier UWin Nanotech Co., Ltd. is undertaking research and development of the refining process. During this process, they use the UW-860 Chemical Gold Stripper, which they developed themselves. UWin Nanotech is successfully increase the gold purity ratio of 8 gram/ton of a gold ore from Canada to a ratio of 9.6 gram/ton, and it is higher than the mining industry in Canada of 20%.


Although the outcome of this technology is outstanding, this recycling rate is actually far lower than the rate produced by “Urban Mining,” which uses waste IC materials.



Figure 3 :  Using the UW-860 Chemical Gold Stripper, UWin Nanotech has successfully increased the gold refining ratio by 20% for gold minerals.
Figure 3 : Using the UW-860 Chemical Gold Stripper, UWin Nanotech has successfully increased the gold refining ratio by 20% for gold minerals.

“Taking an actual client’s recycling case as an example, in IC, gold is always obtained using a burning method. However, UWin Nanotech directly grinds up the IC materials and extracts gold by using UW-860 Chemical Gold Stripper, which enabled them to directly refining gold. Furthermore, the extraction steps were like the steps for processing gold ore, and 1.7 kg of gold could be extracted from one ton of minerals. If weighted and filter separated IC materials were used, the refining rate could be increased to 9.5 kg from one ton of mineral material,” said Kenny Hsu, Managing Director of UWin Nanotech.


9.5 kg of Gold! This refining rate lets people surprised. More importantly, the capital required to invest in it is far lower than for traditional mining. You do not need to use massive machines and tools for mining or to ship ore materials day and night. Of course you also do not need to burn anything, and it does not a stripping procedure that is harmful to the environment or people. You only need a normal sized factory building and simple equipment.


On the other hand, recycling e-waste is an important link in the supply chain for green industries, and governments in countries around the world are actively developing it. Hopefully a comprehensive recycling procedure can be established for this industry that will solve the rapidly growing e-waste problem.


E-Waste Business Opportunities

In the most recent issue of the Global E-Waste Monitor 2014, United Nations University (UNU) mentioned that in 41.8 million tons of buried e-waste, there are 16 tons of iron, 1.9 million tons of copper, and 300 tons of gold, and the total value of these precious metals is equivalent to US$ 52 billion.


This report clearly points out that there are enormous business opportunities for urban mining, and growth in the amount of e-waste is accompanied by rising values for urban mining. Moreover, the continual feasibility of urban mining and e-waste recycling will bring about more and more opportunities for social enterprises.


To electronics product manufacturers, if precious metals can be effectively recycled from e-waste parts and original materials, it will be a step forward in reducing companies’ capital expenditures when they purchase materials. For PCB manufacturers and IC packaging and testing industries in particular, expenditures for gold-grade precious metal materials occupy 10% of the total operating costs. As soon as there are extreme fluctuations in the value of metals, they will immediately have a severe influence on enterprise operations.


As a result, establishing a stable source of recycled precious metals is necessary for the continual operation of related businesses. In addition, using recycled materials is an international trend, and to the extremely internationalized electronics companies it is a kind of value for business name brands.


Eco-friendly recycling produces the best returns.

Owing to the massive business opportunities in e-waste, environmental recycling businesses have already invested in this domain. They recycle waste electronic products and PCB, and extract valuable precious metals from them. Then they provide them to related businesses and establish simple e-waste recycling chains. Nevertheless, there are currently environmental misgivings about their refining methods, and their benefits tend to be low.


“Traditional stripping methods use aqua regia and cyanide as gold-stripping prescriptions. However, these two chemical agents are corrosive and highly toxic and have lethal effects on both people and the environment,” said Kenny Hsu.



Figure 4 :  Uwin Nanotech can strip off tin from DRAM and then separate materials for semiconductors and substrates.
Figure 4 : Uwin Nanotech can strip off tin from DRAM and then separate materials for semiconductors and substrates.

Kenny Hsu also pointed out that aqua regia is highly corrosive, and during the stripping process, base materials will corrode. Furthermore, it is impossible to reuse materials after soaking them, which creates another form of waste.


Being devoted to the research and development of environmentally friendly and non-toxic gold stripping methods, UWin Nanotech supplies a type of neutral and cyanide-free chemical UW-860 Chemical Gold Stripper. The metal stripping additive has a pH value of 7.4, which is neutral and be used in regular polyethylene (PE) or polypropylene (PP) containers; moreover, afterwards the base materials will not be harmed.


Even more importantly, the UW-860 Chemical Gold Stripper does not contain cyanide materials, and it is completely harmless to the environment and human beings. In addition, it still has higher stripping efficiency than stripping methods that use cyanide and aqua regia. The saturation of stripping gold is 7g/L, which is several times higher than the concentrations obtained using traditional methods.


Different Layers of Different Types: Allows for Complete Use of Waste Materials

The current mainstream methods of stripping precious metals mostly begin by sorting, and grinding. After that, the materials are put into stripping solutions for metal stripping. However, for waste PCB, the mainstream method is not the best method. This is because a piece of PCB will have various types of electronic components, and as a result, they will contain different metal elements, including gold, silver, palladium, copper, nickel and tin. If they are pulverized and directly recycled, it is sure to reduce the effectiveness of the metal stripping.


We can first do metal stripping under the prerequisite that base materials will not be damaged, or we can use SnST-550A tin stripper first. Afterwards, we can easily dismantle the other electronic components on the PCB, and then carry out further recycling,” said Kenny Hsu.



Figure 5 :   Through this method of first un-welding and then quenching, the recycling efficiency can be increased approximately five times.
Figure 5 : Through this method of first un-welding and then quenching, the recycling efficiency can be increased approximately five times.

UWin Nanotech’s method makes use of the different chemical properties of different types of metals and strips them off of PCBs in different layers. Taking a RAM module as an example, UWin Nanotech can first remove the tin and then divide the materials into IC and base plate materials. The gold and copper base plate materials can be stripped off from the gold finger, and the IC can be pulverized before carrying out gold recycling.


Based on this UWin Nanotech’s SnST-550A Tin stripping method of first de-soldering and then amalgamating, the recycling efficiency can be drastically increased.


The Vision of Establishing an Ecosystem

Increasing benefits and creating value are of course the greatest advantages that UWin Nanotech’s environmentally friendly metal stripping formulas can provide to clients. However, UWin Nanotech themselves say that their biggest vision is establishing an environmental recycling mechanism for the sake of the natural ecology and living environments.


Kenny Hsu pointed that many companies that are currently developing in China still use burning methods to recycle. Not only is this harmful to the environment, but it is also severely harmful to people’s health. If highly corrosive and toxic aqua regia and cyanide are used for stripping metals, this is a direct hazard to both humanity and the environment.


However, UWin Nanotech hopes that by providing an eco-friendly solution formula, they will enable both industries and the ecosystem to live sustainably. He hopes that in the future, more manufacturers, recyclers, and even government institutions will be able to join the ranks of eco-friendly recyclers and collectively unite to mine urban minerals and allow everybody to have both a golden mountain and green surrounding.


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