Thursday, 22 August 2019

Metal Recycling from Construction and Demolition Waste (CDW)


All construction companies now promote 'sustainable materials management' where they recycle and reuse certain CDW. This is mainly done to reduce the overall construction cost and the total aggregate demand for new building materials for a construction project.


CDW can be mainly divided into two categories: metals and non-metals. Wood, concrete, asphalt, bricks, glass, and plastics come under the non-metals category. On the other hand, ferrous and non-ferrous materials come under the metal category.


Around 95% of the total recovered metal from any construction project is actually steel. Besides, around 1-2% aluminum (mainly from doors and windows), 1-2% copper (mainly from piping and wires), and around 1% stainless steel (from structural supports) can be also recovered from Construction and Demolition (C&D) projects.

(Source: https://www.environment.gov.au/system/files/resources/b0ac5ce4-4253-4d2b-b001-0becf84b52b8/files/case-studies.pdf)


Steel is the easiest metal product to recycle from any C&D site as it can be segregated with minimal effort. And steel products actually produce almost zero waste. Besides, some surplus steel products such as tubes, rebars, pipes, claddings, and internal structural supports can be  reused with  little or  no reprocessing.



Recycling of steel products also has an environmental advantage, since there are  few environmental impacts due to minimal reprocessing. A majority of the steel products recovered from C&D projects can be sandblasted to remove coatings and base painting layers. Then, primer can be applied to use it for a new project. However, engineers do need to inspect and approve their properties and strengths before using it.



Other non ferrous metals, such as copper and aluminum, can be  melted to remove any impurities. They can finally be molded into new products to use in new construction sites.



Tuesday, 30 July 2019

Scrap metals: How they are reused to make new products?



Scrap metals which are generated abundantly from modern consumerism tend to be dumped in landfills or discarded away. Scrap metals may have toxic chemicals and hazardous elements in them so it is imperative to keep them away from landfills by recycling them where there is a danger of those metalspercolating into the environment which could cause soil pollution. Thus scrap metals must be used so that they don’t end up polluting the environment.

Aside from the environmental factor, reusing scrap metals such as copper, aluminium, brass, steel, and iron has economic benefits. It drastically reduces manufacturing costs as recycled metals can be used over and over again leading to a ‘circular economy'.
Some of the areas where reusing scrap metals can be effective are as follows:

1. Manufacturing: As mentioned before,  scrap metals helps to significantly reduce the cost of raw materials for the manufacturing plants. But other than that, the  scrap metals can be used to produce different alloys afterthe melting process..

2. Construction: From roads, bridges to buildings materials, reusable and production surplus scrap metals are used in a variety of ways in the construction industry. Scrap metals like iron, stainless steel and aluminium are used on a common  basis.

3. Packaging: Steel and aluminium are typically used for new food packaging. Canned items usually consist of certain out amount of recycled scrap metal with few being manufactured  entirely of scrap metal.

4. House furnishing: A typical house presents a lot of avenues for scrap metals to be reused. Appliances, lighting, metal roofing, etc., gets manufactured  using alloys that are tcomposed of scrap metals. Furniture like lamps, chairs, tables etc. all, are containing alloys that are composed of recycled metals owing to their durability.

5. Transportation: The bodies of ships, aircraft, and automobiles among others are the modes of transportation, manufactured using alloys produced from recycled scrap metals.
Thus, we can see that recycled scrap metals find a variety of applications and thus they must be recycled to conserve the environment as well as make manufacturing cost-effective. Scrap metals have a lower boiling point than virgin ore and thus can be easily melted and land would not be dug up to extract non-renewable metal ores which up the risk of environmental pollution.




Thursday, 18 July 2019

Effects of Not Recycling


The fact that recycling is one of the most important issues in recent times needs no introduction. Also UAE passed an ambitious law in 2018 to recycle 75% of the waste generated by the country (Gulf News, New UAE federal law aims at 75% of waste recycling), which highlights the importance of recycling with combined efforts around the world to recycle human waste suffocating the environment.
This article is not about the importance of recycling, rather it talks about what would be the results of not recycling. That is, let the landfills fester with ever voluminous mounds of trash. What will be the effects of not recycling that?
The world is already reeling from an unimaginable turnover of waste. According to the World Bank, the global volume of waste is set to increase by 70 percent by 2050. (World Bank, Global Waste to Grow by 70 Percent by 2050 Unless Urgent Action is Taken: World Bank Report)
The developed countries generate the maximum amount of the world's waste with the US being one of the biggest. An estimated 254 million tonnes of waste gets generated by the USA per annum (Environmental Protection Agency or EPA). The UAE being the highest waste generator in the Gulf region, generating an estimated 6.5million tonnes of waste and is one of the world's highest in terms of per capita waste production.(Gulf Business, UAE seeks end to status as one of world’s largest waste producers)
The effects of not recycling can be categorised broadly into two categories: environmental and economic.
1.                  Environmental
First, let’s talk about plastic. Recent reports around the world of the presence of plastic in the bowels of aquatic creatures especially an infamous one have raised alarm over the problem that the accumulation of plastic waste poses. According to a World Bank report, 242 million tonnes of plastic waste was produced globally which constituted 12 percent of the total solid waste generated worldwide (World Bank, Global Waste to Grow by 70 Percent by 2050 Unless Urgent Action is Taken: World Bank Report).
Scrap metal, easily recyclable, when not recycled puts pressure on landfills and serves to increase the toxicity of the environment.
Glass can be recycled ad infinitum thus saving cost as well as lessening water pollution.
If recycling is not done (and not done properly), there are environmental costs to bear globally.
2.                  Economic
There are significant economic implications of not recycling in addition to the obvious environmental effects.
In 2017, the global recycling industry generated an estimated $265.61 billion (975.64 billion dirhams) of revenue. The global plastic recycling industry alone was estimated to have a market size of an estimated $37.6 billion (138.1 billion dirhams).(Cision, Global Waste Recycling Market Outlook Report 2017-2018: $37.6 Billion Opportunities in Plastic Recycling)
Revenue generated leads to more jobs. In the US alone, tens of thousands of people work in the recycling sector. If recycling is stopped, these people along with thousands of others around the world will lose their jobs.
Recycling also helps to reduce prices on many items such as glass and some types of metal. Since the material is recycled every time, manufacturing costs are cut drastically in half. The effect of not recycling would not only put immense pressure on already depleting finite resources but would also make prices inflate for a lot of materials.
Thus, to conclude, the impact of not recycling has a tremendous cost, both environmentally and economically and would only clog the various spheres of the planet with unmanageable clutter, both hazardous and non-hazardous. Therefore, in a world of fast depleting resources, recycling is the need of the hour.

Wednesday, 3 July 2019

How To Properly Care For Brass


 Although brass has an attractive colouring and is versatile, it is more malleable than many other metals.  It is important to take care of your brass bars the moment you receive them because of its malleable nature.

This makes brass prone to easy damage and hence should be handled carefully. Therefore, on receiving a delivery of brass machining bars, you should immediately check the packaging to ensure that each bar is coated with plastic. You have to also make sure that the packaging and palates are not damp, as this can often cause staining. Moreover any damage to the packaging can easily travel through to the metal inside.  Brass should be ideally kept indoors, in positions higher than the ground level.

While handling brass bars, you have to be careful that they do not bang or scrape against each other in order to prevent the surface from denting. To minimise the possibility of corrosion, it is necessary to prevent the brass bars from coming in contact with ammonia based products or ammonia itself. In case of contact, the brass will be rendered useless as it will develop stress corrosion cracking.

Using mild detergent mixed with warm water to clear the surface dirt regularly will preserve the brand new look of your brass material. Refrain from using abrasive cleaners as that may result in removing the lacquer coating on the brass which is done to prevent tarnishing.

Friday, 14 June 2019

Powder coating removal from aluminium


When it comes to metal painting, there are various ways to do it, some more prevalent than others. In Aluminum’s case- powder coating is one of the most used ways of coloring. A colored powder is sprayed on the metal when it is extremely hot, which results in a very strong second bond that ultimately leads to long lasting color.

Sometimes people don’t need the metal color anymore and want their object back in the original color, in which case one can follow the following steps to remove the color-

STEP 1: Set up a location outside home to hang the object so that it is accessible in all the areas. You can use your garage or work station for this work.

STEP 2: If there are any areas that you don’t want to change color of, cover them with paper bags and tape them all around very well so that they stay intact.

STEP 3: Use an industrial strength gasket remover to remove the powder color by spraying it all over. Leave it on for 15-20 minutes, by this time you shall see the powder coating bubbling and peeling down.

STEP 4: Clean the object with a dry rag and if you’re still able to see the color at some places, repeat the process.

Safety precautions:
Wear thick long-sleeved clothing, gloves, safety goggles and a respiratory mask since the gasket remover is pretty poisonous.
Discard all the rugs and bags used in the process.


Wednesday, 29 May 2019

What causes metals to corrode?



Ever seen those dreary red vehicular bridges or metal structures leading to water tanks, creaky gates, fences or handles? The most common example of corrosion that we see in our everyday lives is rust – corrosion of the iron metal. This redness indeed is a typical representation of the phenomenon of ‘corrosion of metals’. Corrosion is when the metal quality has deteriorated.

What causes corrosion of metals?

Corrosion in metals is an electrochemical process; it is part chemical and part electrical. Positively & negatively charged ions from the metal result into a chemical called ‘iron hydroxide’ when they come in contact with water. When both oxygen and moisture work their wrath on the metal, it causes the metal to corrode. It will continue to cause the reaction leaving back nothing but say, a pile of rust (in case of iron) as long as the process continues.

Which metals are prone to corrosion?

In the metal family, magnesium, aluminum, iron, zinc, brass, copper, bronze and tin have higher reactivity so they easily corrode. Rust on steel, greening of copper or tarnish on silver/brass is a common phenomenon that we see every day around us. It also represents danger to human lives as its impact can cause injury.

What are the typical causes of corrosion?

·         Improperly maintained metal
·         Use of low quality metal
·         Ignorance towards maintenance of structural issues such as plumbing problems, leaky areas/roofs, stagnant water, and foundation issues of the building/structure, etc.

Does this mean all metals corrode? No, some metals rarely corrode. This group of metals which are less reactive, also known as ‘Noble Metals’ are metals that can be found in nature in their purest form - rhodium, palladium, silver, platinum, and gold are some examples of metals that are much less reactive than others; thus more expensive!
Understanding of the environmental conditions and metal properties and implementing this understanding into your design structure or foundation is an effective preventive measure against metal corrosion.

Wednesday, 15 May 2019

How is Scrap Metal Processed


In an era of recycling, it is imperative to have knowledge of recycling process in order to take better decisions of the tools and methods of recycling. The recycling process dealt with here in particular, is scrap metal. 

A scrap metal processing yard where one gives away his or her scrap metal for recycling, chiefly categorize the metals into ferrous and non-ferrous metals. Ferrous (from Latin ferrum, meaning "iron") metals comprised of iron and steel (an iron alloy). Copper, aluminium, brass et al., are called non-ferrous metals.

Scrap metal processing in part entails separation of these types of metals from each other using magnetized tools. A number of wrecking yards allow people to purchase scrap metals for specific purposes. Such a sale occurs only after due separation of the metals. This makes for easier identification of the metal by an interested buyer.

The primary basis of the sale of metals by the wrecking yards is the weight of the scrap metal being sold. Quality of the metal is really not that important in such a scenario. This is because the main concern of the yards is what the metalworks factories give them for selling metal. Metalworks factories purchase metals on the basis of weight.

After proper separation and sorting into suitable divisions, the scrap metal is subject to a number of processes which include cutting, shredding, molding and turn into metal cubes. The metal cubes are then purchased by the metalworks factories that melt the metals for the manufacture of new products.