PyroGenesis Inc T.PYR

RE:RE:FYI - Wonder how mch dross a plant like that would create

[BCONTVentures]

And another informative article on DROSRITE:

Aluminum Dross - Stop burning your bottom line!

https://www.linkedin.com/pulse/aluminum-dross-stop-burning-your-bottom-line-david-d-aoust/?trackingId=BMrfWPd9QNqbu8oIrvT3gg%3D%3D

From the smallest 'mom & pop' aluminum die casting facility producing a handful of parts per year, to the largest international primary smelters producing a million tonnes of aluminum billets per year; if you are melting aluminum during your production process, you share an expensive problem. You are losing anywhere from 2-10% of your total smelting capacity in the form of oxides/dross, and it is impacting your bottom line.

Lets use a fictional SME (small/medium sized enterprise) aluminum die casting plant producing 15,000 tonnes per year of cast parts as an example. This casting operation has an extremely advanced facility complete with top of the line foundry equipment and near perfect skimming practices. They are very proud to have reduced their dross production to a mere 2%. This means they are losing around 300 tonnes of aluminum per year in the form of dross, or approximately $658,500 at today's aluminum prices (US$ 2195/Tonne).

At this point, the obvious business decision is to simply ship the dross to a secondary smelter/toller who will process it for a fee of around $350/MT and recover/return around 40% of the dross in the form of usable aluminum billets. Going this route, our example casting plant can return around 120 tonnes of aluminum back into their operations at a cost of $105,000. In other words, they have managed to reduce that original $658,500 loss into an annual loss of $553,500 and they hardly had to break a sweat.

But there must be a way for our example SME die caster to further reduce the impact of dross on their bottom line. Could they vertically integrate the dross recycling process instead of paying a toller to do the job?

No. There are a few reasons why this hasn't been economical in the past. Conventional technology employed by tollers for aluminum recovery from dross is called Rotary Salt Furnace. In the RSF process, dross is charged with a salt flux in the furnace. Salt is added to protect the metal from oxidation and facilitate the separation of the metal from the oxide. As much as 50% salt is added to the dross in RSF, and the resulting byproduct produced is called salt-cake. For every 1 tonne of dross processed in RSF, 1 tonne of toxic salt-cake waste is produced. It is a mixture of oxide, residual metal, salts and nitrides. This byproduct is considered hazardous in many jurisdictions and presents environmental challenges in its management: toxic leachates can be released, and the cake can be reactive in a landfill environment. The salt vapors emitted by the process also cause their own challenges as they tend to be corrosive. Primarily due to the hazardous nature of the salt cake & difficulties with disposal, combined with the natural process inefficiencies at recovering aluminum, it has not been economical for aluminum smelters to install dross recycling systems in house. It simply does not make sense for our example parts caster to take on a 300 TPY toxic waste stream and assume the environmental liabilities.

However, due to a breakthrough innovation by an advanced Canadian plasma green-tech engineering and high temperature metallurgical company PyroGenesis Canada Inc, there is a new environmentally friendly dross separation technology called DROSRITE™, that solves all of these legacy industry issues and makes a very clear cut business case for any company melting aluminum to vertically integrate the dross recycling process. DROSRITE™ is the worlds first truly salt-free dross rotary tilt furnace. DROSRITE™ offers reduced operating costs compared to RSF (no salt & no external oil/gas burner required) and increased revenues due to substantially improved aluminum recovery rates. (20-40% higher aluminum recovery than leading RSF systems). Because the DROSRITE™ process is salt free, it creates no hazardous salt-cake waste residues. It is compact, cheap to maintain & highly automated. The net result is the world's first dross separation process that can be integrated into any aluminum casting plant or primary smelting facility generating substantial bottom line savings. DROSRITE™ comes in various sizing options, DROSRITE™ SL (300-500tpy of dross capacity) & DROSRITE™ HEAVY (3000 or 5000tpy of dross capacity).

Considering the total DROSRITE™ OPEX (backed by data collected on commercial installations which can be obtained at [e-mail]). Our example casting company producing 300 TPY of dross can easily save $396,906 per year through a DROSRITE™ SL installation, effectively reducing their original aluminum loss of $658,500 into an annual loss of only $238,506. Not accounted for in these savings are potential carbon credits that may apply as more jurisdictions implement carbon tax policies, as DROSRITE™ uses the left over, unrecoverable aluminum to reheat the furnace (controlled thermiting reaction), utilizing what would otherwise be landfill/waste byproduct to heat the furnace and power the process. This allows DROSRITE™ to be used without an oil or gas burner, eliminating the production of GHG emissions and further adding to the DROSRITE™ advantages. Because the remaining residues produced are salt free, they are 100% recyclable and can be sold straight back to PyroGenesis.

Technical Summary:

The DROSRITE™ process is illustrated schematically below. In DROSRITE™, hot and/or cold dross is charged into the refractory-lined furnace (step 1) which is (1) sealed and maintained under an inert argon atmosphere and (2) contains a specific amount of preheated filling material leftover from the previous processing batch. After the rotary tilting separation period (step 2) is completed, the metal is recovered (step 3) and returned in the hot/molten phase to the originating furnace or left to cool down as ingots, while a partial amount of the remaining material is discharged (step 4), i.e. the residue, leaving some material inside the furnace, i.e. the filling material. Since this filling material still contains some unrecoverable metal, a controlled amount of oxygen is injected (step 5) to react with it (controlled thermiting reaction) and therefore generate the heat required for melting the next processing batch. Thus, under normal operating conditions, DROSRITE™ does not require any external heat source or salt fluxes, making the process energy requirements very low and the carbon footprint significantly reduced compared to competing technologies. Furthermore, the residue being salt free, it can be fed back to the electrolytic cells of an aluminum smelter or reused as a construction material, as a flux in the steel making industry or for any other application where salt free alumina is required, such as the cement industry

In conclusion, DROSRITE™ is the worlds first highly efficient method of extracting aluminum from dross, without the use of fluxing salts. (no toxic, salt-cake wastes are produced). DROSRITE™ is designed to be used on-site, it is compact, highly automated, and is designed to be charged with hot or cold dross, being fed directly after skimming. The net result is a green technology that enables aluminum casters and primary smelters to vertically integrate the dross separation process, substantially reducing the negative impact of dross on the bottom line.

BCONTVentures wrote: Thanks for the link HARJAY, very interesting.  Here is some great information on PyroGenesis' DROSRITE System:

PYROGENESIS' DROSRITE(TM) SYSTEM: Maximizing Aluminum Recovery Salt-Free

https://www.youtube.com/watch?v=72dPyULE3wc

Sustainable & Profitable Aluminum Dross Practices

https://www.linkedin.com/pulse/sustainable-profitable-aluminum-dross-practices-david-d-aoust/

Dross is a waste stream generated by aluminum smelters, caused by oxygen coming into contact and reacting with molten aluminum to form a ‘scum’ or ‘oxide phase’ on the top of the metal pool. The oxides act like a sponge, floating on the surface and soaking up metallic aluminum beneath it. This presents an expensive problem when skimming the oxides out of a furnace because unavoidably a significant amount of valuable aluminum will be lost with it. Smelters typically lose anywhere from 2%-10% of their total annual melt production in the form of oxides, and the oxides can be composed of as much as 80% metallic aluminum, so the financial impact of this aluminum loss cannot be overlooked.

Dross is usually categorized as either white dross or black dross. White dross is generated from primary smelters and downstream ingot smelting operations. White dross tends to be very rich in aluminum, with aluminum content percentages ranging from 40-80%. Black dross conversely is produced by secondary smelters during their scrap re-melting processes, and as a result the dross typically contains a higher concentration of oxides, salts and various other impurities, and a lower metallic aluminum content which typically ranges from 5-25%

According to a recent report titled "Aluminum Dross Processing: A Global Review" by AlCircle, worldwide production of dross was an estimated 3 million tonnes in 2017. Despite the profitable economies in recycling dross, an estimated 1.6 million tonnes of that material went directly into a landfill. The remaining 1.4 million tonnes was recycled & resulted in approximately 460,000 tonnes of aluminum being returned back upstream into the value chain, yielding a global average recovery rate of only 33%.

Global dross production is projected to grow at 4-5% per annum, keeping pace with increasing global aluminum production, so unfortunately this waste stream will not be disappearing any time soon. So how does the aluminum industry plan to reduce the impact of dross on the bottom line and reduce the environmental impact of dross and dross processing? The industry has set three key objectives below.

Objectives:

 

How are we doing today? Let's take a look at our current dross practices and how they stack up against our objectives.

There are three ways to manage your dross. 1. You can simply sell the material at a percentage of the price of LME (London Metal Exchange) aluminum prices. This practice is typically used by smaller downstream smelting operations who produce 100-500 tonnes per year of dross. Largely this is because it is a hands-off practice and requires almost no effort on the smelters part. However, this practice is usually the worst from a financial perspective, as you will always be selling the material at a fraction of its actual metallic aluminum content value.

Option 2 is off-site thermal processing, by far the most common industry practice across the aluminum smelting industry. Off-site is defined as processing dross far enough away from the dross generation source to require the dross to be completely cooled before processing. Off-site processing is often times handled by a third-party contractor or toller, whereby smelters will ship their dross to the toller who will then recover as much aluminum as they can, and return the recovered material in the form of solid aluminum back to the smelters casting facilities.

Options 1 and 2 share the same pros and cons. On the upside, they are both hands-off practices which will slightly reduce the financial impact of dross while requiring very little effort on the smelters or more specifically the cast-houses part. The downsides are both environmental and economic. The requirement for transporting dross has inherent supply chain and environmental problems. Transporting dross is expensive and extremely challenging, there will always be the risk of spillage, emissions being released, or even spontaneous combustion during transport. The biggest financial downside is in the cooling of the dross. When dross is skimmed from a furnace, it is aggressively thermiting. The metallic aluminum that is attached or entrapped within the oxides is rapidly reacting with the atmosphere, converting into unrecoverable oxides. Hot dross can lose as much as 1% of the metallic aluminum contained per minute due to this thermiting reaction. In order to minimize the aluminum loss at the cooling stage, smelters will typically employ a rapid cooling process or technology such as a dross press. Unfortunately, no dross cooling technology is perfectly efficient, and a large portion of recoverable aluminum will always be lost.

Option 3, on-site processing (defined as processing close enough to the dross generation source to enable hot dross processing) would appear to be the solution to all of these problems. On-site processing eliminates the requirement to transport dross, eliminating the environmental concerns associated. On-site processing enables the dross to be processed while it is still hot, eliminating the requirement for an additional dross rapid cooling step and reducing the amount of metallic aluminum that will be lost to thermiting. Processing hot dross also comes with the added advantage of retaining and reusing the thermal energy in the dross for the recovery process.

 

Why haven't smelters adopted on-site processing?

Unfortunately due to the limitations of the conventional technologies being used today for dross recovery, on-site processing is simply not practical. The most commonly used technology is called the Rotary Salt Furnace (RSF). In the RSF process, cold dross is charged with a salt flux in the furnace. The furnace is heated with either an oxy-fuel burner or fossil fuel burner, usually being either natural gas, propane or fuel oil. The furnace rotates, to separate the aluminum from the oxides and salts. Oxygen is always present during the separation stage, hence why fluxing salts must be added in the furnace. Fluxing salts help protect the metallic aluminum from oxidation during the separation stage, and also to facilitate the separation of the metal from the oxide phase. As much as 30% salt is added to the dross in RSF. 

After rotation, the recovered metal is ready to be tapped. The aluminum is removed from the furnace, cast into ingots and left to cool. Unfortunately the fluxing salts do an imperfect job of protecting recoverable aluminum from oxidation/thermiting during the recovery stage, and as much as 10-20% of the metallic aluminum is lost to thermiting, and another 5-15% will be lost by merging deeply inside the oxides which have now become saturated in salts and are now considered salt-cake or salt-slag residues. For these reasons, RSF can at best recover 85% of the aluminum contained within dross. After the molten metal has been tapped, the toxic by-product residues called salt-cake remain. Salt-cake is a mixture of oxide, metallic aluminum, salts and nitrides. This by-product is considered hazardous in many jurisdictions and presents very serious environmental challenges in its management: toxic leachates can be released, and because landfills are not inert, the cake can be reactive. The resulting reactions can be highly exothermic, heat generating, slowing down or stopping the desirable anaerobic microbial activity and even igniting surrounding solid waste materials. These reactions can also release toxic and flammable gases. For these reasons, managing this waste stream is extremely expensive and challenging, ruining the business case for a smelter or cast-house that otherwise would operate this technology on-site.

 

How can we process dross on-site?

DROSRITE™:

Due to a breakthrough innovation by a Canadian thermal green-tech engineering and metallurgical company PyroGenesis Canada Inc, there is a new, salt-free dross recovery technology called DROSRITE™ enabling smelters to operate their dross recovery on-site, streamlining the dross supply chain, eliminating all environmental concerns, and resulting in significantly improved aluminum recovery rates at a lower operating cost.

In the DROSRITE™ process, hot dross can be charged directly into the furnace. DROSRITE™ automatically injects a controlled amount of argon gas, quenching the thermiting reaction and preventing any further loss of aluminum to oxidation. The furnace tilts and rotates, separating the metallic aluminum from the oxides. After the separation period is complete, the recovered metal is tapped and can be returned directly back into the smelters holding furnaces in a molten condition, or left to cool down as ingots. Because the argon does an exceptional job of protecting the metallic aluminum from oxidation, DROSRITE™ recovers 98% of the aluminum that was contained within the dross. Next, a partial amount of the remaining oxide/residue material is discharged from the furnace, and some residue material is left inside the furnace. This residue material still contains about 2% metallic aluminum, for which there is no economical method to recover. So instead of land-filling this aluminum, as is done in the RSF process, DROSRITE™ now injects a controlled amount of oxygen to react with it (controlled thermiting reaction) therefore generating the heat required for melting the next processing batch.

Thus, under normal operating conditions, DROSRITE™ does not require any external heat source (no burner required) or salt fluxes, making the process energy requirements very low and the carbon footprint significantly lower than competing technologies. Furthermore, the residue being salt free, it can be fed directly back to the electrolytic cells of an aluminum smelter (pure alumina) or in the case of alloyed dross, reused as a flux in the steel making industry. 100% of the residues remaining from the DROSRITE™ process are recyclable.

 

How does DROSRITE™ stack up against the industries dross objectives?

1. DROSRITE™ recovers 98% of the aluminum contained within dross, and the remaining 2% aluminum is used as a source of fuel to power the process, meaning zero metal is wasted.

2. DROSRITE™ uses argon gas to prevent thermiting during the process, instead of fluxing salts. As a result, DROSRITE™ does not produce any toxic salt-cake or salt-slag residues.

3. DROSRITE™ wastes zero metal, and because the residues are salt-free, they can be 100% recycled either being fed directly back into the smelters operations as pure alumina, or being used as a flux for the steel making industry. All dross and dross residues produced through the DROSRITE™ process have commercial applications and avoid going to a land-fill.

The financial impact of these efficiencies is obvious. Increasing aluminum recovery rates alone yields millions of dollars per year in annual savings, exceeding $1,000,000 per 1500-5000 tonnes of dross processed.

 

How will you take advantage of DROSRITE™?

PyroGenesis Canada Inc. offers clients the option of on-site tolling services, whereby they will build, install and operate a DROSRITE™ plant inside the aluminum smelters facility to recycle the dross for a fixed fee per metric tonne, also charging a bonus based upon increased metal recovery rates. These outsourced environmental services allows aluminum smelters to take advantage of the massive operational and environmental benefits in having an on-site dross facility, without having to invest any capital. More importantly, this allows aluminum smelters to focus on their core business, which is smelting and casting high quality semi-finished aluminum goods to compete with steel and plastics.

In conclusion, DROSRITE™ is the worlds first highly profitable and environmentally friendly method of extracting aluminum from dross. DROSRITE™ solves all three of the key dross related issues currently facing the aluminum industry by completely eliminating the use of fluxing salts,thereby avoiding the production of toxic-salt cake residues, and recovering 98% of aluminum contained within dross, utilizing the remaining 2% aluminum as a source of fuel in place of a burner. The result is a technology that minimizes the impact of dross on the bottom line, and eliminates all environmental issues associated with the waste stream.

HARJAY wrote: https://enterprise.news/climate/en/news/story/5a1485f2-09f9-42bf-8135-7b7f440c4805/ma%25e2%2580%2599aden-greenlights-aluminum%253cmark%253e-recycling%253c%2Fmark%253e-plant-in-ras-al-khair