Metal Scavengers

[Smopex]

Lou, Sompex - Thank you for the replies - they answer the first part of my question which is how sompex works - but is it any more effective in recovering (scavenging) the PMs from low grade (acidic) solutions then the age old process of cementing with a metal higher on the reactive series (copper, iron or zinc)

Sompex - My real question here is - you are trying to sell a product used to recover (scavenge) the PMs from low grade (low level) solutions --- as a refiner - recovering these metals has to be to my advantage - meaning I need to see a profit in the end &/or cut the cost of dealing with waste --- I can do so (at least to a point) with the age old process of cementing with a metal higher on the reactivity series & I can do this for next to nothing as I can get these metals as scrap

Another words - trying to simply sell me a product that works - is not going to get me to buy it - what you need to sell me on - is that buying your product is to the advantage of my bottom line profit

You want me to change from my current methods of recovery to using your product but you are not giving me a bottom line reason for doing so - you are simply saying you have a product that works.

I certainly have an interest in buying any product that is going to improve my bottom line --- that is what you need to sell me on.

Kurt

Dear Kurt,
Thanks for your response and continued interest.

Our Scavengers have a large number of applications from recovering low parts per million levels of pgms in process effluent to product purification of pharmaceutical materials.

Of course, here we are discussing Smopex and its application in recovering PMs from low grade process solutions, those typically found in refining processes (including our own refineries). We're not trying to compete with iron/zinc/copper cementation/footing. Where Smopex has a real benefit is recovering the residual ppm of PMs once the cementation/footing has completed. Having said that, Smopex is capable of providing an alternative to cementation or even chemical reduction. We plan to share examples and case studies of this.

As effective as metal footing can be, there will always be residual precious metals in the treated solution. Even if it's down to <5ppm total PM content, there's value there. Now it's this stage where Smopex/scavengers come in. By now treating this ppm containing solution with Smopex, and therefore recovering (in part or full) the PM, you'd be increasing your PM recovery even further. The solution will have to be disposed of either way, with or without the residual PMs.

We’re preparing a number of case studies to better explain the processes and provide economic examples of how scavengers can improve your bottom line. We look forward to sharing them with the forum shortly.

Regards
The ST Team

 

[Smopex]

Just some more detail as I requested would be good so the members can see the advantages or disadvantages of the products and how we could all use it in our waste streams.

Dear Nick

We will fully answer your post, please bear with us.

Regards
The ST Team

 

[nickvc]

The ST Team.
Sorry if I seem pushy but I can see real benefits to all sides from your products, you with sales and the members with recovering more of their values, and if Lou says they are good and work that's good enough for me.
From my point of view a simple how to utilise them, what they cost, what acids or chemicals they can work with and how to put them into our systems will do,in simple terms please, I'm no chemistry major so the technical side will probably just go over my head.

 

[Smopex]

The ST Team.
Sorry if I seem pushy but I can see real benefits to all sides from your products, you with sales and the members with recovering more of their values, and if Lou says they are good and work that's good enough for me.
From my point of view a simple how to utilise them, what they cost, what acids or chemicals they can work with and how to put them into our systems will do,in simple terms please, I'm no chemistry major so the technical side will probably just go over my head.

Not at all we're very glad for the opportunity to discuss these points so thank you for raising them.

Smopex is fully compatible with nitric, sulphuric, and hydrochloric acids as well as highly oxidising aqua regia and also sodium hydroxide. We have run Smopex recoveries through negative pH processes with great success. This is one advantage with Smopex over ion exchange resins which are generally not compatible with nitric acid.

One of our most successful applications has been the use of Smopex 500 in our own refinery effluent. The effluent is a low grade mixed metal, mixed species acidic solution that has been generated after our cementation process. This effluent is treated using a filter press loaded with Smopex. The Smopex offers the opportunity to recover / scavenge the low level ppms of precious metal that have not been reduced by the cementation. Once the Smopex is exhausted, we drop the press and send it for refining. Recoveries vary by metal and a number of other factors influence this, but the principle is viable and metal is recovered that would otherwise be lost in the effluent as trade waste. We have a full case study, including economics on this process which we will post shortly.

As for other refining applications we have a selection guide based on our experience with various pgm sources. It is by no means an exhaustive list, but it does demonstrate how Smopex may be used and where it has been successful, including our own PM refineries. Here's an image of it and you can view/download the full PDF here

Regards
The ST Team

 

[Gratilla]

It appears then that Smopex is "broad spectrum", ie it scavenges a range of PGMs that would then need to be reprocessed and separated after the Smopex is ashed. This would then make it non-competitive against say solvent extraction, where specific organic solvents can target a specific PGM which would only need to be back-extracted and/or precipitated.

 

[nickvc]

Thank you for the reply.
You say that one of your best results was using Smopex 500 on the waste effluent from the refinery but mention using a filter press, will it work using a standard vacuum filter and does it only recover the PGMs and not the gold? My thoughts are that most refiners here use a vacuum filter and in honesty probably do not create huge volumes of waste effluent so if it meant passing the solution over the filter several times before treating it for disposal it probably wouldn't matter too much.
Gratilla most members have no interest in refining PGMs and less have the skill and knowledge required but if they could recover them there are members who could refine them if the quantities were sufficient or they could learn themselves and as these metals are what would have been lost its all a bonus.. As Irons says everything including the squeak! It sounds like Lou has experience of these products and I hope as the thread carries on he can give some much needed advice and guidance I'm still fascinated..

 

[Gratilla]

Nick, nowhere do I claim to champion the interests of "most members". Personally, my interests lie in practical and efficient methods (ie with a minimum number of unit processes) of getting at my values (in saleable condition) - and Smopex doesn't (appear to) fit the bill; it appears (to me at least) to be an interesting (and expensive) curiousity with possible niche application(s). It may be more effective (in mainstream commercial applications) than say activated carbon, but the latter is relatively more targetted and definitely cheaper. I also believe that knowledgeable use of organic solvents (as in solvent extraction) will be at least as effective but more efficient than Smopex and they are also (for the most part) reuseable. So far the Smopex Team has avoided comparisons; perhaps someone should challenge them to do so - OK I will. :mrgreen:

Respectfully <as usual>.

 

[kurt]

The real advantage is in mitigating the amount of zinc or aluminum you need to use.

When you have 3500 L at 215 ppm Pt, that's a ton (literally) of solution to filter.

Smopex is a functionalized polypropylene chop fiber. Filters easy as pie and is (IMHO) easier to incinerate cleanly than say Purolite's S920 thiouronium (which you can get about 22-25 t oz Pt/cubic foot, which is $950/cubic foot from Sirfilco). The IX resins are almost all macroporous crosslinked polystyrene, which incinerates with a HORRID smell. Most loading I've seen on the Smopex is 11% PGE. Kinetically, it's probably the same as resin, as Smopex is used 60-80C.

My main liking for the fiber is ease of handling, good visual indication, clean burn (best to reduce first), and the breadth of moieties available for all the PGMs. Disadvantage is the same as any method, you need ICP and a darn good analyst to deal with the base metal matrix interference. On the cheap, that's what stannous chloride is for!

Lou - thank you for the reply & sorry for my delay in return reply - as you know from my recent talk with you on the phone I am working with a local scrap yard looking into the posibility of processing CATs (& other PM bearing material) At this point we are still in the so to speak R&D phase to determine just what materials we will process in house & what materials we will broker out to other refiners

At this point we are not even sure it's a venture that is going to work out or not - but it is this kind of info that is important to know as to where, when & how it may fit into what we hope to do in our plans for a PM recovery/refining company

Should things go the way we hope I can see a possible fit for a product like sompex in our future plans --- so again - thank you for taking the time to answer my questions concerning sompex

Kurt

 

[Smopex]

It appears then that Smopex is "broad spectrum", ie it scavenges a range of PGMs that would then need to be reprocessed and separated after the Smopex is ashed.

Dear Gratilla

Smopex can indeed recover a range of pgms from a mixed metal solution/effluent as in the example above. The loaded mixed metal Smopex was sent for refining, but it has also been used successfully in single metal processes.

For example Smopex has been used to recover Ruthenium from a mother liquor (ammonium chlororuthenate) containing ~300ppm Ru. Typically this mother liquor would end up in the effluent treatment plant, however there was considerable advantages for the customer by capturing the Ru beforehand. Smopex was able to recover 90% of the Ru and a loading of 12 w/w% was determined. The fibre was calcined, the ash reduced and the resulting Ru sponge re-dissolved to produce a concentrated Ru solution that could be re-introduced into the circuit (and cuts out the entire effluent recovery process for this particular feed).

 

[kurt]

Sompex

Thank you for posting info about your product here on the GRF - as you can see from my post to Lou my interest in your product is hopefully a near future interest

1) I like the idea of being able to load our filter press with your product

2)I like the idea of your sompex 105 &/or 112 to recover Pd from nitrate solutions as an alternitive to ether DMG or cementing

Kurt

 

[Smopex]

Thank you for the reply.
You say that one of your best results was using Smopex 500 on the waste effluent from the refinery but mention using a filter press, will it work using a standard vacuum filter and does it only recover the PGMs and not the gold? My thoughts are that most refiners here use a vacuum filter and in honesty probably do not create huge volumes of waste effluent so if it meant passing the solution over the filter several times before treating it for disposal it probably wouldn't matter too much..

Dear nickvc

Thanks for your post.

Smopex and out other scavengers, are used in a variety of engineering formats. In the effluent example, a filter press was used due to the high volume of effluent to be treated (up to 20,000L/day). One of the most common options is a stirred tank, followed by a filtration step (by vacuum filter, filter press, etc). Also common are fixed beds such as filter bags, columns and filter presses. There's some more info on our webpage here.

One of the most important factors to consider is that there is sufficient contact time between the Smopex and the solution to be treated. We assess the rate of recovery (kinetics) during our screening trials, and this often determines whether the process lends itself to a stirred tank or a fixed bed. A number of other factors also come into play such as plant availability (can existing plant be used) and volume to be treated. Recovery rates for gold tend to be extremely quick relative to other PMs. So to answer your question, yes Smopex can be used in a vacuum filter as long as sufficient contact time is possible. Failing that we would recommend a stirred tank/vessel option.

Smopex 500 is suited for effluent applications (low level, mixed pgms including gold and silver) more info here . However, for specific gold recovery, Smopex 103 and Smopex 105 are the recommended fibres.

Regards
ST Team

 

[Smopex]

Sompex

Thank you for posting info about your product here on the GRF - as you can see from my post to Lou my interest in your product is hopefully a near future interest

1) I like the idea of being able to load our filter press with your product

2)I like the idea of your sompex 105 &/or 112 to recover Pd from nitrate solutions as an alternitive to ether DMG or cementing

Kurt

Thank you Kurt

If you would like to discuss your process and to see if Smopex can assist your recoveries then please feel free to contact us
[email protected]

Regards
The ST Team

 

[Smopex]

No, the fibers are functionalized with different organic groups that possess varying degrees of affinity for a given metal.

I have tested and used Smopex and it does work. I will attach some photos.

Hello Lou

Would you still consider posting your photos? We'd love to see them!

Thanks
The ST Team

 

[Gratilla]

I note from your "Smopex Selection Guide" that Smopex 103 and Smopex 269 are effective for "Au recovery from spent basic solutions" ie from cyanidation.

1.a. How much cyanoaurate typically leaks through a Carbon-in-Pulp (CIP) process?
1.b. How much of this is mopped up by Smopex?
2. Do you have a comparison of Smopex vs CIP effectiveness?
3. Over what pH range are these Smopexes effective?
4. Can they be stripped by pH adjustment?
5. What other metals are collected by these two Smopexes? ie I don't want to find that I'm loading up my expensive Smopex with say just copper.

Better yet, comp me a few kilos and I can try to answer my own questions. :mrgreen:

 

[nickvc]

The ST Team.
Thanks you for the replies and further information on your products applications.
From what I can figure then your Smooex 500 could be the product that most members could utilise in their systems and if I'm reading your replies and website correctly all that would be needed is a further version of what is commonly referred to here on the forum as a stockpot, where we cement our values before waste treatment for safe disposal of our waste acids, and that by simply putting some of it into a mixed solution for a given period it would extract the values to a level of around 80% of those present.
This is very interesting but we still need further details such as costs and the amount of time the product needs exposure to the wastes to achieve good results. The time factor for many probably wouldnt be a major deterrent within reason but costs could be so could we have some specifics about what amount of your product and how much it would cost would we need to say treat 10 litres a week of waste solution and how long you would advise the product be either immersed or how many passes through a vacuum filter would be required to extract the values to a reasonable level. Please remember many members do not have access to inhouse assays so we need guidance to the use of your products. There are members who probably exceed this level of wastes and in some cases by many times but by giving us a base to work from perhaps it will spark interest in your products and their applications.
A question that occurs to me is that I really don't want to refine PGMs, I'll leave that to the pros, but I do want to recover them so could your products scavenge higher grade solutions successfully or would you advise using cementation and then using your products to achieve a better recovery and do any other metals cause problems for your products efficiency.
Thank you for your attention and patience, I'm no chemist as I have stated before and try to ask questions others in my position will be able to understand and which hopefully your replies will shed some light on, I'm not interested particulary in all the details but more in will it work, how to use it and how much does it cost, I'll leave the more technical questions to those who might understand the science behind them :lol:

 

[Smopex]

I note from your "Smopex Selection Guide" that Smopex 103 and Smopex 269 are effective for "Au recovery from spent basic solutions" ie from cyanidation.


1.a. How much cyanoaurate typically leaks through a Carbon-in-Pulp (CIP) process?
1.b. How much of this is mopped up by Smopex?

2. Do you have a comparison of Smopex vs CIP effectiveness?[/quote]

With respect to the above questions, unfortunately we do not have enough information or experience in this area to comment.

3. Over what pH range are these Smopexes effective?

The Smopex range is effective across the whole pH range. This is owing to the polypropylene backbone of the fibre which makes all of our Smopex fibres chemically resistance to strong acids and bases as well as organic solvents. It also makes Smopex very mechanically stable and it will not break up or become damaged when used in stirred tanks, pumps and other plant machinery.
The conditions of the stream (including pH, and which acid is present) will determine the chemical species of the metal and therefore which chemical functionality should be used for recovery. We are happy to advise on this.

4. Can they be stripped by pH adjustment?

The binding of precious metals on smopex is very strong due to the functionalites having a very high affinity for precious metals. The fibres can be partially stripped and re-used under the right conditions, but generally they are fully loaded they are sent for recovery. Our QuadraPure and QuadraSil products are much more amenable to elution and regeneration.

5. What other metals are collected by these two Smopexes? ie I don't want to find that I'm loading up my expensive Smopex with say just copper.

In very general terms the reactivity series can be an indication of which metals will load preferentially. In practice this is very dependent on the chemical conditions of the stream which will determine the speciation of the metal as well as the relative concentration of each of the metals.
Smopex can be very highly selective for some metals over others. For example Smopex 105 has been able to recover 100% of Pd at concentrations of 300ppm from a solution that contained 30-40 g/l of Cu with little to no take-up of Cu. We also observe that even if a high concentration of base metal does load onto the fibre (often due to concentration), the precious metal will usually displace the base metal as the recovery proceeds.
Subtle differences between conditions can have an impact and so we would always suggest initial lab test work (as you mention below) to validate the process.

Better yet, comp me a few kilos and I can try to answer my own questions. :mrgreen:

We’re always happy to discuss arranging samples. PM sent.

Regards
The ST Team

 

[Smopex]

The ST Team.
Thanks you for the replies and further information on your products applications.
From what I can figure then your Smooex 500 could be the product that most members could utilise in their systems and if I'm reading your replies and website correctly all that would be needed is a further version of what is commonly referred to here on the forum as a stockpot, where we cement our values before waste treatment for safe disposal of our waste acids, and that by simply putting some of it into a mixed solution for a given period it would extract the values to a level of around 80% of those present.

Could you perhaps explain to us a little more on this "stockpot" please?

This is very interesting but we still need further details such as costs and the amount of time the product needs exposure to the wastes to achieve good results. The time factor for many probably wouldnt be a major deterrent within reason but costs could be so could we have some specifics about what amount of your product and how much it would cost would we need to say treat 10 litres a week of waste solution and how long you would advise the product be either immersed or how many passes through a vacuum filter would be required to extract the values to a reasonable level.

Amount of Smopex
This depends on how much precious metal there is to recover from the solution. I understand that you may not be aware of this without analysing the solution, but if you can estimate the concentration then we advise on amounts to use.
For example, if you had a total precious metal concentration of less than 0.5 g/L (500ppm) then we’d suggest using 20g of Smopex per lire of solution (2w/v%). So to treat 10L of solution containing <500ppm pgm in total you would need apx 200g of Smopex.

Costs and Loading
AS you highlighted the smopex generally used in these mixed metal streams is Smopex-500.
For orders of up to 10Kg, Smopex 500 has a cost of $170/kg (dry weight basis).

The cost effectiveness of the smopex is really determined by the achievable metal loading i.e. how much metal can be recovered by this 1kg of smopex. We normally express this as a percentage.

Ie: 20 grams of metal recovered by 1kg (dry weight) of smopex would be:
(0.02kgs/1kg) X 100 = 2% metal loading onto the fibre
An example of the impact loading has on the cost effectiveness can be seen below*

*Results will vary

Treatment Time
A general rule is to contact the fibres for as long as possible to ensure maximum recovery. We have treated solutions for up to 16 hours. Of course this depends on the setup, but we have also had fixed beds where the contact time has been around 10 seconds.
Contact time also depends on which elements are present in the solution to be treated. We know for example that in low pH acidic solutions, gold and palladium exhibit the fastest recovery rates (normally less than 5 minutes), followed by platinum, ruthenium, iridium and rhodium (can be hours). Temperature can play a big role in the rate of recovery, but if heating the solution isn’t a viable option then ambient temperature is sufficient (10-25°C is normal)

Please remember many members do not have access to inhouse assays so we need guidance to the use of your products. There are members who probably exceed this level of wastes and in some cases by many times but by giving us a base to work from perhaps it will spark interest in your products and their applications.
A question that occurs to me is that I really don't want to refine PGMs, I'll leave that to the pros, but I do want to recover them so could your products scavenge higher grade solutions successfully or would you advise using cementation and then using your products to achieve a better recovery and do any other metals cause problems for your products efficiency.

We understand that costs are important, but so is maximising the recovery of the precious metal. From an efficiency point of view, recoveries using Smopex will generally be higher on higher grade solutions (the less is has been processed). However, cementation is a tried and tested method of recovering precious metals and Smopex can also be used post cementation to recovery the residual precious metals in solution, but recoveries maybe lower.

Thank you for your attention and patience, I'm no chemist as I have stated before and try to ask questions others in my position will be able to understand and which hopefully your replies will shed some light on, I'm not interested particulary in all the details but more in will it work, how to use it and how much does it cost, I'll leave the more technical questions to those who might understand the science behind them :lol:

Thanks for your continued interested and we’re always happy to discuss your processes and answer questions.

 

[nickvc]

The ST team.
Thank you for further clarification on your products.
A stockpot is what most members use to store waste solutions containing values which are been cemented to recover the values.
Using your calculation of 20 grams per 10 litres of solution with 0.5 grams per litre or less it makes some sense but what if the solution is only very low PM bearing say under 0.1 grams per litre do we still need to use 20 grams per litre and how many times can the Smopex be used, is it a one off use or will it continue to function until saturated with values, also how can we tell when the Smopex has ceased working, is there any visible way to tell.
As an example I have a solution that has Pt and Pd around 80 litres and it's contents are around 25 grams in total of those two metals, would I need 1600 grams of Smopex to recover these metals and after the solution has been treated can the Smopex be used to recover values from further solutions or is it now useless?
The idea percolating through my non chemists head is that if Smopex will work until saturated that the solutions from our stockpots after cementation could be either filtered through Smopex, have a bed of it to pour our waste into or a simple bucket with holes in into which waste solutions could be poured to collect any values still present but allow the solution to be drained away for waste treatment but all these ideas are based on whether Smopex works constantly or just once, also bear in mind assays for many members are expensive so a visual method to tell if it is loaded or not would really help the costs.
I'm sorry if it seems I'm constantly pushing you but the members here by and large are hobbyist or small time refiners and every cent counts and while your products seem to be what we all could profit by I just want clarification so everybody can see the benefits and usability against costs and time spent using it.
Another point I wished to raise is, is there a limit percentage wise that Smopex can scavenge values from solutions or is it down to the time in contact and the actual make up of the solutions, such as the acids and base metals in it.

Edited for a first her query.

 

[kurt]

Nick - thanks for asking the questions you have been asking - they are questions I have wanted to ask but have not had the time to ask

ST team - thanks for answering Nick's questions they are very helpful

A question I have - I have recently been working on some silver that is running relitively high in PGMs & though most of the PGMs are parted & recovered in the silver cell (as slims in anode bag) they are high enough in concentration that I am getting a co-deposit (Pd in particular) on the first run in the cell thereby needing to run it a second time in the cell.

Would Sompex (500) work to recover the PGMs from a "concentrated" Ag nitrate solution "before" cementing the silver to over come the problem

Kurt

 

[Smopex]

The ST team.
Thank you for further clarification on your products.

You're welcome

A stockpot is what most members use to store waste solutions containing values which are been cemented to recover the values.
Using your calculation of 20 grams per 10 litres of solution with 0.5 grams per litre or less it makes some sense but what if the solution is only very low PM bearing say under 0.1 grams per litre do we still need to use 20 grams per litre and how many times can the Smopex be used, is it a one off use or will it continue to function until saturated with values, also how can we tell when the Smopex has ceased working, is there any visible way to tell.

If the solution was less than 0.1g/L (100ppm) then yes less Smopex would be required.
When we are assessing our customers solution, we run a number of experiments that are designed to calculate which of our scavengers are best at recovering the metal in question, how much is needed, how long is needed and the optimum temperature. We also calculate the loading of pgm onto the fibre to ensure the economics stack up. Of course we understand that this process is not always possible, but without the key data generated from these tests it is difficult to be too specific about the conditions required for successful recovery. However, we can of course make recommendations on what we do know!

Our scavengers work by chemically bonding to the pgms in solution. As this is a chemical process, we can calculate how much Smopex is needed to recover a certain amount of metal, providing we know the concentration of the pgms in question. Each fibre has a scavenging ‘capacity’ (imagine a sponge that can absorb liquid, once the sponge is saturated, it cannot soak up any more liquid). For anyone who’s interested the capacity of Smopex is measured in millimoles per gram or mmol/g, so by knowing we have say x amount of gold, we can calculate the mmol equivalent in gold and then equate that to the mmol of smopex required and convert back to g (or kg). It’s easier than it sounds.

So, to generalise on this without the chemistry bit, we recommend the following calculation:

Quantity of Smopex (g)=Volume of solution (L)×Metal in solution (g/L) ×40

Or if you work in ppm or mg/L then:

Quantity of Smopex (g)=Volume of solution (L)×Metal in solution (ppm) ×0.04

This is a rough guide and without analysis will give you a good idea of how much Smopex to use.

Knowing when to stop treatment is either based on:
-the Smopex has become fully loaded
Or
-the metal has been fully recovered.

Generally we use an excess of fibre so the first instance does not become a limiting factor. The second is usually measured by analysis. However, depending on the metal compound to be recovered, a visual change in either the solution or the Smopex can be observed.
Smopex can be used multiple times until fully loaded. However sometimes this isn’t advised as metal could potentially exchange back off the fibre into solution under the right conditions, but this is not normally observed.

As an example I have a solution that has Pt and Pd around 80 litres and it's contents are around 25 grams in total of those two metals, would I need 1600 grams of Smopex to recover these metals and after the solution has been treated can the Smopex be used to recover values from further solutions or is it now useless?

So 80L at 25g metal is 0.312g/L or 312 ppm. This would require apx 1000g Smopex (using the above calculation, this maybe an excess). For this amount of metal I wouldn’t suggest re-using the fibre. For lower concentrations of pgm you could as they’d be less risk of leaching metal.[color]

The idea percolating through my non chemists head is that if Smopex will work until saturated that the solutions from our stockpots after cementation could be either filtered through Smopex, have a bed of it to pour our waste into or a simple bucket with holes in into which waste solutions could be poured to collect any values still present but allow the solution to be drained away for waste treatment but all these ideas are based on whether Smopex works constantly or just once, also bear in mind assays for many members are expensive so a visual method to tell if it is loaded or not would really help the costs.

A column or filter bag would work ideally here where you’d have a fixed bed of Smopex and the solution is pumped through the Smopex. The Smopex is then changed once it’s fully loaded (or no longer recovers any values). Here's an example of this setup we currently have in operation:

I'm sorry if it seems I'm constantly pushing you but the members here by and large are hobbyist or small time refiners and every cent counts and while your products seem to be what we all could profit by I just want clarification so everybody can see the benefits and usability against costs and time spent using it.

No problem at all we’re always happy to discuss any questions you and the other members of the forum have.

Another point I wished to raise is, is there a limit percentage wise that Smopex can scavenge values from solutions or is it down to the time in contact and the actual make up of the solutions, such as the acids and base metals in it.

Yes there is a limit as stated above; it’s based on the chemical capacity of the fibre which we measure in mmol/g. Another factor is the metal species present, not all species have the same reactivity or affinity for Smopex. We can advise on this if you’d like more information.

Edited for a first her query.