# Best method to drop Pt from nitrate solution?.



## HAuCl4 (Oct 2, 2010)

Assume Pt is the main value, with silver, palladium and lead as contaminants.

Cheers guys.


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## lazersteve (Oct 2, 2010)

1. Precipitate lead as sulfate using sulfuric acid, settle, and siphon/decant.

2. Precipitate silver as chloride suing HCl, settle, siphon/decant.

3. Convert Pt and Pd nitrates to chlorides using evaporation and HCl .

4. Precipitate Pt and Pd as typical with NH4Cl and Sodium Chlorate.

An alternate path is to precipitate the lead and silver together with HCl, using multiple hot water extractions of the resulting powder to separate the lead.



Steve


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## HAuCl4 (Oct 3, 2010)

Will silver cement Pt and Pd cleanly?.

I am wondering if there is a direct way to get most of the Pt out quickly.


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## Barren Realms 007 (Oct 3, 2010)

HAuCl4 said:


> Will silver cement Pt and Pd cleanly?.
> 
> I am wondering if there is a direct way to get most of the Pt out quickly.



If silver would drop PT & PD you would not have to recover it from your solution before recovering them. So the answer to your question is no.


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## HAuCl4 (Oct 3, 2010)

I do not understand what you say Barren. I bet Silver cements both out, but I'm after dropping only the Pt out, if possible.


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## Barren Realms 007 (Oct 3, 2010)

HAuCl4 said:


> I do not understand what you say Barren. I bet Silver cements both out, but I'm after dropping only the Pt out, if possible.



The silver will not drop the PT & PD out of the solution. Do some more reading on the subject. No where is is stated that silver will drop PT & PD out of your solution. You need to drop your silver out by adding chlorinated tap water or some 
HCL, this will change your silver to silver chloride and you filter this off then go after your other PM's in the appropriate steps.


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## 4metals (Oct 3, 2010)

Why not cement out all of the PM's and dissolve the resulting metal mixture in dilute nitric, that will put the lead, silver and palladium in solution and leave the Pt on the bottom as an insoluble. Then it can be rinsed and refined classically with aqua regia. Using distilled water and high purity (reagent grade) nitric would perform the best.


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## HAuCl4 (Oct 3, 2010)

4metals: I'm trying to devise a FAST method for refining platinum scrap and/or PGM concentrates. If I alloy with 90% silver and roll it thin (or atomize it!), mostly everything dissolves fast in nitric acid, instead of taking weeks, days or hours.

I'm still wondering if I can get most of the Pt directly with some magically fast method similar to your posted formate reduction of pure silver.

Barren: I'll have to test to see if silver will cement Pt, Pd out of nitrate solution. I know copper will. But again, that's not what I'm after.


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## Barren Realms 007 (Oct 3, 2010)

HAuCl4 said:


> Barren: I'll have to test to see if silver will cement Pt, Pd out of nitrate solution. I know copper will. But again, that's not what I'm after.



I think that would be a good thin for you to do, some people only learn by thier mistakes.


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## HAuCl4 (Oct 3, 2010)

Barren Realms 007 said:


> HAuCl4 said:
> 
> 
> > Barren: I'll have to test to see if silver will cement Pt, Pd out of nitrate solution. I know copper will. But again, that's not what I'm after.
> ...



"Paitence is a virtue".


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## Barren Realms 007 (Oct 3, 2010)

HAuCl4 said:


> Barren Realms 007 said:
> 
> 
> > HAuCl4 said:
> ...




Yes sir it is, it will get you many places in life. And allow you to make many accomplishments that other's can't.8) 

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=6026


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## HAuCl4 (Oct 3, 2010)

Barren Realms 007 said:


> HAuCl4 said:
> 
> 
> > Barren Realms 007 said:
> ...



Well if you are patient enough silver will cement out the target metals (in theory), but it should be slower than copper, and I'm too impatient to wait for copper cementation. :lol:


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## HAuCl4 (Oct 4, 2010)

Overnight I realized that if I leach with sulfuric acid instead of nitric, the residue would be mostly powdered platinum, which can be quickly processed with A.R. and traditional methods. The lead sulphate should't be a problem with a good stirrer. :idea:


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## Barren Realms 007 (Oct 4, 2010)

HAuCl4 said:


> Overnight I realized that if I leach with sulfuric acid instead of nitric, the residue would be mostly powdered platinum, which can be quickly processed with A.R. and traditional methods. The lead sulphate should't be a problem with a good stirrer. :idea:



Where did the lead come in the equation at?


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## Anonymous (Oct 4, 2010)

HAuCl4 said:


> The lead sulphate should't be a problem with a good stirrer.


Can you please let us know exactly what it is that you are doing/processing?
I fear you may be traveling down a dangerous road blindly.There are many here (like barren) that will be more than willing to help you in your endeavor,but when you are told that something WILL NOT work,and you say "I bet it will" then you are defeating the purpose of asking the question in the first place,and spitting in the face of the person trying to help.
If you would be so kind,can you please inform us of exactly what you are trying to do so we can give you accurate advice to the problem.
If you do not want to post information on what you're doing then you may want to consider buying Lazersteves video for PGM's.
http://www.goldrecovery.us/
Like all of his videos,it is in depth and very easy to follow.


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## Platdigger (Oct 5, 2010)

He started this thread with the word "assume"
I assume the question is a hypothetical one.


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## Oz (Oct 5, 2010)

This is a lot of writing if only a hypothetical problem.


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## Harold_V (Oct 5, 2010)

Considering platinum is soluble in a nitrate when in the company of silver, it could be more than a hypothetical problem. Fact is, anyone that inquarts with silver and processes dental waste faces this very problem, albeit generally with minor amounts of platinum. 

My preferred method of recovery was simply to cement with copper, along with palladium and silver, with recovery of platinum and palladium from the slimes from the silver parting cell. The problem was the same, but now much higher in platinum group concentration. My procedure was to process the slimes in dilute nitric, heated, to dissolve silver and palladium, then to introduce HCl, which precipitated the silver as chloride. Continued heating dissolved the platinum. It was well washed, then the resulting solutions evaporated and filtered and processed chemically for the recovery of palladium, then platinum. Any platinum that may have escaped recovery was simply returned to the silver cell after converting the silver chloride to elemental silver, for parting once again. 

I expect one would encounter difficulty in processing a nitrate solution directly----it would have to be converted to a chloride. I may not be right, however. 

Harold


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## Oz (Oct 5, 2010)

I understand what you are saying Harold, I do things very similar with my silver cell slimes. However he has stated that Pt is the primary element in this solution. That will not happen by having silver as a carrier of PGM into nitric. In my experience you start having troubles getting all PGM into solution from a gold/silver inquart digested in nitric once you start getting over 10-15% Pt/silver ratio. Not to mention this is over 50% Pt nitrate.

As difficult as it would be to have primarily Pt in nitric with the others in lesser amounts unless done intentionally I will humor the question since I have opened my mouth.

Based on the fact the he says he wants the Pt out quickly I would add HCl to make the chlorides of lead and silver, then filter. 

With the remaining solution it depends on if he needs metal or wishes salts (the metal route below will give the cleanest separation of your Pd from your target Pt with the least amount of fuss). 

For elemental, cement your remaining solution with zinc, filter or decant. Then digest your solids with nitric, your undigested material is reasonably clean Pt.

For salts, evaporate 3 times with HCl additions to remove nitric, filter. Proceed with classic Ammonium chloride and sodium chlorate for your ammonium hexachloroplatinate and palladate. 

If this is not just a mental exercise solution we are discussing, then my apologies. I would however like to hear just how it came into existence without intentionally trying to make it in the first place.

Perhaps I am just grumpy this evening but this struck me as a goose chase. Some earlier threads tonight did not help my disposition either. I should have just kept my mouth shut in this thread, but once I opened it I felt I should follow through.


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## HAuCl4 (Oct 5, 2010)

Oz said:


> However he has stated that Pt is the primary element in this solution.



I said the main VALUE was in Pt ($1,685 per OZ). The main metal in solution is Silver ($22 per OZ). The original material would be solid Pt scrap and/or high Pt content smelted concentrates. That's where the lead and silver come from, on purpose with a target of 90% silver.

The rest of your post was very useful. Thanks. 8)

Thanks Harold too. I'm trying to avoid the electrolytic cell road. One question: How did you recover Pd before Pt chemically as you stated?.

I have to think that some chemist, somewhere, has figured out how to get the Pt, and only the Pt, out of a nitrate solution. But perhaps not, and the chloride route is the only one.  

Cheers guys!.


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## Lou (Oct 5, 2010)

Sure he has.

It's called S/X. Unfortunately, most of them won't solvate the aquanitrato platinum (II).


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## HAuCl4 (Oct 5, 2010)

Lou said:


> Sure he has.
> 
> It's called S/X. Unfortunately, most of them won't solvate the aquanitrato platinum (II).



So it exists, but it's a proprietary method?. My google search only returns results for Sx of Pt in chloride solutions. :? :?:


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## Oz (Oct 5, 2010)

HAuCl4 said:


> The original material would be solid Pt scrap and/or high Pt content smelted concentrates. That's where the lead and silver come from, on purpose with a target of 90% silver.



This changes things around greatly and very possibly makes all of what I said worthless if you are dealing with “smelted concentrates” especially if they are from ore. If you had “solid” Pt scrap, why would you alloy it with silver and lead? For that matter, I sure hope you did not intentionally add lead, as lead nitrate is not a trivial thing to play with. 

As far as your “high Pt content smelted concentrates”, where did these come from? Are they from ores or bench sweeps (other)? If they are ore concentrates, what type of ore and what other elements are there? If they are bench sweeps, what other work was done at the bench? 

I started off with the assumption you asked us to make “Pt is the main value, with silver, palladium and lead as contaminates”. You have greatly opened up the potential contaminates that may be present (and many will need to be dealt with differently than I outlined above) that will go into a nitrate solution such as chromium, cobalt, nickel, cadmium, copper, to name a few.

Just to be clear, is this a solution you currently have made that you need help in extracting the values from? If so you need to start from the very beginning as to all of your inputs and in what quantities you “smelted” together with what flux, then your procedures to get your nitrate solution. Advice you receive can only be as good as the details you give us to work with. 

As a personal note, this is why I take many of these topics off-forum. I pity the newcomer to refining that has to try to make sense of this thread.


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## HAuCl4 (Oct 5, 2010)

Oz said:


> HAuCl4 said:
> 
> 
> > The original material would be solid Pt scrap and/or high Pt content smelted concentrates. That's where the lead and silver come from, on purpose with a target of 90% silver.
> ...



To dissolve it quickly. Lead is only in traces after cupellation of concentrates and not for processing of Pt scrap. I don't think lead is that problematic to tell the truth, a nuisance perhaps. I have done only small scale experiments though.

I'm not interested in psycho-therapy at the moment, except my own!. :lol:

Maybe Lou will post the magic solvent for Pt in nitrate solution, maybe not. I'll keep searching for it anyway, and meanwhile it'll be sulfuric leach for me, followed by conventional A.R. methods as per Hoke, 4metals, and other forum threads and videos. 8)


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## Oz (Oct 5, 2010)

It is good to hear you are not alloying your solid Pt scrap. The fact that you are cupelling your lead/silver/Pd/Pt would also have been useful information to have. 

You are correct that after a proper cupellation there would only be traces of lead. I was not saying that lead would be problematic to remove with nitric, but it is a hazard that should be avoided if possible. Lead as a nitrate allows the lead to readily enter the body and bloodstream through the skin. 

I would ask if you could please take the time to answer my questions in my previous post, as without those things clarified, useful or accurate advice cannot be given.

If this is just an intellectual exercise, please just say so, and label them as such in your first post on a subject in the future please. 



HAuCl4 said:


> I'm not interested in psycho-therapy at the moment, except my own!. :lol:


I am not offering it, but please remember that there are many people here that are new to refining and chemistry that a thread like this with constantly changing parameters can only serve to confuse them. Worst still, they may try to take “part” of it out of context and do themselves harm. It should be our first responsibility to be clear in what we ask as well as advise of/to others. To be clear, I have no problem with hypothetical problems, just label them as such.

I am not entertained by, or find any humor in, muddy threads of speculation that can only serve to confuse and possibly harm others.


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## Anonymous (Oct 5, 2010)

Oz said:


> I am not entertained by, or find any humor in, muddy threads of speculation that can only serve to confuse and possibly harm others.


I could not agree more emphatically!That is why I asked him to CLARIFY exactly what he was trying to do,I only wish he had done so and saved a LOT of time,for us and the mod's.


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## HAuCl4 (Oct 5, 2010)

I'm sure you guys will not mind if I just ignore you and your requests for more irrelevant information. You seem to take many things far too seriously. Not my problem. You can ignore me too!. I will not mind. I promise!. :lol: 

"Whatever you think of yourself is much more important than what others think of you." Seneca.

You can call it whatever you want. It is a real problem about a real chemical process that has existed for many years for many people, and that has, understandably, many approaches.

Please don't lose any sleep over this!. :lol:


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## Anonymous (Oct 5, 2010)

HAuCl4 said:


> I'm sure you guys will not mind if I just ignore you and your requests for more irrelevant information.


I apologize if you think I was asking for irrelevant information.I was just trying to save a lot of time for the people offering to help you.
I didn't mean to upset you in any way,or insinuate that I was taking things "far too seriously".Unfortunately when dealing with the chemicals that you intend on dealing with,there is no such thing as too seriously.The moment you forget something,or do not respect them,they will remind you that they are there,FAST!If you are fortunate enough,you will live to tell us the story.
My only intention was to gather as much info as possible,to save time on solving the problem.I am not keen on wasting others' time,nor having others waste mine.Any spent time,is time never gotten back,I like to utilize what time I have left.


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## Oz (Oct 5, 2010)

HAuCl4 said:


> You can call it whatever you want. It is a real problem about a real chemical process that has existed for many years for many people, and that has, understandably, many approaches.


 If by that you mean that man has been trying to separate base metals from precious metals, then separate the precious metals from each other is a problem that has existed for many years, then yes, you are right. However the posed problem/question has been changed enough that it offers little more clarity than that.

My apologies for trying to get solid details about a solution that you had, and then asked for help with. With no further details or clarification I can only assume that this thread was hypothetical at best, or a fishing expedition. Without any concrete beginning solution or elements to be smelted, cupeled, digested, removed, precipitated or refined, your inquiry has no purpose or meaning hypothetical or not. The only value I can see in this thread at this time was for your entertainment as evidenced by your :lol: repeatedly. While some good solutions were offered in response to your query, they have been lost as to what we are actually trying to apply them to.



HAuCl4 said:


> "Whatever you think of yourself is much more important than what others think of you." Seneca.


 A very true statement indeed. However that does not mean that others opinions are unimportant when trying to work within a community.



HAuCl4 said:


> I'm sure you guys will not mind if I just ignore you and your requests for more irrelevant information. You seem to take many things far too seriously. Not my problem. You can ignore me too!. I will not mind. I promise!. :lol:


 The details that I was asking for are completely relevant, as proper solutions to your question cannot be given if we do not even know what we are trying to find a solution for or what the question really is. 

I will not mind at all if you ignore my request for further information as I think it is now obvious that trying to answer your question with any accuracy is an exercise in futility. Why you would choose to post even a hypothetical question, then refuse to clarify it so it can be answered is beyond me. As to me taking this too seriously, precious metals chemistry is serious business. This thread has been talking about salts of elements (liquid or solid) that are toxic and can cause permanent disability easily with even the simple absorption through the skin. Examples being but not limited to lead, platinum, and palladium nitrates.

As far as me ignoring you, I will accommodate you, so long as you are not posting something unsafe or that needs clarification so others can stay safe. That should be everyone's first priority. 

Frankly between this thread and the recent threads about how and where we should be allowed to help other members and what we should feel compelled/required to post as to our knowledge I have become rather agitated. 

Perhaps it is best that I do not post to the forum with that opinion/attitude. I will try to answer a post or 2 tonight that I have been meaning to get to, then stick to checking PMs to finish out conversations I have there helping some so as to not leave them hanging.


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## Harold_V (Oct 6, 2010)

HAuCl4 said:


> How did you recover Pd before Pt chemically as you stated?


Simple. When ammonium chloride is introduced to a concentrated solution of platinum/palladium, platinum precipitates. Once the precipitated platinum is removed (that familiar yellow/orange powder), the solution is then heated to near boiling, then sodium chlorate is introduced, precipitating the palladium. It's all in Hoke. 

Harold

Edit:

It has been brought to my attention (thanks, Oz) that I have this damned thing reversed in my mind. For that I apologize. What I said is correct, but that does not precipitate palladium first, which was the question, and is where I got my signals crossed. Seems like once I did, it made perfectly good sense!  

As Oz suggested, one can precipitate palladium first by using DMG, but it isn't a good idea. The results are hugely voluminous and difficult to handle. 

As you suggested, HAuCl4, I did mean sodium chlorate. Seems my head isn't hooked on well tonight. Again, my apology. I'll make corrections in the original post so others don't get the wrong message. 

Harold


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## HAuCl4 (Oct 6, 2010)

Harold_V said:


> HAuCl4 said:
> 
> 
> > How did you recover Pd before Pt chemically as you stated?
> ...





Harold_V said:


> then the resulting solutions evaporated and filtered and processed chemically for the recovery of palladium, then platinum.




Thanks Harold. I had understood that you dropped the Pd first, before the Pt. That could be useful to me and that's why I asked. I'm familiar with Hoke's procedures. I'm sure you meant sodium Chlorate instead of chloride above as well. Both probably unintended typings. Cheers.

Oz: I'm going to pass on a complete answer to your last post. Think what you will. If you think you have a problem with me or my posts, then YOU have a problem. Not me. Cheers. Same goes for mic. No hard feelings, but since I did not do anything wrong, I don't feel bad, and of course will not apologize either for posting!.

Wow!. I didn't think this forum could get so dramatic!.

Now, if someone could tell me and the forum, how to drop Pt cleanly from a nitrate solution, then this thread would not be a complete waste!. :idea:


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## Kats12 (Oct 6, 2010)

It would be nice to use formulas for compounds for example sodium chlorate - NaClO3, sodium chloride NaCl.
People often think those two are the same compound - it is almost similar in English language( I mean speaking it ,not writing it)

To drop Pt fast , the best method would be by adding some sort of hydride compound, I've used NaBH4 , it is very very fast, and it doesn't require any heating, it exothermic reaction.
For example you got Pd and Pt only in solution. The anion might be NO3- , or Cl- whatever, you drop them together , filter them , and the apply pure HNO3 to dissolve Pd again.
What remains is pure Pt black.
That is how I would do it.
The only problem is NaBH4 is expensive, but it can be produced at home...


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## HAuCl4 (Oct 6, 2010)

Kats12 said:


> It would be nice to use formulas for compounds for example sodium chlorate - NaClO3, sodium chloride NaCl.
> People often think those two are the same compound - it is almost similar in English language( I mean speaking it ,not writing it)
> 
> To drop Pt fast , the best method would be by adding some sort of hydride compound, I've used NaBH4 , it is very very fast, and it doesn't require any heating, it exothermic reaction.
> ...



Interesting. Do you have a link or document I can read more about that process and/or how to make the compound?.

But this would be similar to cementing with copper or zinc, only faster no?.

If I leach with mild nitric after leaching the silver out with sulfuric, the residue would be also mostly Pt, and then conventional methods for re-refining the Pt as chloride can be applied. 

Very many steps. If there is a way to separate Pt and only Pt directly from nitrate solution, it would be the most expedite route to refine Pt in a few hours.


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## HAuCl4 (Oct 11, 2010)

Harold_V said:


> As Oz suggested, one can precipitate palladium first by using DMG, but it isn't a good idea. The results are hugely voluminous and difficult to handle.
> Harold



I have never used DMG and I'm a newbie when it comes with the intrincacies of PGM.

Question: Will DMG work in a nitrate solution without converting to chlorides first?. If so, I have read that it produces a very complete separation/drop (in chloride solutions). If it works in nitrate solution and the Pd content is a low %, the costs and hassles of using DMG could be justified because it would pretty much clean up the now mostly Pt nitrate solution from Pd.

What do you think Harold?.


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## machiavelli976 (Oct 11, 2010)

I have found in an old book , you can get (NH4)2[PtCl6] which is solid(precipitate) , by adding NH3+NH4Cl to your nitrate mixture. The book also says the (NH4)2[PdCl6] remains in solution. Hope will help.


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## HAuCl4 (Oct 11, 2010)

Thanks mach. I just re-read a Hoke section and she warns against preparing Platinum Nitrate by treating silver rich buttons: "From which solution the platinum is difficult to recover". Then she goes about the conversion to chlorides and etc in chapter XII on the same issue.

The only issue with what you suggest is that the same contaminated salt of Pt is ever present. I want to avoid the Ammonium Chloroplatinate if at all possible, and drop the metal directly.


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## Harold_V (Oct 12, 2010)

HAuCl4 said:


> What do you think Harold?.


Sorry, no opinion. It's been too many years since I got my hands dirty in the lab, and my memory of these processes isn't what it used to be. However, I think I'd stand by my opinion of not using DMG. A few grains of palladium create a huge volume of the canary yellow precipitate. However, in fairness, vacuum filtration offers a serious compression of the volume. The resulting material is rather sticky, difficult to handle. 

Harold


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## HAuCl4 (Oct 12, 2010)

Thanks Harold. I tend to agree with you. Probably more trouble than it's needed.


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