Proper mixture of various precipitants

[Geo]

I am new to this forum as well as the whole gold refining process and I have to say that i agree with yar though I'm not upset that the OP got the answer to your question. I am afraid to ask any question on here, thankfully I saw one of Geo's videos on youtube before I joined this forum and he answered a few of my questions on there. Since joining this forum i have spent 90% of my time reading on here. The one thing I do not understand is why I can type in the search bar "how to precipitate gold" and get nothing yet read on here that theres 558 posts on it. Why is this?

actually, its more like 4,520. :lol: use the search bar at the top of the page. the one that goes all the way across and has Google™ custom search. i copied and pasted (how to precipitate gold) and it pulled up that many topics.

 

[Harold_V]

I am afraid to ask any question on here,

For that you can thank the countless number of individuals who come here with the thought in mind of becoming a refiner of precious metals in fifteen easy minutes, without lifting a hand. These individuals don't seem to understand that this isn't something you learn quickly, nor do they understand that the information is here for the taking---if they'll do their part. Some of them refuse. They want to be spoon fed. That's not going to happen. I've put my foot down and will now just ban these guys instead of plead with them to start by reading Hoke's book and the forum, so they become familiar with terminology and processes that are commonly accepted as useful.

Having said that, if you've doing what is expected, and you have questions, post them. We're more than willing to talk with folks who are trying, but do that only after you have a basic understanding, so the replies will have meaning to you, not simply answer the questions you'd have because you've done nothing.

We are about refiners helping refiners. We are NOT about refiners helping deadbeats.

In regards to "how to precipitate gold"---Hoke discusses that issue at great length. Perhaps you can see why I keep telling readers to read Hoke?

Harold

 

[eaglewings35]

How many threads like this one do we have to read to find an answer?
Instead of asking so many questions.
Instead of just harping on members to study.
...
We could all be sharing information, and writing threads that can help us and others learn.

I will help anyone, even new members where I can, sometimes, the best advice I can give them is to begin by reading Hokes, other times providing a little of what I have learned and try to point them in a better direction to learn more.

This thread started out as a topic of " Proper mixture of various precipitants" I would like to see members discuss various precipitants, in this thread, so when we search for answers, and come upon this thread it will actually contain something of content and helpful information, not just another thread just full of yada yada we have to read through to find our answer, or even something meaningful...


Thank you Butcher, you and a few other understood the meaning of my posts. I was hoping to put everything in one place so others,like myself,
could find the information all in one place. Butcher, you and I have talked at length about proper procedures. You know by the questions that I have asked you, that I have been reading and putting in the time studying. Just because I asked this specific question, Yar, takes it as I haven't been reading or putting
in time time to study. I am IN NO WAY trying to get by because of my disability!!! I talked about my problems trying to elicit UNDERSTANDING, NOT SYMPATHY, YAR. So, get your panties out of a bunch. Either help contribute for others, or move aside for others who actually have something to contribute.
Easily said, KEEP YOUR RANTS TO YOURSELF !!!

Yar, I ask you to help us to make this thread and forum what it was intended a place to learn, and share information, can you help to discuss a precipitant for precious metals.

A few chemical or metal precipitants we could discuss:
SO2 gas and how to make it.
Copperas and how to make it.
Ammonium chloride How to make it.
Oxalic acid and how to use it.
Sodium metabisulfite.
Sulfurous acid.
Sodium bisulfite
Hydrazine
Ammonium hydroxide
Copper I chloride
Formic acid
HCl or NaCl
Sodium chlorate
Butyl diglyme
Dibutyl carbitol
Dimethyl gloxime DMG
Copper, zinc, iron, aluminum.
Any others you can think of or wish to discuss.




eaglewings35, I also expect that you will further your study on using Oxalic acid, and other precipitants, Taking notes, and doing the best you can, I know the more you work the better you will recover from the stroke.

 

[yar]

Try typing Oxalic acid precipitation in the search box. Its all right there. I will step aside Eagle and watch what pearls of wisdom you bestow on the rest of us. I am content to read and learn and use the search box properly. Any questions I have i am willing to search for the answers myself.
Goodbye
One more thing for those that are interested go back and read some of the op's old posts. All questions and how do I do this and mix that. And the sympathy card was played once before my friend. If I remember correctly it was around oct 9 2010 when you were trying to get someone to buy some computers. And how did the "blue clay" work out for you? Bet you couldn't get anyone here to buy that either!

 

[Geo]

yar, im going to give you some advice, drop this now before it comes to the attention of the moderators. personal attacks are not permitted on the board. if you have a problem with the way things works here, you should take it up with a moderator and not on the public board. in my time here, ive seen more than one charity drive on the forum for members that was having a hard time so that is nothing new. if one member receives more than you (in your opinion), should be angry with that member? i would think that most members would be happy that another member is receiving extra help or attention instead of taking it personally.

in my opinion, you are coming very close to breaking one of our most important rules by personally attacking another member.

 

[rusty]

Try typing Oxalic acid precipitation in the search box. Its all right there. I will step aside Eagle and watch what pearls of wisdom you bestow on the rest of us. I am content to read and learn and use the search box properly. Any questions I have i am willing to search for the answers myself.
Goodbye
One more thing for those that are interested go back and read some of the op's old posts. All questions and how do I do this and mix that. And the sympathy card was played once before my friend. If I remember correctly it was around oct 9 2010 when you were trying to get someone to buy some computers. And how did the "blue clay" work out for you? Bet you couldn't get anyone here to buy that either!

I did just that, out of curiosity went and read some of the OP's previous posts, rings the same bell.

In my humble opinion it would be well advised that this member use the search button more often plus re-read Hokes book until it starts to make sense. I spent a lot of my own personal time making that book available to our members and find it very discouraging that most will not take the time to crack open the pages.

 

[butcher]

I agree with all sides in this discussion :lol:

Read more and ask less stupid questions.

Seek and search and ye shall find.

You cannot learn by asking a few thousand questions, it only leads to more questions and answers you would not understand anyway.

Help your fellow member.

Read Hoke's.

I do search, and spend my free time studying; I also try and spend time contributing to the forum and helping others, from what I learn from my study, and from others.
Many times that help comes by telling the person asking the question to study.


Well let’s see if I can add a little more to this topic.

Here I will do a couple of search’s for information on oxalic acid, I will not spend much time looking for the information, and will use tools available like the forum search, and my computer search engine like goggle.

Several of our members have made some very nice videos

These are also good tools, to go along with your study, seeing it action can also help to understand better what You have been reading about, or what people have discussed although the video will not replace study, because without study you would not understand many of the very important minor details which the video most likely will not go into, or discuss, so without spending your time studying, you most likely would not be able to produce the results seen in the video, and without study the video although very interesting would be of little help.

Goggle search of video:
http://www.youtube.com/results?search_query=Oxalic+acid+gold&oq=Oxalic+acid+gold&gs_l=youtube.3...0.0.0.16982.0.0.0.0.0.0.0.0..0.0...0.0...1ac..11.youtube.

The forum has links to many very good video’s made by our members, reading their threads, and checking out their web sites you can learn from these fine members, who have spent time studying and sharing with others what they have learned.

Just asking these members to repeat information they have shared, will most likely not help you get started, you would not understand what you needed in the discussion, they would most likely just tell you to go and read Hokes book and study the forum, and the safety section and study other safety information. Because there is no way they could explain everything you would need to know or understand unless you spent time understanding the basic principles, this is where studying Hokes, and the forum will help you understand the basic principles.

If you are working hard and studying and ran into something you do not understand, or run into a road block and need pointed into a direction to help you in finding information, and you have studied and wish to learn a few more details, or need help in a process you have been studying and run into trouble or just wish to discuss the topic to learn more these members are more than willing to help where they can.

Forum search oxalic acid, notice how the recent thread (we
Are in now) is in the results of the search, hopefully we can make this thread useful for members who later search the key word oxalic acid or precipitants.

Notice also 617 hits with this word in my search, my guess is that the task of finding how to use Oxalic acid here is going to be very time consuming I will bet most of these posts only mention oxalic acid in the topic, or may help someone with a detail of the subject, it may be very hard for us to find a process or detailed explanation here.

Forum search Oxalic acid:
http://goldrefiningforum.com/phpBB3/search.php?keywords=Oxalic+acid+&terms=all&author=&sv=0&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

The search above was too daunting of a task to read through all of those posts to find information, here is were reading the forum helps, you begin to learn a little about the members, and can use this in your search to possibly help you find more information and to limit or narrow the search results.

Forum search Oxalic acid / Kadriver (author):
http://goldrefiningforum.com/phpBB3/search.php?keywords=oxalic+acid+&terms=all&author=kadriver&sv=0&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

Another way I may look for information on this topic, is to search through the subjects on the forum like Chemical processes, other processes, techniques…, and looking for a title of the topic which may lead me to more interesting information on the subject.
This also is time consuming but sometimes will lead to good results (and normally many others interesting things to learn about).

Search / Board index / techniques:
http://goldrefiningforum.com/phpBB3/viewforum.php?f=39&start=550

A look into the thread with topic of oxalic method as title.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=601


Okay I have searched and searched, read until my old eyes are sore, and still have not found enough information what shall I do?, Ask a question on the forum? And get the answer to read Hoke’s, and read Harold’s Ranting?

After reading Harold’s post I decide to look into Hoke’s index, and I see that on pages 59, and 173 there she discusses Oxalic acid.

From Hoke’s book page 173 we read:

The Use of Oxalic Acid
This method was mentioned briefly in Chapter VI as being especially
suitable for the recovery of gold from solutions that contain
relatively few impurities. Its disadvantage is that it will work only
when all the solutions are hot preferably boiling which means
that the precipitation must be carried out in vessels that will with
stand considerable heat. It costs more than copperas or sulphur
dioxide, about the same as sodium nitrite. Under most conditions
the gold recovered is of high purity.
For each Troy ounce of gold you will need at least a Troy ounce
of oxalic acid crystals. If you failed to expel all the excess nitric
acid, you will need more.
Dissolve the oxalic acid in hot water. Add a little ammonia, say
a teaspoonful or less to an ounce of oxalic acid; add slowly to avoid
spattering.
If you have litmus paper,
use it here, and let the mixture show a slight acid reaction. Have
the mixture in a big beaker or jar that will withstand heat.
Next, heat your aqua regia solution to boiling. Also have the
oxalic solution hot boiling if possible. Pour the gold solution
slowly into the oxalic acid solution. Gold comes down at once with
hot oxalic acid, but takes hours or even days if it is cold.
Some people pour the oxalic into the gold; we think it is better
to pour the gold into the oxalic.
There will be bubbles and fumes, so work slowly or the liquids
may boil over when they come together. If you failed to expel all
the excess nitric acid, brown fumes will appear here; if this happens
you may have to add much more oxalic acid in order to kill all the
nitric acid.
Let the mixture stand for some time, keeping it hot if possible.
The gold comes down as bright clean crystals, often very beautiful,
which usually settle promptly.
Finally pour or filter off the liquid, after testing some of it with
the stannous chloride testing solution to be sure you used enough
oxalic acid. If worthless throw it away at once. In rare cases it
may show enough palladium or platinum to be put in the Stock Pot.
The brown powder of gold should now be washed well with much
hot water, to remove all traces of hydrochloric acid, then boiled with
a little nitric acid, to remove traces of palladium or base metals.
Finally wash with plenty of hot water again, and dry and melt as
usual. This normally gives gold of high quality.

Dang I should have listened to Harold and read Hoke's book first.

Now I can ask the question:

When precipitating gold in the second refining process, Hokes mentions to adding ammonia (she states a teaspoon or less), but gives no details of how much oxalic acid in a water solution she has mixed up, (besides about the same amount as gold ounce for ounce or a little excess), when adding ammonia to the oxalic acid she does not say how much oxalic acid was used or how much gold she is wanting to precipitate, but she states "Do not use too much ammonia the mixture should not smell of ammonia after being stirred. If it does, add enough additional
oxalic acid to kill the ammonia smell.

Is there an ideal pH for the ammonia in the oxalic acid solution? or is smell the best way to tell the proper amount used.
I have seen it mentioned as pH 5, in other information I have studied is this the ideal pH.

 

[bswartzwelder]

I started a thread on July 5, titled "Precipitants in General". I listed SMB, ferrous sulfate and oxalic acid. Others graciously chimed in mentioning sulfur dioxide. Lasersteve even had a chart (I don't know how old it was) that was packed with valuable information. There have been many hours devoted to precipitation, because without precipitation, you can have tons of gold tied up in thousand of gallons of solutions. If you don't precipitate, the gold is just sitting there in an almost worthless state. (You can't take a beaker of solution into any store that I know of and walk out with merchandise.)

There are any number of methods used for recovering gold. Dissolution, electrolytic gold cell, pyrolysis/incineration, and inquartation just to name a few. They all have their pros and cons. They all take different equipment and all have their strong points and weak points. Without precipitation in some form, the processes for recovery and refining don't get you to your end point. Therefore, the different precipitation methods should all be tools in your Recovery and Refining process toolbox.

I have two little neighbor children (about 5 years old) living next door. As I was working in my driveway starting to build a pyrolysis/incineration unit, they appeared on their deck. I have repeatedly warned them not to watch while I'm welding, but it does little good. As a result, I have to physically stand between what I'm welding and them. The conversation usually starts out with them yelling over "Hi Mr. Bert", to which I reply "Hi boys". Then it starts. "What are you doing?" Let me just say, I don't answer their questions as they would like. I refuse to try to tell some 5 year old kids about the nuances of pyrolyzing and incineration. Likewise, if I am working with chemicals, I will not try to explain how or why SMB reacts with gold chloride to precipitate gold. I have tried wearing my shooting headphones which seems to help me not hear them. Asking them not to bother me, no matter how diplomatic I try to be, just doesn't work.

I was using a hot sand bath to remove components from cell phone circuit boards when they showed up on their deck and asked for an explanation of my activities. That time, I told them: "I'm depopulating circuit boards." Funny, all I heard was "Oh", like they knew what I was saying. Truth is, they didn't know what I was saying, but couldn't formulate more questions based on my answers.

I recently started dismantling an unused home-made trailer to make some much needed parking space in my driveway. The questions started again. I have finally found what I think is the perfect answer. I tell them "I'm just minding my own business." I'm almost to the point of telling them to read Hoke.

They once saw me evaporating my poorman's AR. While watching it, I pulled out my copy of Hoke and started re-reading it. Again, the questions. "What are you doing?" "I'm reading a book." "What's it about?" "It's about a lady who took a journey through a land of magic filled with all kinds of interesting things." Since this was about to be an extended session of Q & A, I shut everything down, put it away, then went into my home. As fate would have it, their mom came out within a half hour and loaded them into the car. Didn't see them for the rest of the day.

Any diplomatic responses which will help keep them quiet would be welcome. I will not resort to using foul language with them, but I will tell them to mind their own business.

 

[niteliteone]

I've always believed that Tall Fences make for good neighbors.

 

[bswartzwelder]

I wish I could. But their house is slightly uphill from ours and the fence would, by necessity have to be about 10 to 12 feet high. Fences also make it difficult when cutting grass.

 

[lazersteve]

I'm seeing a lot of threads and posts lately on precipitating gold with Oxalic Acid. I'm at a loss to understand why so many people are pursuing this precipitant as you can get just as pure gold using SMB with the proper filtration, washing, and melting techniques. The advantage to using SMB is that it is much safer, easier to use, cheaper, and faster.

I use SMB exclusively in my refining ( both first and second refining stages) and my gold is as pure as I can possibly get it (99.9%+) every time. Is anyone using Oxalic acid getting paid more money for the added expense and labor of using it? Even if you get an extra fraction of a percent purity as an end result, it makes no sense unless you are getting paid more for the extra effort.

Why is everyone so interested in oxalic acid lately? To me it is much wiser simply to use SMB.

Steve

 

[niteliteone]

(snip)
Why is everyone so interested in oxalic acid lately? To me it is much wiser simply to use SMB.

Steve

I don't know about others, but for myself I am learning / experimenting with other variables to refine my gold. I purchased a pound of Oxalic acid after reading here that SMB might be removed from our use and will try it later this year when I finish building my work shop for gold processing.
I do remember reading in many posts, that we should use different precipitants on "re-refining" to help reduce incidental drag down associated with using only one precipitant.

 

[lazersteve]

I'm not sure if SMB will be removed from the shelf of common stores like Lowes, Home Depot, or wine making shops, but I'm fairly certain it will not be removed from chemical suppliers where I buy my SMB in bulk. I guess that arguments validity comes down to where you get your reagents and if they really remove it from the shelves. If it was removed from shelves, you would be better served using Ferrous Sulphate instead of Oxalic acid in my opinion. For me economy is the name of the game when recovering and refining, so oxalic acid ranks very low on my list for several of the above reasons I already mentioned. When working on the narrow margins that I do, my choice of reagents makes a big difference in my profit margin.

Drag down is not related to the precipitant nearly as much as it is related to the concentration of the gold with respect to other contaminates (base metals and other PMs) in the solution. Switching precipitants after the first refining may have very subtle effects on your gold purity due to precipitation of unwanted contaminates, but these affects are negligible in the grand scheme of the small percentage change in the resulting gold purity verses the effort and cost to get the extra 0.005% to 0.01% purity increase. Palladium contamination may be one exception to this, but trace Pd can easily be removed with much less expensive and easier to use DMG used as a scavenger for Pd. It's much easier to add a few drops of DMG to solutions of gold containing trace Pd followed by filtration, than to go through the fuss of handling expensive carcinogenic compounds, and spending lots of time performing the precipitation process. It takes a fraction of a gram of DMG to precipitate trace Pd impurities.

The precipitant used in the first in second refining phases is not nearly as important to your gold purity as the proper recovery, filtration, washing, and melting of the refined gold. For example if you precipitate gold with SO2 (or SMB) in a dirty copper CuCl2 solution, you will have some CuCl that will co-precipitate. This is easily removed with proper wash procedures after the first refining. Traces of Palladium are removed as stated above.

On the topic of the novelty of using Oxalic acid, I completely understand that mentality, as that is what lead me to try oxalic acid many years ago. After a few experiments with it, I quickly wised up and went back exclusively to SMB. I have several pounds of oxalic acid that I purchase several years ago, and to this day I've only used a few grams of it in my gold refining. My over reaching point in this discussion is when it comes to final purity, time required in labor, safety, economy, and ease of use, SMB beats oxalic acid hands down. If your lab has a specific reason to use Oxalic acid, you can not obtain SMB, or you get paid handsomely for the few extra hundredths of a percent purity increase, these may be a valid points to use it, but using it simply to be using it, is a bad business decision in my humble opinion.

Steve

 

[kadriver]

Is there an ideal pH for the ammonia in the oxalic acid solution? or is smell the best way to tell the proper amount used.
I have seen it mentioned as pH 5, in other information I have studied is this the ideal pH.

I was wondering the same thing. And I would also like to know the reason for raising the pH.

I can't remember where pH of 5 came from - maybe it was Lou.

But I would really like to know the reason as to why it is important to add the ammonia to increase pH.

Hoke does not explain why it has to be done in her book, only that it should be done before we use it to precipitate the gold.

This evening I was trying to precipitate 4.5 Troy ounces of pure gold using Hoke's process for oxalic acid precipitation located in chapter XV "Repurification".

I dissolved 6.5 regular ounces of oxalic acid in 600ml hot distilled water, did a hot filtration, then set to boil.

I added strong ammonia (28% ammonium hydroxide) to the boiling oxalic acid and checked with pH papers.

I ended up adding over 60ml of strong ammonia and got the pH to 2.

I added the boiling oxalic acid to the boiling chloroauric acid - all 600ml of it.

After adding all the oxalic acid solution, I boiled the mixture for over an hour and some gold precipitated nicely, but there is still much gold left in solution.

It was late so I turned it all off and went home.

Hoke says to use about 1oz of oxalic acid for each Troy ounce of gold.

I used about 1.5oz for each Troy ounce of gold and it still did not "bring down" all the gold.

Tomorrow I'll boil again and add another couple of ounces of oxalic to get all the gold out of solution.

My main question here: why is it essential to get the pH up on the oxalic before it is combined with the chloroauric acid (gold dissolved in AR)?

kadriver

 

[butcher]

Why is it essential to get the pH up on the oxalic before it is combined with the chloroauric acid?

This is just a wild guess of mine, from another topic we have been discussing earlier (reduction of silver chloride with the glucose [karo syrup] and sodium hydroxide method).

From that discussion we seen where the NaOH was used to convert silver to an oxide, but then we needed an excess of NaOH which was also needed to open the glucose ring of the aldehyde in the hydrolyzed carbon chain of the glucose (sugar), I am no organic chemist but I suspect that oxalic acid also being an organic carbon compound with the formula H2C2O4, that the adjustment of the pH in our process to precipitate gold from AuCl3 with H2C2O4 oxalic acid also serves a similar purpose with the reduction process of gold when using this oxidized sugar compound of oxalic acid.

The process or reductions of metals in these two different processes, of silver chloride and the karo syrup method, and the gold and oxalic acid seem to me to have a lot in common.

 

[kadriver]

Thanks Butcher.

With respect to what you have postulated above, what would happen if I added the oxalic acid full strength with no ammonia to adjust the pH value up?

I think I am agreeing with Lazersteve - oxalic acid is a troublesome way to go, and SMB can probably get the job done with much less hassle and in much less time that it takes using oxalic acid.

I only did this batch to maintain a certain level of proficiency. Pouring those two boiling liquids together is a little frightening.

kadriver

 

[butcher]

kadriver,

I am not the best one to answer this, but the way I understand it for the oxalic acid to be able to precipitate gold there can be no free acid (this means HNO3 or HCl), and only the solution of gold chloride salts. So here were we basically neutralize the acid (changing it into salts with the base solution of NaOH a base of ammonia) we are eliminating acids from solution, so that oxalic acid can work to precipitate the gold, which in turn produces CO2 gas and makes our remaining solution acidic again of HCl.

Hydrogen from the carbon chain combining with the chlorides from the gold, leaving the gold free to precipitate.

2AuCl3 + 3H2C2O4 --> 2Au + 6CO2 + 6HCl

It is funny to me to look at this, it looks kind of like they took sugar glucose and oxidized it in nitric acid to make oxalic acid and we basically burnt that sugar compound with our gold :lol: to form carbon dioxide of that carbon compound.

 

[sharkhook]

Not to disrupt the conversation, but after reading the entire post I took away a very clear understanding of the reason for multiply washes. Thanks for the information on that. As I am new to this, and have only removed foils from various boards, I am just starting to look into the refining part and was having questions form in my mind about the wash processes.

 

[kadriver]

I'm seeing a lot of threads and posts lately on precipitating gold with Oxalic Acid. I'm at a loss to understand why so many people are pursuing this precipitant as you can get just as pure gold using SMB with the proper filtration, washing, and melting techniques. The advantage to using SMB is that it is much safer, easier to use, cheaper, and faster.

I use SMB exclusively in my refining ( both first and second refining stages) and my gold is as pure as I can possibly get it (99.9%+) every time. Is anyone using Oxalic acid getting paid more money for the added expense and labor of using it? Even if you get an extra fraction of a percent purity as an end result, it makes no sense unless you are getting paid more for the extra effort.

Why is everyone so interested in oxalic acid lately? To me it is much wiser simply to use SMB.

Steve

Steve, if the gold is to be sold to a refiner then there is really no reason to dissolve in AR and precipitate with SMB. If the gold is inquarted right (I calculate the amount of silver needed to get the gold to 6k then multiply the silver by 1.1).

I then treat the inquarted gold in four treatments of BOILING 50/50 nitric/distilled water. The final boil is usually crystal clear and completely free of color. I then rinse until neutral pH with hot tap water, dry and melt.

I get any where from 99.6% to 99.9% on assay. There is always little to no loss, but when I dissolve and precipitate, there is always some loss. The more it is handled, the greater opportunity of losses.

One draw-back: I found that my proficiency suffers, when I do decide to refine a batch all the way, I start to forget steps that used to come automatically when I was dissolving and precipitating all the time.

I can go from karat scrap to a 1 Troy ounce button in about 3 hours, ready for delivery to the refiner with hardly any chemicals used and the gold very pure.

Of course if the gold is for a trusting client things would be different. All my gold is sold to a refiner.

kadriver

 

[lazersteve]

I found this old thread and wanted to reply to it despite its age.

Kevin,
The majority of the scrap I run is from cpus and turbine jet engines. I do get the occasional karat batch which I typically return the customers portion as fine gold. Gold filled is another primary feedstock in my lab.

In all of the above mentioned instances complete refining to an acceptable 99%+ purity is my goal for two primary reasons:
Customer expectations of yields and customer satisfaction.
In other words, I want to provide a high quality product to my customers that reflects the best possible yields from thier scrap that is repeatable given the same feedstock. As an added benefit I have a very accurate idea of what my share is worth when batches arrive and selling my share. You are correct that inquart and several post cleanup stages can accomplish this with true karat scrap.

You make a good point about processing losses, but it's a necessary evil in my opinion to give the customer a clean product so they can resell their share at a know value whenever they choose. It also helps them when buying future lots to send me.
If the customer is interested in quick turnaround times or fast cash on karat, then why bother to inquart (aside from knowing exactly how much Au is present), just melt and sell.
That also brings up a whole separate can of worms and that's "fake" or "mismarked" and even unmarked "karat" items. Over the years I've encountered lots of these pieces, even entire batches. It's never a good feeling to have to give your customer that kind of news especially on sizeable batches. I've seen karat that was passed from generation to generation that turned out to be plated copper with karat hallmarks. Turns out grandmas jeweler was a crook. The specific batch that I am referring to here was acquired and processed by a good friend of mine and it was his own grandma's karat so there was no question where the bad egg was. I can cite other examples, but I'm already running long winded here.
By processing everything to fine Au along with photographing your work, the customer is less likely to think you are to blame for the loss.
We touched on the topic of the dishonest buyers as well in other topics so I won't repeat my feelings on that except to say even reputable companies have untrustworthy employees and the lure of gold has a way of corrupting people in general. There are even the instances where the employee may make an honest mistake in measuring or analyzing the batch depending on their level of knowledge.

Steve