Page 5 of 6 FirstFirst ... 3456 LastLast
Results 41 to 50 of 55

Thread: Removing Tin and Antimony from Lead Alloy?

  1. #41
    Join Date
    Nov 2001
    Location
    Toledo, Ohio
    Posts
    9,142

    Default

    There is quite a discourse on bullet casting here.

    http://www.lasc.us/CastBulletAlloy.htm#antimony1

    The tin and antimony do not float to the top as discrete elements, but the dross does where it can be removed by skimming. It verifies what gmatov and Sam Fadala say.

    Note this statement in particular: "The chemistry of tin and antimony dictates that they oxidize at a higher rate, which accounts for their gradual depletion from the melt."

    The dross floats to the top, it does not sink to the bottom.
    Jim H.

  2. #42
    Join Date
    May 2003
    Location
    52N 122W Western Kanuckistan
    Posts
    40,418

    Default

    This is the common process to remove tin from lead, patented in 1983


    United States Patent 4496394
    A continuous method of removing tin from lead, which method comprises maintaining a pool of molten lead in a stirred reaction vessel at a temperature of from 510 to 570 C., continuously introducing molten lead containing tin as an impurity at or near the top of the pool, injecting chlorine and oxygen gas into the molten lead in an amount to react with the tin present in the lead to form a tin-containing dross, the residence time of the molten lead in the reaction vessel being from 5 to 60 minutes, recovering the mixture of lead and dross from at or near the bottom of the reaction vessel and passing it to a separate settlement zone for separation of the lead from the tin-containing dross.
    Also, the tin does not float to the top. It can't since it is dissolved in the lead.

    Also, the old process does resort to skimming the dross from the top but requires the use of oxygen and usually chlorine gas. It is/was very hazardous. I stand by my statement that it is irresponsible to recommend trying to refine lead at home.

    From the patent application regarding the old process:
    The process requires substantial investment in both capital and energy, since a large body of lead has to be maintained at 500 C. for several hours, is inflexible, metallurgically inefficient, produces toxic wastes and gases, and is labour intensive, particularly at the dross-removal stage.
    Note also that the tin is not the main element that produces the hardening of lead, it is the Antimony. The antimony cannot be removed at the 500C temperature range but requires much higher temperatures. It is at those higher temperatures where dangerously toxic fumes are produced. Removing just the tin, were it possible, would not produce the desired result.
    Free software for calculating bolt circles and similar: Origin now settable to bottom left! All values positive. Click Here

  3. #43
    Join Date
    Nov 2001
    Location
    Toledo, Ohio
    Posts
    9,142

    Default

    If you were to take the trouble to read and understand the link I cited, you would see this statement;

    "Lead/antimony alloy drosses considerably. As your melt reaches liquidus temperature that silvery, lumpy, oatmeal looking stuff floating on top is antimony. Skimming it off seriously depletes the alloy; it needs to be fluxed back into the melt".

    It is quite apparent that drosses indeed rises to the top, and that skimming them off will remove the parent metal from the melt. That is reinforced by this quote from the same link;

    "Dross forms in a pot of molten metal by oxidation of the metal from exposure to heat, air, impurities, and dirt, and from running the alloy below its liquidus. As the metals melt, drosses (oxides of the metals) appear on the surface of the molten metal. They must be returned to the melt by fluxing, or else their removal as dross seriously depletes some of the important constituents of the alloy".

    Certainly, there are industrial processes for refining lead and removing alloys that use methods and reactions that are not advisable for application at home. However, it is quite obvious that this method will work with equipment and methods any experienced bullet caster is familiar with.
    Jim H.

  4. #44
    Join Date
    Feb 2006
    Location
    SW PA
    Posts
    842

    Default

    Jim H,

    Thanks for your support. I probably do come across as an ass sometimes, at least to Evan, but I do and have done some bullet casting, many years ago for centerfire pistol, past 5 years or so strictly pure lead BP round ball percussion.

    BP has made me lose interest in the load 10 and snap them off in 10 seconds, to load 6 in 5 minutes and snap them off in 30 seconds.

    A good day's shooting, now, is 60 rounds over a couple hours, then a couple hours washing the revolvers, and relubing them.

    Thanks much for the link. Much help there. Smart man, that Rick Kelter, but then, the measure of a man's intelligence is how closely he agrees with you, right?

    I must seem stupid because I occasionally do not agree with Evan.

    I particularly like the reference to battery plates. Paul doesn't want to use them, because he says they are not pure lead, and your link says he is more right than he knows .

    " Salvaged battery lead should be avoided at all costs. Since the advent of the maintenance free battery the lead content has been reduced and elements such as strontium have been added. Most of these elements cast very poorly, ruin a pot of good alloy they are blended with and are extremely toxic. The quantity of lead from batteries is not worth the risk or the effort."

    That is nice to know.

    The sites Evan quotes are major recyclers, or reclaimers. Of course, if you have a 1000 tons to purify, you are not going to heat to 700 F and station men on a catwalk to skim the ladle. You are going to experiment and find the most efficient, cost effective, environment be damned method, and assure your respective government that you have it all under control.

    Similar to leaching thousands of tons of gold bearing diggings, 1/2 ounce to the ton, with arsenates, to refine the gold, or silver bearing ores, the same.

    In Canada and the US and in any other precious metals producing region in the world.

    You try to reclaim some precious metal with a quart of the appropriate acid, do the job, neutralize with a pound of bicarb, half a buck's worth, you pour the residue on your garden, totally environmentally friendly.

    Same with what we are discussing. Take off the dross, mostly tin and antimony, with some lead, put it in a tin can, if you can, take it to a recycler, if they won't pay anything for it, give it to them.

    We are so DAMNED scared of everything we read in the scandal sheets we are ****ting our pants over contaminants. We are ALL going to die horrible deaths from benign substances.

    Some of us seem to be more afraid of dying than others of us who are approaching their twilight years.

    Cheers,

    George

  5. #45
    Join Date
    Jun 2006
    Location
    MA, USA
    Posts
    615

    Default

    Quote Originally Posted by gmatov
    elements such as strontium have been added. Most of these elements cast very poorly, ruin a pot of good alloy they are blended with and are extremely toxic.
    Strontium, at least, isn't poisonous.

  6. #46
    Join Date
    Feb 2006
    Location
    SW PA
    Posts
    842

    Default

    Rantbot,

    You gotta cherrypick something from a quote to make your post seem important and informative?

    I think the original quote, not my words, represents battery plates as not desirable for melting into bullet material.

    Go to the link and read it. It may be informative. You may even put a pure lead sinker on a fishing line with your kids without putting on rubber gloves, and fearing that you are going to die from lead poisoning.

    Go buy some aluminum sinkers. There is some evidence that aluminum MIGHT be a culprit in Autism and Altzheimers.

    I take no side in this, except I do not use aluminum utensils. My preference.

    Cheers,

    George

    Oh, by the way, WHICH Strontium is not toxic? I think when I was a kid, it was a given that a nuclear blast would flood the world with Strontium 90, which would contaminate all the grasses, and the cows would eat it and concentrate it to make milk poisonous.

    You are not telling me that 50 years of Government wisdom was wrong, are you?

  7. #47
    Join Date
    May 2003
    Location
    52N 122W Western Kanuckistan
    Posts
    40,418

    Default

    Strontium 90 isn't poisonous or toxic either. It's radioactive, quite a difference. Sulphuric acid isn't toxic as lead is, just corrosive, an easily altered property. There is a reason they make these distinctions when labeling hazardous goods. They still put strontium in toothpaste because it replaces calcium in teeth and oh yes, it helps to plug the microtubules in the dentin that lead to the live nerves in the root.

    Lead is toxic, particularly so in the various oxide forms. This property cannot be changed. It is also insidious. One of the most notable effects of lead poisoning is that it affects your brain first. The greater the degree of poisoning, the less your ability to appreciate that something is wrong. Bluntly, it makes you more stupid the greater the amount in your brain and that impairs your reasoning faculty. This happens long before other more obvious effects appear.
    Free software for calculating bolt circles and similar: Origin now settable to bottom left! All values positive. Click Here

  8. #48
    Join Date
    Jul 2004
    Location
    In my subterrainean lair, okay, it's a basement.
    Posts
    950

    Default

    Quote Originally Posted by deltaenterprizes
    Stop by any tire store and bargain for the scrap wheel weights or try a scrap yard.
    That's getting harder and harder with the price of scrap lead at insane levels, They're getting good money for it from the scrap guys who show up and pick up every week. The big chains actually dispose it "in house" - I know for a fact that Costco and Sears both do it this way.

    Quote Originally Posted by Paul F
    Entirely possible... that's what I'm trying to learn.
    Ahem:
    The commercial procedure for removing tin from lead alloys is to heat the metal up to 1200F and stir it rapidly for 3 hours. This procedure removes tin in the form of a very bright yellow dross and is far beyond the capabilities of most commercial bullet casters equipment.

    Even if you can heat your alloy to 1200F, syou shouldn't even think of doing it. That's 300F beyond th red line of danger to your health and your life.
    The Handbook of Commercial Bullet casting Second Ed. P 145

    Personally, I don't understand why you want to remove tin. Tin doesn't actually make the alloy significantly harder - it mainly aids in mold fillout in low percentages (about 2%, beyond that it's a waste). Antimony I couuld understand, as it makes in significantly harder, especially if this is for a smokepole, but even then, you should "try and see". You may find it works as is.


    Quote Originally Posted by gmatov
    Oh, buck fifty a pound is a bit more than the price listed, today, think it was about 2700, buck 35. I know that is commodity price, surprised you would charge retail. You COULD scrap it for about 85 cents, instead, mebbe.

    I don't think I would deal with you.
    $1.50 isn't "retail". It's actually a decent price. That commodity price? That's in 20 ton lots. "Retail" for lead right now is about 4 bucks a pound, plus shipping, in large pigs - McMaster has 60 pound pigs for $230.

    =============================================

    Aneat, out of curiousity, what are you using for ingot molds, and how much does each weigh? Color me curious.


    HTRN
    EGO partum , proinde EGO sum

  9. #49
    Join Date
    Mar 2008
    Location
    Winchester OH
    Posts
    5

    Default

    Quote Originally Posted by HTRN
    =============================================

    Aneat, out of curiousity, what are you using for ingot molds, and how much does each weigh? Color me curious.


    HTRN

    I use ingot molds I made from 3" channel iron. They were free (scraps) and will hold up for a long time. They weigh about 5lbs each in pure lead.

    I shoot a lot so luckily I stocked up before the price of lead went nuts. Ive probably got a couple tons of assorted alloys/pure








  10. #50
    Join Date
    May 2003
    Location
    52N 122W Western Kanuckistan
    Posts
    40,418

    Default

    It is quite apparent that drosses indeed rises to the top, and that skimming them off will remove the parent metal from the melt. That is reinforced by this quote from the same link;

    "Dross forms in a pot of molten metal by oxidation of the metal from exposure to heat, air, impurities, and dirt, and from running the alloy below its liquidus. As the metals melt, drosses (oxides of the metals) appear on the surface of the molten metal. They must be returned to the melt by fluxing, or else their removal as dross seriously depletes some of the important constituents of the alloy".
    Drosses do not rise to the top and that quote doesn't say that either. It merely says they appear on the surface of the metal, which is true because the surface, and only the surface, is exposed to oxygen. The dross is composed not only of the alloying metals but the parent metal as well. For dross to form within the body of the melt requires the introduction of oxygen. This results in a different type of reaction that traps unoxidized lead in the dross and the dross sinks to the bottom unless very actively stirred.

    The percentage of antimony in the dross regardless of where it forms is temperature dependent. Below the "safe" temperature of 500C very little antimony dross is formed, it is mostly tin and only from the surface material. As the temperature is increased the percentage of antimony goes up. So do the toxic fumes. Also, actively stirring lead while introducing oxygen is a very good way to get badly burned. The temperature of the melt doesn't just depend on the heat applied either. Introduced oxygen will heat the melt since the formation of oxides is an exothermic reaction. This will produce toxic fumes in the escaping gases even if the main body temperature is below the unsafe range. In all cases, regardless of temperature, the dross contains oxides of lead. This material is hazmat waste and should be treated accordingly. Seeking to produce more of this than is normally made is at the least foolish and is without question irresponsible.
    Free software for calculating bolt circles and similar: Origin now settable to bottom left! All values positive. Click Here

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •