X-ray element analysis and some unexpected results

[rusty marlin]

I had three samples shot and the results are not what I expected. There is Silicon in the wheel weight alloy. Why? What does it do?

At any rate just thought I'd share my results.

Sample 1) MICRO marked wheel weights, sorted by name for several years until I had a 5 gallon bucket full. Then smelted the whole lot down and kept it segragated.
Pb...96.00%
Sb...01.72%
Si....01.46%
Sn...00.64%

Sample 2) All the other wheel weights that were mixed together minus the stick on (really soft ones).
Pb...95.68%
Si....01.65%
Sb...01.39%
Sn...01.09%
P.....00.19%

Sample 3) This is an alloy I made up from 1# of 50/50 solder, 9# WW and 10# lead.
The lead was recovered from wall cladding from an x-ray room.
I use this alloy in my .38-55 and in my .45-70 Gould HP. It casts very nicley and the HP does its job.
This ones the real shocker....Where did all that extra stuff come from? (retorhical question)
Pb...92.14%
Si....3.06%
Sn...2.04%
Fe...0.94%
Sb...0.78%
Ti....0.71%
P.....0.203%
Cu...0.080%
Zn...0.039%

[Yodogsandman]

I had to look up silicon, thought it was like dirt.

https://en.wikipedia.org/wiki/Silicon

[corbinace]

When we see high levels of Si in our oil samples, it means dirt getting into the engine. Usually an air filter leak someplace. Not really sure how it correlates to your situation, but rather a point of reference.

[runfiverun]

it is the most abundant element on our planet.

[Oklahoma Rebel]

I thought that was carbon, silicon is a valley in california, don't you guys know anything? geez....:)

[runfiverun]

now that's funny right there.

[leeggen]

Silicon is bouncing in front of us everyday. OOPPs wrong one. Atleast all the extra things were in minute amounts, and the good things in good amounts.
Cd

[BNE]

Can you give more info on the equipment that was used? Did they find Si or SiO2?

I've done a fair amount of work on an XrF, they can spit a meaningless answer out very fast.

[RogerDat]

One scrap yard always gets Si in reading from checking CNC machining chips, they sometimes have an Si based lubricant on them, that lubricant then gets on the clear sensor cover and this then contaminates the future reading. They don't care since they are just interested in what grade of stainless steel or other mixed metal they are buying. 1.5% Si doesn't matter to determining the different metals and compositions.

[scottfire1957]

Not knowing you or your smelting/rendering technique, but did you leave dirt in your alloy?

[dale2242]

Silicon means your alloy has dirt in it.
Learned that from oil samples from heavy equipment diesel engines....dale

[OS OK]

That was most enlightening...thanks for posting.

[rusty marlin]

I guess its possible to have dirt in it.
But the dirt should float when the pot gets fluxed and scraped and then be removed with the other dross that gets skimmed off.
Silicon doesn't alloy with lead at less than 1100DegC (2021 DegF), so I'm reasonably confidant that its not alloying problem. ;)

The samples were scraped to clean shiny lead with a knife prior to sampeling, Not with a peice of sand paper, I was conserned any SiO2 embedded would effect the readings.

BNE, It's an Olympus unit, don't know the model number. The test was done with a "double line scan", it takes about 25 seconds. With the single line scan it took about 15 seconds and no Si was reported. after reading the posts on "time to scan" it seemed more pudent to go with the 25 sec scan. Where are you in SC pard? I'm near NE Columbia.

[BNE]

I'm up in the Greenville area. Holler if you are going to be in the area.

[Oklahoma Rebel]

leeggen, I was gonna go there, but I had already commited to the silicon valley joke. thanks for picking up my slack! Travis

[swheeler]

I see no arsenic in any of yours tested, every sample I had tested showed arsenic.