Cadmium emission
hanson
Your response to this post is important, because regulators intend to make
public policy (= charge big time money), based on the interpretation of
this single set of experiments! I request results of YOUR calculated
evaluation and commentaries on the following situation. Please post and/or
send me your findings. When I have your results I will post them AND the
surprising findings of the regulatory agency. We will investigate why their
results are so different from yours !
Two Cadmium plating tanks (a & b) were analyzed for NaOH, NaCN and Cd.
During plating operations the over-voltage on Anode and Cathode produces O2
and H2 gas, and foam/bubbles from the air-agitation of the solution. These
actions produce a fizzing, a mist, which carries material out of the bath
into the atmosphere, called emissions, which were quantitatively determined
per EPA protocol and methods.
a) The uncontrolled Cad tank analyzed to 1.5 oz/gal NaOH, 12.5 oz/gal NaCN
and 2.8 oz/gal Cadmium. In this "uncontrolled" experiment the emissions
were measured via collection of the mist, 8" over the bath's liquid surface
and yielded 24.8 ugr (micrograms) Cadmium. Question 1: How much total
Sodium (ugr) must have accompanied this collected Cadmium amount (24.8
ugr)?
b) The controlled Cad tank analyzed to 2.0 oz/gal NaOH, 13.3 oz/gal NaCN
and 3.2 oz/gal Cadmium. In this (emission) "controlled" , analog experiment
a simple metal mesh pad was installed over the tank to capture most of the
mist-droplet emissions passing through this emission control device. The
non-captured, passed thru particles were measured in like fashion and
yielded an amount of 4.5 ugr Cadmium in the collected mist. Question 2: How
much total Sodium (ugr) must have accompanied the amount of collected Cad
(4.5 ugr ) this time?
Thank you all. han...@quick.net
PS. This is a live example of what students of chemistry will find once
they enter industrial or govt. regulatory services. This is not a trick
question, it's a simple report of facts received from the government.
Please do NOT comment on the toxicity of Cad at this stage. We will get to
this horror story in the next phase.
Alan "Uncle Al" Schwartz
"hanson" <han...@quick.net> wrote:
[political snip]
>Two Cadmium plating tanks (a & b) were analyzed for NaOH, NaCN and Cd.
>During plating operations the over-voltage on Anode and Cathode produces >O2 and H2 gas, and foam/bubbles from the air-agitation of=
the solution. >These actions produce a fizzing, a mist, which carries material out of >the bath into the atmosphere, called emissio=
ns, which were >quantitatively determined per EPA protocol and methods.
>
>a) The uncontrolled Cad tank analyzed to 1.5 oz/gal NaOH, 12.5 oz/gal >NaCN and 2.8 oz/gal Cadmium. In this "uncontrolled" experime=
nt the >emissions were measured via collection of the mist, 8" over the bath's >liquid surface and yielded 24.8 ugr (micrograms) Cad=
mium. Question 1: >How much total Sodium (ugr) must have accompanied this collected Cadmium amount (24.8 ugr)?
You don't know. The cadmium concentration in the mist is changing as the
tank is depleted during plating, and there may be surface segregation
effects (e.g., Langmuir films enriched in cadmium-containing hydrophobic
material). It is similarly unclear that surface sodium reflects bulk
sodium.
>b) The controlled Cad tank analyzed to 2.0 oz/gal NaOH, 13.3 oz/gal NaCN
>and 3.2 oz/gal Cadmium. In this (emission) "controlled" , analog >experiment a simple metal mesh pad was installed over the tank to=
>capture most of the mist-droplet emissions passing through this emission >control device. The non-captured, passed thru particles =
were measured in >like fashion and yielded an amount of 4.5 ugr Cadmium in the collected >mist.
You might do better (and much cheaper!) with a non-woven fiberglass
furnace air filter. I don't know of any metal mesh which sells for a few
cents/square foot.
Question 2: How
>much total Sodium (ugr) must have accompanied the amount of collected Cad (4.5 ugr ) this time?
You still don't know. It is not clear that differential Cd
concentrations in the mist will be equally scrubbed by the filter. One
may even argue that the droplets with larger Na or Cd concentrations will
preferentially make it through because high salt concentrations in water
drastically change its properties (e.g., breaking emulsions in sep
funnels).
It is also unclear what chemical species are in the mist. You may add
NaOH, NaCN, and Cd(something) to the tank. You probably get NaCd(CN)2,
Na3Cd(CN)4, and perhaps even polynuclear stuff strung together by
hydroxide and cyanide. If that stuff is hydrophobic it may
preferentially accumulate at the liquid surface where mist formation
occurs, or as electrode slime to be whisked away by gas production.. The
mist may therefore show strange cation ratios compared to the bulk tank
composition.
Stuff like Fluorad surfactants creates a stable foam layer whose mists
are more controllable than the stuff belching out of a naked tank.
Another approach is to float a few monolayers of small, hollow
polyolefine balls. The mist gets trapped in the interstices and mostly
drains back into the tank.
Good engineering always obeys KISS. A couple of buckets of balls beat a
$250,000 EPA scrubber.
--
Alan "Uncle Al" Schwartz
Uncl...@ix.netcom.com ("zero" before @)
http://www.ultra.net.au/~wisby/uncleal.htm (lots of + new)
(Toxic URL! Unsafe for children, Democrats, and most mammals)
"Quis custodiet ipsos custodes?" The Net!
Otto Bahn
You idiots! Roiling skies are part of the plan; emissions
are a GoodThing [tm]. The Holy Newsgroup has been
eliminated from the followups and you will pave yourselves.
Welcome to the Pits.
Otto Bahn
Durham Atomic Project
Ted Mooney
hanson wrote:
>
> Your response to this post is important, because regulators intend to make
> public policy (= charge big time money), based on the interpretation of
> this single set of experiments! I request results of YOUR calculated
> evaluation and commentaries on the following situation. Please post and/or
> send me your findings. When I have your results I will post them AND the
> surprising findings of the regulatory agency. We will investigate why their
> results are so different from yours !
>
> During plating operations the over-voltage on Anode and Cathode produces O2
> actions produce a fizzing, a mist, which carries material out of the bath
> per EPA protocol and methods.
> a) The uncontrolled Cad tank analyzed to 1.5 oz/gal NaOH, 12.5 oz/gal NaCN
> were measured via collection of the mist, 8" over the bath's liquid surface
> Sodium (ugr) must have accompanied this collected Cadmium amount (24.8
> ugr)?
> and 3.2 oz/gal Cadmium. In this (emission) "controlled" , analog experiment
> mist-droplet emissions passing through this emission control device. The
> yielded an amount of 4.5 ugr Cadmium in the collected mist. Question 2: How
> much total Sodium (ugr) must have accompanied the amount of collected Cad
> (4.5 ugr ) this time?
> PS. This is a live example of what students of chemistry will find once
> they enter industrial or govt. regulatory services. This is not a trick
> question, it's a simple report of facts received from the government.
> Please do NOT comment on the toxicity of Cad at this stage. We will get to
> this horror story in the next phase.
I'm not sure that I understand the point or see the question. Is the
question whether the evolved mist droplets are of the same ratio of Cd
to Na as the plating solution in the tank? They are.
-- Ted Mooney
------------
Visit 'the home page of the finishing industry'
http://www.finishing.com
------------
hanson
Uncle Al, thanks for your response to the Cadmium emission problem below.
1) Twice you say: "You don't know". Do you mean to say: This is not
calculable..., this is unknowable, unpredictable? (Rem: we are talking
about the compositions of non-volatile ingredients in a bulk solution and
the mist emissions produced from it. Are they the same or not?). Please
clarify.
2) Personally, I go along with the correspondents who think that the
stochiometric ratios remain the same in solution and in the emission mist.
3) Reasons for this is that a) the Cad tank solution composition will NOT
change measurably during the brief emission testing period and b) any
industrial spray-drying method would generate, according to you, different,
unpredictable results in its powdered products. c) Engineering
suggestion-changes are mute in this discussion because we are dealing with
a given situation and fait accompli.
4) So, Uncle Al, please assume stochiometric invariance and corroborate
with a calculation what the accompanying Sodium concentrations should be.
Send me your results.
5) If you can PROVE that such a calc. would not reflect reality, actually
be useless, then you would have indicted the local regulators and EPA. It
would be outright criminal for officials to make public policy from a
single measurement which according to you is flaky to begin with.
This is getting to be interesting. Thanks Uncle Al, hanson.
Alan \"Uncle Al\" Schwartz <uncl...@ix.netcom.com> wrote in article
<55qbnk$j...@dfw-ixnews4.ix.netcom.com>...
"hanson" <han...@quick.net> wrote:
[political snip]
>Two Cadmium plating tanks (a & b) were analyzed for NaOH, NaCN and Cd.
>During plating operations the over-voltage on Anode and Cathode produces
>O2 and H2 gas, and foam/bubbles from the air-agitation of the solution.
>These actions produce a fizzing, a mist, which carries material out of
>the bath into the atmosphere, called emissions, which were >quantitatively
determined per EPA protocol and methods.
>
>a) The uncontrolled Cad tank analyzed to 1.5 oz/gal NaOH, 12.5 oz/gal
>NaCN and 2.8 oz/gal Cadmium. In this "uncontrolled" experiment the
>emissions were measured via collection of the mist, 8" over the bath's
>liquid surface and yielded 24.8 ugr (micrograms) Cadmium. Question 1: >How
much total Sodium (ugr) must have accompanied this collected Cadmium amount
(24.8 ugr)?
You don't know. The cadmium concentration in the mist is changing as the
tank is depleted during plating, and there may be surface segregation
effects (e.g., Langmuir films enriched in cadmium-containing hydrophobic
material). It is similarly unclear that surface sodium reflects bulk
sodium.
>b) The controlled Cad tank analyzed to 2.0 oz/gal NaOH, 13.3 oz/gal NaCN
>and 3.2 oz/gal Cadmium. In this (emission) "controlled" , analog
>experiment a simple metal mesh pad was installed over the tank to >capture
most of the mist-droplet emissions passing through this emission >control
device. The non-captured, passed thru particles were measured in >like
fashion and yielded an amount of 4.5 ugr Cadmium in the collected >mist.
You might do better (and much cheaper!) with a non-woven fiberglass
furnace air filter. I don't know of any metal mesh which sells for a few
cents/square foot.
Question 2: How
>much total Sodium (ugr) must have accompanied the amount of collected Cad
(4.5 ugr ) this time?
You still don't know. It is not clear that differential Cd
concentrations in the mist will be equally scrubbed by the filter. One
may even argue that the droplets with larger Na or Cd concentrations will
preferentially make it through because high salt concentrations in water
drastically change its properties (e.g., breaking emulsions in sep
funnels).
Article Unavailable
Alan "Uncle Al" Schwartz
"hanson" <han...@quick.net> wrote:
>Uncle Al, thanks for your response to the Cadmium emission problem below.
>1) Twice you say: "You don't know". Do you mean to say: This is not
>calculable..., this is unknowable, unpredictable? (Rem: we are talking
>about the compositions of non-volatile ingredients in a bulk solution >and the mist emissions produced from it. Are they the same or not?).
A minute aliquot skimmed under non-equilibrium conditions from a large
reservoir is not bound to have the same composition as the bulk solution.
It is not as though you were spray-drying the stuff. Your gases are
being generated at electrode interfaces where the conditions, ion
concentrations, and species' compositions are certainly NOT those of the
bulk solution. Have you heard of the "Helmholtz double layer"? (Then
Gouy and Chapman, and later Stern jumped on it.)
What you get is what you measure. Bulk solution properties are a zeroeth
order asymptotic approximation. Blowing air through the solution is not
the same as electrochemically generating gases to froth it.
>If you can PROVE that such a calc. would not reflect reality, actually
>be useless, then you would have indicted the local regulators and EPA. It
>would be outright criminal for officials to make public policy from a
>single measurement which according to you is flaky to begin with.
>This is getting to be interesting. Thanks Uncle Al, hanson.
Since when did the EPA care about anything but collecting fines,
increasing its jackbooted powers; laundering money through expense
reimbursement, perks, and litigation; and covering its ass?
What you get is what you measure. If it does not conform to theory, the
theory is wrong. (I'd still go for the non-woven textile fiberglas
furnace air filter over the metal mesh.)
(You haven't lived until you walk past a nickel plating bath and have the
magnetic field attendent to the bus bars wipe your credit cards.)
Douglas W. Marshall
hanson wrote:
>
> Two Cadmium plating tanks (a & b) were analyzed for NaOH, NaCN and Cd.
> During plating operations the over-voltage on Anode and Cathode produces O2
> and H2 gas, and foam/bubbles from the air-agitation of the solution. These
> actions produce a fizzing, a mist, which carries material out of the bath
> into the atmosphere, called emissions, which were quantitatively determined
> per EPA protocol and methods.
> a) The uncontrolled Cad tank analyzed to 1.5 oz/gal NaOH, 12.5 oz/gal NaCN
> and 2.8 oz/gal Cadmium. In this "uncontrolled" experiment the emissions
> were measured via collection of the mist, 8" over the bath's liquid surface
> and yielded 24.8 ugr (micrograms) Cadmium. Question 1: How much total
> Sodium (ugr) must have accompanied this collected Cadmium amount (24.8
> ugr)?
> and 3.2 oz/gal Cadmium. In this (emission) "controlled" , analog experiment
> a simple metal mesh pad was installed over the tank to capture most of the
> mist-droplet emissions passing through this emission control device. The
> non-captured, passed thru particles were measured in like fashion and
> much total Sodium (ugr) must have accompanied the amount of collected Cad
> (4.5 ugr ) this time?
Emissions from a tank are dependent on the vapor pressures of the
dissolved species, the solution temperature, and the rate at which
vapors are perforating the surface. In your case, I don't think that
the vapor pressures of the dissovled species will contribute
significantly to the discharges. If the vapor space is nearly stagnant,
then larger ejecta (droplets) can settle out, but I suspect that your
tank has a purge on it to preclude the possibility of a hydrogen/oxygen
fire or explosion. Here are two aerosol entrainment factors for you to
explore. The first one is based on the carry over of radioactive
contamination in the overhead vapors of an evaporator, namely 1.0 E-4
lb_aerosol per lb_solution. This ignores the vapor velocities and the
rate of vapor generation, so it may not work in your case. Another is
based on the measured carryover of potassium nitrate into the vapor
space of an evaporator; namely, 2.5 e-5 lb_aerosol per lb_vapor breaking
the surface. Both cases assume that the aerosol composition is
identical to the mother solution at the time the ejecta leave the
surface. Many of these droplets may dry out to leave a dry particulate
in your off-gas stream.
Let me know how these fit your particular case.
Douglas Marshall
Scott Hinman
hanson wrote:
>
>(snip)
> a) The uncontrolled Cad tank analyzed to 1.5 oz/gal NaOH, 12.5 oz/gal NaCN
> and 2.8 oz/gal Cadmium. In this "uncontrolled" experiment the emissions
> were measured via collection of the mist, 8" over the bath's liquid surface
> and yielded 24.8 ugr (micrograms) Cadmium. Question 1: How much total
> Sodium (ugr) must have accompanied this collected Cadmium amount (24.8
> ugr)?
Converting NaOH and NaCN to just Na, this tank contains 6.726 oz/gal
Na. One is forced to assume that the ratio of Na to Cd in the mist
remains the same as that in the tank, so Na is (6.726/2.8)*24.8
= 59.6 ugr.
Carrying out the same calculation for the next tank, I get
12.4 ugr of Na.
Is there missing information here, or are you claiming that
the regulatory people couldn't pass high school chem?
Regards,
Scott
Sam McClintock
hanson wrote:
>
> Your response to this post is important, because regulators intend to make
> public policy (= charge big time money), based on the interpretation of
> this single set of experiments! I request results of YOUR calculated
> evaluation and commentaries on the following situation. Please post and/or
> send me your findings. When I have your results I will post them AND the
> surprising findings of the regulatory agency. We will investigate why their
> results are so different from yours !
>
> During plating operations the over-voltage on Anode and Cathode produces O2
> and H2 gas, and foam/bubbles from the air-agitation of the solution. These
> actions produce a fizzing, a mist, which carries material out of the bath
> into the atmosphere, called emissions, which were quantitatively determined
> per EPA protocol and methods.
I have done a considerable amount of work in this field and I for one
would
get fairly irritated if someone presented a couple of hundred hours of
my
work like this for review. An air emission test study generally takes
up
a couple of hundred pages (or more) and is nowhere near as simple a
problem
as you have presented here. I am not questioning validity of your
position, but it would be very unfair to comment on this work with as
little information as you have provided.
Could you please post some of the following:
a) which specific air testing company or agency (branch of USEPA or
state
org) conducted this work?
b) which specific test methods were used to study the plating tanks?
c) which plating tanks (where, who, what)?
d) if you have this report, could you provide a reference to the
report (number, data, originating agency, etc.)
e) if you have the test report, it would be great if you could
find a way to post that on the web (if the sponsoring agency has
not already done so). There is a substantial amount of material,
but there are ALWAYS sections on objectives, test methods, actual
test plan (outline), the contract lab, isokinetic/measurement data
sheet, and laboratory analysis.
Sam McClintock
sam...@nando.net
mikeme...@aol.com
Sam McClintock <sam...@nando.net> wrote:
>Sam McClintock
>sam...@nando.net
you know the earth sucks anyways so why contemplate the destruction of
the earth when it is going to fail systemically in 10 years?
Sam McClintock
mikeme...@aol.com wrote:
>
> Sam McClintock <sam...@nando.net> wrote:
> >e) if you have the test report, it would be great if you could
> >find a way to post that on the web (if the sponsoring agency has
> >not already done so). There is a substantial amount of material,
> >but there are ALWAYS sections on objectives, test methods, actual
> >test plan (outline), the contract lab, isokinetic/measurement data
> >sheet, and laboratory analysis.
>
> >Sam McClintock
> >sam...@nando.net (now scmccl...@ipass.net)
>
> you know the earth sucks anyways so why contemplate the destruction of
> the earth when it is going to fail systemically in 10 years?
And this has what to do with Mr. Hanson's problem?
And the earth is beautiful; it is mankind's treatment of earth that
sucks.
Sam McClintock
scmccl...@ipass.net
Otto Bahn
Sam McClintock wrote:
> And this has what to do with Mr. Hanson's problem?
He's a Pitslave [tm].
> And the earth is beautiful; it is mankind's treatment of earth that
> sucks.
The earth *will* be beautiful when we are done *paving* it. You
are correct that it sucks how few Pavers there are.
Otto Bahn
Durham Atomic Project
Posting at Mach 3...
Sam McClintock
Doesn't sound like anybody at Duke I know. :<)
So where are you in the scheme of Duke admin:
Staff? Student? Or just a lurking dittohead?
Sam