Sciencemadness Discussion Board

Disposal of mercury salts (hazardous waste in general).

BromicAcid - 31-7-2004 at 18:31

I've always at least tried to care for my environment. I don't flush chemicals down drains, except things that normally go down drains (BaSO4, CuSO4, H2SO4), I don't just dump on the ground, except things that normally go on the ground (Some Nitrates, seems to like strong hydroxides and iron salts too). If I have a metal compound in a high oxidation state I will reduce it (Mn+7 and such), if it cannot be made environmentally friendly (i.e., nickel salts, lead salts) I might keep it, theoretically forever (after evaporating it to a solid). Solvents are always a pain, it all depends.

But today I worked with mercury and its salts. I really disliked the idea but I needed about .5 g of mercuric oxide. Now I have 150 ml of a solution that most likely contains mercury contamination, it was a mercuric nitrate solution, I added carbonate to it and precipitated the mercuric oxide which is the procedure that I found, and supposedly mercuric oxide is insoluble in water. Therefore the mercury contamination should be nil.

However the solution is still off yellow-orange. So I didn't want to just dump it, I will evaporate it and keep it forever if I have to. Elemental mercury could be disposed of at a hazardous waste collection agency. So that is a possible disposal route. The sulfide is highly insoluble, I'm wondering if that would be a reliable way to pacify it (Similar to the 'safety' of barium sulfate).

The other mercury thread was an interesting read but no real help.

Regardless, how do the hazardous waste disposal companies get rid of this nuisance? Whenever I tried to find "Mercury Disposal" with any other modifying terms all I could find were clean up kits.

DDTea - 31-7-2004 at 18:59

I know the EPA mixes Hazmats with cement (it might be cement, or some other compound..) and molds them into cylinders. That's all I know about that topic.

chemoleo - 31-7-2004 at 19:04

I would serioulsy consider converting the remaining Hg x+ solution to HgS, simply by bubbling H2S through it. I guess you know that H2S is made rather easily.
In fact, the mercury spill kit we have in the lab intrigued me at first, so I had a look at it.
Surprise surprise, it contains solid sulphur! All you have to do is powder the solid sulphur onto it, and let it be absorbed/reacted for a few hours.
HgS, despite what the MSDS says, is probably the safest Hg salt that is easily made. It doesnt react with most acids/alkalis, and in fact for a long time, and even these days (in special circumstances) it is used for painting.
I think if you just convert it to the sulphide, your conscience should be at ease.

That reminds me... so are you going to get rid of the weeds simply by cutting them? ;) ;)

Nick F - 1-8-2004 at 05:55

Yep, mercury sulphide has a solubility of a few molecules per litre, from what I've heard. That's the safest form you'll get!

BromicAcid - 1-8-2004 at 06:04

Well, I guess I will try to precipitate with solid sulfur, and if that doesn't work I will put a pea sized piece of iron sulfide into a test tube and add a few drops of HCl and bubble that though my solution.

If I get a precipitate I will keep it and store it indefinitely, or I might make some use of it someday. The liquid will be tossed, a few molecules of HgS in the environment is acceptable. More Hg went into the environment when I opened the lid to my Hg then that.

Of course just because I've made up my mind doesn't mean other ideas would not be appreciated.

lab waste disposal

Magpie - 1-8-2004 at 20:43

Bromic Acid,

I must commend you for your environmental consciousness. My goals are similar - i.e., I intend to comply with the law, as a minimum.

As a SQG (small quantity generator) you can put some wastes, up to certain quantities, down the drain legally. Details depend on where you live.

Hazardous/toxic waste is another matter. Everyone should investigate and take full advantage of what waste disposal services their local agencies provide. My city has a "medium hazard" waste disposal station which provides small quantity househould waste disposal free to residents (paid for by our taxes). This is a wonderful way to get rid of pesticides, paint solvents, used oil, etc. Some of the pesticides they take in are surely more toxic than any waste I will likely generate. There will be some exceptions and I, like you, plan to deal with them case by case. I plan to fully address waste disposal in the experiment planning stage.

For air polution my goal here is to never get a complaint from a neighbor. I plan to design an air purifying system for my hood exhaust. It's just another project on my list.

Organikum - 2-8-2004 at 05:19

Neutralize the solution and dip a rod of pure zinc or tin into it. (even Al will work) The Hg will amalgamate into the zink and be removed almost completely.
Give it some time though.

Disposal of mercury salts

KidCurry - 28-7-2005 at 08:01

What are the options for disposal of mercury salts (mercury(I) and mercury(II) chloride)? Small amounts, under 1 gram, used for amalgamation. Dumping it in the sink really isn't ethical, but nearest enviromental station that takes dangerous chemicals is a long way away. Is it ok to use it to amalgamate some aluminium and then throw it away?

garage chemist - 28-7-2005 at 08:18

Dissolve them in plenty of water and bubble hydrogen sulfide through it until no more precipitate forms. (H2S can be prepared by heating paraffin with sulfur in a test tube with stopper+vent pipe into the solution, H2S evolves as a gas and carbon is left behind).

HgS is not listed as a hazardous material.

neutrino - 28-7-2005 at 16:47

Alternatively, you could use a metal sulfide. Na<sub>2</sub>S is sold in some photo stores.

garage chemist - 29-7-2005 at 06:05

Na2S is not recommended, look in the "Preparation of Vermillion" Thread to see why. It forms a soluble complex with the mercury if too much Na2S is used.Therefore it's tricky.

However, he complex is destroyed when HCl is added until it is acidic, this precipitates all the mercury. Beware of the evolving H2S, though!

[Edited on 29-7-2005 by garage chemist]

just checking

Ephoton - 31-7-2005 at 00:16

so after doing an al/hg reduction I could
filter the solution then bubble H2S to get
the mercury back.
wiked

ChemicalBlackArts - 18-8-2005 at 10:00

Wellll, BaSO4 shouldn't exactly be dumped down the drain. The Ba2+ ion poses a significant environmental hazard, as ecosystems really have no way of getting rid of the sulfate. As for mercuric salt disposal, just send it in to the EPA if you can. Last year, the EPA ordered a cleanup of Michigan high school chemistry labs, and all mercury, derivatives and elemental form was sent into the EPA. I'm actually not sure whether or not they're still running the program, however.

chromium - 18-8-2005 at 11:44

BaSO4 is common mineral that can be found everywhere in the world. So it can not be remarkably dangerous to environment. It is insoluble in water and looks like quartz or calcite.

BromicAcid - 18-8-2005 at 16:45

Also, tons of it (probably literally) go down the drain each year, in order to x-ray the colon they force people to consume barium sulfate solutions then they send them home where they deposit it in the normal manner in the toilet.

The_Davster - 18-8-2005 at 18:10

Quote:
Originally posted by BromicAcid
they force people to consume barium sulfate solutions


Force them is right, I had to have one of those done around 6 years ago and it tasted horrible.

12AX7 - 18-8-2005 at 21:53

Quote:
Originally posted by chromium
BaSO4 is common mineral that can be found everywhere in the world. So it can not be remarkably dangerous to environment.


Now now, let's not forget where mercury, arsenic and uranium all come from. :P

Tim

Fleaker - 19-8-2005 at 09:18

Yeah, cinnabar (HgS)....safe, copper matte (arsenides are often present)...safe, pitcheblende....safe.

Typically anything found in the environment is the safest compound/form of that element you'll find.

I don't see what's so wrong with dumping it.

sparkgap - 19-8-2005 at 21:57

All right, so that we can end the discussion on whether barium sulfate is safe or not to dump, does anyone know its K<sub>sp</sub> offhand?

As to the issue of forcing, radiologists usually give you choices: drink it (blech), or they force it up your arse (a.k.a. enema). :D

It's not like they have more readily available radiopaques, you know...

"...Typically anything found in the environment is the safest compound/form of that element you'll find..."

Go tell that to the Bengalis who have to contend with arsenical well water... it's no wonder that they get tumors a bit more often than most.

"...pitchblende....safe..."

You don't suppose that Marie Curie dying from leukemia had absolutely nothing to do with her pitchblende experiments?

...but then again, pitchblende isn't exactly pure uranium/radium ore either... ;)

sparky (~_~)

[Edited on 20-8-2005 by sparkgap]

The_Davster - 19-8-2005 at 22:04

Quote:
Originally posted by sparkgap

You don't suppose that Marie Curie dying from leukemia had absolutely nothing to do with her pitchblende experiments?



The comment was that pitchblende was safe, not that the radium you get from extracting it from several tonnes of ore is.:P
Unless you extract radioactive elements from it it is quite safe.

12AX7 - 19-8-2005 at 22:06

Well to be fair, the pitchblende was being refined, from tons down to what, half a gram...

Tim

Fleaker - 20-8-2005 at 14:22

Pitchblende is safe, relatively speaking. Sure, when concentrated, refined, and ground into a powder, yes it can cause cancer. Hell, the granite countertops in my kitchen increases the background radiation in my house by 40%.

It's all relevant to concentration of the radiation, and even more importantly of what type it is. I'd rather sit on a 5kg block of alpha emitting uranium than have 5 grams of a sinister cesium isotope spewing out gamma radiation.

praseodym - 21-8-2005 at 05:39

Well, places where pitchblende is exploited includes Katanga (Shaba) and Great Bear Lake, Canada. There are many other new localities but are a matter of international concern instead.

Furthermore, it is not easy to find pure pitchblende. It is always oxidised to some degree and grades in composition towards U3O8, containing small amounts of radium, thorium, and other rare elements. Radioactive disintegration gives rise to small quantities of lead and helium.

leu - 14-10-2005 at 03:40

The easiest and safest way to recycle mercury is by amalgamation; steel shavings work quite well if given enough time. Hydrogen sulfide is quite toxic and also odorless; a bad combination to say the least :(

Fleaker - 14-10-2005 at 13:29

Odorless? Hardly (at least to me). I think you mean it loses its nasty rotten egg odor after you've over exposed yourself.

Ephoton - 25-7-2008 at 02:53

HgS will eventualy be converted to mercury and sulfur in the enviroment.
it is also a shit paint it faids and no one will supply vermillion in its true sence
other than one german paint manufacturer (well to my knowlage).
all of the vermillion that is sold were I live is an organic compound :(.

JohnWW - 25-7-2008 at 05:39

If they are selling a purely organic compound, or paint containing only it as the pigment, as "vermillion", when it does not contain any HgS, they would surely be committing an offense under consumer-protection legislation.

not_important - 25-7-2008 at 06:02

Quote:
Originally posted by JohnWW
If they are selling a purely organic compound, or paint containing only it as the pigment, as "vermillion", when it does not contain any HgS, they would surely be committing an offense under consumer-protection legislation.


Vermilion, like ultramarine, is a colour name as well as a substance. For some tine vermilion paint was likely a cadmium selenosulfide rather than mercury sulfide, because thee cadmium pigment is more stable. More recently the toxicity of cadmium has lead to other pigments being used to product the vermilion colour, this may or may not be labeled in a way that makes it easy to tell if it contains mercury or cadmium, the price may be as good of an indicator as the label.

S.C. Wack - 25-7-2008 at 13:48

I cannot imagine why Ephoton resurrected this thread after three years to post that. I challenge anyone to provide any evidence of the color of HgS fading away, or decompose to mercury and sulfur without the aid of heat. I find it very difficult to believe. Would you believe that there is HgS not only many millions of years old, but still quite red?

not_important - 25-7-2008 at 19:32

Quote:
Imaging secondary ion mass spectrometry (SIMS) is applied for the first time to paint cross sections with degraded vermilion (red mercury sulfide) paint to cast new light on the well-known problem of its light-induced darkening. The static SIMS data are combined with light microscopic, electron microscopic studies and energy-dispersive X-ray analysis to identify and localize the various reaction products. The spatial distribution of atomic and molecular species in paint cross sections of the native vermilion and the reaction products leads to the formulation of a new hypothesis on the reaction mechanism of the photodegradation of vermilion where two black and white reaction products are formed sequentially. Under the influence of light, some of the vermilion (HgS) is converted into Hg(0) and S(0). In this process, the chlorine ions, present in the native vermilion, act as a catalyst. We propose that the Hg(0) is deposited on the surface of the remaining HgS as elementary mercury nanoparticles, which turns the vermilion black. Chloride, derived from an external source, is accumulating in the black phase. The metallic mercury and the remaining HgS react away with the excess of chloride. Two intermediate products and a white end product, mercuric chloride (HgCl2), are formed.


Anal. Chem., 77 (15), 4742 -4750, 2005. 10.1021/ac048158f

Analytical Imaging Studies Clarifying the Process of the Darkening of Vermilion in Paintings

Katrien Keune and Jaap J. Boon

Also see attached file.
Quote:
How English and American Vermilion Should Be Mixed for Sign Work, so as to Insure Good Wear.

English vermilion (or quicksilver vermilion) is sulphide of mercury. and very easily affected by strong light, which in time will turn it very dark, no matter how well protected by varnish. The pale shade will darken much more rapidly than the deep shade. There is no protection against that ; it is in the nature of the material. American vermilion, or chrome red, is the basic chromate of lead, and while it is a good wearing pigment it soon loses its original scarlet red color and turns to a dull brown on exposure to strong light. Good, durable outside varnish will protect both of these vermilions from too rapid darkening, but cannot arrest the change for any great length of time.


739 Paint Questions Answered
By National painters magazine
Published 1904
Quote:
the Pre-Raphaelite painter William Holman Hunt wrote of problems he suffered on account of lead and vermilion mixtures:

It seems as tho' I were struggling against Fate, every day sometimes including Sundays I have been toiling every hour, and just as I have got my task nearly completed the whole thing has fallen into disorder again. At last I have found out what has been the cause of this -- Roberson's tube of Orange Vermilion which I used without suspicion because 25 years ago they sold this colour absolutely pure, is adulterated with 10 per cent of villainy -- the greater part lead, which has blackened so rapidly that when it had got dry enough for the final glazings the flesh had got to such a colour that I nearly went crazy with the idea that my eye sight had acommodated itself to what could only be thought right by a fool when he was trying to delude himself. I have had the colour analysed and at the same time have taken the opportunity to have others investigated and find that the fraudulent habit is exercised in many other cases.
letter to John Lucas Tupper, August 1875

And again:

...the fact that vermilion, which was the first colour suspected by me, was analysed and found to contain between 10 and 12 per cent of foreign matter, principally lead; that this vermilion is on two of my trial canvases, and where mixed with flake white (lead white) it has turned to 'café au lait colour'.
Editorial letter to The Times of London



Note that pure vermilion was often mixed with white lead for creating skin tones; the darkening was fairly common due to reactions between HgS and the basic lead carbonates. However straight vermilion also discoloured on occasion.

Attachment: darkening of vermilion in paintings.pdf (1.2MB)
This file has been downloaded 1232 times

S.C. Wack - 26-7-2008 at 04:39

Well I asked for decomposition and I got it, OK. But that isn't exactly what I'm looking for.
Quote:
In this process, the chlorine ions, present in the native vermilion, act as a catalyst.


Native vermillion=cinnabar. The old books that I've read all say that cinnabar was not used as a pigment in the industrial era. Vermillion was a synthetic product or at least sublimed.

I don't see how forming HgS as a waste management solution is affected by someone saying that cinnabar pigments break down on painted surfaces on exposure to light and chlorine.

The darkening is well known and not the same as "faid"ing.

[Edited on 26-7-2008 by S.C. Wack]

not_important - 27-7-2008 at 04:45

You said selling paint labeled "vermilion" but containing no HgS was fraud. I replied that the term "vermilion" had for some time been used to describe the paint colour, rather than the pigment makeup, and this was partially due to the stability problems with HgS in paints You questioned that instability, I showed evidence that said instability was an actual occurrence. BTW, there is a darkening and also the halide catalysed greying, which usually is preceded by darkening and which often ends up giving a shade of grey lighter in tone than the original pigment - lightening or fading. It can happen even with synthetic HgS, being caused by environmental chlorides.

No where did I mention anything to do with waste disposal, my comment was in regards to labeling of paint (and a warning to those seeking HgS that way, if there's no mercury warning on the label then it's likely the paint pigment is not HgS even though it's vermilion in hue).

S.C. Wack - 27-7-2008 at 06:30

Quote:
Originally posted by not_important
You said selling paint labeled "vermilion" but containing no HgS was fraud. I replied that the term "vermilion" had for some time been used to describe the paint colour, rather than the pigment makeup

Oh? Mmm...I think not.
Quote:
Originally posted by not_important

...and this was partially due to the stability problems with HgS in paints You questioned that instability, I showed evidence that said instability was an actual occurrence.

No, I questioned
Quote:
Originally posted by Ephoton
HgS will eventualy be converted to mercury and sulfur in the enviroment.
it is also a shit paint it faids

...since I am unaware of any conversion of HgS to Hg and S in the environment, and the paint has been known to darken, rather than fade.
Quote:
Originally posted by not_important
No where did I mention anything to do with waste disposal

"I don't see how forming HgS as a waste management solution is affected by someone saying that cinnabar pigments break down on painted surfaces on exposure to light and chlorine." does not seem to me like I was implying that you did. This simple statement does not strike me as improper in any way, since the pdf was provided as proof that HgS was instable, as you just said. Note the thread title.

j_sum1 - 23-2-2015 at 23:23

I am developing an interest in Hg chemistry. (No reagents of my own as yet except for a tiny amount of elemental mercury.) At the school where I work there is also a small amount of HgO. I am interested in demonstrating the thermal decomposition of HgO in the manner of Laviosier and Priestly. It seems like an important experiment for both historical and chemistry reasons. There is obviously other chemistry to explore as well.

Before I delve in, I want to make sure that I am covering all of my bases in terms of dealing with toxicity and disposal. There are the obvious principles of converting all waste to stable insoluble forms, working in a fume hood with a scrubber, using gloves, keeping volumes minimal and so forth. But I am new to this element. I don't want to be careless here. I'd like to pick the brains of those who are more experienced here.

My thoughts so far:

Elemental mercury
The main hazard is the vapour given off -- both from the element itself and potentially anything that has touched the mercury. There are environmental issues associated with disposal.
What is the best way to neutralise the impact of elemental Hg? -- I understand that powdered sulfur and powdered zinc are both appropriate for spills. Given the choice between an insoluble ionic solid and a zinc amalgum, which is preferred? Are there other options?
What is the procedure for dealing with contaminated glassware gloves and other equipment that has been in contact with Hg? It is fortunate that mercury beads well, but it is possible to get micro droplets that are hazardous.

Waste of soluble mercuric salt solutions
Adding carbonate to precipitate mercuric oxide seems all too convenient. Is this sufficient?
Bubbling H2S and precipitating the sulfide sounds like a better idea.
Adding zinc has again been suggested upthread. Is this as good an idea as the H2S? I can do zinc powder with a much increased surface area. Or does the extra hassle of dealing with waste as a powder rather than a rod make this unworthwhile?
Again, what is the best procedure for treating gloves, glassware, stirrers and the like? For lead I am content to liberally spray everything with a carbonate solution and either dispose (in the case of gloves) or rinse and filter the rinsings to be disposed of as a solid. Is this good enough? Would it be better to put disposable gloves in a bag containing H2S and leave for a while before disposing?

Mercuric oxide
Since this is my likely start material for my first experiment, I should ask some specific questions here.
How should I deal with cleaning / disposing of a used spatula? What about spills in the fume-hood? What about any unreacted residue on glassware?


Thoughts and experience appreciated. I would like to get this right.

[edit] I have no intentions at this stage of dealing with organic mercury. But if you have advice here I am glad to receive it.

[Edited on 24-2-2015 by j_sum1]

Dr.Bob - 27-2-2015 at 20:02

Your school would likely have a cow if they knew what they had and what you wanted to do. I have known two companies cited and fined $10,000's for waste water issues for having <1 ppm of mercury in their waste water. So the school would likely want to avoid that. I am not saying that people could not safely dispose of mercury compounds, I think the HgS route would work well, and be stable, but I would also just evaporate any finale solution and put the solids in the trash rather than dump down the drain, as some municipalities are being hounded by the EPA for mercury in their waste water at PPB and PPT levels. Note that the EPA in NC was found to be above one forbidden waste water level at their own research building, so it is very easy to exceed the "safe" levels that they have arbitrarily created. I still remember playing with it as a kid and pouring it into my hands and spilling it all over back then... But that might not have been real wise, but I think PPT are not likely that bad. Organomercury compounds ARE that bad, so stay away.

j_sum1 - 27-2-2015 at 21:17

My school has undertaken an overhaul of old chemical stocks and is in the process of having a bunch of chemicals professionally disposed of. As part of building a new lab, there is also a review of chemical storage and procedures.

We have two Hg chemicals still in stock. A couple of hundred grams of elemental mercury, and a small amount of mercuric oxide. There is no problem retaining them in stock but the rationale for doing so is that they will be used for legitimate educational purposes. Duplicating Priestly and Loviosier meets the brief and fits in with the curriculum. And I am keen to maximise educational opportunities for the students. There seems to be little point in having a lot of interesting chemicals and equipment and never using them while trying vainly to keep students interested with lame experiments dissolving salt and boiling water. With the resources we have at school I see no reason why we cannot do this and do it properly.

Obviously I need to plan this ahead of time and learn what I need to know. Part (and only part) of this process is asking those who have had some experience in handling mercury compounds. It is one thing to read in abstract terms about cleaning up. It is quite another to have someone explain what to do with disposable gloves.

I am not in the US so the laws and penalties you cite will not apply. Of course there are local equivalents and I have no intention of tipping toxic heavy metals straight down the sink.

I have asked some specific questions and would really value the input of those with some experience.

MrHomeScientist - 11-8-2015 at 05:39

One thing to keep in mind when working with elemental mercury is its incredible density. Being a very heavy liquid, it can slam around in containers if not handled gently and break glass (so I've heard). It also pours much differently than you'd expect, and tends to rush out pretty quickly.

I haven't worked with mercury compounds yet, but I did generate some Hg-waste when I cleaned my stock of the element using the 'filter paper with a pinhole' trick. That stuff was double bagged and stored in a large tub with my acids. I plan to take it to the local landfill during their "waste amnesty days" and see if they will take it. I suppose I could sprinkle some sulfur dust in the bag with it to help absorb vapors. I think making HgS is probably the safest option if you don't have anywhere to take it.