|WikiProject Chemicals||(Rated Start-class, High-importance)|
|WikiProject Occupational Safety and Health|
- 1 A healthy food source of mineral Calcium ?
- 2 Ksp
- 3 Flue Gas Desulfurization
- 4 Lutefisk
- 5 hazards
- 6 Error Redirect
- 7 article division
- 8 clean up.
- 9 further cleanup
- 10 Production
- 11 Link
- 12 Merger with Portlandite
- 13 Celts and hair
- 14 Decomposition
- 15 Vapor pressure
- 16 sea water
- 17 Metal and slaked lime
- 18 Lutefisk? Really?
- 19 Use in Mass Graves
- 20 use in food
- 21 Niche uses: Bulleting under Calcium Stearate
- 22 calcium hydroxide -- slaked lime: gesso?
- 23 Rewrite this entire article
- 24 Picture caption
A healthy food source of mineral Calcium ?
Humans need 1 g of it per day. It is much cheaper/convinient to eat this (Calcium hydroxide) than milk for calcium. Please advice. — Preceding unsigned comment added by Vwalvekar (talk • contribs) 04:16, 30 May 2015 (UTC)
The values of Ksp and solubility do not get along. They are related by Ksp=4x^3 or x=(Ksp/4)^(1/3)
If Ksp=4.68 you get 1.05E-2 M or 0.6145 g/L or 0.06145 g/100 mL. This is much less than the smallest of all numbers given.
Other sources, e.g. http://www.ktf-split.hr/periodni/en/abc/kpt.html show Ksp=5.02E-6, producing 1.079E-2 M or 0.6291 g/L or 0.06291 g/100 mL.
Alternatively, if you use 0.173 g/100mL or 1.73 g/L you get 0.02338 M (Ca(OH)2 saturated concentration, or Ksp=5.11E-5 — Preceding unsigned comment added by 126.96.36.199 (talk) 20:44, 26 September 2012 (UTC)
Flue Gas Desulfurization
There is no mention under industrial applications of wet scrubbing flue gas desulfurization. Granted, Calcium Hydroxide is not the initial principle reagant for that, CaO is, but by the time the flue gas comes in contact with the sorbent, it is Calcium Hydroxide.Woahmid (talk) 00:09, 29 February 2012 (UTC)
Can cause bad burns
True - not especially toxic - but can cause very bad burns - and while an acid burn hurts right away - if you get some in your shoe - with a little sweat or moisture it will feel slightly uncomfortable while it digests your skin - (Found out the hard way - removed my socks to find skin missing and bleeding - took a month to heal.) . — Preceding unsigned comment added by 188.8.131.52 (talk) 15:14, 1 April 2015 (UTC)
I wrote in Calcium Hydrate, and was redirected to Calcium Hydroxide. These are not the same thing. Calcium Hydrate is Ca·6H2O [or Ca(aq)] (i believe - I actually came to check the number of water molecules per calcium ion), while Calcium Hydroxide is Ca(OH)2. I would stop the redirect, but I don't know how. :( - Baribeau 01:38, 27 November 2006 (UTC)
- Ca.6H2O exists only in solution. If you dissolve CaCl2 in water, you'll probably get Ca2+ . xH2O. But in solid form, the only thing that you can get is the hydroxide, probably with a lot of water in the crystal structure.
There should be separate articles for slaked lime, lime water, milk of lime and common applications, and Calcium hydroxide, Magnesium hydroxide with Chemistry etc. Same goes for Calcium Oxide / lime (mineral). Comments please PeterGrecian 14:26, 19 Apr 2005 (UTC)
- isn't slaked lime the same thing as Calcium hydroxide. If so, why does it need its own article? --Duk 17:55, 6 October 2005 (UTC)
- I disagree with this proposal. Put your effort into fleshing out this article and cleaning it up, as the tag asks us to. In the unlikely event that this one gets unwieldy, something could later be split out. Gene Nygaard 18:52, 6 October 2005 (UTC)
- There are identical articles for calcium hydroxide, slaked lime and hydrated lime. Is triplication necessary or just a waste of reading time, not to mention confusing?
I agree with your comments. Also... the formatting of the article is poor with lines chopped in two. Perhaps it has been copied from somewhere - and there are copywrite issues? Also what on earth is polikar! It looks like something Russian? CustardJack 16:55, 11 May 2005 (UTC)
I have tried to cleanup the grammar and style problems, although a few clunky bits remain. In particular, I was unsure as to whether to change the word "drug" to "chemical" or "preservative" in the last line of the "Uses" section. Also, the line "Because of its strong basic properties, calcium hydroxide has many varied uses as:" is very cumbersome and should be edited further. I also believe the phrase "but unrelated to the citrus fruit (lime)" should be removed and a link to a lime disambiguafication page placed at the top of the article, but I'm running out of time for editing right now. -Paul Foster 9:08, 23 May 2005 (EST)
One question: As to the dangers through overdose section, can't the difficulty breathing and internal bleeding be explained by the hypotension? - Guest 4:09, 3 Feb 2007 (Pacific Time)
The article states: "When heated to 512 °C, the partial pressure of water in equilibrium with calcium hydroxide reaches 101 kPa and decomposes into calcium oxide and water." This sentence needs to be edited, but since I don't have access to the reference, I can't do it. As this sentence reads now, the partial pressure of water decomposes into calcium oxide and water, which is nonsensical. Partial pressures don't decompose. —Preceding unsigned comment added by 184.108.40.206 (talk) 23:29, 27 May 2010 (UTC)
No!! . . . LinguisticDemographer 13:39, 17 March 2007 (UTC)
- There are expensive methods, which does not produces CO2 (but produces SO2). Starting material there would be calcium sulfate. SO2 is worse for environment than CO2, and in such case it could not be filtered, because the cheapest material for removing SO2 from waste gas stream is calcium hydroxide itself. -Yyy (talk) 07:55, 2 March 2008 (UTC)
would it be possible to add an shortcut for Ca(OH)2?because not everybody looks for Calcium Oxide...
Merger with Portlandite
There might be some argument for merging Portlandite (which is the crystalline mineral) into this, but not vice versa. Its crystalline mineral nature is just one of many attributes of calcium hydroxide. . . . LinguisticDemographer 13:45, 17 March 2007 (UTC)
Celts and hair
Now, I've heard that the celts washed their hair with slaked lime, or Calcium hydroxide, and so made it stiff and, also, bleached it. However, I'm struggling to find out if you can actually do this with lime alone, or if there were other ingredients involved, or what?
The details, unfortuantely, are not particularly thick on the ground. Here's a couple of links with most of what I know -
' "Their hair is blond, and not only naturally so, but they also make it their practice by artificial means to increase the distinguishing colour which nature has given it. For they are always washing their hair in lime-water, and they pull it back from the forehead to the top of the head and back to the nape of the neck with the result that their appearance is like that of Satyrs and Pans, since the treatment of their hair makes it so heavy and coarse that it differs in no respect from the mane of horses" '
' The Celts bleached and spiked their hair with lime – one ancient writer wrote that each spike of hair was so sharp that an apple could be impaled on one! '
- I'd be very interested in knowing more about this, if anyone has the time to research it more deeply than I have.
220.127.116.11 15:15, 16 May 2007 (UTC)
One paragraph says Ca(OH)2 decomposes at 512 C, and the chembox at right says 580 C. Which is it? 18.104.22.168 10:02, 11 August 2007 (UTC)
In the intro there is a footnote that claims that 512°C is the temperature at which H2O vapor pressure reaches 101 kPa. What on earth is meant here? At 100°C the vapor pressure of water reaches 101 kPa and it boils. Maybe this is meant to refer to the partial pressure of H2O over Ca(OH)2? --Slashme (talk) 10:22, 21 January 2008 (UTC)
- Yes, it must be the partial pressure of H2O in the equilibrium Ca(OH)2 -> CaO + H2O(g). --Itub (talk) 13:02, 21 January 2008 (UTC)
Metal and slaked lime
- The result depends on the metal, but for most commonly encountered metals, nothing would happen rapidly. In contact with base (such as Ca(OH)2) and water, most metals corrode to the oxides.--Smokefoot (talk) 14:19, 18 September 2010 (UTC)
Use in Mass Graves
I've read a lot about the use of lime for mass graves of plague victims, and have just been reading about the mass graves in the Holocaust. Nothing is mentioned of this usage here and I don't know enough about it to comment (or whether this is the right page!) - any help would be great. Jess xx (talk) 22:12, 19 June 2011 (UTC)
use in food
Niche uses: Bulleting under Calcium Stearate
Under 'Niche Uses", the bulleting is tabbed in under Calcium stearate, so it appears that the following 8 bullets pertain to Calcium stearate. I have checked 4 of the items and they are still seem to be referring to Ca(OH)2. (Neither Ca stearate or Ca hydroxide is mentioned in brake pad or Ebonite wiki entries?). I was interested in the use of Ca hydroxide as an pesticide and had to check to see if it was in fact the stearate or hydroxide being referred to. This is my first entry on Wiki, so can someone else review and/or edit if necessary? Cornyvet (talk) 04:10, 22 April 2012 (UTC)
calcium hydroxide -- slaked lime: gesso?
I am trying to find a source for the slaked lime used to make gesso and it would be helpful to know if food grade calcium hydroxide is used for traditional gesso -- often called gesso sotile. It isn't mentioned in the many uses discussed on this page, but if it is the same thing, then it would make my search for a source very easy and it would also be useful to be included on the page in case other gilders or tempera artists are also looking. I was hoping that someone would know. Pbfasks (talk) 16:51, 25 April 2012 (UTC)
Rewrite this entire article
This article is dysfunctional or semi-functional at best. Can someone please take it upon themselves to do a rewrite (from scratch)? — Preceding unsigned comment added by Gibson88 (talk • contribs) 12:49, 3 June 2014 (UTC)
Quote: “Because it is produced on a large scale, is easily handled, and is cheap, myriad niche and even large-scale applications have been described. A partial listing follows:”
Have been described where? Applications have been described because it is cheap etc.? If this is a section for Niche Uses why has the phrase “…and even large-scale applications…” been included? I have amended this sentence to at least agree with the section heading:
“Calcium Hydroxide is produced on a large scale, is easily handled and is cheap. Numerous niche applications are in use. A partial listing follows:”
although I suspect that not all the applications listed are “niche”. For instance, the use of hydrated lime in making mortar is hardly a niche application. One of the standard mortar mixes in the UK building industry is 1:1:6 cement : hydrated lime: sand.
To differentiate between large-scale and niche applications one presumably needs information on the tonnage of material used in each application listed. Where is exactly is the dividing line between the two categories to be drawn? In the absence of tonnage information, I think it would probably be best to remove the Niche Uses section title completely and reorganise the various listed uses into several broad categories for the moment.
It seems to me that the caption for the two types of corn kernels is reversed. The white ones have been treated and the yellow ones have not. The page on hominy has it right.