Calcuim Oxide (what?)

f-e · Dec 11, 2020

I want to add some Calcium to my tank, which drips into coco.

I saw most bottles speak of the Calcium content in oxide equivalents, So just got some calcium oxide so I have calcium and oxygen with no contaminates. I think?

There is no consistent story to separate calcium from lime. Some science sites claim it's the same thing, while others say it's lime if any of the usual contaminates are present.

I'm then struggling with calciumhydroxide and lime water. Again some are saying it's the same thing, while others make lime water with the hydroxide.

As far as I can see, calcium oxide when added to water is slightly soluble, but most floats about in suspension. I have mixed a little and got hot water with no sign of any particulates.

This isn't going well for me. The more I read the more contradictions I find. When it first arrived I just treated it as 50% Ca and used it, before I even knew it would get hot. After reading more I'm just being put off. I have never seen so much misinformation.

I think I'm left asking what worked for people, or to take chemistry. Which seems excessive. I did read the Canna Mono label which just listed calcium oxide at about 10% iirc. So I presume that's both dissolved and suspended. There was no N listed, so its unlikely calnit. Which I can't get easily.

The internet science sites have failed me so I'm reaching out for people that know how to mix feeds.

BillFarthing · Dec 11, 2020

Calcium oxide is not very soluble. It is also alkaline.

Calcium acetate is probably your best bet until you get into complexed and chelated forms.

f-e · Dec 12, 2020

Any idea how soluble Bill? That's the key information I'm failing to find.

Being alkaline will lead me to use Nitric acid in my home made bottle of Ca boost. I believe this to be beneficial.

I really should of sourced calcium nitrate but mid winter I will look like I'm making explosives. I'm kinda stuck with 2kg of oxide now.

slownickel · Dec 12, 2020

Nasty stuff.

We always mixed it with lots of organic material to get long term build ups.

But to get this stuff liquid? Maybe a good fulvic acid.

TdotGonG · Dec 12, 2020

Wouldn't the oxide turn into a hydroxide once it meets water, and also wouldn't this create a fuggin bunch of heat? I'd go with cal acetate that has humics in it. I forgot why they add humics to the acetate tbh, Maybe make the carbonates more readily avail. edta chelated cal would be be good too.

G.O. Joe · Dec 12, 2020

There are legal formats for presenting required analyses - the analyses are represented as so much of this or that, CaO, Na2O, P2O5 - they don't actually contain the slightest trace of those things. Quicklime is CaO. It hisses, steams, and gets hot when water is added to it, becoming slaked lime Ca(OH)2. Lime water is a solution of Ca(OH)2 in cold water.

f-e · Dec 12, 2020

iirc lime kilns have been baking the co2 out of calcium carbonite to make quick lime for centuries. Likely before we called it Calcium Oxide (CaO). Some unspecific amount of water forms slaked lime, or in modern term, Calcium Hydroxide. Further unspecified amounts of water and we call it lime water, which contains both dissolved and suspended CaO and it's this solubility that again isn't specified anywhere I have found reference to it.

I feel I have looked at solubility tables containing everything known to man, and still have no idea. Lime water as a topic is covered many times but never do these topics cover how much the water actually holds. It's more ancient building material than specific science.

The heat thing is interesting. Lots is used to remove the carbon and if you put it back then lots is created. It gets used in self heating items from hand warmers to ready-meals.

I really don't think I'm going to get my question about solubility answered, which is itself baffling.

Thank you for your input so far gents. It pains me to chuck it away knowing it's what I need but can't use it. It's just not acceptable. It's not who I am.

TdotGonG · Dec 12, 2020

f-e said:
iirc lime kilns have been baking the co2 out of calcium carbonite to make quick lime for centuries. Likely before we called it Calcium Oxide (CaO). Some unspecific amount of water forms slaked lime, or in modern term, Calcium Hydroxide. Further unspecified amounts of water and we call it lime water, which contains both dissolved and suspended CaO and it's this solubility that again isn't specified anywhere I have found reference to it.

I feel I have looked at solubility tables containing everything known to man, and still have no idea. Lime water as a topic is covered many times but never do these topics cover how much the water actually holds. It's more ancient building material than specific science.

The heat thing is interesting. Lots is used to remove the carbon and if you put it back then lots is created. It gets used in self heating items from hand warmers to ready-meals.

I really don't think I'm going to get my question about solubility answered, which is itself baffling.

Thank you for your input so far gents. It pains me to chuck it away knowing it's what I need but can't use it. It's just not acceptable. It's not who I am.

Can you find the solubility with some sort of mathematical forumula? Maybe by mixing the CaO with the water on a scale to determine how much weight was added to each ML of water. Wouldn't this then tell you the amount you dissolve in lets say 100ml? It would give you a base line to start. You could look for the point of precipitation, I think is what its called? where the calcium falls out of solution. That would tell you when to stop adding the CaO. Then work from that Data. Sorry if I'm no help, trying to learn my self.

G.O. Joe · Dec 12, 2020

No you look it up, and it says 1.85 g/l at 0, 0.77 g/l at 100. Lime water is entirely dissolved hydroxide. Undissolved hydroxide in water product is milk of lime - different. There is no CaO in water.

f-e · Dec 12, 2020

TdotGonG said:
Can you find the solubility with some sort of mathematical forumula? Maybe by mixing the CaO with the water on a scale to determine how much weight was added to each ML of water. Wouldn't this then tell you the amount you dissolve in lets say 100ml? It would give you a base line to start. You could look for the point of precipitation, I think is what its called? where the calcium falls out of solution. That would tell you when to stop adding the CaO. Then work from that Data. Sorry if I'm no help, trying to learn my self.

That's about where I stand on the topic. I didn't see any solids though and I was putting quite a bit in. I forget how much, but I bet I was aiming for about 5% as that's whats in my store bought cal-mag.

What does fall out isn't CaO anymore unfortunately. It want's the carbon back that the heat pushed out. What I could filter out is calcium hydroxide but that is perhaps something I can adjust for.

My chemistry constantly needs double checking. Hydroxide sounds like it took on hydrogen not carbon. I did physics not chemistry. It's really more than I want to chew.

I thought it was a simple enough question tbh. Sometimes an answer is so deep into chemistry that I know to walk away. This seems so simple I can't understand why everything I read just circles the 'how soluble' question.

I know a few good blokes have now heard my plight so perhaps I can let this go, having tried so hard I asked for advice.

f-e · Dec 12, 2020

G.O. Joe said:
No you look it up, and it says 1.85 g/l at 0, 0.77 g/l at 100

I think I saw this as the only glimpse of what I wanted, but what is the zero and 100. Temperature without units?

f-e · Dec 12, 2020

This post is a fail. Skip ahead to me next one. Dated:After I got a reply. Read no further.

I'm finding my way now. I think a few of us must of hit google as the search results are becoming a lot more relevant.

If I get some water at 40c I should be able to get it to about 0.15% or 150ppm. After which it would settle out. This solution, if saturated, shouldn't be taken past 40c or more will settle out. The score is, that colder water holds more of this particular stuff. If I saturated a 20c solution, the heat of the room would settle some out. So there is a limit to how much we can put in, based on temperature.
150ppm is still a guess. It looks high beside the quote above but it seems logarithmic. I will find out.

0.1% is in my Ionic so I can work with 0.15% though a bit higher would of been nice. I could just settle on 1g in 1 liter to equal my feed. I like such simple ratios (I mix urea to make 10ml the amount of N my feed puts in 10L. So a 30% lift in N is 3ml of my mix per 10L. Keeping the math on my fingers). I'm not exactly happy with feed strength as that's a lot of fluid. 1:1 though which is really easy on the fingers.

You know... 1:1 is so easy that trying to increase it just 50% is a dosing complication my fingers don't need.

I'm going to put 1g in a liter and know I can double the Ca 100ml of my feed provides with 100ml of my solution.

slownickel · Dec 12, 2020

Report pH.

f-e · Dec 13, 2020

I dropped the ball. Posting at 9am after a good night, I couldn't see straight. My Ionic is 1% not 0.1%. The concentration of Ca it puts in a tank can be doubled with CaO but it literally needs the tanks volume to hold it. I can't mix it any stronger to make a concentrate I can add a few ml of. It would have to be tank mixed.

I have just looked at chelation briefly. My feed is 100% chelated and I expect some of them bonds might be weaker than the CaO's bond with a chelate. I remember when feeds came in boxes with a leaflet. I vaguely remember my feed being chelated in little groups. Like putting the salt, acetic acid and chips together in one newspaper. In a usable group. My CaO could be like the gravy that sticks to everything.

I've found Lime is naturally formed CaO so the slaked lime and lime water, lime milk route is all naturally occurring. Likely ancient terms. If we make the CaO its the same chemically but wasn't mined. Never got rained on and renamed. It's just symbols. It's got no soul the organics might say.

I have found Solufeed here in the UK sell 1Kg of chelated Ca for £15 delivered. No pH shift with that chelated Ca they sell. I'm going beyond my knowledge again looking what it's chelated with. EDTA with no further indicator. Sodium source? My searches keep taking me that way.

Solufeed also sell Calcium Nitrate. £10 a kg delivered. It's £8.50 for 750g of chempac's on ebay. Solufeeds is just aimed at hydro though.

Incidentally solufeed have a few hydro feeds. One they claim is 70 years old. About 30p a liter not £5

G.O. Joe · Dec 13, 2020

There is no such thing as natural calcium oxide or hydroxide. I'm not sure there are naturally occurring simple hydroxides of any kind. The reason why there is no solubility data for CaO is because it becomes Ca(OH)2 on contact with water. No two groups agree exactly on the solubility because it's just tricky that way. If you actually have CaO you should sell it on ebay as a drying agent. The hydroxide will not dissolve completely because it isn't pure and will soon react with CO2 in the air and in water. It dissolves better or worse in things other than pure water. You realize the hydroxide can be turned into anything else, not so alkaline, sometimes more soluble.

troutman · Dec 13, 2020

Calcium oxide can drive the pH to 12.4 when it reacts with water to make hydrated lime with lots of heat given off.

So be very careful with it as it can burn you. Wear gloves and don't breathe any dust in.

Search

Calcuim Oxide (what?)

f-e

Well-known member

BillFarthing

Active member

f-e

Well-known member

slownickel

Active member

TdotGonG

Member

G.O. Joe

Well-known member

f-e

Well-known member

TdotGonG

Member

G.O. Joe

Well-known member

f-e

Well-known member

f-e

Well-known member

f-e

Well-known member

slownickel

Active member

f-e

Well-known member

G.O. Joe

Well-known member

troutman

Seed Whore

Latest posts

Latest posts