Old chemicals

chicken

Premium Member
Hi, I just found half used 5 gallon buckets of Soda Ash, Calcium Chloride and Magnesium Chloride in my storage shed. I must have forgotten about them a few years ago. The shed is not insulated or climate controlled so the chemicals are a little clumpy. The Soda Ash and CA are a little chunky but otherwise look like ok. The Magnesium Chloride though is one giant clump. I can break parts of it off easily though. Are they still ok to use? No water has gotten in them but I assume they have sucked up humidity over the years. I would hate to throw them out. Thanks!
 

Dan_P

New member
My first thought is that the chemicals themselves are OK, but may have picked ip water which means when you weigh an amount, it will contain slightyl less of the chemical. But clumping of the salts may not necessarily mean moisture got into the container. Crystals can fuse over time.

Being stored in a shed and possibly being exposed to and adsoring insecticides or herbicides, might be something to consider. I mentioned it as a paranoid thought not a notion based on science.
 

NewReefer42

New member
Hi, I just found half used 5 gallon buckets of Soda Ash, Calcium Chloride and Magnesium Chloride in my storage shed. I must have forgotten about them a few years ago. The shed is not insulated or climate controlled so the chemicals are a little clumpy. The Soda Ash and CA are a little chunky but otherwise look like ok. The Magnesium Chloride though is one giant clump. I can break parts of it off easily though. Are they still ok to use? No water has gotten in them but I assume they have sucked up humidity over the years. I would hate to throw them out. Thanks!
Analytical chemist here. The chemicals are fine. just break them into chunks and dry them in your oven to get rid of excess water. Calcium Chloride and Mg Chloride don't decompose or anything, I would do like 80C for 4 hours or so. Soda Ash will absolutely decompose into CO and CO2 so I probably would chuck that, unless you want to gamble on the mass. All this advice is premised that they're not contaminated with anything except water and air and time.
 

chicken

Premium Member
Thanks guys. Like I said there are just some small chunks in the CA and Soda ash. If they dissolve am I good to go and don't need to dry it? I feel comfortable that it is only air/humidity contamination over time. There are no chemicals stored any where these were stored. As for the MG similar question. It's in big chunks but if it dissolves am I good to go without drying? Thanks again!
 

bertoni

Premium Member
The soda ash should be fine, as well. It'd take a lot of heat to convert it into anything. Lots of people make soda ash by baking sodium bicarbonate (baking soda) at 350 degrees or so for an hour.
 

disc1

-RT * ln(k)
Thanks guys. Like I said there are just some small chunks in the CA and Soda ash. If they dissolve am I good to go and don't need to dry it? I feel comfortable that it is only air/humidity contamination over time. There are no chemicals stored any where these were stored. As for the MG similar question. It's in big chunks but if it dissolves am I good to go without drying? Thanks again!

If it dissolves go ahead and use it. Your solutions may come out ever so slightly weak if they have pulled some water, and if they do just use a little extra.
 

disc1

-RT * ln(k)
Analytical chemist here. The chemicals are fine. just break them into chunks and dry them in your oven to get rid of excess water. Calcium Chloride and Mg Chloride don't decompose or anything, I would do like 80C for 4 hours or so. Soda Ash will absolutely decompose into CO and CO2 so I probably would chuck that, unless you want to gamble on the mass. All this advice is premised that they're not contaminated with anything except water and air and time.

Pretty sure you're going to want more than 80C. What's the boiling point of water again? Remember, CaCl2 is deliquescent, so it's not so easy to drive that water off.

Decomp of Na2CO3 --- heat---> Na2O + CO2. No CO anywhere in that. And it takes a heck of a lot more heat than you are talking about. IIRC that one is above 400C, way hotter than you're going to get with your regular oven.
 
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NewReefer42

New member
Pretty sure you're going to want more than 80C. What's the boiling point of water again? Remember, CaCl2 is deliquescent, so it's not so easy to drive that water off.

Decomp of Na2CO3 --- heat---> Na2O + CO2. No CO anywhere in that. And it takes a heck of a lot more heat than you are talking about. IIRC that one is above 400C, way hotter than you're going to get with your regular oven.
yea, so I understand you can Google things, that's fine man. the goal of driving the water off is to get the CaCl2 more dry than its current state, not to make it 100.000% dry, so you don't have to go to completion. Furthermore, when you do chemistry in real life, textbook chemical equations tend to fall apart. since you clearly have years of experience in a chemistry lab, you probably already knew that though. that sodium carbonate is not semiconductor grade, there is guaranteed to be tons of other ions in there, such as Fe, Cu, Mn, Mg, Zn, SO4, PO4, NOx, etc. couple that with O2, CO2, CH4 and other organics in the atmosphere and you'll definitely form some CO upon heating. it may not be enough to cause any problems, but my point was that when you start heating impure mixtures, as this most certainly is, you'll get an array of products, something they didn't teach you when you got your associates degree in geology. it's ok though, learn something new every day, right?
 

disc1

-RT * ln(k)
Associate in geology? Check me out again.

Still, any of those decomp reactions are going to take a lot more heat than you describe. We regularly throw sodium bicarbonate in the oven at 350 or 400F to make sodium carbonate and it doesn't decompose.
 

disc1

-RT * ln(k)
PS. I wish I had studied geology. Looking at the Rockies right now. Would be so much nicer to see them through that lens.
 
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