Filter paper question

[willowchar]

Can anyone recommend a suitable type of filter paper or other method to remove fine barium sulfate particles from suspension?

[WSM]

Can anyone recommend a suitable type of filter paper or other method to remove fine barium sulfate particles from suspension?

Fine precipitates like barium sulfate are best removed by using vacuum filtration using a slow grade of lab grade filter paper.

 

WSM

[SharkWhisperer]

Lab-grade filter paper is categorized from Grade 1 (pore size approximately 11 microns) to Grade 4 (20-25 micron pores). Strangely, Grade 2 and 3 have 8 and 6 micron pores, respectively. So it goes smaller, smaller, smaller, huge pores as you go from Grades 1-4. Odd, but how it is. Grade 1 is pretty much all I've used in a laboratory setting all my life. A super-small pore-size (2 microns--about two bacteria long) is found in Grade 602h, but. besides waiting all day to get a drip, it's expensive and there's really very few times you need to capture particles/crystals that small. Used a lot of 0.2 and 0.4 cellulose acetate or cellulose nitrate filters with a vacuum draw for sterilizing tissue culture media and injected medications, but that's prolly way smaller than you will ever use for pyro work. And they get pricey.

 

Many use plain old unbleached coffee filters, or even fine cheesecloth, with good success. I guess it depends on your specific needs. I don't do a lot of filtering in this hobby, so others might have keener insights into what's available and most economical for your purposes.

 

Shark

Edited November 27, 2020 by SharkWhisperer

[justvisiting]

I'm curious as to why one would have a need to filter the barium sulfate. I made my own before, when I got crappy barium chlorate. The particles of precipitated barium sulfate are exceedingly small. To clean up my barium sulfate, I let it settle out, and decanted the liquid off, replacing it with distilled water each time. I probably 'washed' it 5 times. Getting it to give up the water and dry out was an adventure. Next time I think I'll try to draw out the water with a plaster bat before oven-drying. The homemade stuff worked as well as pharmaceutical grade for strobe rockets, so I was happy.

[SharkWhisperer]

I'm curious as to why one would have a need to filter the barium sulfate. I made my own before, when I got crappy barium chlorate. The particles of precipitated barium sulfate are exceedingly small. To clean up my barium sulfate, I let it settle out, and decanted the liquid off, replacing it with distilled water each time. I probably 'washed' it 5 times. Getting it to give up the water and dry out was an adventure. Next time I think I'll try to draw out the water with a plaster bat before oven-drying. The homemade stuff worked as well as pharmaceutical grade for strobe rockets, so I was happy.

Sounds like a smart approach. And easy, too.

[willowchar]

Thanks for the replies. Trying to troubleshoot strobe propellant issues. Thought I would start with baso4. I am currently washing and decanting. Seems the more washings I do (3rd) with distilled water, the longer it takes for the product to settle to the bottom of the glass ware. Currently on day 2 of 3rd washing with most all the precipitate still in suspension.

I believe my magal and AP are ok. I've read that some people have had issues with baso4 and thought I would start there.

[NeighborJ]

I occasionally make exotic benzoates, phalates and salicylates for various experiments. I cut the pleated filter paper from 5 micron water filters. Im not sure what they are made from but they give up qute a lot of wide paper and have resisted even the most harsh chemicals without issue. Edited November 28, 2020 by NeighborJ

[willowchar]

Thanks, I will give it a try.

[WSM]

Thanks for the replies. Trying to troubleshoot strobe propellant issues. Thought I would start with baso4. I am currently washing and decanting. Seems the more washings I do (3rd) with distilled water, the longer it takes for the product to settle to the bottom of the glass ware. Currently on day 2 of 3rd washing with most all the precipitate still in suspension.

I believe my magal and AP are ok. I've read that some people have had issues with baso4 and thought I would start there.

 

 

I believe that magnesium would give better color for green strobe rather than magnalium, if you have access to it (Mg). That was Dr. Shimizu's recommendation, for reasons he described in Fireworks, the Art Science and Technique.

 

WSM

[NeighborJ]

I'm a bit confused, the issue you seek to correct is color or performance? Green (MgAl) strobe "propellant" actually displays as a cool white and doesn't actually make a true green color. The "green" in the name is used to hint to the formulas origin.

 

Shimizu's green strobe formula used Mg and was the precursor to the propellant. It lacks the violence associated with the MgAl propellant pops.

 

Different actions must be taken toward improving either color or sound. Both cannot be achieved from either the origional or the MgAl variant. There are differing schools of thought about how strobe rockets should perform, fast, slow, flashy pitter patter, loud bright pops with clearly defined intervals. The only thing the builder needs to decide is what the goal is then learn what adjustments need done to achieve that goal.

[justvisiting]

Personally, I think a lot of confusion arises from there being two wildly different ideas of what a strobe rocket even is. There's the Ben Smith school of thought. Ben uses black powder tooling and benz whistle to boost. I've never seen or heard a good strobe rocket made that way. Steve Laduke uses a completely different system, and makes MUCH better strobe rockets (in my opinion). I've tried Ben's way, Doc Barr's way, and Steve's way. Steve's way is hands down the best way if you want loud pops. That's how Caleb makes his strobe rockets. So many people want to talk about strobe rocket issues without first addressing the type of rocket tooling and booster used. That should be the first point of discussion, I think.

 

I've made a pretty bold statement about strobe rockets, and I'm willing to admit I could be wrong. If anybody can show me a video of a GOOD strobe rocket made with benz whistle booster, I'll eat my words.

[mabuse00]

I had this problem once, with barium sulfate too.

 

I dont have the notes in front of me now, but the solution was "celite", used with a typical buchner vacuum setup, as a layer on top of a filter paper disk.

 

Filters slowly, but the results where perfect.

[a_bab]

My to cents: generally speaking, boiling a suspension for like 30 mins or less will help the fine particles to conglomerate thus to settle faster.

[willowchar]

Wondering if someone can advise on how many grams of barium chloride are required to fully react with 10 grams of magnesium sulfate and how many grams of barium sulfate are produced?

Thanks in advance

[a_bab]

BaCl2 + MgSO4-->BaSO4+MgCl2

 

208g + 120g --> 233g + 95g

 

 

17.3 grams of anhydrous barium chloride would be needed to react with your 10 grams of anhydrous magnesium sulfate, giving aprox 19,4 grams of barium sulfate.

 

Magnesium sulfate usually comes as heptahydrate (epsom salt)

In this case the real amount of pure magnesium sulfate is about half, meaning in practice that for every 10 grams of MgSO4 you need 8.65g of anhydrous barium chloride the output being 9.7g of BaSO4.

If your barium chloride comes in crystals, then it also contains water and the real barium chloride content is around 85%.

 

In practice, I would start the reaction with the same amounts of chloride/sulfate and then add magnesium sulfate till no more precipitate is formed.

The idea is to have no barium chloride left in solution (it is quite toxic btw ! the sulfate isn't because it's highly insoluble).
Whatever magnesium chloride/sulfate is left will be washed anyway and none of these are toxic.

And, I would hot diluted solutions of each, maybe 10 percent so it precipitates faster.

[willowchar]

Hey a_bab,

Thanks for the fast reply and detailed information on the reaction. I was using a round figure of 10 grams in the original question to get an easy conversion factor.

I actually have a solution of barium chloride with a density of 1.08 gm/ml. Would it be correct to say that I would react .624 grams/ml of magnesium sulfate to get a max yield of barium sulfate?

and yes, my source of magnesium sulfate is Epsom salt.

Much appreciated!

[SharkWhisperer]

BaCl2 + MgSO4-->BaSO4+MgCl2

 

208g + 120g --> 233g + 95g

 

 

17.3 grams of anhydrous barium chloride would be needed to react with your 10 grams of anhydrous magnesium sulfate, giving aprox 19,4 grams of barium sulfate.

 

Magnesium sulfate usually comes as heptahydrate (epsom salt)

In this case the real amount of pure magnesium sulfate is about half, meaning in practice that for every 10 grams of MgSO4 you need 8.65g of anhydrous barium chloride the output being 9.7g of BaSO4.

 

If your barium chloride comes in crystals, then it also contains water and the real barium chloride content is around 85%.

Though Epsom Salts are usually the hepta (n=7 waters) hydrate, it can be easily converted in the oven to anhydrous MgSO₄. That'd make your calculations easier. However, it easily reverts back to the hydrated form by absorbing atmospheric water, so needs to be kept dry or used immediately. Also, cooking to anhydrous requires temps around 300C, which is close to 600F. This would be much easier to achieve in a pan over a fire than in most kitchen ovens that rarely get above 500F. At super high temps (you'll need to check which--not hard to find) it'll break down into white MgO and the gaseous sulfuric acid precursor. I'd probably cook my Epsom Salts if I wanted better accuracy because it can exist in other hydration states besides the heptahydrate, which could throw off your calculations.

 

A_bab's right that barium chloride (take care--very soluble and very toxic) usually exists as a dihydrate and his 85% value sounds about right; easy to adjust for. Not sure, but it might require near-decomposition temps to make it lose its water (again, would need to check this value). Barium sulfate's essentially insoluble and nontoxic (used for radioimaging in medicine--the ol' barium cocktail or enema), but without 100% conversion or thorough washing, it probably will contain some soluble toxic carryover. So wash it a few times.

 

If you're in the US, barium sulfate only costs $4/pound at FWC, btw. Probably could be legally shipped overseas by a friend (not FWC--not international shipping from him) since its not toxic. Hard to imagine, though, that wherever you're located that you have easier access to barium chloride than barium sulfate.

 

edited for clarity...

 

Edited December 8, 2020 by SharkWhisperer