problem in potassium chlorate production

[djcruzer]

hi iam new to kclo3 production...but i encounter some problem...like the first batch i made...i make a saturated solution of potassium chloride by boiling then cool to room temperature then run the cell i got crystal but i test the product nothing happens...

 

then the second batch i made i try to boil a solution then cool to 45-50C then start the cell but i waited for 3 days no sign of crystal percipating...the solution was stayed in 75C i guess(can barely hold the cell for 9sec)...what iam doing wrong??

 

iam using psu 5V 25A and mmo on anode and cathode

Edited July 22, 2018 by djcruzer

[Mumbles]

How did you test the product? I'm not surprised there are no crystals in the second run yet. Potassium chlorate is much more soluble at increased temperatures. If you cooled down a sample I bet you'd see some product come out.

 

You don't need to use MMO as the cathode by the way. Titanium works just fine, and you can save the more expensive electrode for another anode if you need it.

[djcruzer]

How did you test the product? I'm not surprised there are no crystals in the second run yet. Potassium chlorate is much more soluble at increased temperatures. If you cooled down a sample I bet you'd see some product come out.

 

You don't need to use MMO as the cathode by the way. Titanium works just fine, and you can save the more expensive electrode for another anode if you need it.

i just quickly dry the crystal and try with dark aluminum...on the second batch you mean that when the solution is over 75C no crstal begin to percipatate and i have to cool the solution...btw how many days of running the cell should does kclo3 crystal begin to percipatate??...sorry for double post iam new to this site...

[Arthur]

With potassium salts you will make chlorate with low current efficiency so after three days -what current you don't say(it's important) you will convert a little of the chloride to chlorate but then you have to separate the two so that you product is chlorate not just a mix.

[djcruzer]

With potassium salts you will make chlorate with low current efficiency so after three days -what current you don't say(it's important) you will convert a little of the chloride to chlorate but then you have to separate the two so that you product is chlorate not just a mix.

 

thanks for the info...btw is there any disadvantages using mmo as anode and cathode cause some say its best to use titanium in cathode??

[WSM]

thanks for the info...btw is there any disadvantages using mmo as anode and cathode cause some say its best to use titanium in cathode??

 

Using MMO as a cathode may negatively affect the coating over the long run, but I believe this can be minimized by periodically reversing polarity from the power supply.

 

If you have access to some, making your cathodes from CP titanium sheet metal should yield a better overall result (plus be easier on the expensive MMO material).

 

Metering (measuring) the current drawn by the cell is one effective method of determining the end-of-run for your batch of chlorate. When the current drawn drops to roughly half the starting current, it's a good point to stop the run, harvest the potassium chlorate crystals, recharge the depleted electrolyte with potassium chloride and start the next run of the cell.

 

Read through the first few parts of my Blog, Homegrown Oxidizers, for more information and details about running hobbiest scale electrochemical cells.

 

WSM

Edited July 24, 2018 by WSM

[djcruzer]

How did you test the product? I'm not surprised there are no crystals in the second run yet. Potassium chlorate is much more soluble at increased temperatures. If you cooled down a sample I bet you'd see some product come out.

 

You don't need to use MMO as the cathode by the way. Titanium works just fine, and you can save the more expensive electrode for another anode if you need it.

does the cell normally hit 80C or you need to maintain into certain temperature??

[djcruzer]

Using MMO as a cathode may negatively affect the coating over the long run, but I believe this can be minimized by periodically reversing polarity from the power supply.

 

If you have access to some, making your cathodes from CP titanium sheet metal should yield a better overall result (plus be easier on the expensive MMO material).

 

Metering (measuring) the current drawn by the cell is one effective method of determining the end-of-run for your batch of chlorate. When the current drawn drops to roughly half the starting current, it's a good point to stop the run, harvest the potassium chlorate crystals, recharge the depleted electrolyte with potassium chloride and start the next run of the cell.

 

Read through the first few parts of my Blog, Homegrown Oxidizers, for more information and details about running hobbiest scale electrochemical cells.

 

WSM

theres a batch when i run in a small container probably 200ml...then after a day it got steady at 45C but suddenly theres a 4 hour blackout and the cell rappidly cool and i notice theres small crystal falling out in the solution...is that potassium chloride or potassium chlorate percipating??

 

but for now the power come back...now i reconnect the cell hoping the crystal is potassium chlorate

[WSM]

theres a batch when i run in a small container probably 200ml...then after a day it got steady at 45C but suddenly theres a 4 hour blackout and the cell rappidly cool and i notice theres small crystal falling out in the solution...is that potassium chloride or potassium chlorate percipating??

but for now the power come back...now i reconnect the cell hoping the crystal is potassium chlorate

It's important for electrode longevity, that if the power goes off, the electrodes are removed from the electrolyte (to protect them from damage).

 

As to the crystals floating down, if the cell has run long enough (and I suspect it has), they're likely to be potassium chlorate.

 

Potassium chloride tends to stay in solution as long as the concentration of it is low enough, and potassium chlorate tends to drop out of solution if the concentration of it is high enough.

 

In the normal operation of the cell, the high (initial) concentration of chlorides diminishes as the concentration of chlorates increases (and drops out due to their lower solubility). This also changes the specific gravity of the electrolyte and has been one method used by savvy amateur electrochemists to determine the end-point to their run of the cell.

 

The simplest way to measure the specific gravity (s.g.) is by using a hydrometer, which floats in the electrolyte and the s.g, level is read on a scale on the device at the surface of the liquid (Google search "hydrometer" for a better description of these devices and how they work).

 

You may want to test the crystals and see if they are indeed chlorate.

 

WSM

 

Edit: potassium chlorate is less soluble than other things in the electrolyte and tend to drop out as they form, if the temperature isn't too high. I suspect this is what you're seeing.

 

What size are your electrodes? I'm wondering why your cell is so small? (200ml is tiny)

 

I think 2 to 4 liters seem more useful if you have the space to operate one of this size.

Edited August 1, 2018 by WSM

[djcruzer]

It's important for electrode longevity, that if the power goes off, the electrodes are removed from the electrolyte (to protect them from damage).

 

As to the crystals floating down, if the cell has run long enough (and I suspect it has), they're likely to be potassium chlorate.

 

Potassium chloride tends to stay in solution as long as the concentration of it is low enough, and potassium chlorate tends to drop out of solution if the concentration of it is high enough.

 

In the normal operation of the cell, the high (initial) concentration of chlorides diminishes as the concentration of chlorates increases (and drops out due to their lower solubility). This also changes the specific gravity of the electrolyte and has been one method used by savvy amateur electrochemists to determine the end-point to their run of the cell.

 

The simplest way to measure the specific gravity (s.g.) is by using a hydrometer, which floats in the electrolyte and the s.g, level is read on a scale on the device at the surface of the liquid (Google search "hydrometer" for a better description of these devices and how they work).

 

You may want to test the crystals and see if they are indeed chlorate.

 

WSM

 

Edit: potassium chlorate is less soluble than other things in the electrolyte and tend to drop out as they form, if the temperature isn't too high. I suspect this is what you're seeing.

 

What size are your electrodes? I'm wondering why your cell is so small? (200ml is tiny)

 

I think 2 to 4 liters seem more useful if you have the space to operate one of this size.

yeah i know my cell is small i planning to upgrade it...btw can i use fresh kclo3 from the cell to pyrotechnique without recrystalizing it?? Edited August 4, 2018 by djcruzer

[WSM]

yeah i know my cell is small i planning to upgrade it...btw can i use fresh kclo3 from the cell to pyrotechnique without recrystalizing it??

Sorry about the slow reply, I'm at the PGI Convention.

 

Whether or not you can use the homemade chlorate crystals directly, depends completely on the quality of them. I imagine you'll need to mill them to a fine powder before use.

 

WSM

Edited August 7, 2018 by WSM

[Arthur]

An advantage of electrolysing a sodium salt is that the higher salt concentration makes for an easier life for the electrodes.

An advantage of having a solution of a sodium salt is that you precipitate out the Potassium salt by adding a KCl salt and the crystal size is controlled by the rate of KCl addition.