Colored smoke mixtures without potassium chlorate are already known, for example:
sodium nitrate 25, sawdust 35, rhodamine 40
This composition has poor efficiency as lot of the dye decomposes due to high burning temperature.
I tested another forgotten recipe that contains ammonium nitrate. I already used similar composition to sublimate engine oil, resulting white smoke, but I was very surprised that it actually can be used for colored smoke.
Composition:
wood chips or sawdust - 41.6%
ammonium nitrate - 58.4%
engine oil - 5%
Ammonium nitrate was dissolved in water and sawdust was soaked in the solution. Then the mixture was dried for several days. Then engine oil was added. I took 40g of this composition and added 10g of dye, Sudan 1 https://en.wikipedia.org/wiki/Sudan_I
The composition was ignited from inside using a sparkler.
Additional information can be found in patent https://patents.google.com/patent/BG64003B1/en?oq=BG64003 where authors sublimate everything with nitrates including insecticides and even tear gas.
Testing original composition from patent with synthetic indigo:
Trying to improve composition.
I removed engine oil from original composition, and increased dye to base mix ratio and it worked much better.
The composition:
ammonium nitrate 58.4%
wood chips 41.6%
to 30g of base mix I added 10g of dye, this is the result:
Unfortunately this ratio doesn't work for all dyes(for example, this doesn't work for solvent blue 35), if the mixture struggles to burn try 35-40g of base mix to 10g of dye.
Testing aniline yellow (diazoaminobenzene), 15g of base mix(no engine oil) + 5g of dye:
Trying to increase burning speed using a catalyst.
All catalysts were added to ammonium nitrate solution, then sawdust was soaked with this solution and dried.
Burning times:
uncatalized AN+sawdust - 94sec +/-5
AN +sawdust + prussian blue - 88sec +/-5
AN +sawdust + K3[Fe(CN)6] - 70sec +/-2
off camera tested AN + sawdust + red iron oxide(Fe2O3) - 81sec +/-2
off camera tested AN + sawdust + Ammonium bichromate 95 +/-2 sec
Conclusion: Prussian blue slightly increased burning speed although it was claimed that this is the most potent catalyst for AN, maybe the problem is that it is insoluble and cannot penetrate to wood pores. Potassium ferricyanide was the most potent catalyst in this experiment, it increased burning speed by 35% and also reduces the amount of smoke, that is good, unfortunately this is also an indicator of increased burning temperature, this is not good as it may cause the dye to decompose and reduce the color saturation. Fe2O3 was pretty good too, but weaker.
Testing catalyzed mixture with Sudan 1, the mixture is AN-sawdust with 5% of K3[Fe(CN)6], ratio of the base mix to dye is 3:1, (15g of base mix with catalyst, 5g of dye):
Color saturation dropped sighnificantly, dye is indeed decomposing. Not a big problem Potassium chlorate - lactose mixtures also burns the dyes if no magnesium carbonate was added. Unfortunately I cannot add magnesium carbonate as it will react with AN. But the patent already has a solution, need to add motor oil.
Testing with Sudan 1, Trying to add motor oil, mixed 15g of base mix with catalyst with 1.5g of motor oil, then 5g of dye was added, good color saturation:
Testing with with solvent blue 35 with motor oil, 15g of base mix with catalyst + 2g of motor oil + 5g of solvent blue 35:
Testing 2 dyes aniline yellow and solvent blue 35,
30g of base mix with catalyst + 3g engine oil + 10g of dye
Testing newly arrived dyes from US, solvent red 111, solvent blue 78, solvent yellow 33:
nice result although mixture burns too slowly, especially with yellow dye, need to increase base mix content.
Trying sublimation with Sodium nitrate
I tried newly arrived dyes with sodium nitrate, I thought they shoudl be stable enough to survive such aggressive sublimation and it worked! I took the mixture from patent as a base(sodium nitrate 25, sawdust 35, rhodamine 40). I dissolved 25g of sodium nitrate in water and mixed it with 35g of sawdust, then dried. To 10g of this mixture I added 4.5g of the dye. All three dyes perfectly survived sublimation and gave vibrant colors, then I tested sudan 1, althogh it gave colored smoke the color was pale especially at the end that a sighn of dye decomposition at high temperatures. Maybe addition of motor oil can reduce the temperature. Video:
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