Sorbitol motors with LiNO3 as oxidizer (and LiNO3/KNO3 combinations) were made and problems recorded. Success, if any, is also happily recorded. The chemical reasoning for this investigation can be found in the background discussion page

Lithium nitrate was not easily located at a reasonable cost so it was made using Li2CO3, and H2SO4 titered to PH neutrality. The resulting LiS04 solution was then precipitated with appropriate amount/concentration of Sr(NO3)2 solution yielding SrSO4 precipitate and LiNO3 solution. Dry Lithium nitrate was obtained by evaporation of the supernatant and baking till fully dry.
A second batch was made with Ca(NO3)2 as the nitrate source, however the resulting CaSO4 precipitate is slightly soluble so the resulting batch of LiNO3 contained a trace amount of CaSO4 (gypsum) contaminant.
Grains were made and observations recorded. Percentages of ingredients were based on the rational described in the background page.
Static tests were attempted and recorded.
Due to lousy record keeping I lost track of which grains had the trace gypsum contaminated Lithium nitrate. :-(
Despite this page being written in scientific format it is more a series of trial and error steps recorded as such in Results.

A control grain was made with no LiNO3, 65/35 KNO3/Sorbitol formula. This cored grain weighed 13.1 grams.
The second grain was LiNO3/KNO3/Sorbitol, 27.5/32.5/40 ratio. This grain weighed 12.2 grams
The third grain was LiNO3/Sorbitol, 55/45 formula. Grain weighed 11.2 grams
It was noted that even short exposure to air allowed visible amounts of moisture to form on the LiNO3 crystals. It was very difficult to work fast enough to avoid this.
The three grains were stored for weeks in double baggies with CaCl2 dessicant. When I went to do the static testing the KNO3/Sorbitol grain looked fine and tested the same as earlier single grain motors of this type
The grains containing any LiNO3 had gained significant moisture on storage. Core goop was reamed out and static testing attempted. A soft ruddy flame was noticed on the LiNO3/KNO3/Sorb motor. However the motor did not come up to pressure and took 9 seconds to burn with no thrust.

The third grain was similar except very difficult to light.
At this point it appeared that the moisture and/or the low motor KN-avg ~60 were the possible problems.
To address the motor KN question a two grain motor was made keeping the nozzle diameter the same, KN-avg ~120. These two grains had been stored in an air tight container but moisture during casting had caused them to be soft enough to slump. They were place in a casing and tested the same evening at a VAROOM pour night.
By the time we went to test this motor it had accumulated a lot of moisture. The ignitor hit goo so it was pulled out and the core reamed out with a dowel.
Several ignitors failed. This was a night test and when the motor finally ignited it burned with NO flame and NO thrust and little sound causing Brett to exclaim, "It's a stealth motor !" :-)
So an increased motor KN did not solve the problem. Moisture is probably the culprit so a LiNO3/KNO3/So 27.5/32.5/40 grain was made by mixing a 20 gram batch in a sealed container with ball milling.
This was melted as fast a safely possible in the open air and poured. The grain was allowed to cool and cure in a sealed dry container. Grain was stored in this same container.
After storage this is the first Lithium grain that looked dry. So I installed it in a casing and sealed the end with 5 minute epoxy and static tested as soon as possible.
This was a single grain so I used a smaller nozzle to get the average motor KN at about 100.
FINALLY SOME THRUST ! the motor burned at a lower thrust for a longer time period as compared to standard propellant. A problem came up though; since I had such trouble igniting the earlier grains I primed the core and ends of this grain with a lot of meal powder slurry. This caused a POP on ignition which set the spring thrust scale into oscillations.
Smoothing out the oscillations and plugging the curve data into EngEdit gave some preliminary rough data on the performance of this hybrid oxidizer formula.

SEE TABLE BELOW:

Formula	Grain volume mm3	Grain mass	Avg Thrust Newtons	Total Impulse NS	Peak Thrust N	Burn Time seconds	Flame color
KN/So	6503	13.1	9.6	7.9	16	0.83	none
LiN/KN/So	6503	13.0	3.1	5.9	4.4	1.9	none

This is just a preliminary investigation into the possibilities of this oxidizer. It is horrible to work with due to it's hygroscopicity.
If moisture can be controlled better and motors run at higher KN perhaps it can provide a better ISP than KNO3 as predicted by Propep. However the difference in predicted ISP is not that great and the pain of handling to avoid moisture makes this propellant impractical.
I doubt I'll pursue it further. If I do it will be just the fun of the challenge of making the theory work (with no added KNO3). I would increase the motor KN incrementally from 120 to over 200 to see if there is a sweet spot where the theoretical ISP could be demonstrated.
But this is NOT a formula for routine use as far as I can see. Too much hassle.




Diagram of single grain static test lithium motor.
Light that thing before it turns into a puddle of Goo !