The Manganese/Nitrate process
The following has been cut and pasted from here:
http://www.versuchschemie.de/ptopic,241420,permanganate.html
It comes from a book entitled 'Elements of Explosives Production' by James Glackin, 1976, Paladin press.
Anyone here every tried it?
The Manganese/Nitrate
Process
The Manganate process is one of the best—adapted to field
production of nitrates. Most raw materials are readily obtainable in
large bulk, and the most expensive constituent, the manganese
compound, is recycled in the process.
The key to this process is the fact that when manganese dioxide is
heated with strong alkalai in open air, it reacts with the alkalai and
oxygen in the air to form a manganate salt. The manganate salt can
either be used as is, or converted to permanganate; conversion of
manganate to permanganate is accomplished by acidifying a solution
of the salt. This can even be done by blowing carbon dioxide through
the solution. The green manganate will be converted to the purple
permanganate.
Ammonia bubbled through a permanganate solution is oxidized to
the nitrate, while the permanganate (or manganate) is reduced to
manganese dioxide which comes out of the solution as a brown
precipitate; this precipitate can subsequently be reheated with fresh
alkalai to reform manganate or permanganate to produce fresh
batches of nitrates.
Strong alkalai added to an ammoniacal solution is the ammonia
source. Salts such as ammonium chloride or siulfate, compounds such
as urea fertilizer or even urine can be used. Urea and urine offer the
distinct advantage that the salt formed is a carbonate, which upon
strong heating, is converted to the oxide, and this, when added to
water, returns the hydroxide compound. With other salts,
metathetical reactions are necessary to retrieve the useful ions. E.g.
with sodium hydroxide and ammonium chloride, the product salt is
sodium chloride; use of potassium sources, such as wood ash, yields
a valuable by—product in the form of potassium chloride which can be
used in production of chlorates. In such cases, the side product is
saved for subsequent use in a different process.
Production equipment consists of tightly stoppered containers for
gas generation using the pressure of the gas to drive it through a tube
to permit it to bubble up through the manganate or permanganate
solution. An outstanding feature of this process is that the ammonia
will discolor the solution as the green mangariate or purple per-
manganate is used up. Because gas absorption is not entirely efficient,
a two holed stopper is used, with several containers hooked in series,
so ammonia that escapes the first container bubbles through the
second, and gas escaping from this bubbles through a third.
In this process, when the first bottle is exhausted, the hose from
the ammonia generator is moved to the second bottle, so the reaction
W continues while the first bottle is pulled off and processed. Ammonia
generators may be manifolded in parallel so the ammonia feed is
continuous. After pulling the bottle off, time is allowed for most of
the manganese dioxide to settle. It is then poured through a filter.
This strains out the manganese dioxide which is saved for re—use.
The solution is then evaporated to throw out the nitrate crystals. It
is not evaporated completely, as some alkalai is also formed in the
process. E.g. with sodium manganate or permanganate, some lye is
reformed; with the potassium salt, potassium hydroxide is formed,
etc. After the nitrate crystals are filtered out, this hydroxide can also
be recycled, saving materials. This material may have to be
recrystalled three times to get a reasonably pure product. The liquor
remaining is not thrown away; it is added to preceding batches. That
is, the liquid from the third evaporation is added to the second, the
liquid from the second is added to the first, and the liquid left from
the first is added to the solution that came fresh from the generator.
In other words, backtracking it one step to crystallize it over again.
A freshly prepared bottle of solution is added to the tail of the chain
each time one at the head is taken off. This way, the gas always passes
the same number of bottles; the number of bottles will vary with the
gas pressure, since the gas pressure will determine the height of
liquid permissible; e.g. at the same pressure you would have to have
more half full bottles than three quarters full. The bottles should
never be completely full. The number depends on the pressure. This
in turn is limited by how tight the corks are and the strength of the
bottles; carbonated beverage bottles, naturally, can take more
pressure than thin, glass bottles or ordinary lab flasks.
After a processed bottle is removd from the stream, the manganese
dioxide can be allowed to settle, in which case the clear nitrate-
containing liquid is poured off, or it can be filtered; this depends on
the equipment available. The clear liquid contains both the nitrate
and regenerated alkalai, so recrystallization is necessary. This is
another repetitive or "chain" process.
The liquid is boiled down, or left to evaporate, to throw the
nitrat out. Boiling is fastest. However, evaporation doesn’t consume
fuel; flébest compromise is to let it evaporate to a small volume then
boil it down the rest of the way. This gives a raw nitrate with a good
bit of contamination.
The liquid is set to one side for reprocessing. The raw nitrate is
then dissolved in the smallest amount of boiling water that will
completely dissolve it. This is boiled down till it starts coming back
out and is then taken off the fire and cooled. The nitrate then
crystallizes out in large amounts. This filtered out nitrate is then
added to FRESH boiling water, while the liquid is returned to the
previous stage. After a couple of boiling runs, the nitrate is fairly
pure.
Exact specifications are difficult to lay down, owing to the
variability in equipment used and the purity of the raw materials.
Several lab runs may be necessary to get the “feel" for the process.
This is a multi—stage operation in which each stage must be planned
in advance. As with most processes, it is important to bear in mind
which component is most desirable — the solid or the liquid — at
each point.
The most common source of manganese dioxide is dead dry cell
batteries; it is part of the black powder inside. In the dry cell, this
powder is soaked with a liquid containing ammonium chloride and
zinc chloride. This powder is first washed to remove all soluble
components (the washings can be added to your urine, or other
ammonia source, as the zinc would mess it up for other uses); the
remaining powder is both black manganese dioxide and carbon. The
carbon will not interfere greatly with the use of this material when
you use it to make manganate by heating with lye in air. But in the
next stage, where the green salt formed in the fire is dissolved in
water, any crud that does NOT dissolve is of no further use in the
process and can be discarded.
The situation is different with the ammonia generator. lf lye or
sodium hydroxide is used to generate the ammonia, whether the
liquid that is left afterward is worth saving depends on the compound
used as the ammonia source; for example, if ammonium chloride or
sulfate is used, the sodium chloride or sulfate remaining in the liquid
is of no real use. On the other hand, if urea or urine is used, the liquid
left will contain sodium carbonate which can be subjected to strong
heat to convert it to sodium oxide, recycling it to form lye. If wood
ash is used to make potassium salts, any of the compounds can be
used in other processes and should be saved.
In the actual nitrate process itself, the solution resulting contains
three useable products in the form of nitrate, hydroxide, and
manganese dioxide. None of the products are thrown out after this
point.
Quite clearly, the overall efficiency of this process depends on
step—by—step organization. Efficiency is developed as the process gets
under way and it improved as time goes on, and people become
familiar with the ‘ ‘which component goes where at what stage’ ’ end
of the organization. Fortunately, this is a good process for the
inexperienced, since major hazards or losses are low if something
goes wrong. If the nitrate doesn’t come out quite right, an extra
crystallization or two will cure it.
Even if the process is sloppily run, the very number of stages
simplifies control of the final product. The material from the nitrator
will have only two impurities: the manganese compound, which is
green or purple, or the manganese dioxide precipitate, which is a
brown powder. lf you get a clear liquid after all this, there are only
two components left: hydroxide and nitrate. If there is any doubt that
the nitrate from crystallization still contains any lye or potassium
hydroxide, simply adding a bit of PURE ammonium nitrate will clean
it out. It will react with lye (sodium hyrdoxide) or potassium
hydroxide to give sodium or potassium nitrate plus ammonia.
Because ammonium nitrate is fairly easy to produce in pure form
from any other nitrate salt, due to its incredible solubility in hot
water, it is an efficient purification agent for the removal of
hydroxides from nitrate stock.
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