RICIN

Ricin is just about the easiest, and at the same time, most toxic poison that a criminal can
make. Less than a milligram (1/1,000 of a gram) injected or inhaled will kill a person several
times over. For individual killings, it has the advantage of being undetectable in toxicology
scans since the poison is a catalyst the starts a chain reaction in the body, and is destroyed
before the symptoms begin to show.
With properly sized and dispersed dry particles, ricin is at least 10x more toxic than the most
potent nerve gas. A 1% water solution atomized with a small explosive burster has the same
effectiveness as sarin nerve gas. The only disadvantage ricin has is the time it takes for the
victims to die is about 1 – 2 weeks. So you won’t have the quick tactical effect of nerve gas. But
this can also be good in that, using a covert dissemination, the criminal has time to escape
before the attack is detected.
The information presented below is from a US Patent #3,060,165

Tips
Here’s a few things you need to know to make your production go much easier.
The seeds are readily available through wholesale seed suppliers for about $20 for a
pound of seeds.Castor bean seeds are very tough to crack or peel. Soak them for an
hour in a solution of 2 tablespoons lye in 1 cup water. Then use pliers to crack the shell.
The shell will peel of the bean easily then.

1. Use a 1/2 cup of acetone to every ounce of bean pulp. Blend well. Let sit for several days
with occasional shaking. Pour off the acetone and add an additional 1/2 cup of acetone
and repeat. This will remove almost all the castor oil from the seeds.

2. The patent doesn’t mention it, but you can use magnesium sulfate (Epsom salt) instead of
sodium sulfate. Epsom salt is easily available in any drug store for just about a dollar a
pound.

3. Use a plastic membrane filter if you can get them. The ricin forms a layer that is difficult to
remove from a regular coffee paper filter without scraping off fibers as well.

4. Wear a gas mask and gloves. Try to keep the ricin wet at all times to avoid generating
any dust (DEADLY!). And always shower and change clothes after handling.

5.Preparation
Ricin is a protoplasmic poison prepared from castor beans after the extraction of castor oil
therefrom. It is most effective as a poison when injected intravenously or inhaled, the latter
requiring extreme commutation and small particle size to be effective, It is believed that the
toxic action is catalytic rather than stoichiometric which probably accounts for the high toxicity
of the agent.

Because of its relative instability ricin must be handled with extreme care. In neutral aqueous
solution it is stable only up to 60″-75″ C., and in solid form up to 100″- 110″ C., although for
short exposures, temperatures up to 130″ may be tolerated. It is sensitive to acids, alkalis and
halogens and may also be inactivated by mechanical working such as grinding or pulverizing.
These factors are of great importance in developing a satisfactory method for preparing the
material.

Although ricin has been prepared in crystalline condition in the laboratory in small quantities, it
becomes necessary, for purposes of toxicological warfare, to prepare relatively large quantities
in a high state of purity. This necessitates that as much as possible of the non-toxic material
present be removed in the process.

In preparing the protein material, the castor beans are first ground and pressed to remove most
of the oil. The pressed cake still retains about 15% oil and this may be removed by means of
solvents which will extract an additional 150 pounds of oil per ton of beans and reduce the oil
retained in the cake to a little over 1%. In the event that the expressing step is supplemented by
solvent extraction, it is important to prevent detoxification of the protein during the solvent
removal step. If residual solvent is removed from the ground beans by blowing with steam,
considerable detoxification results. Blowing with nitrogen effectively prevents detoxification but
is expensive when carried out on a large scale.

After the oil has been removed, the pressed cake or pomace is extracted by agitating with
water at a pH of 3.8+-0.1 at 25″ C. which removes substantially all of the toxic protein. The
extraction process is operative within a pH range of about 3 to 4.5 although the preferred range
is about 3.5 to 4. The optimum operating point is a pH of 3.8+-.1, as indicated above. A careful
pH control is essential in order that as much non-toxic protein as possible may be eliminated
and also that the filtration rate may be held at a satisfactory value. Either HCl or H2SO4 may be
used to get the desired pH for the extraction water, but H2SO4 is preferred due to its lower
corrosion rate and ease of handling in concentrated form. The acid should be used in
reasonably dilute form to prevent undue local concentrations during its addition. A 5%
concentration is satisfactory.

Following the extraction, the slurry is filtered using either a conventional recessed plate filter or
a continuous string discharge vacuum filter. With the latter about 7% of filter aid, based on meal
weight, was found necessary for satisfactory filtration.
The filtrate from the water extraction step, which contains the ricin, was treated with a 16.7%
solution of Na2SO4 to precipitate the protein. This solution is composed of 20 pounds of salt in
100 pounds of water and the amount used was such that the salt content equaled 20% of the
filtrate weight. This amount and concentration of salt solution was about optimum considering
the factors of cost and toxin recovery. Somewhat higher concentrations and larger amounts of
solution can be used, however.

The precipitation process is not limited to the use of Na2SO4 since a saturated solution of NaCl
can be used successfully, but Na2SO4 solution gives better nitrogen fractionation, more rapid
precipitation, and can be operated under wider pH limits. It is desirable to raise the pH to about
7-8 before precipitation as this gives better recovery and greater non-toxic nitrogen removal.
The pH was raised to this value by using NaOH or Na2CO3 the latter being preferred. The
base used was quite dilute in order to prevent detoxification due to high local concentrations in
the solution. A 5% solution of NaOH was used, whereas with Na2CO3 a 12% solution was
preferred.

In general, this higher pH during precipitation gave a greater non-toxic nitrogen fractionation
and at the same time maintained the toxin loss at less than 2%. After precipitation, the slurry
was filtered using from 1 to 4% filter aid, based on slurry weight, for satisfactory filtration, the
amount of filter aid needed being dependent on the type of press used. Washing the filter cake
with Na2SO4 solution removed additional non-toxic nitrogen which is desirable. In this washing
step a 16.7% solution of Na2SO4 was again used. This washing step removed an additional
15% of non-toxic nitrogen from the cake.

After filtration the filter cake which contains the ricin in combination with the Na2SO4 may be
dried and slurried with CCl4 to separate the ricin by flotation. Separation of the ricin after a
single precipitation and washing step is possible, but it is preferred to carry the process through
an additional extraction and precipitation step. This is accomplished by slurrying the filter cake
in three times its weight of water and the pH of the slurry is again brought to 3.8+-.1 by means
of 5% H2SO4 The slurry is filtered and a second precipitation is brought about by adding
Na2SO4 solution. Although pH control here is not wholly essential it is advantageous to bring
the pH to approximate neutrality by adding 12% Na2CO3.

A precipitation time of 45 minutes was necessary to obtain complete removal of the toxin. In
filtering out the precipitate, no filter aid was used and the filter cake was washed with Na2S04
solution on the filter whereby an additional amount of non-toxic nitrogen was removed from the
cake. This washing was effective only the first time and repeated washings had little effect in
removing further non-toxic nitrogen.

The ricin-Na2SO4 precipitate was dried at about 50″ to 60″ C. on a hot air tray dryer. The dried
product was ground to pass a 40 mesh screen and agitated with 5 times its weight of CCl4
which served the separate the ricin from the Na2SO4 by flotation. After settling. the ricin was
skimmed off the top. This reduced the Na2SO4 content of the mixture from a previous 40 to
50% down to 15 to 18%. About 1 to 2% of nitrogen remained in the Na2SO4 salt which could
then be used for subsequent precipitations.

The final precipitation produced a particle size of 1-2 mu. On drying the wet cake, however, the
ricin cemented together forming larger particles. These could not be broken down to their
original size by ordinary grinding methods and since a very line particle size was necessary in
order that the product might be used as a toxic weapon, it was thought desirable to seek some
method to prevent the agglomeration or cementing process that took place on drying.
To attempt lo affect this result, physical conditions prevailing under the precipitation process
were changed. This included changing the temperature of precipitation and the rate of agitation.
Other changes included precipitation with only partial saturation of Na2SO4 and the use of
wetting and seeding agents. None of these expedients produced any significant improvement in
particle size. Ordinary dry ball and hammer milling of the dried ricin produced considerable
detoxification perhaps due to the generation of excess heat. The use of CCl4 slurry plus the
use of low temperature and low moisture content of the ricin reduced detoxification during ball
milling.

Spray drying proved to be an even better method of securing a reasonably small particle size.
Best results were achieved by using a solution having about 20% solids, an inlet temperature of
150″ C. and an atomizing air pressure of 150 to 180 p.s.i. The particle size secured was 6 to 8
mu.

The best means of securing a small particle size was by air grinding. This was carried out in an
apparatus having a chamber with conical top and bottom. The material to be ground has been
fed into this chamber and is withdrawn from the bottom and forced back into the center of the
chamber tangentially through a venturi. Compressed air of about 100 p.s.i. was fed to the
venturi to provide the grinding force. The fines are drawn off the top and the large particles
settle to the bottom to be recirculated and reground. This process produced particles having a
mass median diameter of 2.5 to 3.5 mu.

Numerous variations are possible in the several steps of the process commencing with the
water extraction and precipitation which may be a single or multiple step. Although a single
extraction step can be used, as indicated before, some process modifications are necessary for
its successful operation on a plant scale. Double extraction proved to be quite efficient but
additional steps beyond the second extraction step were not found necessary. The drawing is
self-descriptive and shows the various steps of the process described.