Mechanical drying of raw opium

Abstract

The present method of obtaining opium in the Soviet Union is to make repeated incisions in the capsules and then collect the effluent latex. The whole process of getting the opium is extremely laborious and does not lend itself to mechanization; moreover, the opium crop frequently depends on fortuitous elements (such as rainfall, wind and drought).

Details

Author: V. A. Shevelev,, A. I. Bamlpvsky, V. I. Mravyova
Pages: 6 to 7
Creation Date: 1958/01/01

Mechanical drying of raw opium

V.A. Shevelev,
A.I. Bamlpvsky,
V.I. Mravyova All-Union Scientific Research Institute for the Study of Medicinal and Aromatic Plants

The present method of obtaining opium in the Soviet Union is to make repeated incisions in the capsules and then collect the effluent latex. The whole process of getting the opium is extremely laborious and does not lend itself to mechanization; moreover, the opium crop frequently depends on fortuitous elements (such as rainfall, wind and drought).

The capsules are cut and the opium is collected at the particular phase of the plant's growth known as the stage of technical maturity, which coincides with the lactic maturity of the seeds. The capsules are incised during the latter half of the day with a specially designed three-bladed knife, and the effluent latex is allowed to remain on the capsules overnight, during which time the latex coagulates and becomes somewhat thicker and slightly darker in colour. In the morning, usually before sunrise, it is removed from the capsules with a special scraper, in the form of a semi-liquid substance known as raw opium. On average, each capsule is incised three or four times. The moisture content of the raw opium collected varies between 40% and 60%, according to the conditions of cultivation. The whole of the raw opium collected each day must be handed over to the state organization concerned.

The raw opium thus obtained in the Soviet Union is used exclusively for medical purposes.

To obtain opium in powder form, the former practice was to spread the raw opium thinly several times a day on sheets of parchment paper and dry it in the sun for six to eight days. The dark brown viscous mass of opium was then cut up into briquettes. These were dried in a drying kiln for ten to twelve days to 8% moisture, and then ground into powder.

This method of drying inevitably involved some loss of morphine and other alkaloids, and also meant employing a large number of workers, who were in contact with the raw opium for long periods during the drying process.

Experiments which we made showed that the process of drying the raw opium on parchment paper resulted in a morphine loss of up to 8%, owing to the action of the atmospheric oxygen and direct sunlight, while the subsequent drying of the briquettes in the kiln resulted in a further loss of up to 5%, making a total loss of up to 13% of the morphine content of the opium.

With a View to improving the conditions of work of those engaged in producing opium powder and eliminating losses of morphine and other alkaloids during drying, experiments were made to evolve a more efficient drying method.

It was found that raw opium can be successfully dried in a vacuum roller machine in which all the processes are fully mechanized, and which can be serviced by a mere handfulof workers who do not come into direct contact with the opium. With this process, drying takes 20 seconds (one revolution of the rollers) under vacuum conditions at 60°C to 70°C, and the original morphine content is retained in the resulting opium powder, as can be seen from the following table:

 

Morphine content, in % of absolute dry weight.

 

Raw opium, sample number

in raw opium

in opium powder

Moisture content of opium powder, %

1 9.55 10.03 2.29
2 8.80 8.80 3.20
3 9.66 9.89 2.60
4 9.66 10.01 3.40
5 11.95 11.98 0.46

It should be noted that the moisture content of the opium powder test samples did not exceed 4%.

Our proposed method for mechanically drying raw opium was tried out under production conditions with a Sanger-hausen-type vacuum roller dryer.

Results of mechanical drying of five tons of raw opium

 

Raw opium processed

Opium powder yield

Lot number

Raw opium in kg

Morphine content of raw opium, in %

Morphine content, in g

Opium powder in kg

Morphine content, in % of weight (air dried)

Morphine content, in g

1 1012.140 5.850 58758.282 495.33 11.95 59209.396
2 846.050 5.460 46172.000 375.20 11.66 43767.800
3 713.080 5.240 37414.142 342.80 11.11 38079.660
4 895.294 7.197 64434.786 503.15 13.09 65905.075
5 878.030 5.670 49793.028 429.97 11.40 49009.556
6 812.645 6.200 50379.756 443.04 11.12 49267.820
TOTAL
5157.239
 
306951.99 2589.49
 
305239.3

The morphine retention rate for the mechanical drying of 5 tons of raw opium, according to the gramme figures, was 99.43%.

Proceeding from these laboratory and production-scale tests, the conditions recommended for mechanically drying raw opium are as follows: pressure of steam for heating the rollers, 0.5-1.0 at ; pressure of steam for heating the body of the machine, 3-4 at ; vacuum in the chamber, 0.7-0.75 at; temperature in the chamber, 60-70°C. The raw opium is pumped into an automatic measure, from which it is gravity-fed in portions on to the rollers. The automatic measurer cylinder has three cavities, and is geared to the rollers as it turns. Drying takes 20 seconds - i.e., one revolution of the rollers. A two-roller vacuum machine can handle 30 kg. of raw opium an hour.

The morphine retention rate amounted to 99.43% with mechanical drying (in the processing of 5 tons of raw opium), whereas the old method of sum-drying and kiln-drying gave an 87% morphine yield and also required a large number of workers. Opium powder in the Soviet Union is now produced by the new method exclusively.