A. P. Kalishev.

Study of Marine Algae of the Primorsky Region for the Industrial Production of Iodine and Potassium Salts from Them

Iodine was discovered in 1812 under the following circumstances. The Frenchman Courtois, owner of a saltpeter factory in Paris, noticed that the iron boilers (evaporating pans) in which calcium nitrate was processed into potassium nitrate by means of an extract from the ash of marine algae very quickly spoiled and corroded. Courtois asked Gay-Lussac to determine the cause. Gay-Lussac vigorously undertook the study of the extract from the ash of marine algae and discovered an element unknown up to that time, to which he gave the name “iodine,” from the Greek word—ἰώδης—violet-colored, because the vapors of this element were bright violet in color. Gay-Lussac explained the corrosion of the walls of the iron boilers by the presence of iodine salts in the salts of marine algae. Thus a new element—iodine—was discovered, which in the future was to play a considerable role in medicine. Iodine, its salts, and its preparations, over time, acquired such great importance in medical practice that at present, perhaps, not a single physician, and especially not a surgeon, can do without them.

Iodine belongs to the group of haloids and, as an analogue of bromine and chlorine, possessing a great affinity for other bodies, is not found in nature in the free state. Iodine salts, however, are very widespread in nature, but in such insignificant quantities that at times they are even difficult to detect. Sea water contains more iodine than the earth’s crust, but even so this quantity is so negligible that obtaining iodine is not economically possible. Certain species of algae covering the sea floor are, as it were, accumulators for iodine salts in sea water, and the ash of these algae is a source for the practical production of large quantities of iodine.

In the forties of the last century, on the coasts of northern France and Scotland, there already existed a fairly large factory industry for extracting iodine from the ash of marine algae. But with the passage of time, 40–50 years ago, a new source for obtaining iodine was found—the mother liquor obtained in the production of saltpeter in Chile. According to Landbein’s analysis, the mother liquor contains: NaNO₃—28%, NaCl—11%, Na₂SO₄—3%, MgSO₄—3⅔, NaJO₃—22% and 33% water, whereas the ash of marine algae contains iodine from 1% to 2.5% and very rarely up to 3%. Hence it is clear that Chilean iodine very soon, by its quantity and cheapness, destroyed almost the entire iodine industry; thus, of 14 English factories, only three exist at the present time¹).

At present there are two sources for obtaining iodine: the ash of various marine algae containing iodine, and the mother liquors of Chilean saltpeter.

Marine algae containing iodine (the iodine content is given in %% on dry algae)²):

1) Fucus Filum — 0.0894%
2) Fucus digitatus — 0.135%
3) Fucus sacharinus — 0.23%

¹) Industry and Technology. Vol. VII, p. 350.
²) Gmelin–Kraut’s, B. I, Abt. 2, Seite 289.

4) Fucus nodosus — very little
5) „ vesiculosus — 0.001%
6) „ Saccatus — 0.124%
7) „ Lorcus — traces
8) „ Siliquosus — 0.142%

In addition, iodine is also contained in Fucus cartilagineus, membranaceus, rubens and palmatus; Laminaria, Fucus serratus, and many others. Of the algae listed, only four are of industrial importance—Fucus Sacharinus (0.23), F. seliquosus (0.142), F. digitatus (0.135), and F. Saccatus (0.124). According to the data of the professor of the Agricultural Academy in Sapporo (Japan), Indo Kichisaburo¹, iodine is contained in Fucus vesiculosus (0.043%), F. nodosus (0.066%), F. serratus (0.157%), and Laminaria digitata (0.574%). Indo Kichisaburo asserts that, among the algae found near the seas of Japan (the Okhotsk, Japanese, Bering, and others), iodine is contained only in species of Laminaria and Fucus; the rest contain no iodine. According to Stanford’s data², the following algae contain iodine: Laminaria digitata (0.4535%), L. sacharina (0.2794%), Fucus Serratus (0.0856%), F. nodosus (0.0572%), F. vesiculosus (0.0297%), Zostera maritima (0.0457%), Rhodomella pinnostroides (0.0378%), Hyderix seliquosa (0.2131%), Chordaria flagelliformis (0.2810%).

According to investigations by the author of the present article, many lakes of Siberia contain iodine (Shira, Karachi, Plotbishchenskoe, and others), but in such an insignificant quantity that it can be demonstrated only qualitatively, by evaporating 50 liters of water. In 1899 V. A. Balandina investigated the water of Lake Plotbishchenskoe and found that one liter of water contains 0.234 milligrams of iodine³.

In 1917 Prof. Tishchenko proposed that I repeat the investigation of the water of Lake Plotbishchenskoe, which I did. The water contained the most insignificant traces of iodine, which could be demonstrated only qualitatively, by evaporating 50 liters of water. I also investigated the algae of certain Siberian lakes, including Lake Plotbishchenskoe, but no iodine was found in them.

Before the war of 1914, Russia obtained iodine exclusively from Germany; with the closing of the borders, the import into our country of iodine and its salts also ceased. The Resettlement Administration supplied both its own stations and private pharmacies almost throughout all of Siberia with medicaments and galenic preparations, and, in order to develop this activity more broadly, it decided to establish a whole series of productions of those preparations that could not be obtained on the market or that were very expensive. To this end it organized in Tomsk a chemical-pharmaceutical laboratory, the management and direction of which it entrusted to the author of the present article.

The shortage of iodine and its preparations compelled the Resettlement Administration to pay special attention to this question, and it entrusted me, as head of the laboratory, with investigating the coast of the Primorsky Region in this direction. At the end of 1914 I began the investigation.

In the Primorsky Region, from ancient times the Chinese and local inhabitants had collected edible sea kale in large quantities, which they sent to China. This kale was purchased by the Vladivostok Resettlement Administration and sent to me. In all, for investigation during six months of 1915 I received at different times 8 lots of kale. The submitted specimens of kale, according to the determination of Prof. Sapozhnikov, were Laminaria Sacharina.

The examination of the named algae was carried out in accordance with the procedure set forth below. A weighed portion of 500 g of air-dry kelp was burned in a muffle furnace in an iron cup at a temperature of dark-red heat; the burning was continued until the ash turned white. The latter was then leached as completely as possible with water, the water was evaporated on a water bath, and the dry salts obtained were analyzed. At the same time another test (control) was carried out: 100 g of air-dry kelp were finely ground in a mortar, sifted through a fine sieve, and extracted with water at boiling. The solution was then evaporated to dryness and heated until the organic substances decomposed; the dry residue was dissolved in water and filtered off from the insoluble portions. The solution was evaporated, and the salts thus obtained were analyzed only for iodine content.
The results of the analyses are expressed in the appended Table No. I. The ash is calculated on air-dry kelp, and the salts—on the ash.

Table of Analyses No. I.

On the basis of the analytical data obtained, the probable composition of the salts in the ash of kelp may be represented in Table No. I-a.

Table of the Probable Composition of Salts No. I-a.

These preliminary studies showed that the ash of the marine algae of Primorsky Oblast is a valuable material from which potassium sulfate, potassium chloride, and iodine can be obtained in large quantities. The Japanese have long obtained iodine and potassium salts from the ash of sea kale and find it economically advantageous, despite the fact that their sea kale contains almost half as much ash and salts as our Primorsky sea kale. I cite the data of Prof. Ijdo Kichisaburo¹.

It was decided to conduct further studies in two directions: 1) to study sea kale in detail, and 2) to study on site the methods of catching and drying the kale and to designate the place for building an iodine plant. The area chosen was north of Vladivostok up to the mouth of the Amur River. It was possible to obtain kale from the following places: at Matveev Island, Cape Rekord, and Chelnovai Bay—in three places: north of it, south of it, and at the bay itself. The kale caught was exclusively Laminaria sacharina, i.e., other species also grow there, but in considerably smaller quantities, and it is more difficult to harvest them because of the natural characteristics of these species. The kale was caught by specialists—Chinese and divers. The drying of the kale used was the most primitive: on the shore the algae were spread out on dry sand. The dried kale was tied into pood bundles.

According to the place, depth, and time of catching, the algae obtained may be distributed as follows:

No. I. Kale bought from the Chinese north of Chelnovai Bay, caught at the end of May at a depth of 2–5½ sazhens, dried quickly on sand; grows in enormous quantity.

No. II. Kale bought in the region of Chelnovai Bay, caught at the beginning of July at a depth of 4–5 sazhens; grows in enormous quantity.

No. III. Kale caught by divers and Chinese specialists in mid-June at a depth of 5–6½ sazhens: 1) at Matveev Island, 2) at Cape Pavlovsky, 3) at Sibiryakov Island, 4) at Rekord Island and at Chelnovai Bay in three places, 5) to the north, 6) to the south, 7) at the bay itself. Dried on sand. Everywhere it grows in enormous quantity.

No. IV. Kale caught in the same places in mid-July.

No. V. Kale caught in the same places in mid-August.

No. VI. Kale caught in the same places in mid-September.

No. VII. Kale caught in the same places at the beginning of October.

No. VIII. Kale caught in mid-August at Sibiryakov Island and at Chelnovai Bay.

No. I-a. Kale cast up by the sea at Chelnovai Bay in June, gathered on the day of a storm.

No. II-a. Cabbage thrown up by the sea near Chenyuvaya Bay in August, taken on the day following a storm.

No. III-a. Cabbage thrown up by the sea near Chenyuvaya Bay in September, taken on the day following a storm.

A complete analysis of each sample was made twice, and the average was taken for the table. Nos. III, IV, V, and VII each had seven samples; the difference between the individual analyses was very small and, in order to avoid a large quantity of figures, it was necessary to take the average of the seven analyses and present it. The results of the analyses are given in Tables Nos. II and II-a. The ash is calculated on air-dry cabbage, the salts on ash.

Table of analyses No. II.

Table of the probable composition of salts No. II-a.

Comparing the obtained results of the analysis of kelp thalli collected at different times and in different places over the period May–October, one may say that the average ash content, calculated for air-dry kelp, will be 35.03%; the average content of soluble salts in the ash is 25.09%, or, calculated on the ash, 73.90%. The lowest NaJ content, 1.40%, occurs in young kelp. Beginning in June, the NaJ content in the kelp increases, reaching a maximum of 2.05% in September; thereafter it again decreases. As for KCl and NaCl, apparently no dependence can be found here, since these salts are rapidly leached out by water and, probably, their content is directly dependent on the method and time of drying the kelp. That leaching does take place is evident from Table No. II: analyses I a, II a, III a of kelp cast up by the sea and collected on the same and on the following day; here the kelp lost, on average, 13.1% of soluble salts, while about 1/5 of the iodine salts remained; consequently, the loss amounted to 1/5 of the original quantity. The leaching out of K and J salts may be explained in two ways: either K salts diffuse through the organic skeleton of the kelp more strongly than Na salts, or the salts are not bound to the organic skeleton of the kelp. In the leaching of K and J salts there occurs an apparent increase in Na salts. In reality, the situation is as follows: the sodium salts may remain in the same quantity, or may even be leached out a little, but in percentage terms, after the departure of K and J salts, the Na salts increase.

On the basis of the investigation carried out, the following conclusions may be drawn:

1) Kelp may be harvested from the moment the sea is freed of ice until it freezes.

2) Kelp cast up by the sea loses half of all salts and 1/5 of the iodine salts on the first day after a storm.

3) Young kelp contains slightly less iodine than mature kelp.

4) The maximum iodine content in kelp occurs in September.

5) The content of iodine and salts in sea kelp does not depend on the distance from the shore or on the depth at which it grows.

6) In addition to iodine, potassium salts must also be extracted from the ash of sea kelp. Potassium chloride is used in large quantities for fertilizing soil, while potassium sulfate is used in medicine.

1. “Vrachebnaya Gazeta,” 1915, No. 27, p. 512. ↩↩

2. Extracts from the book of Indo Kichisaburo, ed. 1910, Politech. Jurnal—226, 89. ↩

3. V. A. Balandina, Yur’ev, 1910, “Chemical Analysis of Lake Plotbishchenskoe near the town of Yeniseisk, Eastern Siberia.” ↩