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THE INDIA RUBBER WORLD 



[May 1, 1917. 



Agriculture survey of these kelp beds in 1914 showed that there 

 are available about 59,300,000 tons of kelp, if it were harvested 

 semi-annuallj', or equivalent to 2,266,000 tons of potassium chlo- 

 ride. Our total imports of potash salts are about 1,000,000 tons, 

 equivalent to 400,000 tons of potassium chloride. 



The kelp groves are densest off Point Loma, San Nicholas 

 Island, and San Clemente Island, due west from San Diego. 

 The government report gives 16,000,000 tons of kelp on an area 

 of 91 square miles from Cedros Island to San Diego, and 18,- 

 000,000 tons on an area of 97 square miles from San Diego to 

 Point Concepcion. Thus the kelp industry has sprung up about 

 San Diego, and the $175,000 government kelp plant and 

 laboratory, under the direction of Dr. J. W. Turrentine, will be 

 built there or at San Pedro. 



There are three principal firms at San Diego working in as 

 many different ways. The Swift Packing Co. has a $250,000 

 wharf and plant employing about 75 men, which is merely a 

 temporary project for the duration of the war. The kelp is 

 dried in nine large revolving drums by direct heat, then ground 

 like feed, sacked and shipped for fertilizer. As 90 per cent of 

 the kelp is water, the fertilizer yield by drying is 10 per cent. 



The San Diego Kelp Ash Co. buys and sells the ash of 

 burned kelp for fertilizer. The kelp is gathered and prepared 

 by small independent companies or individuals, who sell the 

 ash to the distributing company as a farmer sells his grain. The 

 crude improvised implements with which the harvest of the sea 

 is gathered, dried and burned, render this the most picturesque 

 aspect of the industry, though of scant significance. Altogether 

 about 100 of these independent workers prepare about 200 tons 

 of ash a month, about IJ^ tons of ash being produced from 20 

 tons of kelp. 



Not these two concerns, but the activities of the Hercules 

 Powder Co. have brought the kelp industry to the attention of 

 the nation. This firm has expended $2,000,000 on a great plant 

 to extract potash from kelp for the manufacture of munitions 

 by means of chemical solutions. It covers 30 acres, includes a 

 2,300-foot wharf, and employs over 1,100 men in three shifts, 

 SO of them being expert chemists, engineers and superintendents. 

 The payroll is said to be $70,000 to $80,000 a month. There are 

 several buildings, such as a large still house, centrifugal drier 

 house, huge filter press house, 2,700-horsepower steam plant, 

 and numerous great storage tanks aggregating 12,000,000 gallons, 

 including 156 wooden tanks of 50,000 gallons capacity each, used 

 as digesters of the pulp. 



For cutting the kelp and transporting it to the plant, three 

 curious kelp harvesters, three tugs and nine barges are em- 

 ployed. Because of their unique character a peculiar interest 

 attaches to these great sea-going mowing machines for cutting 

 at a depth of six feet under water this giant seaweed, which often 

 grows to a length of 100 to 200 feet, or considerably more. Re- 

 sembling the familiar dredge, they are' twin-screw barges with 

 great cycle knives that work on a bar like a mower in front of 

 the vessel. As the barge moves forward the kelp is gathered 

 up on a screen and conveyed by an endless drag to the pits 

 of the boat, where it is ground finely and transferred to the 

 barges to be taken to the plant. A crew of 12 men operates 

 and lives on each harvester. 



The $20,000 harvester of the Swift Packing Co., 38 by 150 

 feet, differs in that the kelp, after being cut into pieces about 

 six inches in length, is dropped into six large bins in the hold 

 until taken to shore by the harvester itself. The mower con- 

 sists of knives attached to an endless chain, and cuts a swath 

 of 40 feet. This harvester has a capacity of 50O tons a day, 

 although on account of unfavorable weather conditions and rough 

 seas, which reduce the working day to four or five hours, does 

 not average over 20O tons. 



Numerous secret processes effect the change of kelp into 

 potash, although most of the details are well known. First the 

 macerated seaweed is allowed to ferment in great wooden tanks 



for 10 days. The coarse leaves are then screened off, and the 

 liquor is pumped into vats, where a chemical solution is added. 

 It is then boiled to kill the bacteria and run into large sediment 

 vats to settle. From there the liquid goes through filter presses 

 and the mud is left on the cloth of the press, while the liquor 

 filters through. By means of multiple effect evaporators the 

 water is removed from the liquor without precipitating the salts. 

 Then by means of evaporation again, in large vertical tanks with 

 conical bottoms, the salts are precipitated from the liquor into 

 the chambers below and scraped out with a hoe. The potassium 

 chloride, which is the starting point for the manufacture of other 

 potash salts, is separated from the sodium chloride, or common 

 salt, by crystallizing first at one temperature and then at another. 

 As the potassium chloride is more soluble in hot than in cold 

 water, whereas the sodium chloride is about equally soluble, the 

 potassium salt accumulates in the cool vat and the sodium salt 

 in the hot one. After several refining processes the chemically 

 pure potassium chloride is scraped out from the chambers below 

 the evaporating tanks, when the usual processes of converting 

 this into other potash salts may be begun. 



Besides potash and saltpeter for the manufacture of matches 



Pumping Ground Kelp from the H.\rvester into a Barge. 



and various explosives, acetone, for the making of smokeless 

 powder, and also iodine, are taken from the mother liquors, 

 while the trailings or mud from the filter presses, which retains 

 a small percentage of potash, is sold for fertilizer. No part of 

 the three barge loads of kelp that pass through the plant daily 

 go to waste, for science and inventive genius have found ways 

 to utilize everything in the composition of kelp, and the experi- 

 ments now in progress by the government, the Hercules and 

 other companies, promise to develop still further uses, some of 

 which may be closely allied with the rubber industry. 



When the war is over and munition manufacture languishes, 

 potash salts will not be in such great demand, and a greater 

 percentage of the output of the kelp industry will be available 

 for other uses. Why not a rubber plastic? Meantime nearly all 

 of the immediate and later products of this new American in- 

 dustry are employed by rubber manufacturers as coagulants, 

 solvents, compounding or vulcanizing ingredients with rubber, 

 gutta percha or their substitutes ; also in waterproofing and in- 

 sulating mixtures, rubber reclaiming and the manufacture of 

 artificial leathers. Therefore, a new source tending to insure an 

 ample supply at moderate prices is of interest in itself, aside 

 from future possibilities. 



