Chemical & Engineering
NEWS FEBRUARY 20, 1967
Chemical World This Week Stereo rubbers lead synthetics Stereo elastomers continued to lead the growth in production of synthetic rubber during 1966 in terms of relative gain. For example, production of stereo polybutadiene rose 32,300 long tons in 1966 to more than 186,100 long tons, a gain of 2 1 % over 1965 production of almost 154,000 long tons. Production of other stereo elastomers also increased greatly to more than 86,000 long tons, up 32% over the 1965 production of 65,000 long tons. Consumption gained substantially, according to figures compiled by the U.S. Department of Commerce and the Rubber Manufacturers Association. Consumers took 36,000 long tons of polybutadiene in 1966 for a total of 169,000 long tons, 27% more than they did in 1965. In addition, they used 7400 long tons of other stereo elastomers in 1966, raising domestic consumption to 62,000 long tons (13.6% more than 1965). U.S. production of all types of synthetic rubber reached almost 2 million long tons, totaling about 1.97 million long tons. Imports of natural rubber were about 439,000 long tons, about equal to imports of the past few years. Exports of polybutadiene dropped slightly in 1966-less than 1%-but still totaled almost 19,000 long tons. This slight drop could be the beginning of the expected long-term decline in exports of polybutadiene as new plants in western Europe and Japan produce nearer their capacities. More competition in world markets by foreign producers of polybutadiene also may be coming. The export picture for other stereo elastomers—which includes those made from ethylene-propylene, ethylenepropylene diene monomer, and isoprene-is brighter. Last year, the gain in exports of these elastomers accounted for almost a third of the increased production of 21,000 long tons. Actual exports were about 15,000 long tons, up 77% from 1965 exports of 8400 long tons. Stocks of stereo elastomers also moved up during 1966. Polybutadiene in stock at the end of last December was about 25,000 long tons. This is a seven-week supply at the
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Gains in stereo rubbers give boost to synthetic rubber totals
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Type of rubber
U.S. production
U.S. consumption
(Tho usands of long tons , including latexes)
1966
1965
1965
1966
Polybutadiene
186.1
153.8
169.1
133.1
Other stereos
86.4
65.2
62.0
54.6
All synthetics
1,969.4
1,814.0
1,673.8
1,540.9
Source—U.S. Department of Commerce and Rubber Manu facturers Association
December consumption rate of 14,350 long tons. At the end of December 1965, stocks of polybutadiene were 20,400 long tons, slightly more than six weeks' supply at the then consumption rate of 12,900 long tons. Stocks of stereo elastomers other than polybutadiene are much larger, relative to consumption, than are those of polybutadiene. Stocks of these materials at the end of December 1966 totaled 25,200 long tons (slightly more than polybutadiene stocks) and equal to nearly four months' consumption at December's rate of 6700 long tons. The large number of different ethylene-propylene rubbers which are inventoried probably accounts for much of the larger stocks.
Thoria deposit substantial On the Idaho-Montana border, in the Lemhi Pass area, hard by the point where Lewis and Clark crossed the Continental Divide in 1805, a new chemical horizon is opening up. Substantial deposits of high-grade thorium- and rare-earth-bearing ore are located there and demand for these elements is poised on the brink of an exciting future. Sawyer Petroleum Co., headquartered in Oatman, Ariz., has acquired 64 claims (covering about 1280 acres) on the Montana side of the deposit. Sawyer is collaborating with Union Pacific Railroad in developing the claims. Analyses of core drillings indicate that the thorium oxide content goes as high as 9.67% by weight and
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that a host of other elements—such as cerium, neodymium, europium, and yttrium—are present in workable quantities. But the ore generally runs about 0.75% thorium oxide and its equivalent in total rare-earth content. Sawyer and Union Pacific aren't the only companies that have been attracted to the site. Dow has leased 26 claims from Nuclear Fuels and Rare Metals, Inc., and has been studying ways of processing the thorium. It has not made a move as yet. The U.S. imports practically all of its thorium requirements from Canada, primarily from Rio Algon Mines' uranium operations in the Elliot Lake district of Ontario. In 1965, the latest year for which there are statistics, some 5000 pounds of the metal, valued at more than $50,500, came from this source. Monazite ore, chiefly in Australia, Ceylon, Korea, Malaysia, and Nigeria, is the other source of thorium. Supply is limited, however, because the thorium is a by-product of titanium and zirconium monazite operations. The cost of the oxide runs between $5.00 and $10 per pound, depending on density and quality. Dr. Ralph Borrowman of the U.S. Bureau of Mines in Salt Lake City has developed an improved solvent extraction process for isolating thorium from the Lemhi Pass deposit. The method consists of leaching the crushed ore with sulfuric acid and solvent extracting the sulfate with Primene JMT (a tert-slkyl primary amine) in kerosine. Stripping with ammonium hydroxide-ammonium carbonate solution converts the sulfate to a thorium carbonate complex. Steam FEB. 20, 1967 C&EN
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