Rhenium production increased significantly during the first half of 1971 to meet the growing demand for bimetallic platinum-rhenium catalysts used in nonleaded gasoline refining operations. As a result of this demand the quoted price of

rhenium metal powder was increased in 1971. Production of rhenium fell off during the last half of the year as several companies substituted other materials for rhenium as catalysts in petroleum refining operations.

Production of rhenium, a byproduct material recovered primarily from the molybdenite (MoS2) associated with southwestern and Chilean porphyry copper ores, increased during 1971 to an estimated 7,250 pounds of rhenium contained in rhenium salts. Cleveland Refractory Metals (CRM), Solon, Ohio, a division of Chase Brass & Copper Co. (a subsidiary of Kennecott Copper Corp.), continued to be the country's major rhenium producer. CRM reported that sales of rhenium chemicals, used as catalysts in petroleum refining operations to produce low-pollution gasolines, were strong during the first half of the year, but declined sharply during the second half. In 1971, the company's sales and earnings fell below 1970 levels primarily because other platinum group materials were substituted for rhenium in catalytic applications. Rhenium salts were recovered for CRM at Kennecott's molybdenite roasting facility (Figure 1) near Garfield, Utah, from domestic molybdenite

concentrates and from MoS2 imported from Chile.

Concentrate containing 90 percent MoS2 recovered from Kennecott's Ely, Nev., copper operation is believed to contain between 2,000 and 3,500 parts per million (ppm) of rhenium.

Rich rhenium-bearing molybdenite was recovered from porphyry copper ores at the San Manuel mine of Magma Copper Co. in Pinal County, Ariz. In 1971, Magma, a subsidiary of Newmont Mining Corp., sold this material to Engelhard Minerals & Chemicals Corp. Shattuck Chemical Co., Denver, Colo., a division of Engelhard, reportedly operated at peak capacity during the year and recovered rhenium salts from the Magma MoS2 concentrate. M&R Refractory Metals, Inc., recovered rhenium salts primarily from Magma concentrates for Engelhard on a "toll" or contract con1 Metallurgical engineer, Division of Ferrous Metals.

2 Kennecott Copper Corp. Annual Report 1971. 32 pp.

version basis at their plant in Winslow, N.J., with recoveries reportedly in excess of 60 percent.3 This facility has capacity for processing about 1,200 tons of molybdenite concentrate annually.

During the year, a process was developed by Molybdenum Corp. of America (Molycorp) and special facilities were installed at the company's plant in Washington, Pa., for production of high-purity molybdenum oxide and recovery of byproduct rhenium from MoS2 concentrate associated with porphyry copper ores and from primary molybdenite recovered from the Questa molybdenum mine in New Mexico.4 This new facility, which will have an initial capacity of over 1 million pounds of contained mo

Recycle Scrubber

lybdenum (about 830 tons of molybdenite) per year, is expected to be completed and to begin full-scale rhenium recovery operations by mid-1972. The primary molybdenite feed material from Questa is believed to contain about 50 to 70 ppm of rhenium.

During the year, Continental Rhenium Corp., a wholly-owned subsidiary of Continental Ore Corp., completed construction of a large semiproduction pilot plant for

3 Metals Week. Whittaker Selling M&R Holdings. V. 42, No. 46, Nov. 15, 1971, pp. 2-3. * International Mining Corp. Annual Report 1971. 17 pp.

Molybdenum Corporation of America. Annual Report 1971. 12 pp.

the recovery of rhenium at Golden, Colo.5 The plant is scheduled to be fully operational by mid-1972 with an annual capacity of over 1,000 tons of molybdenum concentrate. Preliminary information indicates that the operation can process both foreign and domestic molybdenite feed materials to various rhenium salts at recoveries in excess of 80 percent.

At its Danbury, Conn., Metallurgical Research Center, Newmont Exploration Ltd., a subsidiary of Newmont Mining Corp., started a long-range study of methods to improve the recovery yield of rhenium from molybdenum.6 If successful methods are developed, a pilot plant may be constructed to evaluate the economics of large-volume recovery operations.

Other domestic molybdenite roasting facilities which might be adapted for rhenium recovery include those of Climax Molybdenum Co. at Langeloth, Pa., Duval Corp. at Mineral Park, Ariz., Duval-Sierrita Corp. at Esperanza, Ariz., and Republic Steel Corp. at Canton, Ohio.

Porphyry copper deposits in Canada, Chile, Mexico, Peru, Zaire (formerly Congo-Kinshasa), the United States, and the U.S.S.R. represent the major significant or potential sources of rhenium. Rhenium recovery facilities exist at molybdenite roasting plants in Belgium, France, Sweden, the Soviet Union, the United Kingdom, the United States, and West Germany.

Approximately 95 percent of the estimated 1971 rhenium metal consumption of 7,600 pounds was used as bimetallic platinum-rhenium catalysts impregnated on durable alumina-base carriers for refining high octane unleaded gasoline. This application received added impetus during the year as requirements were developed for obtaining reduced levels of air pollution from automotive emissions through the use of lead-free gasoline.

During the past 3 years (1969–1971) the accumulated rhenium consumption in catalytic applications in the U.S. and Canada was estimated to total about 12,800 pounds. Consumption of rhenium metal as catalysts in the rest of the free world was estimated to total over 7,000 pounds during this period. By the end of 1971, platinum-rhenium catalysts were being used in about 125 refining or reforming units in some 35 countries. The total capacity of these units is believed to be about 1.4 million barrels per stream day (BPSD). An additional 28 units in seven countries having a capacity of 0.4 million BPSD were scheduled to become operational in early 1972.

Shortly before the first commercial use of Engelhard Mineral & Chemical Corp.'s platinum-rhenium catalysts began, patents were issued to Chevron Research Co., a subsidiary of Standard Oil Co. of Calif., covering the use of platinum-rhenium catalysts. An agreement was entered into between Engelhard and Chevron whereby

users of Engelhard's platinum-rhenium catalysts have worldwide rights to operate under Chevron's patents covering such catalysts.8

To meet anticipated demand for bimetallic platinum-rhenium catalysts, Engelhard redesigned a catalytic production facility in Newark, N.J.

During the year, an estimated 300 pounds of rhenium was consumed as metal powder primarily in refractory metal alloys. Other applications of rhenium continued to be in high-temperatures thermocouples, flashbulb filament wires, electrical contacts, and coatings.

Special reviews of rhenium were pub lished which discussed and evaluated supply-demand patterns and projected these relationships to future years.9 These reviews indicated that continued develop ment of platinum-rhenium catalysts could cause a short-term rhenium supply problem.

5 International Minerals & Chemical Corp. Annual Report 1971. 12 pp.

Newmont Mining Corp. Annual Report 1971. 32 pp.

Engelhard Minerals & Chemicals Corp. Annual Report 1971. 20 pp.

Standard Oil Co. of Calif. Annual Report 1971. 34 pp.

Universal Oil Products Co. Annual Report 1971. 34 pp.

8 Nevison, John A., M. H. Dalson, and John Mooi. Catalytic Reforming Advances With E-501 Catalyst. Proc. API Division of Refining, v. 50, 1970, pp. 304-323.

9 American Metal Market. International Exotic Metals Report, Sec. 2. Dec. 23, 1971, 8 pp.

Metals Week. Precious Metals-Platinum: Focus on Reforming. V. 42, No. 19, May 10, 1971, pp. 6-7.

During the year, prices paid for rhenium metal powder used in rhenium metal wire and in mill products made from rheniumrefractory metal alloys reportedly ranged from $875 to $1,600 per pound of rhenium. The prices paid for rhenium used in catalytic applications ranged from about $1,200 to $1,400 per pound.

Effective June 1, 1971, CRM, increased prices for rhenium salts and metal powder

to contract customers. The price of rhenium metal powder, in lots of 10 or more pounds, was increased to $1,400 per pound from the previous quotations of $875 to $1,200 per pound, depending upon quantity purchased. CRM's new quotation for perrhenic acid (HReO), feed material for bimetallic platinum-rhenium catalyst production, became $1,325 per pound.

Imports of unwrought rhenium metal and scrap increased 80 percent during 1971 and totaled 377 pounds, gross weight, valued at $452,842. These imports, all of which represented rhenium metal powder, came primarily from Belgium-Luxembourg (58 percent), West Germany (29 percent), and France (12 percent). There were no imports of rhenium scrap during the year. Rhenium imports from Belgium were believed to have been recovered from molybdenite associated with porphyry copper ores from Zaire. The remaining, unwrought rhenium imports were believed to have been recovered from byproduct molybdenite obtained from porphyry copper ores mined in Chile. The price of unwrought rhenium metal imports, excluding U.S. duty, averaged $1,201 per pound during the year and ranged from $397 per pound (United Kingdom) to $1,273 per pound (West Germany). Two pounds of wrought rhenium valued at $1,498, excluding U.S. duty, were imported from France during 1971.

Effective January 1, 1971, the tariff on unwrought rhenium metal was reduced to 6 percent ad valorem and the duty on

wrought rhenium was reduced to 10.5 percent ad valorem. From August 16 through December 20, 1971, a 10-percent ad valorem surcharge (Presidential Proclamation 4074) was imposed on all imports. During this period, the duty on unwrought rhenium was 16 percent ad valorem and the duty on wrought rhenium was 20.5 percent ad valorem.

As the final part of the 5-year program of tariff reductions agreed upon at the Kennedy Round Tariff Negotiations, duties on unwrought and wrought rhenium imports from non-Communist countries were further reduced. Effective January 1, 1972, the import duty on unwrought rhenium metal and scrap was reduced from 6 to 5 percent ad valorem and that for wrought rhenium from 10.5 to 9 percent ad valorem. The import duty on unwrought rhenium from Communist Bloc countries remained unchanged at 25 percent ad valorem and that on wrought rhenium remained unchanged at 45 percent ad valo

rem.

During 1971 the import duty on rhenium scrap was suspended.