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Bureau of Mines / Minerals yearbook: Metals and minerals 1977
Year 1977, Volume 1 (1977)

Absalom, Sandra T.
Boron,   pp. 191-200 PDF (1.2 MB)


Page 192

192 MINERALS YEARBOOK, 1977 
provided the balance. Boric acid sold or used by U.S. producers increased
to 158,500 short tons valued at $42.4 million, compared with 130,000 tons
valued at $30.5 million in 1976. 
 At Boron, in Kern County, the open pit tincal-kernite mine and adjacent
refining plant of U.S. Borax and Chemical Corp., a member of the RTZ Group
of London, England, continued to be the primary world supplier of sodium
borates. U.S. Borax mined daily as much as 12,000 tons of ore, from which
it processed at the Boron refinery crude and refined hydrated sodium borates
and their anhydrous derivatives, and anhydrous boric acid. At a plant located
at Wilmington, Calif., U.S. Borax produced boric acid and a variety of specialty
chemicals. Toward yearend 1977, the company began production of a boric acid-sodium
sulfate chemical in the temporarily idle anhydrous boric acid plant at Boron.
This product was produced for the cellulosic insulation industry. Future
production will depend upon continued strong demand for flame-retardant chemicals
in cellulose. 
 During the year, the U.S. Borax project to expand productive capacity for
sodium berates was redirected to the proposed construction of a new boric
acid facility at Boron. Due for completion in 1980, the $74 million facility
will have double the capacity of the existing Wilmington plant, which eventually
will phase out production of technical-grade boric acid. 
 Despite the redirection of its expansion program, U.S. Borax increased output
and sales of all primary borate products in 1977. Output of refined decahydrate,
pentahydrate, and anhydrous borax increased 41% and accounted for over one-half
of the company's total sales. Production and sales of crude sodium borates,
Rasorite 46 (a pentahydrate) and its anhydrous derivative, for foreign markets
increased 2% over the 1976 figure. In the past, the crude products represented
almost one-half of U.S. Borax's output and sales; however, the substantial
increase in refined sodium borate products in 1977 had the effect of reducing
this proportion to slightly more than one-third. 
 The previously planned 25% expansion of boric acid capacity at Wilmington
was achieved in 1977 despite engineering problems in the 50-year-old plant,
which is also used for the manufacture of borate soap products, herbicides,
and other high-quality specialty chemicals. In addition, the Wilmington facilities
served as a warehouse 
and overseas shipping point for bulk shipments. A large percentage of U.S.
Borax's exports were shipped to Europe via the warehouse and distribution
facility at Botlek, Rotterdam, Netherlands. RTZ Borax, Ltd., another member
of the RTZ Group, maintains this facility. 
 U.S. Borax operated a plant and warehousing facility at Burlington, Iowa,
for compounding, packaging, and distributing household soaps and other consumer
products to the Eastern and Midwestern United States. The combined capacity
of U.S. Borax operations in 1977 exceeded 600,000 short tons of boric oxide
(B203) equivalent (about 187,000 tons of contained boron). 
 Kerr-McGee Corp. operated the Trona and Westend plants at Searles Lake,
San Bernardino County to produce sodium berates and boric acid from the mineral-rich
lake brines. Coproducts included potassium compounds, lithium carbonate,
soda ash, and salt cake. Combined capacities of the two plants normally approach
130,000 tons of B203 equivalent per year; however, in response to the expansive
market for boric acid during 1977, Kerr-McGee adjusted its products ratio,
effectively increasing output of boric acid by 26% while decreasing output
of refined sodium borates by 18%. As a result, total output and sales were
8% below the 1976 level. Kerr-McGee's marketable supply of borax pentahydrate,
which is used to produce boric acid, was most affected by the adjustment;
output and sales of this compound decreased 65%. 
 At the Trona plant, Kerr-McGee utilized its differential evaporative process,
with annual capacity of 100,000 equivalent tons of B2O3, to produce pentahydrate,
decahydrate, and anhydrous borax, and boric acid. Solvent-extraction capacity
to produce additional boric acid from weak lake brines and recycled plant
liquors was expanded during the year. Production of borates by the carbonation
process at the Westend plant was formerly limited to 25,000 tons of B203
capacity in the form of sodium borates, but during the latter part of 1977
equipment for boric acid production was installed. KerrMcGee predicted that
overall capacity for boric acid at both plants would soon double that of
1976, contingent upon continued growth of the market. 
 American Borate Corp., the third U.S. producer, increased sales of colemanite
(calcium borate) and ulexite-probertite (two similar sodium-calcium borates
mined and 


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