Corrosion Studies in High-Temperature, Hypersaline Geothermal Brines Available to Purchase

One of the largest identified liquid-dominated geothermal resources provinces in the United States is in the Imperial Valley of California, where several distinct known geothermal resource areas (KGRA's) occur that contain substantial quantities of recoverable minerals. The Salton Sea KGRA contains brines that are very high in mineral content as well as being among the most corrosive naturally occurring fluids known. The Bureau of Mines research and development investigations are conducted to determine the optimum materials of construction for domestic geothermal resources recovery operations. These investigations include both laboratory and field research and testing to assess the corrosion and scaling problems encountered in the highly mineralized high-enthalpy brines of the Salton Sea KGRA. The laboratory studies have included screening tests⁽¹⁾ to narrow the list of potentially useful commercially available metals and alloys; detailed corrosion studies of the selected metals and alloys, including general, crevice, pitting, weld, and stress corrosion; and studies of the effect of the major gas constituents found in the hypersaline brines. The field tests conducted in the Imperial Valley use the brines from two geothermal wells (Magmamax #1 and Woolsey #1). These tests have been directed toward studying in situ corrosion and scaling processes in relation to⁽¹⁾ commercially available metals and alloys and⁽²⁾ the chemistry and physics of flowing geothermal brines. A geothermal testing facility situated on a Salton Sea KGRA test site provided several typical environments expected to be found in most geothermal resources recovery operations^{(2, 3)}.