Offshore Sulphur Production

INTRODUCTION Sulphur is an abundant element that has been used by man since ancient times and is today a key basic raw material for the modem chemical industry. The invention of the Frasch hot water mining process in the late 1800's gave the United States a plentiful low cost supply of pure sulphur. The Frasch process makes possible the mining of sulphur from the limestone caprock of offshore salt domes. The latest of these mines is the Main Pass Mine located on Main Pass Block 299 approximately 36 miles east of Venice, Louisiana. BRIEF HISTORY OF SULPHUR Sulphur, in the form of sulphides, sulphates, and elemental sulphur, is one of the more abundant elements in the makeup of this planet, ranking eighteenth behind chlorine. The sulphides are among the most common minerals pyrites, galena or lead sulphide, zinc sulphide, and cinnabar or mercury sulphide. Vast beds of gypsum or calcium sulphate are found all over the world, and barite or barium sulphate is widely mined is several countries. Sulphur also occurs in elemental form imbedded in limestone caprock over salt domes, in craters of volcanoes, and encrusting the edges of hot sulphur springs. In addition to the sulphur in caprock limestone, it also occurs in strata bound layers of limestone such as the deposits in West Texas, Poland, Iraq, the Ukraine, the Sinai, and Sicily. This bright yellow substance that burned with an odd sputtering blue flame, and giving off evil, choking fumes was one of the first elements used by man. Early priests and witch doctors burned sulphur to drive away bad spirits. Later man learned that sulphur fumes would kill insects and take the color out of fur, feathers, and wool. In the ODYSSEY Homer mentions the use of burning sulphur to cure ills and to avert pests. The primary use of sulphur for the past 250 years has been in the production of sulphuric and sulphurous acid. The first production of sulphuric acid in America took place at Philadelphia in 1793 where John Harrison produced 45,000 pounds by burning sulphur in a lead lined box and collecting the fumes in water. The modem chemical industry was born in 1823 when a soda alkali plant using the Leblanc process was built at Liverpool, England. This process starts with the decomposition of common salt by sulphuric acid. The start of the soda alkali industry thereby established a strong demand for the sulphur to produce the required sr, dphuric acid. The bulk of today's sulphur production is used by the fertilizer industry to produce sulphuric acid which is reacted with phosphate rock to produce phosphoric acid, the source of the phosphates in fertilizer. Sulphur consumption has, for many years, been recognized throughout the world as an index of a country's industrial development and the extent to which its industrial capacity is utilized. About one hundred years ago, Herman Frasch provided momentum to industrial expansion by developing the Frasch process for mining sulphur horn the salt dome deposits along the Gulf Coast.