Frasch process


The Frasch process is a method to extract sulfur from underground deposits by taking advantage of the low melting point of sulfur. It is the only industrial method of recovering sulfur from elemental deposits. Most of the world's sulfur was obtained this way until the late 20th century, when sulfur recovered from petroleum and gas sources became more commonplace.
In the Frasch process, superheated water is pumped into the sulfur deposit; the sulfur melts and is extracted. The Frasch process is able to produce high-purity sulfur of about 99.5%.

History

In 1867, miners discovered sulfur in the caprock of a salt dome in Calcasieu Parish, Louisiana, but it was beneath quicksand, which prevented mining. In 1894 the German-born American chemist, Herman Frasch, devised his Frasch method of sulfur removal using pipes to bypass the quicksand. This replaced the inefficient and polluting Sicilian method. The process proved successful, on December 24, 1894, when the first molten sulfur was brought to the surface. The Union Sulphur Company was incorporated in 1896 to utilize the process. However, the high cost of fuel needed to heat the water made the process uneconomic until the 1901 discovery of the Spindletop oil field in Texas provided cheap fuel oil to the region. The Frasch process began economic production at Sulphur Mines, Louisiana in 1903.
When Frasch's patent expired, the process was widely applied to similar salt-dome sulfur deposits along the Gulf Coast of the United States. The second Frasch-process mine opened in 1912 in Brazoria County, Texas. The Gulf Coast came to dominate world sulfur production in the early and middle 20th century. However, starting in the 1970s, byproduct sulfur recovery from oil and natural gas lowered the price of sulfur and drove many Frasch-process mines out of business. The last United States Frasch sulfur mine closed in 2000. A Frasch mine in Iraq closed in 2003 due to the U.S. invasion of Iraq.
The Frasch process is still used to work sulfur deposits in Mexico, Ukraine and Poland.

Process

The Frasch sulfur process works best on either salt domes or bedded evaporite deposits, where sulfur is found in permeable rock layers trapped in between impermeable layers. Bacterial alteration of anhydrite or gypsum, in the presence of hydrocarbons, produces limestone and hydrogen sulfide in the sulfur cycle. The hydrogen sulfide then oxidizes into sulfur, from percolating water, or through the action of anaerobic, sulfur-reducing bacteria
In the Frasch process, three concentric tubes are introduced into the sulfur deposit. Superheated water is injected into the deposit via the outermost tube. Sulfur melts and flows into the middle tube. Water pressure alone is unable to force the sulfur into the surface due to the molten sulfur's greater density, so hot air is introduced via the innermost tube to froth the sulfur, making it less dense, and pushing it to the surface.
The sulfur obtained can be very pure. In this form, it is light yellow in color. If contaminated by organic compounds, it can be dark-colored; further purification is not economic, and usually unnecessary. Using this method, the United States produced 3.89 million tons of sulfur in 1989, and Mexico produced 1.02 million tons of sulfur in 1991.
The Frasch process can be used for deposits 50–800 meters deep. 3-38 cubic meters of superheated water are required to produce every tonne of sulfur, and the associated energy cost is significant. A working demonstration model of the Frasch process suitable for the classroom has been described.

Economic impact

YearUnited StatesItalyJapanChileSpainTotal
19003,147535,52514,2111,661738555,282
19016,867554,20316,2872,037600597,994
19027,446530,91317,9962,594443559,394
190335,097545,00522,5133,5041,653607,772
190485,000519,23125,1653,538595633,529
1905220,000559,94224,2643,417600808,223
1906295,123491,92027,8854,525689820,142
1907188,878420,22932,8032,8593,555648,324
1908364,444438,27932,8912,6622,941841,217
1909273,983428,18936,3174,4373,375746,301
1910247,060423,56343,1543,7623,773721,312
1911205,066407,62049,4814,3806,476673,023
1912787,735383,30053,6924,3614,5191,233,607
1913491,080380,20958,5096,5427,381943,721
1914417,690371,87572,9449,8507,933880,292
1915520,582352,45171,0669,6159,517963,231
1916649,683265,120104,70714,64410,4611,044,515
19171,134,412208,501116,22417,78712,6811,489,605
19181,353,525230,59663,74819,24812,5371,679,654
19191,190,575222,55549,83118,61111,2631,492,835
19201,255,249259,44038,97513,12912,2001,578,993
19211,879,150269,54736,0139,5175,1702,199,397
19221,830,942154,69634,09512,05713,0282,054,818
19232,036,097252,29336,82511,2008,3822,344,797
19241,220,561290,24146,1339,6119,3881,575,934
19251,409,262259,42846,9628,9297,8591,732,440
19261,890,027267,10747,0208,7879,3512,222,292
19272,111,618300,88860,37112,30310,0652,495,245
19281,981,873291,43068,95615,42310,1992,367,881
19292,362,389323,00058,71816,00010,0002,770,107

List of Mines

DomeStateCompanyFromUntilTotal long tons

Sulphur MineLaUnionDec 27, 1894Dec 23, 19249,412,165-
Bryan MoundTxFreeportNov 12, 1912Sep 30, 19355,001,068
Big HillTxTexas GulfMar 19, 1919Aug 10, 193612,349,597-
Hoskins MoundTxFreeportMar 31, 1923May 26, 195510,895,090
Big CreekTxUnionMar 6, 1925Feb 24, 19261,450-
PalanganaTxDuvalOct 27, 1928Mar 10, 1935236,662-
BolingTxUnionNov 14, 1928Aug 30, 19299,164-
BolingTxTexas GulfMar 19, 1929>61,118,065-
Long PointTxTexas GulfMar 19, 1930Oct 19, 1938402,105-
Lake PeigneurLaJefferson LakeOct 20, 1932Jun 7, 1936430,811
Grand EcailleLaFreeportDec 8, 1933>30,885,243
BolingTxDuvalMar 23, 1935Apr 25, 1940571,123-
BolingTxBaker-WilliamsJun 2, 1935Dec 18, 19351,435-
ClemensTxJefferson LakeMay 3, 1937Dec 14, 19602,975,828-
OrchardTxDuval1938---
OrchardTxJefferson LakeJun 7, 1946>4,551,472-
Moss BluffTxTexas GulfJun 24, 1948>5,081,343-
Starks DomeLaJefferson LakeJun 15, 1951Dec 13, 1960840,249-
Spindletop MineTxTexas LakeMay 12, 1952>6,310,721-
Bay Ste. ElaineLaFreeportNov 19, 1952Dec 29, 19591,131,204
DamonTxStandard SulphurNov 11, 1953Apr 20, 1957139,618-
Garden Island BayLaFreeportNov 19, 19531991>7,006,991
NashTxFreeportFeb 3, 1954Nov 23, 1956153,115
ChacahoulaLaFreeportFeb 25, 1955Sep 28, 19621,199,015
FannettTxTexas GulfMay 6, 1958>1,773,737-
High IslandTxUnited StatesMar 25, 1960Feb 8, 196236,708-
Grand IsleLaFreeportApr 17, 19601991>4,466,021
Lake PeltoLaFreeportNov 26, 1960>2,474,693
Big HillTxTexas GulfOct 8, 1965>107,830-
Sulphur MineLaAllied ChemicalSep 18, 1966>1,447-
NashTxPhelan SulphurNov 7, 1966>622-

Mexico

In 1955 Mexico became the world's second largest producer of sulfur behind the United States.