World sulfur

Sources of sulfur are called voluntary if sulfur is considered to be the principal, and often the only, product. Sulfur has also been recovered as a by-product from various process operations. Such sulfur is termed involuntary sulfur and accounts for the largest portion of world sulfur production (see Sulfur REMOVAL AND RECOVERY). 

Salt-Dome Sulfur Deposits. The sulfur deposits associated with salt domes in the Gulf Coast regions of the southern United States and Mexico have historically been the primary sources of U.S. sulfur. These remain an important segment of both U.S. and world sulfur supply. Although the reserves are finite, many are large and voluntary productive capacity ensures the importance of these sources for some time to come. In 1994, the output from the salt domes in the U.S. was about 2.09 million metric tons (21). 

Pyrite is the most abundant of the metal sulfides. Eor many years, until the Erasch process was developed, pyrite was the main source of sulfur and, for much of the first half of the twentieth century, comprised over 50% of world sulfur production. Pyrite reserves are distributed throughout the world and known deposits have been mined in about 30 countries. Possibly the largest pyrite reserves in the world are located in southern Spain, Portugal, and the CIS. Large deposits are also in Canada, Cypms, Einland, Italy, Japan, Norway, South Africa, Sweden, Turkey, the United States, and Yugoslavia. However, the three main regional producers of pyrites continue to be Western Europe Eastern Europe, including the CIS and China. 

Table 2 shows the estimated aimual world sulfur production capacity in all forms. Figure 2 shows actual annual world sulfur production by type. 

Fig. 2. World sulfur production by type, where ( ) represents brimstone (Ml), SOF (B), pyrites and ( ), total sulfur (33).

Sulfur consumption reached peak levels by the beginning of the 1990s. The apparent annual consumption of sulfur in all forms in the United States nearly reached 13.2 million metric tons by 1995. World sulfur production increased steadily from 53.6 million metric tons in 1984 to an all-time high of 60.1 million metric tons in 1989, declining to 54.6 million metric tons in 1995. 

Since the 1950 s there has been a remarkable growth in sulfur production from the hydrogen sulfide of natural and refinery gases. Once a minor source of world brimstone, sour gas now makes a very significant contribution to world sulfur production. 

The intervening years to 1981 have seen several world market sulfur demand cycles which have effected the rate of acceptance of these new sulfur sources but slowly the recovered sulfur product has taken its place alongside other world sulfur sources such as Frasch mined and pyrites. In very recent times there have even been moves to re-open very sour gas wells as sulfur wells as world demand for this key commodity has grown and prices have crossed 100/tonne FOB the plant gate. 

These new developments of high H2S natural gas come at a time when the world sulfur market is particularly bouyant, sufficiently... 

World sulfur supplies are expected to grow at roughly 3.7% per year over the coming decade as compared with 2.6% per year from 1973 to 1980. Sulfur production will grow markedly in the United States, primarily due to increased recovery of sulfur from natural gas processing and petroleum refining. 

Over the six years from 1973 to 1978, sulfur production capability on a global basis increased from about 48 million long tons (sulfur equivalent) to about 55 million tons per year (2.8% per year). Since world sulfur demand has historically averaged well above 3 percent per year, the gap between demand and supply narrowed noticeably. It should not be surprising, therefore, that recently sulfur prices have begun to increase. 

Table I provides a summary of the outlook for world sulfur supply over the coming decade. This table shows the combined totals of all sources and forms of sulfur elemental and non-elemental as well as discretionary and non-discretionary, including the use of pyrites. As the bottom line in the table shows, we anticipate that world sulfur supplies will grow at a faster rate over the coming 5-10 years than they have in the recent past. Of particular interest is the considerably expanded sulfur production outlook that we forsee for the U.S. and Mexico over the coming decade, the basis for which will be discussed later in this paper.

As the table shows, we have assumed that production of sulfur in Poland would increase by 2.0-2.5 million tons per year by 1985. While there is no official word as yet that Poland will actively move forward with their long anticipated expansion, we believe that the current rise in world sulfur prices will provide adequate incentive for Poland to expand its output. Also, recent negotiations... 

WORLD SULFUR PRODUCTION, 1973-1990 (In millions of long tons of S equivalent)... 

In 1978, world sulfur demand (in all forms) totalled about 49 million long tons. This compares with U.S. sulfur demand in 1978 of about 12 million long tons. Over the coming decade, world sulfur demand is expected to increase to about 78 million long tons, with U.S. demand expanding to about 17 million long tons. Thus, by the end of the next decade, domestic sulfur uses will still account for 20-25% of world consumption. 

Table 1 provides a forecast of the United States and world sulfur supply and demand for the years 1985 and 2000. Table 1 also includes estimates of the identified recoverable world sulfur reserves using 1978 technology at 1978 sulfur prices and at all price levels. A visual representation of the importance of price in determining the availability of sulfur is provided by Figure 1. Note that this figure is based on the assumption that these quantities of sulfur will be produced only if the sulfur price levels are maintained for a sufficient period of time. 

Fig. 2.1. World sulfuric acid production, 1950-2003, in millions of tonnes of contained H2S04. The increase in production with time is notable. It is due to the increased use of phosphate and sulfate fertilizers, virtually all of which are made with sulfuric acid. Data sources ...

The first of the previous reactions is responsible for a good portion of the acid rain problem troubling the industrialized world. Sulfur, present in small quantities as an impurity in coal and oil, is converted to sulfur dioxide when the coal or oil is burned then the sulfur dioxide reacts with the moisture in the air to produce sulfurous acid. Sulfurous acid can react with the oxygen in air to produce sulfuric acid. These acids are washed from the air by rain (or snow), and the solution can cause some corrosion of concrete and metal in buildings. Acids in the air and in the rain or snow also injure trees and other plants, as well as animals, including humans. In high concentrations, acids and acid anhydrides in the air can make breathing difficult, especially for people who are already in poor health. 

In the inorganic world, sulfur would have been available in a variety of oxidation states. Even in a reduced atmosphere, transient SO would have been present from volcanic sources, supplemented by interaction between sulfur-bearing aerosols and oxidants produced by photolytic chemistry in the early UV flux, or from escape of hydrogen to space. Reduced sulfur species would have been widely available in lavas and volcanic vents. Thus, for the early organisms, shuffling sulfur between various oxidation states would have been the best way of exploiting redox ratchets. 

The United States is now the major sulfur producer, accounting for 20% of world production. The most important sources in the US are from Louisiana and Texas, and other major producers are Japan, Canada, China, Russia, and Mexico. World sulfur production (and apparent consumption) peaked at nearly 60 Mt in 1989 and declined by almost 14% to 52.8 Mt in 1993 (Figure 7). There was a partial recovery from this time and future growth is expected. 

More than 90% of world sulfur consumption is used in the production of sulfuric acid, much of which goes to the fertilizer industry. Smaller amounts of sulfur are used in the manufacture of gunpowder, matches, phosphate, insecticides, fungicides, medicines, wood, and paper products, and in vulcanizing rubber. Despite slight uncertainties in sulfur demand in the 1990s, its use is still predicted to grow. 

Figure 7 World sulfur production (source http //pubs.usgs.gov/of/of01-197/html/app5.htm).

World sulfur reserves. The earth s crust contains about 0.6% S, where it occurs as elemental S (brimstone) in deposits associated with gypsum and calcite combined S in metal sulfide ores and mineral sulfates as a contaminant in natural gas and crude oils as pyritic and organic compounds in coal and as organic compounds in tar sands (Tisdale and Nelson, 1966). The elemental form commonly occurs near active or extinct volcanoes, or in association with hot mineral spings. Estimates by Holser and Kaplan (1966) of the terrestrial reservoirs of S suggest that about 50% of crustal S is present in relatively mobile reservoirs such as sea water, evaporites, and sediments. The chief deposits of S in the form of brimstone and pyrites are in Western European countries, particularly in France, Spain, Poland, Japan, Russia, U.S.A., Canada, and Mexico. World production of S in the form of brimstone and pyrites was approximately 41 Tg in 1973 other sources accounted for about 8 Tg, making a total of 49 Tg (Anon, 1973). Byproduct S from sour-gas, fossil fuel combustion, and other sources now accounts for over 50% of S used by western countries, as shown in Fig. 9.1. This percentage may increase as pollution abatement measures increase the removal of SO2 from fossil fuel, particularly in the U.S.A. Atmospheric S, returned to the earth in rainwater, is also a very important source of S for plants. 

Manderson, M.C., 1970. World Sulfur Outlook into the Late 1970 s. Presented at American Chemical Society Annual Convention, Chicago, Illinois, September 1970. Arthur D. Little, Inc., Cambridge, MA, 14 pp. 

World sulfuric acid production has grown by a factor of 1.4-1.6 every 10 years since 1930, except for nearly doubling during the 1950-1960 period. A growth in a country s sulfuric acid production that exceeds this rate is... 

Figure 2. World sulfur dioxide emission by regions (ESCAP, 2000).

At the end of World War I, the Frasch sulfur industry in the United - States had grown to the point where it could seek a share of the world sulfur market. Until the advent of World War II, it was the source of most of the worlds sulfur and provided a dependable supply of this vital commodity for the sulfur-consuming industries. 

A sharp increase in price and decrease in availability of sulfur reduced the experimental effort temporarily, but laboratory work based on the above findings continued. Pourable paving mixes were developed containing one-sized sands which could be cast in place without rolling, much as portland cement concrete is handled. Based on satisfactory laboratory findings, a test road was constructed in Richmond, British Columbia in 1970, where a sand—asphalt—sulfur mix was cast between forms (5). The success of this trial, coupled with a decrease in the price of sulfur and the forecast for a long-term world sulfur surplus, led us to initiate an extensive research and development program to exploit sand-asphalt-sulfur mixes as road base and surface materials. 

Fig. 1.2 World sulfuric acid supply totaled 200 million tonnes in 2006 of which smelter acid accounted for 26% of total production...

The output of sulfuric acid at base metal smelters today represents about 26% (Fig. 1.2) of all acid production. Whereas in 1991 smelter acid production amounted to 27.98 millions tonnes, it is calcnlated that the output in the following decade will have grown to reach 44.97 millions tonnes in 2001. Smelter acid will be more than 25% of world sulfuric acid production compared to some 18% in 1991. 

Directory of world sulfur and sulfuric acid plants and their locations... 

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