1Overview and Introduction to Industrial Inorganic Processes Overview and Introduction to Industrial Inorganic Processes
The common lore in the 21st century is that in Ancient Greece, the philosophers of the day believed that all materials in the world were made from the four elements: earth, water, air, and fire. Materials such as wood were explained as being a mixture of some amount of probably earth, water, air, and possibly even fire (that had not yet been released). Perhaps ironically, even in the chemically complex world in which we live today, all our materials can be traced back to sources that come from the earth, the water, and the air â and many of them are transformed with fire of some sort.
It is always difficult to delineate the sources of what get called the major chemicals because it is difficult to determine what constitutes âmajorâ, and because there are sometimes multiple sources for the same material. For example, the amount of iron produced annually on a national and a global scale is tracked by several organizations such as the United Nations and the United States Geological Survey (USGS), and is usually recorded in thousands of metric tons [1,2]. Another metal, gold, is also tracked by organizations including the USGS and the World Gold Council, but is measured in tons, and is priced in ounces [2, 3]. As far as materials that are derived from different sources, sulfur can be extracted from in-ground deposits through what is called the Frasch process, but it is also recovered from oil-refining operations. In both cases, the sulfur is used for the same end product â sulfuric acid [4].
Materials that are mined
Numerous materials that are used in some chemical process or another, or that ultimately are formed into some end-user product, are mined. The term mining often implies certain processes, such as the removal of a hilltop and creation of a large pit, or digging a deep shaft into the earth to extract some metal or ore. But mining can also include inserting pipes into the ground and using hot solutions or pressurized liquids or gases to extract a material from the ground. This book contains examples of materials that are obtained through all of these methods.
Materials from water
Numerous reactions must be run in water, but in several other cases, large-scale chemistry is performed that uses water as one of the reactants. The production of sulfuric acid, as well as of three other large commodity chemicals: sodium hydroxide, elemental chlorine, and elemental hydrogen â known as the chlor-alkali process â are examples of such processes.
Inorganics extracted from organic sources
Perhaps the most difficult processes to categorize neatly are those in which some inorganic material is produced from an organic one, or in which some inorganic product depends upon an organic one for its production. The large-scale production of sul- furic acid can have an organic source of sulfur. The large-scale production of carbon black represents another material that is generally defined as inorganic that requires an organic feedstock.
Materials from air
Even many chemists and chemical engineers do not often think of air as a starting material for chemical transformations and chemical production. Yet air provides oxygen and nitrogen, as well as carbon dioxide and argon, all of which can be involved in further chemical reactions. Air liquefaction plants provide vital starting materials for processes that make sulfuric acid, ammonia, and nitric acid, to name just a few of the larger processes.
List of producers by country
The USGS claims in their annual Mineral Commodity Survey that the economic health of a nation can be measured by its production of sulfuric acid [2]. In this book, we mention and examine the geographic sources for all the materials in the different chapters. While some materials are wide spread across the planet, others are much more localized. These localized source materials are never used to determine the economic health of a nation. But an economically weak nation cannot generally afford to extract, refine, and produce such commodities.
This book discusses the major inorganic chemicals that are used in industry, and also tries to discuss the possibilities for recycling and re-use of these materials. In every case, time, energy, and money are required to produce these commodity chemicals and materials. This is because it is often more economically sound to re-use or in some way recycle a material when the item in which it is used reaches the end of its usable life span.
Bibliography
[1] | United Nations, UN ComTrade. Website. (Accessed 17 November 2014, as: http://comtrade.un.org/db/mr/rfCommoditiesList.aspx?px=H2&cc=28). |
[2] | United States Geological Survey. Website. (Accessed 17 November 2014, as: http://www.usgs.gov/pubprod/). |
[3] | World Gold Council. Website. (Accessed 17 November 2014, as: http://www.gold.org). |
[4] | Sulfuric Acid Today. Website. (Accessed 17 November 2014, as: http://www.h2so4today.com/). |
[5] | United States Environmental Protection Agency. Website. (Accessed 17 November 2014, as: http://www.epa.gov/). |
2Sulfuric Acid Production, Uses, Derivatives
2.1Introduction
The production of sulfuric acid does not come readily to mind when a person thinks of a chemical or material that they use on a daily basis. Yet this material has many uses, either in the production of other bulk chemicals, or ultimately in the production of some user end products.
The production of sulfuric acid has been linked to the economic health of a developed nation. The United States Geological Survey (USGS) annual Mineral Commodity Summaries [1] does not specifically track sulfuric acid, only because it must be made from another material, namely sulfur. The Mineral Commodity Summaries 2013 does track sulfur production, and comments that in the recent past, âelemental sulfur and byproduct sulfuric acid were produced at 109 operations in 26 States and the U.S. Virgin Islands.â [1] Clearly, the production of sulfur and sulfuric acid is a large, widespread operation. Such a statement also implies that sulfuric acid production is the major use of elemental sulfur.
2.2Sulfur sourcing
For the last century, sulfur has been mined from underground deposits via what is called the Frasch process. This involves inserting three concentric tubes into the ground and into the sulfur deposit, blowing superheated water into the deposit through the outermost tube, blowing hot air into the central tube, and thus forcing out the water-sulfur mixture. The air needs to be blown into the mix because the sulfur-water mixture is denser than water, and it will not rise without this increased pressure. This is shown in Figure 2.1.
Sulfur is also obtained as a by-product of metal refining from sulfide ores. The roasting of ores had, in the past, released large amounts of sulfur oxides, but with increasing environmental awareness that these gases can be major sources of pollution, they have been captured and used.
In recent years, increasing amounts of sulfur are obtained in the form of hydrogen sulfide from refining the lightest fractions of crude oil. In what is called the Claus process, this is converted to sulfur, which is then used to produce sulfuric acid. Scheme 2.1 shows the reaction chemistry for the production of sulfur via this method in a simplified form.
Feed gases generally need at least 25% H2S for this recovery to be economically feasible. Also, the reaction must be run at approximately 850 °C, which means that ...