YEAR 12 CHEMISTRY RESEARCH TASK - CHEMICAL EQUILIBRIUM in INDUSTRY - THE CONTACT PROCESS

HISTORY OF THE CONTACT PROCESS
The contact process is the modern industrial method of producing sulphuric acid in large quantities, over the year many processes have come and gone but one has been efficient and that is the contact process.
Although sulphuric acid is now one of the most widely used chemicals, it was probably little known before the 16th Century. It was first prepared by Johann Van Helmont (c.1600) by destructive distillation of green vitriol or ferrous sulphur. The first every major industrial demand for sulphuric acid was the Leblanc process for making sodium carbonate (c. 1790). This was an expensive process hence the need for a much improved and cheaper process. Then a man named Johann Glauber used a process of burning sulphur with potassium nitrate, this was done in the 17th century and was developed commercially by Joshua Ward in England (c.1740). This process was then superseded by the lead chamber process.
The lead-chamber process was first used by John Roebuck in 1746 in Birmingham, England, where he began producing sulphuric acid in lead-lined chambers, which were stronger, less expensive, and could be made much larger than the glass containers that had been used in previous methods of making sulphuric acid. This method became the standard method of production of sulphuric acid for almost two centuries that is until the Contact process came into play.
The Contact process was first patented in 1831 by a British vinegar merchant who went by the name Peregrine Philips. The contact process was a much more improved process than previous methods because in addition to it being a much better economical process for producing concentrated sulphuric acid in large quantities, the contact process also produces sulphur trioxide and oleum, both of which are quite useful products in today’s society.
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USES OF THE PRODUCT
Sulphuric acid is one of the most important industry chemicals to date and more of it is made each year than is made of any other manufactured chemicals. Annually more than 170 million tons of sulphuric acid is produced and about 30% of this production comes from the U.S. It has many varied uses and also plays a part in the production of nearly all manufactured goods.
One of the major uses of sulphuric acid is in the production of fertilisers such as ammonia sulphate, (NH4)2SO4, and superphosphate, Ca(H2PO4)2. Sulphuric acid is also used in the manufacturing of hydrochloric acid, nitric acid, phosphoric acid, ether, plastics, metal sulphates, cellophane, dyes, drugs, perfumes, disinfectants and even glue. It is also used to manufacture nitro-glycerine acid and tri-nitro-toluene (TNT) in the explosive industry. Sulphuric acid is also used as an electrolyte in lead acid batteries in our vehicles and sulphuric acid also helps in the removal of oxides from iron and steel before electroplating or galvanising.
So as you can see sulphuric acid is a very important chemical as it is used in the production and manufacturing of many different things we use today.



ENVIRONMENTAL IMPACT
The process of creating sulphuric acid doesn’t really have any impact on the environment due to the fact that it is produced in a purification unit, but sulphuric acid still exists as particles or droplets in the air if released into the atmosphere, which it is through the use of its many uses. It dissolves when it is mixed with water and has both a moderate acute (short-term) toxicity on aquatic life and a moderate chronic (long-term) toxicity to aquatic life. Sulphuric acid is very corrosive and would badly burn many organisms in the environment like plants, birds or land animals that get exposed to the acid. Small quantities of sulphuric acid will be neutralised by natural alkalinity in aquatic systems , while larger quantities may lower the pH for an extended duration.
How does sulphuric acid enter our environments? Well industrial emissions of sulphuric acid can produce increased concentrations of the acid in the atmosphere, and exists as particles or droplets which may dissolve in clouds, fog, rain, dew or now, which results in very dilute acid solutions. When sulphuric acid is present in clouds and moist air it travels along the air currents until it is deposited as wet acid deposition (acid rain, etc.). In waterways the acid mixes with the water, which causes pollution and can seriously affect an environment and its organisms.
Sulphuric acid can enter the air during its production, use and its transport. When in the air it will react with other chemicals present in the air, like ammonia, magnesium and calcium, to form salts, which neutralise the acid. The acid dissolves hence resulting in and impact on the environment as wet acid deposition or ‘acid rain’.
As you read in the history of the contact process, there were many different processes of creating sulphuric acid before the discovery of the contact process, these previous processes would cause more damage than the contact process because of the method of the other processes and because of an enhancement of technology which helps us to minimise the impact it has on the environment.



CARTOON
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LINK TO A VIDEO FOR THE CONTACT PROCESS
http://www.youtube.com/watch?v=Bu3ns9Ii80M

SOURCES
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Aus-e-TUTE. (2012). Sulfuric acid: production, properties and uses. [Online]. Available:
http://www.ausetute.com.au/sulfacid.html
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Pearson Education. (2000-2012). Sulfuric acid. [Online]. Available:
http://www.factmonster.com/ce6/sci/A0847159.html
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Wikia. (Date Unknown). Contact Process. [Online]. Available:
http://gcse.wikia.com/wiki/Contact_Process
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Slideshare Inc. (2012). Contact process. [Online]. Available:
http://www.slideshare.net/rchoong/chapter-9-contact-process-haber-process-and-alloy
[April 05, 2012]

Nature Publishing Group. (2012). Peregrine Phillips. [Online]. Available:
http://www.nature.com/nature/journal/v117/n2942/abs/117419a0.html
[April 05, 2012]

TutorVista. (2010). Manufacture of Sulfuric Acid by the Contact Process. [Online]. Available:
http://www.youtube.com/watch?v=Bu3ns9Ii80M
[April 05, 2012].

Yahoo. (2012). Does the manufacture of sulfuric acid affect the environment?. [Online]. Available:
http://au.answers.yahoo.com/question/index?qid=20100518042734AAmZw75
[April 05, 2012].