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Gold chemistry presentation


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By Alex, Aaron, Prakhash and Samuel

Published in: Education, Technology, Business
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Gold chemistry presentation

  1. 1. By Samuel, Prakhash, Aaron, Alex
  2. 3. <ul><li>Mining originally in the 1800 during the gold rush </li></ul><ul><li>Scientists now use soil sampling to find gold. </li></ul><ul><li>LODE deposits (when there is lots of gold in a rock and the gold is visible. </li></ul><ul><li>Drill a hole and fill with explosives and block with a top layer of ground. </li></ul><ul><li>If underground they then make shafts and use a process when they make stopes these extend form the top of the ore block to the bottom. They then insert explosives that when detonated cause the ore to fall to the bottom of the stope and then hauled. </li></ul>
  3. 4. <ul><li>PANNING </li></ul><ul><li>Accumulation of gold at the bottom of the sea bed or in sand. </li></ul><ul><li>The sand is scooped up and water is added </li></ul><ul><li>The gold, as it is very dense, sinks to the bottom and is siphoned off. </li></ul>
  4. 5. <ul><li>The ore is broken down into large chunks </li></ul><ul><li>The rock is then broken into smaller pieces </li></ul><ul><li>Large machines known as crushers crush the rock into pieces no bigger than road gravel. </li></ul><ul><li>The material enters rotating drums with steel balls that abrade the gold into a fine slurry or powder. The balls are steel so they don’t abrade each other. </li></ul><ul><li>Water is added into the powder to form a pulp. </li></ul><ul><li>This is run through a series of leeching tanks which dissolve the gold out of the ore using a chemical solvent. </li></ul><ul><li>The most common solvent used in cyanide which must be combined with oxygen in the process </li></ul><ul><li>This is known as carbon impulp. </li></ul><ul><li>As the cyanide and oxygen reacts, gold in the pulp dissolves. </li></ul><ul><li>Then the workers put in small carbon grains that stick to the gold </li></ul><ul><li>This is filtered out </li></ul><ul><li>The carbon moves into a stripping vessel where a hot corroding solution separates the gold from the carbon </li></ul>
  5. 6. <ul><li>The final stage of gold production – refining, which is where you remove the impurities after the smelting process. Workers add borax and soda ash to the molten metal, which separates the pure gold from other precious and less precious metals. Pure Gold is too soft for most practical applications so workers create an alloy. Scientists often use colouring to show which gold is an alloy and what the gold was combined with for example white gold is a combination of nickel silver or palladium. Karatage refers to how much gold is in the alloy. 24 karat is 100% gold whilst 12 karat has exactly half as much. </li></ul><ul><li>What are its importance’s: Gold is important to modern day life as it is used for currency. This is because gold is not very abundant and can be easily turned into objects such as coins however we no longer trade in gold coins anymore instead any amount of money we have represents an amount of gold in the world gold council. The world gold council only has 20% of all the gold available whilst the rest is either used as jewellery or in other industries. </li></ul>
  6. 7. <ul><li>Dentists use gold for crowns, and certain medicines, such as sodium aurichloride for rheumatoid arthritis, which also contains gold. </li></ul><ul><li>It can be used as Jewellery. </li></ul><ul><li>It can be used as a form of money due to its value and non-magnetically attracted properties(or else robbers or pick-pockets will have an easy time stealing money made of gold it were magnetically attracted with just a magnet). </li></ul>
  7. 8. <ul><li>Characteristics : Gold is malleable and ductile (able to be drawn out) but it is also hard depending on which alloy of gold it is. Gold is a good conductor of electricity and heat and reflects infrared. Gold does not corrode and though air or moisture which is another reason why it is used in coins and jewellery. </li></ul>
  8. 9. <ul><li>Food and beverage : Small amounts of gold sometimes brighten foods such as jelly or liqueurs, like Goldschläger. </li></ul><ul><li>Chemicals : Gold can catalyze, or speed up, certain chemical reactions more efficiently than other toxic catalysts. </li></ul><ul><li>Environment : Gold can play a role in reducing pollution. For example, scientists have recently discovered that gold particles energized by the sun can destroy volatile organic chemicals. </li></ul>