Acids

Nitric Acid

  • Explosive and corrosive, yet widely used.
  • Polishes if controlled, dissolves if unleashed.
  • Causes burns on skin contact.
  • US manufactures ~100,000,000 tons annually.
  • Used in plastics, films, textiles, and fertilizers.
  • US produces 8,000,000 tons of nitric acid per year.
  • Primary catalyst in 3,000,000 tons of explosives detonated annually in North America.
  • Used in ammonium nitrate fuel oil (ANFO).
  • Nitric acid is a powerful oxidizing acid.
  • Nitric acid reacts with substances like glycerin to form nitroglycerin.
  • During detonation, nitrate molecules steal electrons, causing rapid decomposition.
  • ANFO is used in civil construction.
  • RDX is utilized for military explosives; it has over twice the explosive velocity of ANFO.
  • Holston Army Ammunition Plant is the largest supplier of high-performance explosives.
  • Concentrated nitric acid is 98% nitric acid with a small amount of water.
  • Nitric acid is mixed with hexamine and other chemicals to synthesize RDX.
  • Mixed at 150°F and 140 RPM.
  • The chemical cocktail crystallizes into RDX in 40 minutes.
  • Mixing RDX with molten TNT produces Composition B-4 for minefield detonation.
  • Exits pellet pot at 226°F and travels through cold water to solidify.
  • Holston also produces C-4, a general-purpose explosive.
  • Demonstration: 70 grams of C-4 on a 1/4" steel plate leaves an imprint.
  • US makes 2,500,000 tons of ammonium nitrate fertilizer annually.
  • Ammonium nitrate can be used as an oxidizer for explosives when mixed with fuel.
  • Texas City Disaster (1947): A freighter packed with ammonium nitrate exploded, killing 581 and injuring 5,000.

Sulfuric Acid

  • Roughly 40,000,000 tons produced annually, making it the leading chemical manufactured in the US.
  • A country's productivity is measured by the tons of sulfuric acid produced each year.
  • Classified as a strong acid due to the high concentration of hydrogen ions.
  • The pH scale measures acid strength: water is 7 (neutral), >7 is a base, and <7 is an acid.
  • Each number less than neutral contains 10 times the hydrogen ions of the next greater number.
  • Concentrated sulfuric acid has a pH of 1.
  • Saliva has a pH of 6.
  • Concentrated sulfuric acid is 100,000 times more acidic than saliva.
  • Adding water to acid generates heat.
  • Sulfuric acid is highly corrosive to metals, including aluminum.
  • Sulfuric acid is a powerful dehydrator.
  • It draws moisture out of substances, such as sugar, leaving only carbon.
  • Mosaic Company produces 35,000 tons of sulfuric acid a day.
  • Sulfur is heated to ~270°F.
  • Sprayed through a sulfur gun into a furnace.
  • At 2,055°F, sulfur combusts with oxygen to form sulfur dioxide gas.
  • Sulfur dioxide travels to a converter and combined with oxygen; it passes through a catalyst and converts to sulfur trioxide.
  • Sulfur trioxide combined with water in an absorption tower creates additional sulfuric acid.
  • 40,000 gallons of cold water are circulated per minute to cool the tower.
  • Operators discharge sulfuric acid into trucks to make fertilizer.
  • At 98.5% concentration, sulfuric acid is powerless against stainless steel.
  • Onions emit a gas that reacts with moisture in the eyes, forming sulfuric acid.

Acid and Dissolving Bodies

  • Experiment with 37% hydrochloric acid, hotdog, and chicken bone.
  • After 6 hours, the bone is floppy and the hot dog has fallen to pieces.
  • After 9 hours, the hot dog is gone and the bone is in bad shape.
  • After 9 hours in hydrochloric acid, your body is completely disintegrated.

Gelatin Production

  • Eastman Gelatin Corporation has been making gelatin for nearly a century.
  • Bones are the starting material.
  • Each railcar contains ~200,000 pounds of bone.
  • Each bin holds ~500,000 pounds of bone, leftovers from ~41,000 head of cattle.
  • Vats are filled with 33,000 pounds of bone chips.
  • Hydrochloric acid removes minerals from the bone, leaving protein (collagen).
  • A stick test determines bone readiness.
  • Bone is transferred to a lime bath to break down collagen proteins.
  • The bone is then washed and pumped into an extraction bag for gelatin removal.
  • Gelatin extracted in hot water and pumped through an extruder looking like wet spaghetti.
  • Then cooked until bone dry, cut into granules, boxed, and shipped.
  • Used in film emulsions, pharmaceuticals, golf balls, and foods.

Acids in Food

  • Oranges (citric acid): pH ~3.8
  • Ginger Ale (citric acid): pH ~3
  • Cola (phosphoric acid): pH ~2.6
  • Red Wine Vinegar: most acidic.
  • Americans consume > 6,000,000 tons of vinegar a year.

Vinegar Production

  • Heinz plant in Holland, Michigan.
  • Grain-source alcohol (95%) shipped in 30,000-gallon railcars.
  • Alcohol is added to water in 18,000-gallon mash tanks to produce a 13.5% concentration.
  • Nutrients are added to the mash to promote Acetobacter growth.
  • Acetobacter oxidizes alcohol to acetic acid.
  • The mash solution is pumped to an acetator, where oxygen is added.
  • Propeller spins at 3,600 RPMs to disperse oxygen.
  • After 18-22 hours, the 13.5% alcohol is converted into 13.5% acetic acid.
  • Diluted to 5% acetic acid for household vinegar.
  • Vinegar is a prized food preservative.

Acids' Destructive Applications

  • Romans mixed acetic acid in lead pots (sugar of lead) causing lead poisoning.
  • Electropolishing uses strong acid and electricity to take stains out of steel.
  • Passivation - removing impurities making stainless steel clean.

Electropolishing

  • Dustin Kalina owns Albright Electropolishing.
  • Electropolishing gives an essential tool for any industry that demands sterilization, even the tattoo industry.
  • Ninja tree for racking tattoo tips.
  • Diox cleaner tank removes organics from the part, oils, grease, weld discoloration.
  • Electropolishing baths with a mixture of sulfuric and phosphoric acid.
  • Two copper bars are immersed at opposite ends of the acid tank.
  • A 20-volt DC current passes through the acid.
  • An ionic charge etches the metal, exposing chromium, forming chromium oxide.
  • Albright recycles acid using Profix to separate metal salts.

Recycling Precious Metals

  • Heraeus metal processing uses acid to recycle gold, silver, and platinum.
  • The plant produces >1,000,000 troy ounces per year.
  • Platinum is used in the manufacturing of gasoline and jet fuel.
  • Catalyst contains 0.3 weight percent of platinum content.
  • Drum holds ~400 pounds of catalyst with $24,000 worth of platinum.
  • Sulfuric acid dissolves the alumina substrate. The platinum remains solid.
  • Aqua regia (mixture of strong acids) dissolves precious metals.
  • Aqua regia is made by mixing hydrochloric acid and nitric acid.
  • During separation, the pure platinum looks like cheese sauce, worth $3,000,000.
  • Platinum emerges in the form of a sponge.
  • Acid helps recycle >62,000 pounds of precious metal a year.

Miscellaneous facts about acids

  • Acid rain: combination of nitric and sulfuric acid, pH similar to tomato juice.
  • Since 1983, American pennies are made out of zinc with copper plating.
  • Nitric acid dissolves the entire penny.
  • Hydrochloric acid only absorbs the zinc.

Metal Etching

  • AutoFab uses ferric chloride acid to etch metal.
  • Photoresist is applied at 35 PSI at ~220°F.
  • UV light exposes the film onto the metal sheet.
  • Bare metal is exposed for etching.
  • Acid is sprayed at 60 PSI.
  • Fotofab spikes ferric chloride acid with hydrochloric acid (muriatic acid).

Acid on the battle field

  • World War I: Mustard gas and phosgene gas turn into hydrochloric acid in the lungs.
    Gases were combatted by diluting with fluid, causing soldier to drown in fluids.

Yellowstone National Park

  • Acid pools lie above a magma chamber where volcanic deposits mix with water.
  • Pools like thermophiles are very hot and acidic (pH ~2.7).
  • Cyanidium uniquely adapts to high-temperature areas.
    Thermoacidophiles generate special enzymes that protect cells from decay in hot, acidic water.
  • Enzymes may have application in industrial processes.
  • Hyperthermophiles produce an enzyme that produces ethanol fuel from corn at high temps and low pH.
  • Enzymes raise questions about life in extreme environments, here and throughout the solar system.
  • Enzymes can be used in starch liquefaction is high temperature and low pH.