Acids in Manufacturing and Nature

Nitric Acid

Explosive and corrosive.
Widely used chemical.
Polishes metal when controlled, dissolves it when unleashed.
Causes burns on skin contact.
U.S. manufactures approximately 100,000,000 tons annually.
Daily production equals two pounds per person per year.
Used in manufacturing plastics, films, textiles, and fertilizers.
U.S. produces 8,000,000 tons a year.
Primary catalyst in 3,000,000 tons of explosives detonated annually in North America.
Mainly in the form of ammonium nitrate fuel oil (ANFO).
Concentrated nitric acid is a powerful oxidizing acid.
Reacts with substances like glycerin to form nitroglycerin.
Nitrate molecules steal electrons during detonation, causing rapid decomposition, generating gas and heat.
ANFO is the leading explosive used in civil construction.
RDX is used for military explosives.
RDX detonates with more than twice the explosive velocity of ANFO.
Key ingredient in over five dozen explosive formulations used by the US Armed Forces.
Holston Army Ammunition Plant in Kingsport, Tennessee is the largest supplier of high performance explosives for military.
Concentrated nitric acid is 98% nitric acid with a small amount of water.

RDX Synthesis

Nitric acid is mixed with hexamine and several additional chemicals inside an eight-foot tall nitration tank.
The mix is heated to 150 degrees Fahrenheit and agitated at 140 RPMs.
In forty minutes, the chemical cocktail crystallizes into RDX.
Mixing RDX with molten TNT produces Composition B-four, an explosive used to detonate minefields.
Composition B-four ingredients are mixed in a kettle, dropped to a pellet pot, and onto a stainless steel exits the pellet pot at 226 degrees Fahrenheit.
Material travels through cold water, which solidifies the material where it then falls into a collection bin.
Holston also produces C-four, a general purpose explosive strong enough to blast through a steel door.
70 grams of C-four can blast through a one-quarter inch thick steel plate.

Ammonium Nitrate Fertilizer

The US makes 2,500,000 tons every year.
Can be used as an oxidizer for explosives when mixed with a fuel (e.g., powdered zinc).
A drop of water starts a chemical reaction that ignites the mixture.
In 1947, explosion in Texas City, Texas occurred after a freighter packed with ammonium nitrate fertilizer exploded, killing 581 and injuring 5,000.
Small arms ammunition ignited ammonium nitrate to catastrophic results.
Considered the worst industrial accident in U.S. history.

Sulfuric Acid

Roughly 40,000,000 tons is produced a year, making it the leading chemical manufactured in The United States.
Used in a wide variety of industrial applications.
A country's productivity measured in tons of sulfuric acid produced each year.
Classified as a strong acid because it contains a high concentration of hydrogen ions.
The pH scale measures the strength of an acid.
Water (neutral): pH of 7.
pH > 7: Base
pH < 7: Acid
Each number less than neutral contains 10 times the hydrogen ions of the next greater number.
Concentrated sulfuric acid (pH of 1) is 100,000 times more acidic than saliva (pH of 6).
The heat from the dissociation is being absorbed by a relatively small amount of water.
Do not add water to acid.
Highly corrosive to most metals, including aluminum.
Generates steam as the reaction proceeds.
Powerful dehydrator, capable of drawing moisture out of substances such as sugar.

Sulfuric Acid Production

Mosaic Company in Mulberry, Florida, produces sulfuric acid on a massive scale: 35,000 tons a day.
Sulfur arrives by railcar and is heated to approximately 270 degrees Fahrenheit.
Molten sulfur is sprayed through a sulfur gun into a furnace.
At 2,055 degrees Fahrenheit, the sulfur combusts with oxygen to form sulfur dioxide gas.
The sulfur dioxide travels to a converter where, combined with oxygen, it passes through a catalyst that gradually converts it into sulfur trioxide.
The sulfur trioxide enters an absorption tower, where it's combined with water in a sulfuric acid solution, creating additional sulfuric acid.
The tower is monitored and controlled via a cooling system that circulates 40,000 gallons of cold water per minute.
Operators wearing acid-resistant suits discharge it into trucks and distribute to satellite plants to make fertilizer.
At 98.5% concentration, sulfuric acid is powerless against the stainless steel enclosure of the truck.

Acid Effects

Onions are high in sulfur and emit a gas that reacts with the moisture in the eyes, forming a solution of sulfuric acid.
Tears help to dilute the acid.
37% hydrochloric acid does dissolve a hotdog and a chicken bone in nine hours.

Gelatin Production

Eastman Gelatin Corporation in Peabody, Massachusetts.
Bones are unloaded from railcars and sifted.
Larger pieces of bone go into a storage bin.
Each bin holds roughly 500,000 pounds of bone, leftovers from roughly 41,000 head of cattle.
Bones are transferred to a vat and filled with 33,000 pounds of bone chips, then hydrochloric acid is added.
The hydrochloric acid is removing minerals from the bone.
After the acid demineralizes the bone, the bone is transferred to a lime bath.
Here, lime finishes the job of breaking down the collagen proteins that have been exposed by the hydrochloric acid.
The bone is then washed and pumped into an extraction bag for gelatin removal.
The gelatin is extracted in a hot water solution and pumped through an extruder.
The gelatin is then cooked until it's bone dry, cut into granules, boxed, and shipped.
Can be used in film emulsions, pharmaceuticals, golf balls, and foods.

Acidic Foods

Oranges (citric acid): pH ~ 3.8.
Ginger ale (citric acid): pH ~ 3.
Cola (phosphoric acid): pH ~ 2.6.
Red wine vinegar: most acidic.

Vinegar Production

Heinz plant in Holland, Michigan.
Starts with grain source alcohol made from grain corn shipped in 30,000 gallon railcars at 190 proof (95% alcohol).
Alcohol is added to water, producing a 13.5% concentration.
A mix of nutrients is added to the mash to promote the growth of Acetobacter.
Nutrients are needed to promote the bacteria have sufficient nutrition to grow.
The mash solution is pumped to an acetator, where oxygen is added.
Inside the temperature-controlled acetator, a propeller spinning at 3,600 RPMs draws in oxygen through a charcoal filter and disperses it throughout the solution.
After 18-22 hours, the Acetobacter converts the 13.5% alcohol into 13.5% acetic acid.
The tank is discharged and diluted further to 5% acetic acid.
Few flavoring ingredients are added, and the acidic solution is bottled as household vinegar.

Electropolishing

Electropolishing is a process of soaking metal in a corrosive cocktail of strong acid and hitting it with a jolt of electricity.
Passivation is removing impurities and making the stainless steel clean.
Albright Electropolishing provides an essential tool for any industry that demands sterilization, even the tattoo industry.
Electropolishing tips for tattoo guns starts with carefully placing them on a rack of razor sharp spikes.
Diox cleaner tank removes the organics from the part, oils, grease, weld discoloration.
A mixture of sulfuric and phosphoric acid is stored inside a plastic lined 900 gallon tank.
A 20 volt DC current passes through the acid, which acts as an electrolyte to distribute electricity through the tank.
As electricity flows through the bars, an ionic charge microscopically etches the metal, exposing the layer of chromium in the alloy.
The acid reacts with the chromium to form a protective layer of chromium oxide that passivates the stainless steel.
A chemical called Profix separates all the metal salts from electropolishing where it solidifies those metal salts.

Metal Recycling

Heraeus metal processing in Santa Fe Springs, California uses acid to recycle gold, silver, and platinum from spent parts.
The plant facility produces over 1,000,000 troy ounces per year of precious metals from various recycling and recovery operations.
100% of all gasoline and all jet fuel in the world is manufactured using a platinum catalyst.
Normal average reforming catalyst will contain 0.3 weight percent of platinum content per pound of actual catalyst.
Isolating the platinum from the 99.7% of unwanted material starts with removing oversized debris.
After the catalyst is screened, it's fed into a tank of sulfuric acid.
Sulfuric acid will completely dissolve the alumina substrate but completely leaves the platinum untouched.
The chemical employed to unravel the mystery is a mixture of strong acids, which forms the only acid cocktail capable of dissolving precious metal, aqua regia.
Aqua regia involves mixing hydrochloric acid and nitric acid.

Acid Etching

Since 1983, American pennies have actually been made out of zinc.
Nitric acid dissolves the entire penny, the hydrochloric acid only absorbs the zinc.
AutoFab, based in Chicago, harnesses the largely indiscriminate appetite of ferric chloride acid to etch a wide assortment of metal.
Sheets of metal that have been cleaned are Laminated with photoresist, which is sensitive, acid resistant polymer.
UV light is exposed onto the film.
The areas that have been developed away are bare metal.
The sheet is placed onto a conveyor belt, which carries it into a hermetically sealed acid etching machine.
As the sheet enters the machine, a pair of 220 horsepower motors pump acid from a 300 gallon reservoir through a series of nozzles housed on a spray manifold.
The acid exits the nozzles at 60 pounds per square inch, gradually eating through the unprotected areas on the sheet.
To extend the use of ferric chloride acid, Fotofab spikes it with hydrochloric acid, also known as muriatic acid.

Yellowstone National Park

Within these acidic bubbling springs, scientists have discovered mysterious life forms that could revolutionize future technology.
Acid pools lie above a magma chamber.
Water percolates through the ground, it mixes with volcanic rock deposits, becoming acidic.
Residing in their scorching acidic waters are colonies of microbes called thermoacidophiles.
Thermoacidophiles like cyanidium survive in these extreme conditions by generating special enzymes that protect their cells from decaying in the superheated acidic water.
Thermoacidophile enzymes may one day help pioneer a biological industrial revolution as its enzymes may have application in industrial processes.