Discovery How Stuff Works : Salt

it is the multi-purpose jekyll-and-hyde of the mineral world if you say view and it can kill you it can also conduct electricity whiten your whites and ward off the devil it tastes like no other rock and just try cooking a decent meal without it not gonna happen we literally can't live without it the ceilings soft for assault the walls are soft stand aside solar and wind could salt be the amazing energy source of the future now salt on how stuff works geologists call it halite chemists call it sodium chloride the rest of us just call it salt it's in nearly everything from our blood to this stone and it has 14,000 known uses some refer to salt as the fifth element as essential to our world as earth air fire and water but what is salt while there is a technical chemical definition of salt what we'll be talking about is the ever-present compound sodium chloride the sodium is a metal a chloride a halogen and the ratio is about 40% sodium and 60% chloride they come together and form an ionic bond when multiple sodiums and chlorides come together they form a cube when multiple cubes come together they form a crystal as we're accustomed to seeing in nature so what talents does this little crystal have salt is hygroscopic a fancy word that means it attracts water salt dissolves pretty easily in water once dissolved it breaks up into its positively charged sodium ions and it's negatively charged chloride ions that makes it infinitely useful in chemical applications salt lowers the freezing temperature of water making it great for de-icing winter roads but it also rusts vehicles and bridges in the process the most obvious use of salt is in our food where it's both a luxury because it tastes good and a necessity because it's an amazing preservative what sets salt apart from some other resources is that it's naturally recyclable so we're never going to run out if you think about it the salt on your eggs or on the sidewalk could be millions of years old so where does salt come from salt covers the earth it's everywhere it's mixed in with all the ocean water that covers the planet salt crystals developed from evaporating salt water the ocean water from dried ocean beds this looks like a dried ocean bed doesn't it many millions of years ago after the Earth's surface cooled centuries of rainfall turned puddles into oceans the ocean floors were littered with sedimentary rock which is full of sodium meanwhile chloride spewed from volcanoes and hydrothermal vents still the amount of salt content in these early oceans was likely pretty low it took billions of years of water runoff eroding Rock dissolving the salt and carrying it into the oceans to create the saltiness we know today though it varies by location seawater is roughly 3.5 percent salt that translates to about a quarter pound of salt per gallon of seawater or a total of nearly 50 quadrillion tons of salt in all the Earth's oceans okay so how do we get all that salt out of all that seawater harvesting sea salt on a grand scale requires some serious patience the other key to this process location location location he located on Grady nagua Island the most suddenly island in the Bahamas chain gradient agua is approximately 500 miles southeast of Miami Florida at one Bahamas limited we have a unique partnership with nature aside from having access to a limitless supply of salty seawater this location is ideal for other reasons the requirements are high incidence of solar energy as you can see be out here in this then a steady but not strong wind low rainfall hive operation large land area that is suited for solar salt production 30,000 acres of an agua is devoted to the solar salt operation each year hundreds of millions of gallons of seawater are pumped into these primary reservoirs shallow basins where the water will sit exposed to wind and the sun's rays as the water slowly evaporates the result is a concentrated Drive that's drawn into secondary reservoirs and eventually into the final concentration ponds each stage becomes a mini ecosystem based on the increasing level of salt and primary resident was millions of microorganisms flow in the ocean water also coming in as millions of fish eggs and other marine animal eggs these puns are just teeming with wildlife and biodiversity of life the secondary reservoirs are too salty to support in most life with the exception of algae and brine shrimp and only salt-loving aka hallo Felix red bacteria can survive after prolonged evaporation the real magic happens in the last phase crystallization against a point where the sodium chloride in that solution cannot be held in solution any longer so crystallize into a solid once the salt layer is about four inches thick the harvesters mechanically scarified or break up the surface and truck it out to the wash plant at the wash plant the saws is dumped into a hopper and it is conveyed on a conveyor belt into spiral classifiers these out washing tubs where the sediments from the crystallizes like dirt sand is washed out of the product the 1 million tons of salt harvested here each year mainly goes toward road de-icing and water softening all this salt produced with little human intervention in some parts of the world salt lakes are oceans evaporated with zero help from us resulting in salt flats big exposed beds of salt Utah's Great Salt Lake is a salt flat in the making as is the Dead Sea in the middle east you can find salt encrusted sea beds in California's Death Valley and at the Bonneville Salt Flats in Utah here in a salt flat in Bolivia salt is collected right off the surface just as people have been doing for thousands of years today salt has many uses but in the beginning it was all about food and survival we've known about salt preservative properties ever since the cavemen and so men have been locating their settlements near Salt Works salt has been used since antiquity as a preservative so before there was refrigeration people salted meat and they salted fish prior to modern geology and industrialization if you didn't live near the ocean procuring salt was an arduous proposition this made salt precious trade routes were set up to haul it from mines and coastal regions salt was valuable in ancient Rome because it was used to preserve rations on long journeys the paycheck of the Roman soldiers was in salt it was for salario from this salary would be good if we can convince my people over here to be paid salt spawned countless superstitions like warding off bad luck by throwing spilled salt over your left shoulder into the eyes of the devil and proverbs if you read the gospel of some matthew san matias says what did jesus telling his disciples you are the salt of the earth with a double meaning basically having a life with salt with with interest and also being the savior of the people or the humanity it's impossible to imagine that we could live without salt and that's why our watchword is solved the essence of life evaporating seawater is just one of the ways we get our salt fix a - here a pinch there the salt we eat comprises less than 15% of all the salt produced worldwide but it's the salt with which we're most familiar thanks to that unmistakable taste but why do we eat salt at all it's an essential nutrient and the central nutrient is defined as one that our body doesn't make itself so if we don't take salt in we compromised our health the body contains about 0.15 percent salt by mass so for a 50 kilogram human about 110 pounds that works out to 75 grams of salt or 7 tablespoons salt is an electrolyte that keeps ourselves muscles and nervous system working because when you come right down to it we run on electricity electrolytes act as the electrical conductor that allows our nerve endings to fire our muscles to move and our thoughts to form well the human body is actually a machine it's an electrical machine and electrical impulses move into and out of the cells over the cell membranes and that transmission is facilitated by the sodium if that's true could salt water act as a conductor connecting two electrodes lighting this light bulb pure water doesn't complete the electrical circuit I'm gonna add a small amount of household salt stir bar there is the light as it goes into solution the water separates the sodium and the chloride ions and they allow the electrons to flow from one side to the other completing the circuit lighting our light bulb all our bodily fluids are salty because salt and water are inherently attracted to each other but there's a flip side to life sustaining salt where salt goes water will follow and so if you have too much salt in your body that can increase your blood pressure to regulate your blood pressure if you get rid of salt you'll also get rid of water in other words too much salt in your body in your blood attracts more water than your arteries and veins are used to lose the salt and you lower the pressure how much salt is too much depends on your size age and genetics but health agencies recommend a daily intake of no more than 2,400 milligrams of sodium or about a teaspoon full with prepackaged and fast foods flavored with large doses of salt the average American consumes over 3,300 milligrams per day but why what makes salt taste so well salty salt has that unique flavor because of the sodium ions it contains picture a tongue if you zoom in very closely into the tongue you'll find the taste buds the taste buds are made up of individual cells and at the tip of each of those cells are receptors to each of the different flavors for salt there's a particular channel that only allows sodium through so when you eat salt the sodium from the salt goes through the channel causes a change in the cell and that change is telegraphed to the brain your brain can then detect oh I've eaten salt according to the famed tone map salt is best detected on the tip of the time or so we thought in practice we now know that isn't true and that you can detect salt all over the tongue salt doesn't just add flavor to food it preserves it it even preserves something as potentially dangerous as uncooked pork which can be full of harmful pathogens the recipe for making an Italian cured ham known as prosciutto has it changed in about 2,000 years it still depends on salt and just two other ingredients the pork salt and time anything else that's T IME time people that work here they know the meat they know the salt and they know the time that it takes to make up a shooter we consider them partial to Jetta if these are the prosciutto Jedi then this is their master prosciutto actually is the past tense of the verb Pro sugar ra which in Italian means to dry it out and that's just how salt makes raw pork safe to eat by dehydrating and killing dangerous bacteria we apply the wet salt on the skin of the product just to eliminate some eventual bacteria King K grow at the skin level but important salt is the dry salt which penetrates the head once salted the hams will age for about a year in different chambers giving the salt a chance to work its bacteria killing magic each chamber simulates the environmental conditions of a particular season in Italy that first stage is if you will replicas of what is the winter season so winter being cold being humid at least of course in the Mediterranean countries the salt works its way into the ham as it draws out moisture and inhibits bacterial activity the prosciutto is safe to eat because there is no more active bacteria anyone within the hand but assured of being safe isn't good enough what else has to be something pleasant hence you have the summer and the fall and that's really where flavor is further brought out by the salt as you traverse this vegetarian nightmare a hundred thousand legs of salted hams at various stages of completion hang triumphantly as a testament to time old tradition but vegetarians don't despair salt can also render vegetables virtually unspoiled or this salt-loving bacteria aids in the fermentation and pickling process in the process of going from a cucumber to a pickle the salt is added to the fermentation bright it suppresses most microorganisms but through a selective process allows the lactobacillus organism to grow and flourish throughout the fermentation the lactobacillus will take the sugars in the cucumber and it will convert it to lactic acid and thus further preserve the pickle once the fermentation begins its active state will start incrementally increasing salt oil time with these shovel this carefully controlled salinity in the brine lens the pickles their ultimate flavor texture and immortality so where do we get the table salt that goes in our food at morton salt in Hutchinson Kansas salt is mined from underground using water it's called solution mining this salt derivations technique exploits salt deposits leftover from ancient bodies of water that were cut off from the oceans millions of years ago these prehistoric salt lakes evaporated and the residual salt was left on the Earth's surface ages of subsequent sediments covered the salt deposits the weight and pressure of these accumulating sediments compacted the minerals into solid rock layers hundreds of feet below today's ground surface solution mining followed by pan evaporation primarily yields food grade salt a very pure form of salt that the one we eat fresh water is injected into deep wells the water dissolves the dry salt deposits into a saturated brine more water pushes the brine to the surface brine is brought into a covered evaporator it's a big teardrop-shaped evaporator that's up to three stories tall and the water and the vaporators being boiled and as a spoil the steam is rising off the water and it's evaporating and that's causing the salt brine to condense and form salt crystals and the salt crystals fall to the bottom of the evaporator and as they're falling they're being cleaned a heat dryer removes any excess moisture but this is easier said than done with salt because it's hygroscopic it attracts moisture from the air so how do they keep the crystals from clumping we put free-flowing additives or anti-caking agents in the salt and those work kind of like a sponge they absorb the moisture in the salt to help keep it dry and to help keep it from cakey that additive paves the way for that famous Morton Salt slogan now the salt would flow freely even in humid weather so when it rain it pours salt has a virtually infinite shelf life both on the shelf and underground after all it's just a rock a really old rock geologists tell us that this salt deposit was formed about 250 million years ago it was during a time where what is now Kansas actually lay close to the equator and all of the continents were pushed together into a large supercontinent which the geologists call Pangaea today there are several large ancient salt deposits throughout North America some geologists estimate that the one under Kansas alone could satisfy America's salt needs for the next 250 thousand years so how do they get the prehistoric salt out from underground miners have been chipping away at rock salt here since 1923 using a big boom and some heavy machinery okay maybe it's a bit more complicated than that we're going 650 feet on the ground and I think it's approximately a minute and a half we're going up to the face to where the mining is actually being done and that'll take us about 20 minutes down here salt is a way of life obviously the environment down here is all saw the ceilings soft for assault the walls are salt and to an extent the air is so and you breathe that in and you can constantly taste the salt and a lot of the miners they get to a point where either they go to one of two ways they don't put any salt on their food or they put way too much salt on their food in order to taste it this mine is approximately two and a half miles north to south and a mile and a half east to west and growing every day the mining method they use here is called room and pillar this is because large caverns are carved out leaving behind 40 by 40 foot load bearing salt pillars the first order of business undercutting and drilling twelve foot deep holes the reason under cutter is to relieve the pressure from if you shoot it without cutting it to just stand there it wouldn't blow out it'd just be one big glob what we're doing here we're gonna fill these in 29 holes that they just drilled with ammonia nitrate and a diesel fuel mix it's just the fertilizer you just take your booster you're frying the death stick sticking the end of the hose then you try to hit that hole up and five and a half minutes later the blasts dislodges 300 tons of rock salt the salt that we mined today will be used on roads this winter all over the Midwest Tuesday we take out about 2000 tons in a year we aim at about 500,000 tons up to 700,000 tons we are very dependent on the weather if there's a lot of Isis still like last year we can hardly keep up and at about $20 a time it takes a lot of salt to pay their salaries after decades of underground salt mining there must be something that can be done with all these room and pillar caverns but what deep below the plains of central Kansas lies a company called underground vaults and storage encased in these prehistoric rock salt walls hidden away from anyone who doesn't know this place exists if you're searching for a place to store important stuff look around space is no object the available space that's already mined out is over 980 acres so we will never run out of space at least in your lifetime or my lifetime the current facility uses 1.7 million square feet of storage space and over 6 million boxes stacked on many miles of shelving and your stuff would be in fine company there's just tons of movie film and we store for various film companies throughout the world we have a complete series of friends we see the Doctor Zhivago that was a favorite Ocean's eleven and what do you know here is one of my favorites The Shining with Jack Nicholson right back here in the salt mine so why is this environment such a good place to store things because salt lowers and stabilizes the humidity to a constant 45% back up at the surface Kansas suffers through hot humid weather for several months of the year large fans bring that warm humid air down from above through the elevator shafts the warm air mixes with the cool underground air dropping and stabilizing its temperature the salt ceilings pillars walls and floors suck up the moisture lowering the humidity level the now cooler drier air circulates around the storage facility to the adjacent underground salt museum through the salt mine and ultimately back out to the surface we do not have to air-condition the facility we do not have to heat the facility which saves on utility costs one of the concerns that we do have underground of course is fire with all the paper and the boxes and the documents we have here but it's very unlikely because salt will not burn something the Nazis knew when they squirreled away stolen valuables in German salt mines during World War two the Hutchinson facility it was established in 1859 during the Cold War to protect sensitive information and assets we have lots and lots of things that we can talk about and other things that we cannot talk about because of the security that we have a remarkable example of human ingenuity partnering with salt to solve a very modern problem of storage space salts properties harness properly can solve many modern problems the relationship between salt and water is a complicated one in the oceans a delicately balanced life-sustaining coexistence in the body it's more of a codependent spreading salt on icy roads becomes a real love/hate situation we know that if we salt the roads we cut accidents by 88 percent well in the first couple of hours after we do that water freezes at 32 degrees Fahrenheit however if you add salt you can depress the freezing point and this is exceedingly useful because if you live in a cold climate where you have ice and snow you'll often want to put salt on the ice to keep the streets from being so slippery the transition of water from liquid to solid is a kind of chemical reaction when you throw salt into the equation the sodium and chloride ions interfere with waters ability to assume the structure of ice this property of salt combined with its abundance and low cost makes it an ideal winter road the icer over 50 million tons of salt get dumped on roads in the each year but another characteristic of salt comes into play and this one's not so beneficial this is the hate part of salts love-hate relationship with water when applied to wet roads de-icing salt breaks up into its components sodium and chloride ions the water layer becomes conducting oxygen from the air transports through the conducting water layer to the iron in your car or on a bridge oxygen atoms contain six outermost shell electrons a highly unstable configuration while eight is stable as a result oxygen is always swiping electrons from other atoms a process known as oxidation this could spell doom for the metal components of cars and infrastructure the de-icing salt penetrates the concrete until it makes contact with the rebar structural supports the salt goes to work facilitating the oxidation of the metal the rebar erodes until it's load-bearing capability becomes so diminished that the structure is at risk of collapse we are going to inspect one of these poles that have been exposed to the icing salts we have around seven and a half inches of material that 90% of it has been corroded perforated and there is evidence of corrosion products that I'm going to collect for lab analysis all you need is a bit of force or wind to cause it to have a catastrophic failure back at the Matco lab dr. Zee and his team do a cause and effect analysis but just as importantly they test different materials and coatings in an attempt to curb a future salt corrosion what we do here in this lab is we test on different metals to see their corrosion resistance we're gonna be putting these into our salt spray chamber this is what carbon steel looks like after prolonged exposure in our salt spring cabinets the salt spray test helps determine how these materials and coatings hold up against a water and salt Laden environment but it isn't just the snowbelt that should be shaking in its winter boots Midwest and Northeast and Colorado or areas that they are affected by de-icing sauce East Coast and Vesta both are affected by the salt from the ocean now if you have a situation that you have for the icing salts and also salt from the ocean obviously you will have the maximum damage from corrosion still studies showed that the benefits of de-icing salt outweigh the dangers we cannot avoid salt because salt is very positive salt is very low cost and they are abundant so in my opinion they are gonna be used for long term we just have to control the corrosion process we can never prevent it completely but we can detect it and slow it down through coating selection and material selection with about 70 percent of US residents digging their way out of snow each winter when it comes to road salt we'll take the bad with the good Americans use up about 16 tons of salt over their lifetimes per person that's over 400 pounds a year but don't reach for the blood-pressure meds just yet sometimes salt is lurking where you least expect it the most common use of salt is generally unknown by the public and that is about 40% of the total salt is used to make chemicals like petroleum is the feedstock for the petrochemical industry salt is the feed stock for the chlor-alkali industry salt is comprised of sodium which is an alkali and chloride which is chlorine so really the industry gets its name chlor-alkali from salt itself most people think of salt as common table salt but when mixed with water and electricity has passed through that salt water solution you get compounds like chlorine caustic soda and hydrogen which are essential building blocks and everything from food to clean drinking water to pharmaceuticals a major manufacturer of these building blocks is this Olin chlor-alkali plant strategically located near the sources of its main ingredients we actually located here in upstate New York not only due to the abundance of salt but also because we are near historic Niagara Falls which makes it a ready resource for low-cost hydropower electricity we actually receive the salt as a solution from a company about 60 miles away from here we're really taking advantage of the properties of salt which is that it's highly soluble and water miles of pipes and wires carry the salt water and electricity to the cell membrane room here electrolysis breaks down the brine into chlorine sodium hydroxide and hydrogen separated by a membrane this membrane just looks like a sheet of paper it's much more than that it's really a very ion selective high-tech polymer technology that allows the sodium ions to pass through the membrane while leaving the chlorine ions on the other side now what to do with these separated ions every year in the u.s. we produce about twelve point seven million tons of chlorine chlorines molecular outer shell is missing one electron giving it a unique ability to bind with other elements and compounds this makes it extremely useful in all kinds of industrial applications Florine specifically is really known due to its disinfectant properties that's been used for well over 100 years in the US for providing purified drinking water to millions of people well over 85 percent of agricultural crop protection products use chlorine in their manufacturing process but it actually has hundreds of other uses and winds up in many other products you name it there's likely some form of fluorine chemistry used to make it on the other side of the membrane is the caustic soda as the name implies it's probably not wise to touch this stuff in its raw state because it can burn caustic soda is another name for sodium hydroxide and as a number of important uses it's used as raw material and soaps and detergents it's also used in the pulp and paper industry to break down the pulp to make paper the u.s. industry produces about thirteen point three million tons of caustic soda every year and that equates to about 21 million tons of salt consumed to make those products after all that effort went into splitting salt apart there's something else made at this plant that involves a reunion of sorts just add water bleach is produced by combining chlorine caustic back together and it's important as a disinfectant in keeping our food safe in that it disinfects the surfaces that come in contact with our food not only in our house but also in restaurants and also in healthcare facilities chlorine bleach kills those nasty microorganisms by attacking them at the cellular level and it gets those stains out of your whites but not how you think let's say you spilled some spaghetti sauce on your white shirt now this spaghetti sauce is red due to the color in the tomato of the chromophore and so bleach won't actually clean the clothes all it simply does is it denatures the chromophore the color and therefore returning your shirt to white the byproduct of electrolyzing saltwater hydrogen doesn't go to waste either hydrogen is able to displace natural gas in our boilers and we're not only saving money for the operation of the plant but we're also helping reduce our carbon footprint and our impact on the environment salts molecular structure can be harnessed separated and altered proving that it's more than just the sum of its parts salt is edible it makes food safe and our bodies are full of it so why can't we drink this it may be the most ironic way to go dying of thirst in the middle of the ocean but the reality is drinking too much seawater will kill you and that's because of assault drinking saltwater is a bad idea because your body will try to expel the extra salt by urinating and it will actually urinate more water than you drink it has to get that water from somewhere so it gets it from the rest of your body it gets it from a circulatory system and from your cells so drinking saltwater actually dehydrates you 97% of the planets 326 million trillion gallons of water is in the salty oceans rendering it undrinkable more than half of the remaining 3% is tied up elsewhere so that doesn't leave us with much some areas like Tampa Bay are looking to desalination as a solution through this complex filtration process you can actually force the salt out of the salt water ironically the first part of the salination involves a product made from salt this is where the raw sea water comes into our plant this is the first stage of our pretreatment process and what we do here is we add some chemicals sodium hypochlorite and ferric chloride the sodium chlorides common bleach we're trying to get the particles to settle and collect together get heavy and settle to the bottom next the water is stripped of its minerals and particulates and subjected to reverse osmosis which removes the salt in this case osmosis is the passage of water through a semipermeable membrane from an area of high salt concentration to an area of low salt concentration reverse osmosis uses pressure to push water through the membrane leaving highly concentrated salt on one side and pure water on the other it takes about an hour to get from seawater to drinking water the leftover concentrated brine now contains six percent salt to salty to discharge back into the bay so they first diluted with seawater of course environmental watchdogs patrol any impact on local marine life we have an extensive monitoring program we spent over a million dollars a year here at Tampa Bay water checking for changes in the bay to date we have not seen any changes at all the desalination process can be pricey reverse osmosis requires a lot of energy and there's another cost to consider when working with salt in a wet environment stainless steel is corrosion resistant because it has a super thin chromium oxide barrier worth the extra cash maybe sea water desalination would be less cost prohibitive if there was a way to produce say hydrogen energy in the process sound a bit far-fetched not to this Erie Pennsylvania inventor while researching a way to kill cancer cells using a radio frequency transmitter he stumbled upon a way to make saltwater burn and release hydrogen the saltwater is just regular sea salt water the saltwater is actually taken from the Gulf of Mexico so it hasn't been altered in any particular way we have taken salt water and put morton salt in it and it burns the same ways when a saltwater solution is placed in a specific radio frequency field the signal breaks the hydrogen oxygen bond in water molecules releasing hydrogen and oxygen upon recombination through combustion the hydrogen and oxygen produces the flame and the byproduct distilled water could saltwater and the quests for fresh water and alternative energy there's no reason why it could not run an engine just the way whale runs an engine the implications are are huge the purpose of this test was to show that there's energy released inside the test tube and it expands like gasoline does in a piston inside a vehicle the gas gets sprayed in it ignites and of courses the piston back in this particular case our cork is our piston the real-world viability of this is still debated because it takes more energy to generate the radio frequency than releasing hydrogen produces and the role of this salt is not yet fully understood but scientists do know that this doesn't work with plain water they're also testing this process on other substances though probably none as plentiful as salt water if this works then I think it's a great gift to in the world yeah especially if it lowers those gas prices while many of our most precious resources are endangered we can rest assured we're not running out of salt any time soon we naturally recycle most of the salt that we use we for example put salt on the roads in winter Road safe and that will run off into the streams into the rivers and back to the ocean my doctor said that salt is bad for me but I don't trust too much my doctor this dinner-table stable seasons and preserves not only our food but our very existence and who knows maybe this humble chemical compound found all over the world with its 14,000 known uses from seasoning our foods keeping them safe from bacteria regulating our water content deicing our roads and even saving our beloved movies actually has 14001

Channel: Manu John

Views: 2,095,874

Rating: 4.6348081 out of 5

Keywords: Salt, Discovery

Id: gI5qV-kvLeg

Length: 42min 34sec (2554 seconds)

Published: Tue Apr 16 2013