Huge 'treasure' in the ocean: It took more than 60 years that humans still have not recovered!

The oceans cover 70% of the Earth's surface, host many of the geological processes responsible for the formation and concentration of mineral resources, and are the ultimate storehouses of much of the material that has been eroded or dissolved from the ocean. land surface.

Therefore, the ocean contains a large amount of material that is now considered the main resource for humans. Today, direct resource extraction is limited to salt; magnesium; placer gold, tin, titanium and diamond; and fresh water.

Scientists already know that many minerals and metals exist, dissolved in seawater and in the water of saltwater lagoons/lakes.

It is estimated that in total, there are approximately 50,000,000,000,000,000,000,000 tons (50 billion billion tons) of minerals and metals dissolved in all of the world's seas and oceans.

With uranium alone, it is estimated that the world's oceans contain more than 4 billion tons of uranium.

According to Stanford University (USA), seawater contains 47 minerals and metals. The most abundant is chloride, with concentrations of 18,980 parts per million (ppm) in seawater, sodium (10,561 ppm), magnesium (272 ppm), sulfur (884 ppm), calcium (400 ppm), potassium (380 ppm), bromine (65 ppm), inorganic carbon (28 ppm) and strontium (13 ppm). This is followed by boron (4.6 ppm), silicon (4 ppm), organic carbon (3 ppm), aluminum (1.9 ppm), fluorine (1.4 ppm), nitrogen in the form of nitrate (0.7 ppm). ), organic nitrogen (0.2 ppm) , rubidium (0.2 ppm), lithium (0.1 ppm), phosphorus in the form of phosphate (0.1 ppm), copper (0.09 ppm), barium (0.05 ppm), iodine (also 0.05 ppm), nitrogen in the form of nitrite (also 0.05 ppm) and nitrogen in the form of ammonia (again 0.05 ppm).

Next is arsenic (0.024 ppm), iron (0.02 ppm), organophosphate (0.016 ppm), zinc (0.014 ppm), manganese (0.01 ppm), lead (0.005 ppm), selenium (0.004 ppm). ), tin (0.003 ppm), cesium (0.002 ppm), molybdenum (also 0.002 ppm) and uranium (0.0016 ppm), gallium (0.0005 ppm), nickel (also 0.0005 ppm), thorium (also 0). 0.0005 ppm), cerium (0.0004 ppm), vanadium (0.0003 ppm), lanthanum (also 0.0003 ppm), yttrium (also 0.0003 ppm), mercury (0.0003 ppm), silver (also 0.0003 ppm), also 0.0003 ppm), bismuth (0.0002 ppm), cobalt (0.0001 ppm) and finally gold (0.000008 ppm).

Each million liters of water contains 300 kg of magnesium, 900 kg of sulfur, 400 kg of calcium and 400 kg of potassium.

Knowing these minerals and metals exist in seawater is one thing, extracting them from seawater is quite another.

Researchers continue to propose and seek to develop practical processes for extracting other metals from seawater and brine. One proposal put forward by researchers in Singapore since 2012 was to use specific bacteria to extract metals from brine produced as a waste product for desalination. The island nation is looking to produce 9 million liters of fresh water per day through desalination by 2060, which will produce large amounts of brine. Instead of just being dumped back into the sea, this brine can be biologically treated to extract the calcium, magnesium, potassium and sulfur in it.

On average, each million liters of water contains 300 kg of magnesium, 900 kg of sulfur, 400 kg of calcium and 400 kg of potassium. This could lead to Singapore, which has no natural resources, to develop a $4.5 billion "mining" industry.

Treasure Mining Efforts

Japan is the world's leading center for metal extraction research from seawater. It started working on extracting uranium from seawater in the 1960s, as did Germany and India (in cooperation with France). All three pilot plants have been developed, and all three use the principle of adsorption (in which atoms, ions, or molecules of an element stick to a surface). The Japanese have achieved the greatest success in recovering uranium.

Around 2009, using fibers made from amidoxime, lined up in braids 60 meters long anchored on the seabed, the Japanese are said to have recovered uranium at a cost of $140/0.45kg, at market prices. uranium is 120 USD / 0.45kg.

In the US, the research at Oak Ridge National Laboratory is focused on developing adsorbents and they have been much improved. The material, called HiCap, can extract five to seven times more uranium, seven times faster than previous best adsorbents.

If uranium prices return to the higher levels seen in the mid-2000s, the technology could very well prove economically viable. And, of course, further improvements in mining efficiency could be made in the coming years, further reducing the cost of obtaining uranium from seawater.

Most recently, the Chinese have created a new material inspired by the fractal nature of blood vessels that can absorb 20 times more uranium from seawater than previous approaches. In natural seawater, one gram of such material can extract 9.03 milligrams of uranium.

A team of Chinese researchers believe that, with this new uranium filter material from sea water, they will soon have an abundant source of nuclear fuel, serve for nuclear power plants and meet the demand at the same time. human present.

Meanwhile, the Japanese continued to find ways to extract lithium from seawater. Of course, lithium is essential to creating the lithium-ion batteries that are so important in today's world, powering laptops, tablets and mobile phones, as well as electric vehicles and power supplies. power supply on the latest generation aircraft.

It should be pointed out that most of the world's current supply of lithium comes from South America, which is extracted from brine pumped to the surface and released into shallow ponds, where evaporation removes water and other minerals. The remaining solids are collected and treated.

Lithium demand is expected to exceed supply in the coming years. As a result, in 2014 the UK Center for Energy Research predicted that by 2030 it could be commercially viable to extract lithium from seawater.

More than 60 years since Japan tried to "pick up" uranium from sea water, the extraction of minerals and metals from the ocean has not shown many positive signs, however, this process is not the answer. science fiction story. It is happening now and is likely to increase in the future.

The main mineral resources currently being exploited and likely to be exploited in the near future:

Salt

Salt, or sodium chloride, occurs in seawater in concentrations of about 3%. The amount of salt available in all oceans is so great that it can satisfy human needs for hundreds, even thousands of years.

Although salt is extracted directly from the oceans in many countries by evaporating water and leaving salt behind, most of the nearly 200 million tons of salt produced annually is extracted from large salt layers. . These salt layers, now deeply buried, were left behind when water from the ancient oceans evaporated in shallow seas or coastal basins, leaving behind thick layers of salt.

Potassium

Like the sodium and chloride of salt, potassium occurs in large quantities in seawater, but its average concentration is around 1,300 parts per million (or 0.13%) - generally too low to permit economic exploitation. direct economy.

However, potassium salts occur in many thick volatile chains along with common salts and are extracted from these strata at a rate of tens of millions of tons per year. Potassium salts are deposited as seawater evaporates to about one-twentieth of its original volume.

Magnesium

Magnesium, which is dissolved in seawater at a concentration of about 1,000 parts per million, is the only metal that can be extracted directly from seawater. Currently, about 60% of magnesium metal and many magnesium salts produced in the US are extracted from seawater by electrolysis. The remains of the magnesium metal and salt were extracted from ancient oceanic sediments where the salts precipitated in evaporation or formed during diagenesis. The main minerals mined are magnesite (MgCO3) and dolomite (CaMg[CO3]2).

Sand and gravel

Ocean basins form the final accretion site of land-eroded sediments, and beaches are home to the greatest amount of residual sand. Much of the beach and nearshore sediments are mined locally for use in construction, glassmaking, and silicon metal processing. Gravel deposits are often more heterogeneous but occur in the same way and are extensively processed for construction materials.

Limestone and Gypsum

Limestone (rock consisting of calcium carbonate) is forming widely in the tropical to semi-tropical oceans of the world today as a result of deposition by biological organisms ranging from mollusks to mollusks. to corals and plants.

Most limestone is used directly in cut or crushed form, but much of it is also calcined (cooked) to be converted into cement used for construction purposes. Gypsum (calcium sulfate hydrate) is a sedimentary mineral that is mined and used for construction.

Manganese

The bottom of the deep ocean contains an extremely large number of nodules ranging from centimeters to decimeters in diameter. Although commonly referred to as manganese nodules, they generally contain more iron than manganese, yet constitute the largest known source of manganese.

Despite the abundance and abundance of metals contained in manganese nodules (iron, manganese, copper, cobalt and nickel), no economic way has yet been developed to extract these resources from the deep ocean floor. deep. Therefore, these abundant multi-metallic nodules remain a potential source for the future.

Metals near volcanoes and undersea hydrothermal vents

Underground investigations of oceanic rift zones have found that zinc and copper rich deposits, along with associated lead, silver, and gold, are forming at sites with sub-hydrothermal vents seabed.

These metal-rich deposits formed where deep circulating seawater dissolved metals from the rocks below and released them to the cold seafloor along major faults. These rich metal deposits are untapped today because of their remote location in the deep sea.

Placer Gold, Tin, Titanium and Diamond

Sandstone deposits are accumulations of resistant and insoluble minerals that have been eroded from their original site of formation and deposited along rivers or at the edge of oceans. The most important of these deposits contain bran gold, tin, titanium and diamonds.

Today, much of the world's tin and many gem diamonds are recovered by dredging nearshore ocean sediments for minerals carried by rivers to the sea. Previously, placer gold (bran gold) was collected in Nome, Alaska, USA. Large amounts of placer titanium minerals occur in beach and nearshore sediments, but today's extraction is generally limited to beaches or onshore deposits because of higher costs and environmental constraints. of marine mining.

Drinking water

The world's oceans, with a total volume of more than 500 million cubic kilometers, contain more than 97% of the total water on Earth. However, the 3.5% salt content of this water makes it unusable for most human needs.

The extraction of fresh water from seawater has been practiced for many years, but provides only a very small part of the water used and is still quite expensive compared to land-based water sources. Technological advances, especially reverse osmosis, continue to increase the efficiency of freshwater extraction. However, geographical constraints and dependence on world energy costs pose major barriers to large-scale mining.