How to extract gold from sea water. Biologists have obtained a substance that releases gold from sea water

In the second half of the 19th century, gold was first discovered in seawater. True, in such minute quantities that the conversations that had begun about extracting gold from the ocean quickly died out.

Scientists soon discovered that certain heavy metal compounds could precipitate gold from solutions. Iron sulfide, pyrite, “assimilated” the yellow metal especially intensively.

That's when they tried towing bags of ore behind the stern of the ships. Upon returning from the voyage, an increased gold content was found in the pyrite.

In 1902, the famous Swedish scientist Svante Arrhenius determined the total amount of gold in the World Ocean. According to his calculations, it turned out to be 8 billion tons. Today we know that Arrhenius's data is greatly exaggerated, but there is no exact data yet.

Disputes about the average gold content of seawater flare up again from time to time. Scientists have different estimates of the content of this metal in sea water. Moreover, there are discrepancies of several orders of magnitude.

The neutron activation method for fine analysis of the composition of liquids, developed and mastered in recent years, has made it possible to conduct interesting research. Employees of the research vessel "Mikhail Lomonosov" conducted research in exactly this way.

Cruising the tropical zones of the Atlantic Ocean, they made 89 samples of sea water for gold, taken from a variety of points and at different depths, even from a depth of more than five kilometers.

They are precipitated with special reagents, and the sediment is placed in a nuclear reactor. Irradiated there by a stream of neutrons, the elements begin to emit gamma rays - they give a “voice”. Based on the characteristics of this induced radiation, the gold content of the sample can be determined.

According to Mikhail Lomonosov, the average concentration of precious metal in sea water is significantly higher than previously established. Some samples contained almost a thousand times more gold than could be expected.

This convincingly confirms the previously stated assumption that the gold content varies very significantly in different places and at different depths. Until now, the very existence of zones with high gold concentrations has been questioned.

Scientists have not yet undertaken to explain the reasons for such anomalies. You can, of course, remember that in areas of gold deposits, groundwater contains hundreds of times more gold than in other places.

The data of “Mikhail Lomonosov,” in the words of Academician A.P. Vinogradov, can again “excite passions in connection with gold in sea water.” The researchers themselves believe that large and systematic work is needed, which is not only of natural scientific interest, but may also have practical significance. Reliable identification of zones of increased gold concentrations, the reasons for their formation and the conditions for sustainable existence may once again raise the question of extracting gold from sea water.

The amalgamation process and equipment for extracting gold in metallic form from seawater were proposed as early as 1903.

Pre-filtered seawater was pumped through a tube to the bottom of a conical funnel-shaped vessel containing mercury and divided into many sections by perforated sheets (Fig. 92). Once brought into contact with the mercury, the upward flow of water was passed through a screen to catch the fine pumice mercury, then through perforated contact sheets, and finally through an amalgamation sluice located at the top of the apparatus and designed to completely capture the amalgamated gold from the flow. The amalgam was processed using generally accepted methods (squeezing, stripping and melting).

Similar equipment was proposed by Ritter1 and differs in that the thin mercury and the gold it contains, having passed through the mesh, are captured in a corrugated device.

Ion flotation

As noted above (see Chapter IV), ion flotation is based on the ability of some heteropolar compounds to interact with ions of heavy metals, and in particular gold, to form a flotable insoluble compound. The most famous work in this direction is in relation to the sea water of Sebba (South Africa) 189 J.

Sorption

Carbon-containing materials were tested as one of the first sorbents for extracting gold from sea water. Thus, at the beginning of the 20th century, Parker established that viscous carbon-containing materials such as asphalt, bitumen, mineral resin and others have an affinity for free gold. On this basis, Parker proposed capturing finely dispersed (or so-called floating) gold from sea water by selectively fixing it on solid viscous carbon-containing beds deposited on bars and strips installed in the flow. Ensuring continuous contact of fresh water with the viscous material must be carried out by the action of the ebb and flow of the sea.

However, most researchers believe that among the carbon-containing sorbents, activated carbons are the most interesting for the sorption of gold from sea water.

The pioneers of this direction - German researchers Nagel and Baur (1912-1913), proposed using coke, charcoal and animal charcoal and some other adsorbents for the sorption of gold from sea water. In the experiments, seawater, after preliminary clarification using a sand filter (to remove suspended material and gelatinous microorganisms), was passed through a filter bed of coke, coal or other carbon-containing material using the method of free percolation or ascending filtration (Fig. 93). The enriched adsorbent was periodically removed and melted.

To reduce the cost of pumping seawater, it is proposed to use perforated containers with an adsorbent bed on board the ship, or coastal tanks with a false bottom and a layer of adsorbent covered with wire or fabric mesh, filled by the action of the tides.

In parallel with the use of a classic adsorbent (active carbons), studies were carried out with inorganic sorbents with a highly developed surface, such as freshly precipitated hydroxides (aluminum, iron, silica gel), coagulated hydrocellulose, etc. In this case, it was proposed to use coastal vats or special stands filled with inorganic sorbent and completely covered with a double layer of fibrous textile material. The stands are immersed in sea water for weeks, and often months, after which they are exposed to cyanide solutions to extract the adsorbed gold. Gold-plated stands are used repeatedly.

When investigating possible sorption methods, it was found that colloidal metallic gold is preferably recovered in this process. Therefore, it was natural to look for a sorbent that would simultaneously reduce halogen gold to a metallic state and create a freshly formed active surface. Having examined a wide range of such possible sorbents, Parker came to the conclusion that for the most complete extraction of gold from sea water, ferrous sulfate is preferable, the optimal consumption of which is 2 kg/t of water.

Subsequently, Parker received a separate patent2 for the hardware design of the adsorption method using ferrous sulfite.

The combination of the processes of halide reduction and adsorption of colloidal gold is also observed in the proposals of other researchers. Thus, Bardt recommended treating seawater with sulfite liquor (a waste product from cellulose production) as a reducing agent, followed by mixing it with a mixture of finely ground coal and atomized metal (for example, copper, iron, etc.) 3. The sediment containing noble metals was first burned ( to remove carbon) and then smelted, collecting gold in the accompanying metal.

A similar goal (reduction of halide gold and complete capture of colloidal gold) was pursued by Glazunov and his co-workers (Paris, 1928), proposing the use of sulfides, and in particular pyrites, as an adsorbent for gold dissolved in sea water.

This idea was practically realized only in 1953 by Walters and Stillman, who went their own original way. According to their proposal, the sulphide ore was piled behind a concrete wall built near the lower tide line and curved towards the shore. At high tide the ore was submerged by water, and at low tide the water percolated through the ore. This cycle was repeated many times. After a certain time, the decomposed sulfide sludge containing adsorbed gold was removed at low tide and smelted. The inventors noted that the precipitation of gold by sulfides is facilitated when seawater is exposed to radioactive elements.

Stokes later showed that a variety of natural and artificial sulfide materials can be used to precipitate gold from seawater, with antimony sulfide being very effective.

To intensify the process of gold sorption by sulfides, while simultaneously eliminating the cost of pumping sea water, Gernik and Stokes proposed a special apparatus called in the literature “antimony-sulfide trap” (since it was conceived for use as an adsorbent, antimony sulfide) or "tidal energy system". This apparatus is made in the form of an inverted U-shaped pipe, in one elbow of which there is an expansion into which an adsorbent (activated carbon or sulfides) is placed between the grids. Sea water flows through this tube under the influence of a tidal current or during the movement of a vessel to which the described apparatus is attached.

Over the past 10-15 years, a number of patents have appeared that improve the sorption extraction of gold from sea water using metal sulfides 2. The most original idea and equipment in this direction were presented by the American researcher Norris 3.

His latest invention is based on the use of freshly precipitated metal sulfide colloids adsorbed on the surface of durable organic, synthetic or natural fibers. A typical example of synthesized organic fibers is polymerized acrylonitrile or vinyl cyanide fibers. Of the natural fibers, the most suitable is Ramie fiber (Chinese nettle). Such fibers, if immersed in a thin colloidal suspension (for example, freshly precipitated zinc sulfide prepared by mixing dilute solutions of zinc chloride and sodium sulfide at a pH value of approximately 6.0), will actively adsorb a significant portion of the colloidal sulfide particles and firmly retain them on their surface .

When sorption fibers prepared in this way come into contact with poor gold-containing solutions (for example, sea water), noble metal ions are adsorbed. They can be removed from the fibers by treating with heated dilute solutions of sodium cyanide with a small addition of hydrogen peroxide or sodium hypochlorite with a small addition of hydrochloric acid. Once the adsorbed ions have eluted, the fibers can be washed and reused repeatedly after pretreatment with a zinc sulfide slurry. In addition to zinc sulfide, iron, manganese, copper, nickel and lead sulfides can be used in this process.

Long-term research by Norris has established that certain oxidizing gases, which are often dissolved in most sea waters, can adversely affect the collectors and adsorption fibers used. These gases include oxygen, nitrogen and carbon dioxide. Therefore, to achieve the greatest effect, the proposed apparatus must have a means of continuously removing such gases from the flowing seawater before it comes into contact with the collecting structure of the fibers. Moreover, due to the relatively small number of metal ions that are collected in one normal operation, as well as the complexity of processing and handling the fiber mass, it is advisable to perform all operations continuously and automatically. All these factors were taken into account in the apparatus proposed by Norris (Fig. 94).

Of particular interest to researchers is the use of natural and artificial ion exchangers to extract gold and silver from seawater.

Priority in this direction belongs to Brook, who in 1953 proposed using iron and manganese zeolites to extract silver from sea water

Later, in 1964, Bayer and his colleagues (Germany) created so-called chelate ion exchange resins, capable of extracting up to 100% of valuable metals from sea water.

Of the most recent works devoted to the use of solid ion exchangers for the extraction of gold from sea water, the most interesting is the study of a group of experimenters from the Guff Research and Development Company (USA).

To collect precious metals, it is proposed to use a water-insoluble ethylene polymer containing pendant carboxylate or amide groups. One of the best ways to obtain this polymer is the saponification of an ethylene alkyl acrylate copolymer or the synthesis of a copolymer of ethylene and an ester of acidic groups, including maleic, fumaric and taconic acids. The production of such sorbents is described in detail in the patent.

Upon reaching a sufficient degree of loading of the polymer film, sorbed gold can be extracted by smelting from ash after burning the polymer or precipitated from solutions from dissolving polymers in caustic soda (caustic soda).

The ways of using natural and artificial ion exchangers are basically the same as the sorbents discussed above, namely: installation in a stream of sea water, filtration through a bed in a vat, loading of porous containers.

Merro proposed a completely new way of using artificial ion exchangers - applying them to the hull of a ship making its commercial voyage. Upon arrival at the destination port, the ion exchange resin can be stripped from the vessel and processed. Resin processing consists of washing with acids and special elements, followed by electrolysis of the eluate containing noble metals. Regenerated resins can be used repeatedly.

The most economical proposal is to use special devices located in the hold of the ship and filled with ion exchange resins. Here it is provided that the forward movement of the vessel causes sea water to continuously flow through the vessel with the ion exchanger. This vessel should have a cross-sectional area of ​​about 9.5-10 m2, a length of 3 m and contain about 28 m3 of resin. The maximum flow rate of seawater during sorption onto the resin should be -0.8 m3 through 1 m2 of surface per minute (0.8 m/min).

At this flow rate, -12,500 tons of seawater will pass through the sorption device per day. Even when kept in water

1 mg!t of gold per day will yield 12.5 g of gold. During a year of continuous voyage, about 4.5 kg of gold, worth about $5,000, can be adsorbed.

Cementation

One of the few information about the practical application of the method of cementing gold from sea water relates to the Parker method patented in the USA. Nickel dust has been proposed as a cementitious metal. By reduction, substitution and adsorption, gold, present in both halogen and elemental forms, can be isolated from seawater.

When carrying out cementation by mixing nickel powder with sea water, it is possible to achieve a gold loading of 15 to 20% by weight. The loaded nickel powder is removed from the vat and melted.

To precipitate gold from very poor sea waters, Sneeming proposed using the increased affinity of gold for tellurium. It has been established that it is most advisable to carry out deposition with amorphous tellurium with a highly developed reaction surface. Such a cementitious agent is obtained by treating soluble tellurium salt with sulfur dioxide. Seawater is filtered through a fixed layer of amorphous tellurium. To extract the deposited gold, the enriched mass is heated to sublimate tellurium (with its subsequent capture), and the remainder is melted into gold.

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Electrolysis of gold from sea water

The idea of ​​extracting gold from seawater under the influence of an electric current is based on the fact that gold, in its halogen form, is a positively charged Au 3+ cation.

This idea found practical implementation in the proposal of Brinker and Gray 2 to pass sea water between oppositely charged electrodes carrying the corresponding potential. In the proposed installation (Fig. 96), the cathode is made of silver or copper, and the anode is made of carbon or other electrode material. To completely capture the reduced gold, it is recommended to cover the cathode with mercury, which promotes the accumulation of gold. Periodically, the gold-containing mercury film is removed from the cathode and processed using generally accepted methods.

According to the researchers, this method can be used to extract not only gold from seawater, but also copper and silver.

An indispensable condition for the economic feasibility of using the electrolytic method for extracting valuables from sea water is a sufficient amount of cheap electrical energy.

In this regard, the inventor Zonna proposed a marine power plant operating under the influence of wave force. The power equipment is installed in shallow water and at such a depth that the surface of a calm sea is 60-90 cm above the base of the equipment. The movement of the waves affects the floats that rise and fall between the guides, which are designed to rotate continuously.

In the horizontal direction, the horizontal shaft of the machine with the flywheel
a wheel from which energy is removed from the pulley. This energy can be used not only to generate electric current for electrolysis, but also to pump water into onshore tanks during chemical, sorption and cementation sedimentation, for heating and other processes that require energy.

Despite certain negative statements by opponents of the development of marine metal reserves, sufficient awareness of the form of gold in sea water, places of its increased concentration and possible methods of its extraction have now allowed some countries to fully raise the issue

On the continuous industrial extraction of gold from the world's oceans. In particular, in India, problems associated with the recent decrease in gold mining from rocks have been considered. It was decided to make up for these losses and cover them by separating gold from sea water using sorption, extraction on amalgamated sheets, and plankton processing. At the same time, the profitability of the proposed route was assessed in detail and at the same time the possibility of isolating rare earth elements was considered.

In addition to the methods described, the possibility of biometallurgical precipitation of gold from seawater using biomass prepared from grown molds has recently attracted special attention from researchers. As preliminary studies have shown, the possible gold capacity of such biomass significantly exceeds the capacity of active carbons and even special ion-exchange resins.

Gold mining began in ancient times. Over the entire history of mankind, approximately 168.9 thousand tons of precious metal have been mined, almost 50% of which is used for various jewelry. If all the mined gold were collected in one place, a cube would be formed the height of a 5-story building, with an edge of 20 meters.

"Golden Story"

Gold is a metal that humanity became familiar with at least 6,500 years ago. The oldest treasure is considered to be found in the Varna necropolis, which is located in Bulgaria, and the items are dated back to 4600 BC.

Gold has played an important role throughout human history and is still considered a reliable investment. Currencies have come and gone, but it has remained a universal and stable standard for thousands of years.

Owning this metal has always been prestigious. Not only wealth was assessed by the amount of gold, but position in society also depended on it. This is still the case today.

It was gold that was often the cause of wars and crimes, but at the same time it played a huge role in the progress of mankind in general. On its basis, a monetary system began to take shape, cultural values ​​and architectural masterpieces were created, which are priceless and still amaze everyone. Thanks to the desire to produce this metal, scientists obtained many chemical elements, and gold rushes helped to discover and develop new lands.

How gold is mined in Russia

In the upper crust of the earth, gold is contained in small quantities, but there are quite a lot of such deposits and areas. Russia is in 4th place in the ranking for its production and has 7% of the world share.

Industrial gold mining began in 1745. The first mine was discovered by the peasant Erofei Markov, who reported its location. Subsequently they began to call him Berezovsky.

Today in Russia there are 16 companies that mine this precious metal. The leader is the Polyus Gold company, which has 1/5 of the share of the entire mining market. Diligent artels mainly mine metal in the Magadan, Irkutsk and Amur regions, Chukotka, Krasnoyarsk and Khabarovsk territories.

Gold mining is a complex, labor-intensive and expensive process. Such costs are reduced by closing low-income and unprofitable mines. Reducing volume and introducing new technologies that save capital are quite effective measures.

Gold mining process

As centuries passed, the process of extracting this metal was constantly changing. Initially, manual gold mining was popular. Miners obtained gold dust thanks to simple primitive devices. River sand was collected into a tray and then shaken in a stream of water, the sand was washed away, and the metal grains remained at the bottom, since they were heavier. This method is often used today.

However, this is not the only extraction process. For example, in the past you could often find gold nuggets along rivers. They were thrown onto land during the erosion of gold-bearing veins naturally. However, by the 20th century there were no rich placers left, and they learned to extract gold from ore.

Nowadays, manual gold mining is rarely practiced; the process is completely mechanized, but at the same time it is very complex. A deposit containing 3 g of gold per ton is considered profitable. At 10g it is considered rich.

A few years ago, a method such as amalgamation was often used, which is based on the special property of mercury to envelop gold. Mercury was placed at the bottom of the barrel, then the gold-bearing rock was shaken in it. As a result, even the smallest particles of gold simply stuck to it. After this, the mercury was separated from the gangue rock, and with strong heating, the gold flaked off. However, this method also has disadvantages, since mercury itself is very toxic. At the same time, it still does not give up the gold completely, since the very tiny particles of the precious metal are poorly wetted.

The second method is more modern - gold is leached with sodium cyanide, which can convert even the smallest particles into water-soluble cyanide compounds. And then gold is extracted from them using reagents. In this way, it is possible to obtain precious metal even from already existing ones, which makes them profitable again.

Getting gold at home

Mining gold manually is also possible at home. In order to mine it, you don’t need to go to the mines and shake trays for hours. There are calmer and more civilized methods. There are a lot of objects around that contain gold. For example, old Soviet watches in their yellow cases contained real, pure precious metal without impurities.

In order to get it from there, you just need to buy such watches in very large quantities. Then you will need a plastic bucket and basin, an electric stove, razor blades, a heat-resistant glass pan, a brush and a cotton cloth for filtering, rubber gloves and a spray bottle. The chemicals needed are nitric and hydrochloric acids.

Recycling begins when you already have 300 cases on hand. The process will take only 4 hours, and you will use 4 liters of acid. From this number of cases you can get 75 grams of pure gold.

Who would have thought, but everyone, even children, carries gold in their pockets and bags every day. It's simple - each SIM card for a mobile phone contains a certain amount of precious metal. It can be extracted from there too. This is done in two ways: electrolysis or etching. For the latter, the chemical reagent “royal vodka” is required.

The simplest method is considered to be etching, in which gold is obtained due to the chemical inertness of the precious metal, namely its ability to react with other elements. For etching, you will need the oxidizing agent “regia vodka”, which is made from concentrated acids: hydrochloric and nitric. The liquid is orange-yellow in color.

Gold from water

Gold can also be mined from water. It is also contained in it, and in any: sewer, sea, water supply, but in very small quantities. For example, in the sea it exists in a proportion of 4 mg per ton. Despite this, it can still be extracted using quicklime, which will require only a ton per 4.5 thousand tons of water.

In order to obtain gold from sea water, you will need to mix it with milk of lime. After some time, the liquid must be released back into the sea, and the precious metal must be extracted from the sediment. Kirov engineers propose another waste-free method in which lime is replaced with ash from thermal power plants. This method is considered the least expensive of all known.

Golden bacteria

In Canada, scientists actually discovered bacteria that are capable of releasing gold from various solutions. Amazing, isn't it? For example, the bacterium Delftia acidovorans has a substance that releases precious metals from solution. And the reason is simple - she simply defends herself, protecting herself from gold ions, which are toxic to her. The second bacterium, Cupriavidus metallidurans, on the contrary, accumulates it inside itself.

Both were found in 2006 in “gold” mines. Canadian studies have shown that bacteria that accumulate gold manage to avoid poisoning due to their genetic nature.

Draghi

Gold is also mined using dredges. They are called floating mining machines that have dredging, processing or other equipment that provides comprehensive mechanization of the mining process. They enrich minerals and remove

The purpose of dredges is to develop flooded mineral deposits and extract valuable components (gold, platinum, tin, etc.) They are used mainly in alluvial, deluvial, deep- and coastal-marine sedimentary and placer deposits. The only exceptions are bouldery, strong rocks and viscous clays.

Types of dredges

Dredges are divided into two classes.

1. Offshore, with the help of which deposits in the coastal zone and deep mines in lakes and oceans are developed. They are mounted on keel towed or self-propelled vessels, which ensure operation in storms.
2. Continental, which are used to develop deposits on continents. Mounted on a flat-bottomed boat.

Dredges are classified according to:

• the type of energy used by the drive mechanisms;
• deep excavations of rocks in the section below the water level;
• type of apparatus (many scoops with an intermittent chain, with a continuous chain, a rotary complex, a dragline bucket, a grab bucket);
• scoop capacities (large, medium and small);
• method of maneuvering (rope-anchor and rope-pile).

In the Russian Federation, dredges are now used for gold mining, mainly in the Far Eastern Federal District. However, mining by this method can negatively affect the ecosystem, destroy river landscapes, and severely pollute the area located downstream.

Therefore, this method can only be used if the development projects are carefully followed. Their implementation will require the reclamation of lands that have been disturbed by mining, as well as the restoration of forests, soil and vegetation of river valleys.

How to make a dredge for gold mining yourself

Many gold miners would like to have their own dredge and save a lot on costs, since the prices for this equipment are very high. In this case, the easiest way is to do it yourself. Despite the fact that the most inexpensive materials will be purchased, a certain amount will still be required to create the dredge.

Initially, you need to make lists and assembly diagrams; for this you can take as an example the most famous dredges for gold mining at the moment. Basically, the first stage is studying, the more you know about them, the better and better you will make your own.

Some important parts can be found in an ordinary landfill, and can be purchased for next to nothing, for example, an engine for a device. Next, you need to decide on the size of the dredge; the larger it is, the greater the amount of soil that can be processed, but its weight and cost will also be higher than that of a small assembled product.

It needs to be built with a hose diameter of up to 12 cm, so that you can handle the dredge yourself. The most optimal size is 10 cm. If you need compressed air, you need to purchase an air compressor, diving equipment and an air intake tank. However, this is not the first need; this can be done later.

In order to build the coveted apparatus, you will need: an engine with a pump, various tools (hacksaw, hammer, wrenches, screwdrivers). It doesn't hurt to buy a welding machine. You can buy used parts, but some that are especially important and problematic or difficult to replace, it is better to purchase new ones in the store.

Some dredge parts are often impossible to make with your own hands, so you still have to purchase them: engine, water pump, air compressor, hose, ore chute. It is the latter that is the most important detail; without it, gold simply cannot be captured, and accordingly, the entire constructed apparatus loses its meaning.

The dredge bell should be installed at the head of the sluice so that it directs flows of water and soil into it. The suction valve draws water into the pump (this is also one of the important parts). If sand is sucked in, the pump can quickly break down, so you cannot dredge without a valve.

The hydraulic elevator is placed at the end of the hose, while water is supplied to the beginning and a vacuum is created. It is best to use a suction nozzle here. It is difficult to operate an elevator on large dredges, so it is mainly used on small machines if the work takes place in shallow water.

The buoyancy of the apparatus is a separate stage in creating a dredge. This can be achieved in several ways. Initially, they used tires from trucks; they weigh little and are cheap. The only obstacle is that getting them is not as easy as it might seem. However, this would be the best option.

Now many dredge manufacturers use them. They are quite reliable, but also heavy. However, there are many options here too. Some dredges that are assembled at home have various plastic pontoons. One of the interesting ways is when they use plastic containers or barrels with a capacity of up to 40 liters. You can buy them quite inexpensively. If you don’t mind spending a large amount but buying something ready-made, then it’s easier to purchase from the manufacturer.

Another important detail that affects buoyancy is the frame. It is on this that the motor and the ore washing chute are attached. If you do it yourself, you can take simple pieces of aluminum, which are easy to find in any landfill. It will be inexpensive and requires almost no effort. If the frame turns out to be flat, then truck tires are simply attached to it.

You can check the operation of the dredge after it is completely assembled. To do this, take two dozen small pieces of lead, which are leveled and painted in a bright color. Soil is collected in the reservoir and they are placed there. This is where you can try the dredge. See how many pieces of lead came back after washing the rock. During normal operation of the dredge, losses are possible only up to 2 pieces. If there is not enough lead, then you should check the entire assembly again according to the diagram, and if necessary, make additional improvements.

Future gold mining plans

There are fewer and fewer gold deposits, they are now being discovered mainly in South Africa, others are being significantly depleted, and deposits with low and average precious metal contents are simply unprofitable to develop.

According to experts, mineral reserves that contain gold can be developed for another 50 years. Then they will run out. Simply because humanity has been mining gold very intensively in recent decades. And there is less and less of it in nature. Now we have to find new opportunities for mining this metal in the coming years. The most promising method is considered to be gold leaching technology.

In recent years, there has been a lot of talk about ocean mining as another way to extract gold. There are a lot of sea placers and deposits, but the bottom has not yet been fully studied. It is possible that most of the deposits of the precious metal are hidden in the ocean. Our descendants will have to find out.

The magic word that makes dreams come true does not only exist in fairy tales. It sounds simple - gold. At its core, it is an ordinary yellow metal, which is how it got its name. The question of how to mine gold interested people 7 thousand years ago, in the distant Neolithic era. It was then that it began to gain incredible popularity due to its color, which was associated with the sun and the power given by the gods. Nowadays, few people associate it with the inhabitants of heaven, but as a symbol of power and wealth, gold not only has not lost its meaning, but has also become the standard of economic, and with it, political independence of all countries.

Gold in nature

It is important to know not only how to mine gold, but also where it came from on our planet. The answer to this question helps you understand where to look for this coveted metal. Scientists suggest that gold is formed during the explosion of neutron stars, when tons of dust containing gold, along with other metals, are thrown into space. Subsequently, the dust concentrates, forming star systems and planets. So it was with our Earth. Now the bulk of the gold is in its molten interior and is thrown out “drop by drop” to the surface with lava. That is why gold-bearing veins, where gold can be mined relatively easily, are mainly located in places of post-magmatic and hydrothermal processes. Other igneous rocks, being lighter ones, are washed away over time, and gold remains in placers. The same thing happens with gold brought to Earth by meteorites. It can be found in pure form (gold nuggets), or in some minerals, for example, sulfides, arsenides and 15 others.

Properties of gold

Before we tell you how to extract gold and from what, let’s get acquainted with its properties. This knowledge will help you not to lose a single milligram of precious metal during extraction. So, what are the properties of gold?

1. It is very dense and heavy. A golden ball with a diameter of only 5 cm weighs a whole kilogram! This property is used in the main method of its extraction - washing.
2. It is very plastic, soft, and, as a result, malleable. Gold can be used to make threads as thick as a human hair and translucent plates thinner than paper. This makes it possible to use it even in SIM cards!
3. It can melt and boil, however, the temperatures must be quite significant. Important: in its molten form, even without waiting for it to boil, gold can quickly evaporate.
4. It is unusually inert, that is, practically insoluble in acids (only in aqua regia and a few other solvents).

All these properties of gold are used in methods of its extraction both in nature and at home.

Where is gold mined?

There are several countries in the world to which nature has given gold deposits. These are China (the leader in gold mining), Australia, Russia, Canada, the United States, South Africa, once-Soviet Uzbekistan, Peru, Brazil, Mexico, Chile, Indonesia, Ghana and New Guinea. Gold mining is also carried out in other countries, but in too small quantities. Our country ranks third after Australia and China. Russian citizens are undoubtedly interested in where gold is mined in Russia. We have 37 companies engaged in this business. The leader among them is Polyus Gold. Almost 95% of the total volume of gold is located in the Far East, in the Amur, Krasnoyarsk, Magadan, Irkutsk regions, Chukotka, Khabarovsk Territory, Yakutia (Sakha), Buryatia, Transbaikalia, Chelyabinsk and Sverdlovsk regions. At the same time, the maximum production is carried out in the Krasnoyarsk Territory, and the maximum dynamics of its increase is observed in the Sverdlovsk and Magadan regions and in Chukotka. But in Transbaikalia, less and less gold is being mined. Among the mines and deposits are Kupol, Kyuchussky, Maysky, Karalveemsky, Vorontsovsky, Eldorado, Devil's Trough, Sukhoi Log and others.

Amalgamation

This is one of the oldest and most harmful methods of gold mining, officially prohibited in Russia, but used in other countries by our artisanal gold miners. It involves the use of mercury. How to extract gold by amalgamation? To do this, mercury is added to a plastic or glass tray containing sand and very fine fractions of gold. She will not dissolve the coveted metal, but will draw it into her balls. To help the process, you need to turn the tray, allowing the mercury to roll over the entire surface of the sand. Mercury beads containing gold are called amalgam. It is collected, separated from the sand and subjected to either treatment with hydrochloric acid, in which mercury will dissolve but gold will not, or by evaporating the mercury over a fire. This can be done in a simple frying pan. In acid, the gold freed from mercury settles in flakes to the bottom, after which it is thoroughly washed. If you don’t want to lose mercury, you need to dip a piece of foil into the acid. This simple technique allows the mercury to precipitate. You can extract gold from amalgam by simply filtering it through suede or tarpaulin, but in this case there is always a large loss of expensive metal.

Flushing

This is the most ancient and environmentally friendly method based on the high density of gold. Flushing is used both in industrial mining and in individual mining at placer deposits. It consists of washing the rocks with water. In this case, all light particles are removed, and heavy particles, including gold, remain at the bottom of the tray. The disadvantage of this method is that too small particles of gold are washed out with water, significantly reducing its production. Some people are interested in whether it is possible for private individuals to mine gold. Yes, you can. Russia has passed a law allowing prospectors to work in small deposits and spent gold-bearing veins. To do this, you need to buy a license, which is valid for 5 years.

Cyanidation

This least labor-intensive method is based on dissolving gold in hydrocyanic acid. How to extract gold by cyanidation? It is necessary to crush the rock that contains the noble metal, pour it into a waterproof tray, and fill it with hydrocyanic acid, in particular sodium cyanide. It will begin to seep through the rock, dissolving the gold in the process. The resulting solution is poured into a separate container. The gold it contains is precipitated, for example, with zinc dust, and hydrocyanic acid is returned to the process.

Flotation

This method cannot be called pure gold mining, but it significantly enriches the rocks and facilitates the further process. “Fleet”, “flotter” in translation, is what keeps afloat. It turns out that there are rocks that get wet well and settle to the bottom, and there are those that do not get wet, but are only enveloped in particles of liquid, like air bubbles, and thanks to this they “float” on the surface. This is flotation. It is used to extract gold from sulfide, gold-pyrite, gold-copper and some other minerals. The ore is crushed, filled with water and oil (for example, pine), and mixed. Gold particles float to the surface. In industry, instead of oil, they can use air passed through a mixture of water and crushed ore, and some other reagents. Further purification of gold is most often carried out by cyanidation.

How to mine gold at home

The methods of industrial gold mining are, of course, interesting, but for most citizens they are not very practical. Not everyone can afford to go somewhere to Siberia, to abandoned mines. Yes, this is not necessary, because you can become a prospector without leaving the walls of your own apartment. How to mine gold at home? There are several methods. The easiest and most popular since the times of the Union is the extraction of precious metal from watches and other yellow products. It turns out that previously, using the inertness of gold, that is, its anti-corrosion properties, many metal objects were coated with it. Of course, the percentage of gold in them is small, but it is also small in rocks.

Thus, ore containing only 5-10 grams of gold per ton is considered rich. What should you do with your watch? First, collect as many of them as possible. Next, take an inert container (glass, plastic), put the watch there, fill it with nitric acid and wait until it dissolves everything except the gold. The resulting solution must be filtered through several layers of gauze, and the gold that has settled on it must be placed in vodka and allowed to stand for a day. You will get a brownish precipitate. Next, rinse it all thoroughly with water, filter again and set to melt. To make this last step effective, soda is added to the melting gold. It must be remembered that the desired metal can evaporate, but when melted, excess impurities leave it, and it itself turns into a small ingot.

Gold from radio components

Gold is used in circuit boards and radio components due to its inertness and low electrical conductivity. How to extract gold from radio components and microcircuits? Aqua regia (a mixture of nitric and hydrochloric acids), which is prepared immediately before the process, is suitable for this. This infernal mixture dissolves gold at room temperature. There is even a historical example of dissolving gold medals in aqua regia to hide them from the Nazis. The process produces the chloraurate ion, to which sodium sulfide is added. The gold should precipitate. It is filtered, washed and melted into an ingot.

Before starting the dissolution process, you need to sort gold-containing parts from others. Next, you should try to remove as much as possible from the “correct” radio components everything unnecessary. Particular attention should be paid to metal parts, such as caps and legs. If possible, they should be collected with a magnet. Boards can be placed in a mixture of hydrochloric acid and hydrogen peroxide in a 2:1 ratio.

Gold from water

Incredible, but true: gold is contained in any water, from which it can theoretically also be extracted. In what concentration is it contained there? It turns out that it is approximately 5 kg per square km, and in sea water it is several times more than in tap water. There is also a relatively large amount of gold in melt water flowing from the mountains and in silt sediment, especially mineralized ones. It is estimated that a ton of Red Sea mud contains approximately 5 g of gold. The main way to extract it is as follows: add quicklime to water, filter out the precipitate, pour the water back into the sea or river, and subject the sediment to further processing, for example cyanidation.

Virtual gold

For all gambling people who care about the process of gold mining, computer scientists have come up with the game “Minecraft”, the goal of which is to become a successful gold miner after passing dozens of tests. How to get gold in Minecraft? You need to go through several levels, “work” as a miner, turn the mined ore into ingots, and only then use it to make, for example, battle armor. You can also look for the desired metal in ancient castles and dungeons, and “ask around” people you meet on the difficult roads of passing levels. To real gold miners, this seems like empty fun, but the game Minecraft has conquered all continents except Antarctica, and brought its developers so much money that any miner would envy.