Scientists from many countries have studied the genesis and topography of the distribution of gold in sea water, and sought methods for its extraction.

Gold was found in the various kinds seaweed and in marine sediments (at a depth of 89-198.6 m), in coastal waters, in the geysers of Arkansas (USA) and in sea water. The gold content, according to various definitions, ranged from 3 to 200 mg/t. Silver was also found there.

The content of gold in sea water and methods for its extraction

According to geochemists, one liter of sea water contains - 0.000004 milligrams of dissolved gold, one cubic kilometer - 0.004 tons, in the entire volume of the oceans more than 6 million tons.

Gold can be extracted by filtering seawater through adsorbents (coal fines, cellulose compounds, pyrite, sulfide ores, rags soaked in reagents) and then burning or dissolving them.

• precipitation by chemical methods;
• electrolysis;
• sorption by ion-exchange resins;
• placed in a special container;
• ionic flotation through special networks;
• impregnated with reagents.

Associated extraction of gold from sea placers

Of practical interest is the associated extraction of gold from titanium-zirconium coastal sea placers. The value and economic significance of coastal placers are determined not only by large reserves of ore minerals, but also by the possibility of complex use of raw materials.

In the study of seven samples of sands of titanomagnetite sea placers of Primorye, an increased gold content was established. In addition to the main components (ilmenite, magnetite, rutile and zircon), garnet, staurolite, kyanite, disthene, sillimanite, etc. can be extracted. The content of ilmenite in various deposits ranges from 0.6 to 19%, titanomagnetite from 1 to 28%.

The bulk of gold (95%) is concentrated in the -0.3 + + 0.1 mm class. Associated gold was not found. Gold is mostly thin-lamellar, scaly, isometric in plan, oval, elongated, less often irregular in shape, completely rounded, heavily abraded, deeply altered by corrosion processes. Laboratory experiments have established that gold can be extracted by jigging machines, although the mass of one gold flake (flake) from a sea placer is five times less than the mass of gold of the same size from a river placer. Extraction of gold by jigging was 84% ​​from river placer and 67% from sea placer. When tailings are cleaned, gold recovery increases to 88%.

In the study of the sands of one of the titanium-zirconium deposits of marine origin in the central region of Russia, it was found that free gold contains 29%, associated with other minerals - 71%. The conducted mineralogical analysis established that gold is very small and pulverized, the size of gold particles is from 0.05 to 0.25 mm (the predominant size is -0.12 + 0.05 mm). The shape of gold grains is lumpy-angular and lamellar. Gold in the main yellow color and only a small part of the greenish-yellow. The surface of most large gold grains is changed by corrosion, some of them are covered with a thin film of iron hydroxides, some grains are rounded. The fineness of gold, according to the definition of the largest weakly corroded crystal, is about 890.

Processing of titanium-zirconium sands in semi-industrial conditions was carried out according to the scheme, including screening, disintegration, mechanical scrubbing, desliming and flotation. The selection of the bulk flotation concentrate and the refinement of the final concentrates were carried out by a combination of magnetic and electrical separations with flotation and gravity processes on a concentration table. The highest concentration of gold was observed in the rutile concentrate and intermediate products of electro-separation of non-magnetic and magnetic fractions.

A noticeable concentration of gold is also observed in zircon concentrate. However, the extraction of gold into these products is low, and most of it is lost in quartz sands, according to fishingby.com. The extraction of gold into the bulk flotation concentrate is 22% of the original or 75% of the gold found in the sands in free form.

Experience in industrial installations

On the sands of one of the placers of the Baltic Sea, the Moscow Mining Institute (MGI) carried out research on an installation mounted on board a dredger to determine the effect of sea waves on the enrichment process. Hydrocyclones, jet concentrators and a belt friction separator were installed on board the dredger. Two concentrators worked at the main operation with the production of final tailings and crude concentrates, which were cleaned at the third concentrator.

According to the scheme, a crude concentrate is obtained with a content of 45-60% of the heavy fraction and an extraction of useful minerals of 81%. The test results fully confirmed the data obtained during the enrichment of sea sands at the onshore facility.

To refine the crude concentrate in laboratory conditions, a scheme was developed using gravity, magnetic and electrical separations with preliminary roasting of the zircon-rutile product. Later, under laboratory conditions, a scheme was developed for obtaining a gravity concentrate with a heavy mineral content of about 80-85%. The scheme included the main concentration of sands in the jet concentrators and four recleaning of the concentrate.

The development of rich subsea deposits will require less capital investment than the development of continental deposits.

Uranium, gold, lithium - billions of tons of valuable raw materials are dissolved in salt water. Earlier extraction process useful substances out of the water was unusually laborious. Now the researchers are finally going to extract this treasure from the depths of the sea.

16 05 2016
14:18

The oceans store approximately four billion tons of uranium and tens of thousands of kilograms of gold.

The sea is a gold mine. At least if you know where to look. Usually one liter of sea water contains only a few billionths of a gram of gold. But recently, researchers from Germany and Iceland discovered a boiling gold-bearing spring: on the Icelandic peninsula of Reykjanes. There, the concentration of gold is half a million times higher than in ordinary sea water.

Not only this precious metal, but also other valuable substances are dissolved in sea water in huge quantities. About four billion tons of uranium rest in the sea. This is enough to meet the energy needs of humanity for 10,000 years. Or, for example, lithium: This rare earth chemical element is used for batteries in tablets or smartphones. More and more countries are investing in learning how the oceans can be used as a new source of resources. But you need to understand that catching raw materials from the water is far from a trivial task.

In Germany, the Helmholtz Center for Ocean Research (Geomar) in Kiel has been involved in the discovery of gold deposits in hot springs in Iceland. "Measured concentrations are fairly accurate in indicating significant gold deposits," says Mark Hannington, working group for the exploration of marine resources Geomar.

The team believes that the geothermal reservoirs of the Reykjanes Peninsula contain at least 10,000 kg of gold. The researchers hypothesize that gold dissolved in seawater and circulating in underground rock crevices must have accumulated over long periods before it left the underground reservoir and then poured out through the wells in very high concentration.

golden microbes

"This gold can appear in liquids as fine gold nanoparticles," suggests Dieter Garbe-Schoenberg of the University of Kiel. The so-called nano gold is in demand in many areas of technology. Its special surface properties can, for example, provide better control of chemical reactions in catalysts.

But how can you extract such finely ground gold from water, and even so that this process is inexpensive, simple and environmentally friendly? Young researchers from the University of Heidelberg and from the German Cancer Research Center came up with a brilliant idea. In order to make gold precipitate out of solution, they use the properties of specially adapted bacteria.

Delftia acidovorans is the name of a microbe that only grows in gold mines. This microorganism has adapted to the environment, it separates the precious metal even from solutions with a relatively low concentration of gold. The researchers identified the necessary genes and inserted them into the microbe E. coli, which is distributed throughout the world.

This allowed them to re-extract the precious metal from gold-bearing solutions, which are obtained, for example, when extracting gold from electronic scrap. The researchers applied for a patent on these biotechnological processes, as they have already demonstrated high competitiveness compared to the classical chemical processing of gold. This discovery could also revolutionize the way gold is mined from the sea.

Billions of tons of uranium

The United States, meanwhile, is supporting a major research program to extract uranium from the oceans. Huge reserves dissolved in water come from natural minerals, which were washed into the sea during weathering and other erosive processes. However: uranium is not easy to fish out of the water. Back in the 1980s, Japanese scientists were experimenting with materials that purposefully capture and bind uranium from seawater.

The Americans are trying to make this method more efficient. A research consortium wants to literally fish for uranium with a fishing rod. In the journal "Industrial and Chemical Engineering Research", for the first time, materials and a description of the method itself were presented to the public. This method is likely to be able to reduce the cost of extracting uranium from the sea by three to four times, while increasing the volume of raw materials extracted.

"In order to secure the future of nuclear power, we need to find an economically viable and reliable source of fuel," explains Philip Britt, program director at the US Department of Energy. The method is primarily developed at two public research institutes, Oak Ridge National Laboratory in Tennessee and Pacific Northwest National Laboratory in Richland.

Long threads (cords) of polyethylene fibers serve as "fishing rods (catchers) for uranium". Thin but stable fibers are specially processed so that in the process part of their molecules are converted to amidoxime. This organic compound, consisting of carbon and nitrogen, is a "bait" for uranium dissolved in water, since it preferentially forms compounds with this substance.

Impact on environment

In order to "catch" uranium, the cords simply need to be placed in the sea, preferably in that area of ​​the water masses where there is a current and mixing occurs. After a few weeks, the uranium-bearing cords can be removed. They are placed in an acid bath where the uranium is released as uranyl. The compound can be easily removed from solution, and then it can be easily enriched and processed into uranium. The uranium "rod" survives this procedure without problems and, according to the researchers, can be reused directly again in the ocean.

How much uranium can be extracted from the sea in this way has already been demonstrated by tests at three different locations on the US West Coast, in Florida and off the coast of Massachusetts. After 49 days in seawater, the cords fished out and tied up about six grams of uranium per kilogram of absorbent material. Japanese researchers at one time were able to achieve a result of two grams of uranium per kilogram of absorbent material. And at the same time, the plastic cords of the Japanese had to remain in the water for 60 days.

"Understanding how absorbent material works naturally in seawater is critical," says Gary Gill, associate director of Pacific Northwest National Laboratory. Because in addition to the highest possible uranium mining rates, it must be guaranteed that this method does not have a negative impact on the environment. "But we've already found that most of these absorbent materials are non-toxic," says Gill.

The team has been working on improving the method for five years now. It all started with computer modeling. The program tested which of the chemical groups selectively trap and bind uranium. This was followed by thermodynamic and kinetic studies, which determined how quickly uranium from water binds to one or another absorbent substance and where the equilibrium of this reaction is located. The whole process only functions when more uranium binds than dissolves.

Lithium for batteries

The project also involved the Chinese Academy of Sciences and the Japan Agency for atomic energy(JAAE). At the Rokkasho Fusion Institute, which is part of the Japan Atomic Energy Agency, Japanese researchers continue to study technical methods for extracting strategically important raw materials from sea water.

These substances include lithium, a metal that is one of the rare earth chemical elements. It is needed primarily for the manufacture of compact lithium-ion batteries, which are now common in tablets, digital cameras and mobile phones, and are also used for efficient energy storage in electric cars.

While known, accessible deposits of lithium in the world are estimated at about 50 million tons, scientists suspect that 230 billion tons of lithium could be dissolved in the water resources of the oceans. However, the raw material is only found as a trace element. About 150,000 liters of sea water barely contain even 30 grams of lithium.

But Tsuyoshi Hoshino from the Rokkasho Institute of Synthesis is not at all embarrassed. The scientist has just presented to the public a method by which the desired metal can be filtered out of water, even if it is present there in very small quantities. This method does not require additional use of energy, because it is brought by the electrically charged particles of lithium themselves.

In a filter composed of a thin glass-ceramic membrane that has lithium ion conductivity, charged particles move from the negative side to the positive side, thus producing an electrical voltage. "Microporous ceramics allow only electrically charged lithium particles dissolved in sea water to pass through," explains the researcher. In the 72 hour test, the filter achieved a recovery rate of about seven percent.

Researchers know this is just the beginning. Experts from the UK Energy Research Center suggest that in 2030 it will be possible to obtain raw materials from the sea in commercial volumes in 2030, provided that the prices of gold, uranium or lithium remain high enough.

Sylvia von der Weiden.

Gold mining began in ancient times. In the entire history of mankind, approximately 168.9 thousand tons of noble metal have been mined, almost 50% of which goes to various jewelry. If all the mined gold was collected in one place, then a cube would be formed as high as a 5-storey building, having an edge - 20 meters.

"Golden Story"

Gold is a metal that mankind met at least 6500 years ago. The oldest treasure is considered to be found in the Varna necropolis, which is located in Bulgaria, and the items are dated 4600 BC.

Gold played important role throughout the history of mankind, it 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 estimated by the amount of gold, but also the position in society depended on it. This is what is happening to this day.

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, the 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 layer, 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 in terms of its production and has a 7% share of the world share.

Industrial gold mining began in 1745. The first mine was opened by the peasant Yerofey Markov, who reported its location. Subsequently, he began to be called Berezovsky.

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

Gold mining is a complex, laborious and expensive process. Reduce such costs by closing low-income and unprofitable mines. Reducing the volume and introducing new technologies that save capital are quite effective measures.

gold mining process

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

However, this is not the only mining process. For example, it used to be common to find gold nuggets along the rivers. They were thrown onto land during the erosion of gold-bearing veins in a natural way. However, by the 20th century there were no rich placers left, and gold was mined from ore.

Now gold mining by hand is rarely practiced, the process is completely mechanized, but at the same time it is very complex. A deposit is considered profitable if it contains 3 g of gold per ton. With a content of 10 g, 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 that, mercury was separated from the waste rock, and with strong heating, the gold exfoliated. However, this method also has disadvantages, since mercury itself is very toxic. At the same time, she still does not give gold completely, since very tiny particles precious metal poorly wetted.

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

Getting gold at home

Gold mining by hand is also possible at home. In order to mine it, you do not need to go to the mines and shake trays for hours. There are more calm and civilized methods. There are a lot of items around that contain gold. For example, the old Soviet watches in their yellow cases contained the purest 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 glass heat-resistant pan, a brush and a cotton filter cloth, rubber gloves and a moisture sprayer. Of the chemicals needed nitric and hydrochloric acids.

Processing starts when you already have 300 hulls in your hands. The process will take only 4 hours, while 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, daily carry gold in their pockets and bags. It's simple - each SIM card for mobile phone contains some precious metal. It can be taken from there as well. This is done in two ways: electrolysis or etching. For the latter, a chemical reagent "royal vodka" is needed.

by the most simple method it is etching that is considered, in which gold is obtained due to the chemical inertness of the precious metal, namely, its ability to react with other elements. For etching, an oxidizing agent "royal vodka" is required, which is made from concentrated acids: hydrochloric and nitric. The liquid has an orange-yellow color.

gold from water

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

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

golden bacteria

In Canada, scientists generally found bacteria that are able to isolate gold from various solutions. Amazing, isn't it? For example, the bacterium Delftia acidovorans has a substance that just separates the precious metal from the solution. And the reason is simple - she is just 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. Studies by Canadians have shown that bacteria that accumulate gold manage to avoid poisoning due to their genetic nature.

dragee

Gold mining is also carried out with the help of 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-sea and coastal sedimentary and alluvial deposits. The only exceptions are bouldery, strong rocks and viscous clays.

Dredge types

Dredges are divided into two classes.

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

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 solid chain, a rotary complex, a dragline bucket, a clamshell bucket);
• scoop capacity (large, medium and small);
• maneuvering method (rope-anchor and rope-piling).

On the territory of the Russian Federation, dredges are now used for gold mining, mainly in the Far Eastern Federal District. However, mining by this method can adversely affect the ecosystem, destroy river landscapes, and heavily pollute the territory located downstream.

Therefore, this method can only be used with careful adherence to development projects. 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 gold mining dredge yourself

Many gold miners would like to own their own dredge, and at the same time 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 a dredge.

Initially, you need to make lists and assembly schemes, for this you can take as an example the most famous dredges for mining gold on this moment. In principle, the first stage is the study, 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 they can be purchased for next to nothing, for example, an engine for an apparatus. Next, you need to decide on the size of the dredge, the larger it is, the more soil can be processed, but its weight and cost will also be higher than that of a small assembled product.

You need to build it 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, then you need to purchase an air compressor, diving equipment and an air intake tank. However, this is not the first need, you can do it later.

In order to build a coveted device, you will need: an engine with a pump, a variety of tools (hacksaw, hammer, wrenches, screwdrivers). It does not hurt to buy a welding machine. You can buy second-hand parts, but some of the most important and problematic or hard-to-replace parts are better to buy new ones in the store.

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

The dredge socket should be installed in the head of the lock so that it directs water and soil flows into it. The suction valve takes water into the pump (this is also one of the important details). If sand is sucked in, the pump can quickly break down, so dredging without a valve is impossible.

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

The buoyancy of the apparatus is a separate stage in the creation of a dredge. It can be provided in several ways. Initially, they used tires from trucks, they weigh a 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 manufacturers of drags use They are quite reliable, but also heavy. However, there are many options here as well. Some dredges that are assembled at home have various plastic pontoons. One of interesting ways- when using plastic containers or barrels, the capacity of which is up to 40 liters. You can buy them quite cheaply. If you are not sorry to spend a large amount, but buy ready-made, then it is easier to purchase from the manufacturer.

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

You can check the operation of the dredge after its complete assembly. For this, two dozen small pieces of lead are taken, which are leveled and painted in bright color. Soil is collected in the reservoir, and they are placed there. That's just on it and you can try the dredge. See how many pieces of lead came back after washing the rock. At normal operation dredge losses are only possible up to 2 pieces. If the lead is not enough, then you should once again check the entire assembly according to the scheme, and, if necessary, make additional improvements.

Plans for gold mining in the future

There are fewer and fewer gold deposits, they are now being discovered mainly in South Africa, others are being significantly depleted, and it is simply unprofitable to develop deposits with a low and medium content of the precious metal.

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

AT last years there is a lot of talk about ocean exploration as another way to mine gold. There are a lot of sea placers, deposits, but the bottom has not yet been fully explored. It is possible that it is in the ocean that most of the deposits of the precious metal are hidden. Our descendants will have to find out.

.. 70 71 72 73 74 75

CHAPTER XV EXTRACTION OF GOLD FROM SEA WATER

It has long been known that the world's oceans contain billions of tons of minerals and valuable metals, such as gold, uranium, copper, and others.

Although in general in the entire hydrosphere of the planet the average gold content is no more than 1-10%, in the oceans (the mineralized part of the hydrosphere) the average gold content reaches 5 mg / m3. It has been established that gold concentrations in sea water are not the same everywhere, and in industrially recoverable quantities, gold is found in salt waters only in very limited areas and more often in coastal waters.

After establishing this fact, from 1901 to the present, the genesis and topography of the distribution of gold in sea water have been carefully studied. So, back in 1901, Wagner, using a complex analysis method, determined in some coastal waters of the United States the content of gold 16 mg / t and silver 1900 mg / tn. At the same time, he noted the enrichment with gold of some living organisms and plants living in the seas, as well as their remains. In particular, about 200-300 mg of gold were found in a ton of seaweed and floating organic remains, and in six samples of sea bottom sediments taken from a depth of 89-1986 m, Wagner determined the gold content on average 110 mg / t and silver 1070 mg /t.

Haber and Arrhenius in 1923 established a very low gold content in the waters of the Atlantic Ocean off the coast of Northern Europe. At the same time, Yusada recorded a gold content of 3-20 mg / t in the coastal waters of the Pacific Ocean near Japan.

At the same time, an increased content of gold was found in continental highly mineralized hot springs. Thus, according to Leid, the gold content in the hot spring of the state of Arkansas (USA) was 260 mg/t. Parker also cites the gold content in the water of the Great Salt Lake on Utaka ~ 360 mg / t, and in the water from Mono Lake in California - up to 540 mg / t.

Using Data a large number scientists and researchers who analyzed the sea waters of various regions of the globe in the period from 1872 to 1964, metallurgist-researcher Pannier

compiled a summary table of the gold content in sea water (Table 24).

It has now been established that gold in sea water is both in dissolved form in the halide (mainly iodine) form, and in the form of a reduced, very finely dispersed (colloidal) metal. At the same time, both ionized and free metallic gold are mostly adsorbed on suspended mineral particles. At the same time, an interesting feature was noted: an increased concentration of gold in sea water is also accompanied by an increased natural radioactivity. This is most clearly noted off the coast of New Wales in Australia, where the gold content in sea water rises to 250-300 mg/t with increasing radioactivity.

After establishing the form of finding gold in sea water and the topography of its distribution in the oceans, many proposals appeared on how to extract gold from sea water. Much of the information in this area has come from individuals, and many of the patents pending from this research are very similar. The listed methods for extracting gold from sea water are briefly described below.

N. V. Pertsov, 3. P. Ulberg, L. G. Iarochko, P. I. Gvoedyak, S 3 1 u4M lYa

"F Tumansky (7l) Applicant

Institute of Colloid Chemistry and Chemistry of Water (5Y) METHOD OF EXTRACTION OF GOLD FROM WATER

The invention relates to colloid chemistry and can be used for the purification of aqueous dispersions and wastewater from suspended solids, including finely dispersed gold, in gold mining and jewelry industry and at other enterprises of non-ferrous metallurgy.

There is a known method of extracting gold from the rock with the help of bacteria, which consists in the fact that they transfer gold into a solution, from which it is removed by the ion-exchange method O).

However, microorganisms extract the gold contained in the rock particle, simultaneously cultivating on its surface, in the absence of the latter, their use to extract, for example, colloidal gold from a solution, does not lead to an effect. The consequence of this is the impossibility of using the method for very dilute solutions. The method is also very specific, complex and lengthy.

There is also a known method for treating waste and wash water, which consists in filtering them through ion-exchange columns, which is based on the process of fixing metal ions or metal compounds in ionic form, most often dinka, copper or more expensive, for example gold, particles ionite (2).

However, this does not retain highly dispersed metal particles, incl. gold, the dispersion of which is 200-300A. When passing through the ion exchanger a solution containing gold in the ionic state with a concentration of 0.03 r / ë (in the form of dicyanurate) and colloidal gold 0.03 g / l, gold in the ionic state remains less than 0.001 g / l, while the content of colloidal gold changes by 10-12F. In washing

3 and wastewater from jewelry factories and other industries remains up to

15 mg/l colloidal gold that cannot be removed existing ways. Ion exchange technology provides for the need for a regeneration stage associated with the consumption of a significant amount of salts, acids and alkalis, as well as the finished product - pure water. The percentage of extraction of colloidal gold is 10-143, and ionic

The aim of the invention is to increase the degree of extraction of gold from water.

This goal is achieved by introducing yeast, genera Saccharomyces, or Candida, into water containing gold in a colloidal state. or Rodotoru1a, or Escher i chia bacteria, the mixture is preferably kept for 5-45 minutes, the dispersed phase is separated and the gold is recovered. It is preferable to introduce microorganisms in the amount of 106-10 cells/ml per 1 mg/ml of gold.

The method is carried out in the following way: 30

Cultures of well-known and used microorganism technology are used - yeast Sa ccha romyces or Candida, or Rodotorula, or

Escherichia from 11.

Yeast cultures are grown during the day on wort agar, and bacteria - on meat-peptone agar, washed off with saline (10 4 mol / l NaC

b" 8 on the FZK-56 nephelometer cuvette 3.055, and light filter 6 is introduced into an aqueous solution of gold with a concentration of 0.030.24 mg / ml, kept for

5-45 min, then the dispersed phase is separated by centrifugation or electroretention and gold is recovered, for example, by burning the resulting mass. The gold content is determined by. UV spectrophotometer using a calibration curve.

The optimal time varies for different types microorganisms, e.g. for Saccharomyces vini u Candida ,util!s 15 min, Rodotorulà glutinis—

30 min, and for Escherichia bacteria

coli - 45 min, in addition, the ability of microorganisms to aggregate with gold depends on the age of the culture ° For example, for a 4-day culture, the required contact time increases compared to a 2-day culture.

Example 1. To 50 ml of wastewater from a jewelry factory containing colloidal gold with a concentration

0.03 mg/ml add 50 ml of a suspension of the culture of Saccharomyces vini with a concentration of 3 ° 10 cells/ml. Contact time 30 min. The resulting mass is centrifuged for 5 minutes at

5000 rpm, separating water. The gold content in the latter is

0.001 mg/ml. At the same time, they extract

1.40 kg of gold.

Example 2. To 50 ml of an aqueous dispersion containing 0.24 mg/ml of colloidal gold, add 50 ml of a suspension of a culture of Saccharomyces vlni with a concentration of 3.108 cells/ml. The contact time is 45 minutes. The suspension is passed through an electroretention cell, which consists from the central working chamber and two electrode chambers separated from the working cellophane membranes.

The central chamber of the cell is filled with granular silica gel. In the working chamber create an electric field with a strength of 50 V/cm at a flow rate of 1.5 ml/min. According to

UV spectrophotometer is a complete extraction (retention on silica gel) dispersed gold. The table presents comparative data on the degree of extraction of gold from water by the proposed and known methods.

The method makes it possible to extract highly dispersed gold almost completely (by 98-993) from aqueous solutions and wastewater.

The use of the proposed method on only one jewelry fiber will provide the expected economic effect of 50-60 thousand rubles. per year, 948897

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Compiled by G. Lebedeva

Editor M. Tovtin Tekhred M. Nagy Proofreader G. Reshetnik

Order 5688/1

Circulation 981 Signed

VNIIPI of the USSR State Committee for Inventions and Discoveries

113035, Moscow, N-35, Raushskaya nab., 4/5 branch of PPP "Patent", Uzhgorod, st. Design, 4

The formula of the invention is introduced into water in the amount of 10 10 cells/ml per 1 mg/ml of gold.

1. The method of extracting gold from water - 3. The method according to paragraphs. 1 and 2, differing in that, in order to increase the degree of extraction by microorganisms, the water is kept in currents, it is first introduced into the water - we 5-45 min. yeast of the genera Saccharomyces, or Can- Sources of information, dida, or Rodotorula, or bacteria taken into account in the examination