Dore alloy what is it

Exorbitant money: the myth of the suitcase with gold

dore alloy what is it

In the finale of the classic western "McKenna's Gold," Gregory Peck's hero rides off to a bright future on a horse with a pair of large leather trunks stuffed with gold bars strapped to his back. Until now, this scene has not raised any questions in my mind, but now I think that in reality this horse would have broken its back.

After all, there are films from half a century ago - and in modern action films there are often scenes where a robber quickly runs away from his pursuers, carrying in both hands huge bags or suitcases filled with bars of gold or platinum. In fact, this is absolutely impossible. After all, silver, gold, platinum are very heavy

To verify this in practice, and not just by studying the table of densities of precious metals, you need to go to where gold is available in large quantities. A measured bank bar the size of a chocolate bar weighs 1 kg! I put a platinum bar on my palm and can’t believe my eyes. A metal parallelepiped, similar in size to a piece of laundry soap, pulls the hand like a weight. The stamp gives the exact information: 3.359 kg!

Not everyone gets the chance to weigh almost four kilograms of precious metal in the palm of their hand. Fortunately, this chance was provided to us by the Yekaterinburg Non-Ferrous Metals Processing Plant (EZ OCM), which also operates under the Plaurum brand.

This is one of the few enterprises in Eurasia that extracts precious metals from natural raw materials in their purest form. Then these metals are turned into bullion and used in instrument making, nuclear energy and the jewelry industry.

The plant's products are known not only in Russia, but also in many countries around the world.

Measured bank bars made of gold and silver Unlike heavier standard bars, measured bars are weight standards and weigh exactly 1 kg.

First trial by fire

Gold occurs naturally in primary and placer deposits. Primary deposits were formed in the earth's crust due to magmatic processes. They contain native gold in the form of veins, which are usually mined using the quarry or mine method. However, when the vein comes to the surface, nuggets can be found right on the ground. But this is very rare.

Placer deposits, derived from primary deposits, are formed after prolonged exposure to natural factors. Placer deposits are located in the beds of mountain rivers, on the shores of lakes and mountain slopes. To extract precious metal from them in the form of gold grains, the rock must be washed away, separating the concentrate from it (translated from German as “washed ore sediment”).

The extraction of gold-containing concentrate is carried out by gold mining companies and teams of prospectors.

The concentrate, an enriched raw material, already contains a large percentage of gold and looks like a coarse, dirty yellow powder. It is in this form that it arrives at the EZ OCM and, before turning into gold of the highest standard, goes through a whole technological chain. We happened to see its beginning in the smelting shop. The master places a crucible with spot gold in an induction furnace.

As it heats up, the powder slowly settles, as if melting sugar or crushed ice. Finally, the last grains melt, and the melt bubbles in the crucible. This is how the receiving smelting goes: a small batch (at the plant they say “place”) of concentrate arrived at the plant from the prospecting team.

The task of the first smelting is to evaluate the chemical composition of the raw material and select the optimal scheme for separating pure gold from it. Melter Evgeny Vetoshkin takes a long quartz glass tube with a black rubber bulb at the end and lowers the other end directly into the melt. Thanks to the vacuum created by the bulb, part of the metal is sucked into the tube, where it hardens.

Then the tip of the tube breaks and a metal rod—the sample—falls out. “It is quite difficult to take a representative sample from a frozen ingot, since due to the large number of impurities, the main component being determined, in our case gold, will not be evenly distributed throughout the entire volume of the ingot,” says Dmitry Serikov, head of production management at EZ OCM JSC.

“That’s why a fire-liquid sample is taken. It is more representative, since during induction melting the contents of the crucible are intensively mixed.”

Bowl of fire The crucible for melting is the main tool for the production of non-ferrous metals. After the end of its service life, it is ground into powder, from which particles of precious metals are extracted.

Boiling gold and frost stone

The melt continues to “boil”, and meanwhile the master pours a scoop of white powder into the crucible. Then another one. This is a ground mineral cryolite (“frost stone” in Greek), which acts as a flux. The concentrate contains base impurities, as well as organic matter - cryolite pulls all of this into itself, forming a block of slag that is easily separated from the ingot. The melting is finished.

The crucible is removed from the furnace and its contents are poured into a mold (mold). Due to the special shape of the mold, the resulting ingot after cooling resembles an artillery shell. The “warhead” is a cone with a rounded end in yellow metal color, the “case” is a gray cylinder of slag. “Looking at the resulting ingot,” says Dmitry Serikov, “we can already say that the gold content in the raw material was high.

What exactly and what else is contained in the ingot can only be determined based on the results of chemical analysis.”

The melter takes a frozen fire-liquid sample, makes a thin strip of foil from it on a special rolling mill, and then sends it to the laboratory by pneumatic mail. There the metal will be dissolved in acid and, by examining the solution, the chemical composition of the sample will be determined with high accuracy.

The photograph captures the moment the silver smelting was completed. The liquid metal flows into a barrel filled with water and cools there in the form of granules. The stream of silver in the water is stirred with a wooden spatula.

Disappears in acid

Mined gold is never 100% pure. Native gold always contains silver. If the silver content is more than 25%, then such a mineral is called electrum. The ore from primary deposits, rich in such minerals, is smelted after enrichment to produce Doré alloy. The alloy, containing both gold (about 70%) and silver (about 30%), is sent to refineries.

Doré alloy is thus the raw material for the production of both precious metals. If the share of, for example, silver in a batch of gold concentrate received at the plant exceeds 5%, a special technological operation is needed to remove the excess. This is vacuum distillation. The alloy is heated in a furnace under high vacuum to the temperature at which silver evaporates from its surface, followed by the capture of these vapors in a special funnel-condenser.

There are also technologies for removing large impurities of mercury or lead.

Then the gold undergoes the next melting process: it is turned into granules. Due to the presence of too many impurities in the metal, when cooled, the granules take on a ragged shape, reminiscent of popcorn. But the form is not important here - soon it will not exist at all.

The granules are sent to the refining shop (usually the minimum batch is 50 kg), where the metal is completely dissolved in aqua regia (a mixture of nitric and hydrochloric acids).

Refining is a chain of chemical reactions, and its product is a “metal sponge” - a precipitated clumped dark brown powder.

The Yekaterinburg plant works not only with gold, but also with silver and platinum group metals. The weight of a standard silver bank bar is 28−32 kg. It is incredibly difficult to tear a silver “brick” off the floor.

But, despite this appearance, the “sponge” is already pure gold. It again goes to the smelting shop, where it turns into granules - now smooth, round. The granules can be used as finished products for the production of technical alloys based on gold, used in the production of industrial parts (contacts, conductors, etc.

THIS IS INTERESTING:  What are neodymium magnets?

), can become a component of jewelry alloys. Here, in the smelting shop, they are used to make bank ingots - measured (from 50 g to 1 kg) and standard (about 12 kg). “An ingot is an investment instrument and at the same time a weight standard,” says Dmitry Serikov, “so when melting, we cast exactly one kilogram of melt plus 0.04 g into the mold.

 This is insurance in case of a slight error in the scales anywhere in the world where our bullion ends up.” The bank bar consists of gold of the highest standard. This means that it contains 99.99% pure gold and only a maximum of one thousandth of impurities, which cannot be removed anyway.

However, the composition of these impurities is regulated, and depending on their total amount and the amount of each element, different grades are assigned to gold.

At the plant they tell a story about how one of the directors of EZ OCM gave a tour of the workshops and, as a small attraction, offered the tourists to pick up an inverted standard bank gold bar with one hand and put it in their pocket.

In this case, they say, the excursion participant could take the bullion as a gift.

But no one, of course, managed to perform such a trick: a standard bank bar has the shape of a truncated pyramid, and fingers simply slipped off the inclined edges of the 12-kilogram “brick.”

Granules of pure gold, which will be used for bank bullion or industrial parts, and will also become part of jewelry alloys.

Bit by bit

Most of us have little idea of ​​the true properties of gold, because we communicate with it mainly through miniature and light jewelry. And therefore we do not know that gold is not only a heavy metal, but also a very soft metal. It is distinguished by its unique plasticity; it can be used to roll the thinnest foil and draw ultra-thin wire, but it is a useless constructive material.

Therefore, 585-carat jewelry gold contains a little more than half of the precious metal (58.5%). Everything else is strengthening alloying components: copper, silver, nickel. There is no “white” or “red” gold in nature: in its pure form it is always yellow, and different colors appear in jewelry alloys depending on the presence of one or another alloying additive.

If you make, say, a gold ring that is used for bank bullion, it will not last long - it will wear out and break.

With each contact with foreign objects, gold easily gives up part of its mass. And therefore, special measures have been taken against losses at EZ OCM. The person who picked up the bullion goes to wash his hands. But the water does not go down the drain, but settles in a special tank, after which the precious metals that got there are released from it. Trap filters are installed on ventilation systems.

Nothing - not cleaning materials, not old work clothes, not gloves - leaves the plant until they are burned and the ash is sent for refining. Old crucibles that have spent their time, containing the smallest traces of precious metals, are ground into sand, from which particles of gold, silver, and platinum are then washed out. And all these measures make it possible to save a significant amount of precious raw materials.

The last point of our acquaintance with the enterprise was the storeroom, where ingots of precious metals were very prosaically laid out on the shelves. It’s scary to even imagine how much all this costs. However, what does money have to do with it? Getting acquainted with a unique production and weighing a “brick” of gold in the palm of your hand is an invaluable experience.

Source: https://PopMech.ru/technologies/451632-nepodemnye-dengi-mif-o-chemodane-s-zolotom/

Tiny joys. Russian biathletes lost, but fans were encouraged

dore alloy what is it

The Russians wanted to finish the Biathlon World Cup in Ruhpolding as quickly as possible. In mid-January in Germany, our team is not really doing anything. The men, even in the combat team, took only fourth place in the relay race, and did not shine in the individual races. And it was hard to believe that the sixth race of the stage – the men’s pursuit – would change everything for the better.

The biathletes are again without medals, and this is not surprising. But skier Bolshunov has gold!

The fifth stage of the World Cup has ended in Ruhpolding. The medal-free streak of our biathletes is already 20 races.

There were few objective prerequisites for success. Following the results of the sprint, Alexander Loginov entered the race in 11th place, 44 seconds Martin Fourcade Matvey Eliseev was a little further – in 17th place and 51 seconds. Garanichev and Latypov started two minutes after the leader from 53rd and 55th places. There was no talk of fighting for medals; we just had to push through.

French alloy

Fillon Maillet clung to Fourcade's , and the French pair gained a few seconds from the pursuers on the first lap. However, it was more important to shoot cleanly, and the two leaders managed to do this in complete calm.

Another Frenchman Detieux , as well as the German Doll and the Norwegian Christiansen, also did not experience any problems at the shooting range. But for the Russians everything went wrong again: Loginov and Eliseev missed once each, and the lead immediately grew to a minute.

Latypov and Garanichev shot accurately, but what was the point? This pair was in 43rd and 44th places, two minutes behind the leaders.

The second round did not contribute to the emergence of additional intrigues. Fillon Maillet and Fourcade did not let anyone get close to them and were flawless at the line. The Doll – Christiansen – Child trio didn’t crash either. Sasha Loginov shot accurately, but since his competitors made almost no mistakes, he did not move forward much - he left on the third lap in 17th place, a minute and 8 seconds behind the leaders. Eliseev and Latypov missed twice each, but Garanichev was accurate and soared to 28th position.

Ours don't shine. But the German is even worse!

After the first “stand,” the intrigue in the fight for gold began to disappear. Martin Fourcade was flawless at the shooting range for the third time in a row, but Fillon Maillet took one penalty loop. However, he had enough reserve to remain second.

THIS IS INTERESTING:  How to seal an aluminum canister

Rounding out the top three was another Frenchman, Dethieux, but Christiansen was very close to him.

Doll missed once and fell behind, and his compatriot Johannes Kühn shocked the German public: on the third lap he joined the fight for bronze, but at the shooting range he ruined everything - he made five misses in a row and lost 21st place at once.

Loginov also missed once and finished 16th. Garanichev shot clean – 24th place. Eliseev was 28th, and Latypov was 48th. It was possible to say goodbye to hopes for high places for Russians.

It's not funny anymore. Russian biathletes were again left without a medal in the men's relay

Loginov had a chance to grab bronze, but his shooting let him down. The mistake can only be corrected at the World Championships.

What to be happy about?

Martin left no chance for his opponents - five hits and early gold. Fillon Maillet did the same, but only secured silver as a reward. But in the battle for bronze, the trio Christiansen - Detieux - Doll reunited - they would be nowhere without each other! The fight for the medal turned out to be spectacular, and the Norwegian won it with a minimal margin at the finish line.

France celebrates a golden hat-trick at the stage in Ruhpolding and is upset that a complete podium did not happen in the pursuit. Well, Russia is happy that Alexander Loginov still got into the top ten, Edurad Latypov, with four misses and 38th position, showed a decent seventh move, and Evgeniy Garanichev was able to shoot to zero and, having started 53rd, became 22nd.

As they say, feel the difference.

Source: https://championat.com/biathlon/article-3951281-loginov-stal-10-mv-presledovanii-na-kubke-mira-furkad-vyigral-chetvjortuju-gonku-krjadu.html

Refinery in Kara-Balta, or What REAL GOLD looks like in reality

dore alloy what is it

"My 24." How disappointed I was in gold

I come from Kara-Balta. I drove past the refinery for many years and dreamed of going there. My dream came true: I saw with my own eyes how gold is produced. And at the same time, she debunked the myth that real ingots should be perfectly smooth and shiny.

It is here, in the industrial zone of Kara-Balty, that absolutely all the gold that is mined in the country is processed. The refinery is the only one in the republic.

Outsiders are not allowed into the plant. Even the very fact that someone will wander here by accident is excluded. Director Vladimir Melnikov meets us at the entrance. This is the only employee who is allowed to photograph. The faces of the others are prohibited from being shown for security reasons.

The refining plant in Kara-Balta was built in 1992 by KGRK, following the example of a similar plant in Zarafshan (Uzbekistan). The technology was finalized at the Central Research Laboratory (CNRL) at the KGRK.

Vladimir Melnikov is the only employee who is allowed to be photographed

The plant was focused on processing gold from the Makmal deposit. Due to the small volume of mining in the republic, it was designed to produce two tons of pure gold per year. Today, the main supplier of raw materials to the plant is Kumtor. The Doré alloy is brought here, consisting mainly of gold and silver and 5-6 percent of various impurities - from copper to iron.

Come on in, take off your clothes!

It takes eight days from the moment the doré alloy is delivered to the plant until the finished refined ingot is received. The process is not fast, and it is impossible to speed it up. The director of the enterprise, Vladimir Melnikov, allowed us to enter the plant and showed how the process was going.

According to the rules, employees cannot go inside in their own clothes. They completely undress, they are searched, and only then they go through and change into work clothes inside.

This rule is the same for all refineries. The company is responsible for the safety of every gram of precious metal, and therefore security measures must be unprecedented.

An exception was made for the journalist. I didn’t have to show the refinery security how negligible I looked. We were even allowed to bring a notepad, pen and camera - unheard of generosity. In the workshop where the ingots are branded and weighed, photography had never been allowed before. But they couldn’t get the cell phone past the security, no matter how much they asked. I had to come to terms with it.

The refinery is the only one in the republic. All gold is processed here

Every door here is locked, stamped and the alarm is turned on. There are cameras everywhere. Yes, even where completely naked employees are searched.

So, we go through the inspection procedure. Even a doctor doesn’t study my nose, ears and mouth so carefully. But health is one thing, and taking even a gram of precious metal out of a factory is quite another. You can get a very real sentence for this.

Study chemistry, poor students!

The plant's primary task is to separate gold and silver. Then, from the resulting unrefined products, refined gold and silver with a purity of 999.9 can be produced. The primary separation of gold and silver occurs using high temperature chlorination, or the Miller process. And then comes the refining of the resulting products - gold and silver - using electrolysis.

How does the process of metal separation occur? There is nothing supernatural here. Simple chemistry. Those who were even slightly interested in the subject at school will understand the essence of the process.

Doré alloy from the Kumtor mine is placed in a crucible with a quartz tube

“How did you learn chemistry at school? Do you know what electrolysis and chlorine are?” - Vladimir Nikolaevich asks me with a smile.

“She taught well. I definitely remember about chlorine and electrolysis,” I timidly justify myself.

It turns out that Doré alloy from the Kumtor deposit is placed in a crucible with a quartz tube. It is through this tube that chlorine gas is supplied. This gas reacts with all impurities and silver. But chlorine does not react with gold.

Here's your first chemistry lesson. Impurities and silver form chloride slags. This is how the primary separation into gold and silver with impurities occurs. The slag floats to the surface, and a melt containing approximately 96 percent gold is concentrated below.

Vladimir Melnikov

Gold anodes are cast from primary refined gold and suspended in electrolysis. Plates hang in a bath of liquid. Under the influence of electricity, the anode dissolves, and chemically pure gold with the highest purity of 999.9 is deposited on the cathode plate.

The ingots are small, but their weight is significant - on average 12.5 kilograms

“Gold has a compact and dense sediment. It is torn off with a special scraper. The process for obtaining gold and silver is the same. But during electrolysis they behave differently. Silver is deposited in the form of a fine-crystalline precipitate. It even crumbles to the bottom of the electrolyzer,” says Vladimir Melnikov.

THIS IS INTERESTING:  What is ferrous metal scrap

Everything silvers and sparkles

Have you ever seen what unmelted silver of the highest standard looks like? I first saw this at the refinery. The spectacle is simply mesmerizing. There is probably no such sparkle anywhere. It's a pity, you can't touch it.

It turns out that after separating gold and silver in a crucible, the resulting slag is processed to produce silver. All harmful impurities from the slag are separated and the silver-containing slag is reduced with soda, melted in furnaces, and metallic silver is obtained. And then the process is similar to gold - anodes are made and hung in another separate room for electrolysis.

The process of obtaining refined gold and silver from a Doré bar takes eight days, regardless of the volume of the metal. This is due to a large number of preliminary procedures.

“You need to carefully weigh everything with an accuracy of one tenth of a gram, then process everything, process all the waste. But we still have a high electrolysis rate. At other factories it can be much longer - two or three weeks,” admits the director.

Control and analysis - at every stage

The plant also has its own laboratory. It is here that the product is studied at each stage of refining.

The laboratory determines the gold and silver content in bullion. Here they give a complete breakdown of what impurities are included in the composition, how many harmful substances are in a particular ingot.

Major disappointment

For me, probably, like for most girls, the main thing was the workshop where they mark and weigh the finished refined ingots. They not only let me in there with a camera, but they even allowed me to touch the very gold that is obtained from Doré bars from Kumtor.

The unpresentable appearance of the ingots indicates that this is a real high-quality product

And here, perhaps, the most important disappointment of the day awaited me. The finished refined ingot looks completely different from what we imagine and how it is shown in the movies. It is uneven and unpolished. To be honest, at first I even decided that they showed me ingots that were not yet ready. But for some reason they had a mark, number and sample on them.

It turned out that these inconspicuous ingots were the very same ones. And their unpresentable appearance suggests that this is a real high-quality product. And no one will grind and polish them. These are the rules.

“According to the conditions of the London Stock Exchange, a gold bar obtained by casting must not bear traces of mechanical processing. This is done to avoid the risk of counterfeiting, when a foreign substance was put into the ingot, then it was filled with gold on top and polished, and there was a dummy inside. The absence of any processing is a guarantee that the bar is truly gold,” experts explain, seeing my reaction.

There was a case when ingots were discovered on a Chinese exchange that contained tungsten inserts inside.

Interestingly, the weight is never indicated on the ingot. The reason is simple - during transportation, a part may be erased and when re-weighed, the weight may turn out to be completely different. And this is a real scandal.

They allowed me to touch those same ingots. True, I almost knocked the factory employees unconscious with my manicure when I tried to lift the biggest one.

“Girl, be careful!!!” — several people exclaimed in unison as soon as I tried to pick up the ingot. I was surprised: what’s the problem, I won’t break it.

“What are you doing? It’s heavy, although it’s not very big and you can easily scratch it,” they answered me right away.

What a surprise! The highest purity gold produced here, 999.9, is very soft. Even a small impact can damage it. One awkward move and I could scratch the finished branded ingot with my fingernail, completely ruining it. And it costs several tens of millions of soms.

It is small, but the weight of the ingot is significant - on average 12.5 kilograms. No matter how much I love gold, this piece was too tough for me. Having lifted it just a couple of centimeters, I honestly admitted to the friendly laughter of the employees that I couldn’t take such a piece away. It's a pity, it's a pity!

No harm to the environment

When I first heard that chlorine was used in the process of separating gold and silver, I thought that all the employees were practically wearing spacesuits. Well, at least they wear respirators, because it’s impossible to breathe.

This did not happen. The smell, of course, is not the most pleasant, but it cannot be called suffocating either. It turns out that the plant installed a special gas purification system. It works with 99 percent efficiency.

“We can safely say that we cause virtually no damage to the environment. But our system solves two problems. She not only takes care of the ecology of the city of Kara-Balta, but also does not allow the precious metal to evaporate,” said Vladimir Melnikov.

Cast ingots and graphite molds

In addition to the main work of processing gold supplied from Kumtor Operating Company, the refinery works with private companies that develop small deposits and transport concentrates for processing, which are obtained by washing gold-bearing sands. Agreements have been concluded with Altynken and Full Gold Mining.

We also work with the National Bank. At his request, we certify the gold that the regulator purchases from companies. We test it and put our stamp on it. It is registered on the London Non-Ferrous Metals Exchange. The so-called concept of Good delivery is a good supplier. Gold bearing our hallmark is not tested anywhere else in the world.

Vladimir Melnikov

Determination of the quality of gold in finished bars is carried out at the Central Research Laboratory (CRL), which is part of the KGRK. In March 1998, this laboratory received accreditation from the UK National Accreditation Service (UKAS) to carry out analytical analyzes on Doré alloy, and to certify bars: gold bars - 999.9 fineness, silver - 999.

The plant's products are standard bank bars (with an approximate weight of 12.5 kilograms each) and silver bars of 25 kilograms, as well as kilogram and 100-gram measuring bars.

Ingots weighing from one to 70 grams are produced only by stamping. By casting, a normal ingot is obtained from 70 grams and above.

A separate room has been allocated for the production of those 100-gram bars of the National Bank, which are most popular. Gold is filled with sand into special graphite cells—molds. And then it is melted and cooled.

Next, a stamp is carefully applied to the finished ingots so as not to damage the product. For bars weighing 1 kilogram and 100 grams, in addition to the Kyrgyzaltyn stamp, the fineness and weight must be applied.

To leave the room where gold is refined and bullions are made, we again undergo a thorough search. And this despite the fact that we were accompanied by company employees who monitored every step and movement.

We went out, the solid metal door behind us closed with a roar and the alarm went off. The process of making gold from inconspicuous doré bars continues.

News agency "24.kg". Tatiana Kudryavtseva

Source: https://kbcity.kg/?p=6722

Did you like the article? Share with friends:
Metals and their processing
-- Sideb lion (lipk) -->
How to distinguish real gold from fake

Close
For any suggestions regarding the site: [email protected]
Для любых предложений по сайту: [email protected]