Zinc and its impact on the environment. Reports to Rosprirodnadzor will become every second

Thousands of invisible sensors installed at industrial enterprises in the region will help clear the sky over Chelyabinsk, disperse the smog and rein in polluting factories. Rosprirodnadzor and the Ministry of Ecology have found a way to influence the critical situation with emissions. New project Atmospheric monitoring will allow you to receive data on air conditions online around the clock. Indicators from ultra-sensitive gas analyzers will flow to a single information server and be broadcast via the Internet to general access. Such control will make it possible to decompose the Chelyabinsk air into its ingredients and identify those who have gone too far with emissions. To assess the readiness of industrial enterprises to join the “green” project, the management commission of Rosprirodnadzor, headed by the head of the department for the Urals Federal District Boris Leontyev and the head of the regional administration Vitaly Kuryatnikov, visited the Chelyabinsk zinc plant and assessed the environmental policy of the enterprise, where the growth in production volumes occurs simultaneously with modernization and introduction of clean technologies.

The question hangs in the air

In fact, the Chelyabinsk zinc plant is located in the city - between the Metallurgical District and the north-west - within a large industrial center. Therefore, the industrial facility has always given primary importance to the modernization of production and monitored the reduction of the negative impact on environment. Back in 2011, the plant was one of the first enterprises in Chelyabinsk to sign a contract with the city authorities on cooperation in the field of environmental protection. And today, under this agreement, the results of measurements are transferred in real time to GorEcoCenter and posted on the enterprise’s website. All data is in open access both for supervisory agencies and for ordinary citizens.

To control emissions of sulfur dioxide into the atmosphere during the production of sulfuric acid at CZP, gas analytical complexes manufactured by ZAO ENAL, Moscow, are used. The cost of purchasing gas analyzers amounted to 3.6 million rubles; annual maintenance of the complex is about 350 thousand rubles.

During a visit to the Chelyabinsk Zinc Plant, the head regional administration Rosprirodnadzor Vitaly Kuryatnikov, as a member of the commission, positively assessed the efforts of management to reduce the negative impact industrial production on the ecology of the city:

— The main objective of the visit is the implementation of the air quality monitoring project. To date, the zinc plant has confirmed its commitment to move in this direction,” noted the head of Rosprirodnadzor for Chelyabinsk region Vitaly Kuryatnikov.

Applicable modern technologies emission reductions and environmental measures impressed all commission participants. As part of the delegation, the enterprise was also visited by the heads of the Rosprirodnadzor department of the Kurgan region, Yamalo-Nenets and Khanty-Mansiysk autonomous okrugs.

— The foundations of the environmental monitoring system were laid in 2011. The zinc plant was one of the first in the city to sign an agreement on cooperation with the city administration in the field of environmental protection. So for the seventh year now, the results of measurements have been transmitted in real time to GorEcoCenter and to the official website of the enterprise. The same data is sent to Rosprirodnadzor and the Chelyabinsk administration. Over the past three years, emissions of pollutants into the atmospheric air have not exceeded 30% of the established standard,” said general manager CZZ Pavel Izbrecht.

CZP today is Russia's largest producer of zinc and zinc-based alloys and the only producer of zinc. On the London Exchange this metal is sold at own brand Chelyabinsk Zinc Plant Special High Grade. In addition to zinc, the company also produces sulfuric acid, indium, cadmium.

Let's talk frankly

Over the past nine years, the company has invested more than four billion rubles in environmental protection measures. These funds were used to implement at least six projects to protect atmospheric air, about which CZP management speaks directly:

• acquisition of a mobile atmospheric monitoring laboratory;
• reconstruction of sulfuric acid shop systems and dismantling of technically outdated shops;
• equipping sources of sulfur dioxide emissions in the sulfuric acid shop with gas analyzers for continuous monitoring;
• construction of gas purification systems for furnaces of the roasting shop during their start-up and shutdown;
• construction of a bag filter for air purification when receiving dusty raw materials;
• start of construction of a unit for receiving, unpacking and granulating dust-like VCS.

The main substance that can have a negative impact on the surrounding air is sulfur dioxide produced during the roasting of raw materials. The waste gas utilization technology implemented in the sulfuric acid workshop is recognized as the optimal available technology ITS 13-2016 “Production of Lead, Zinc and Cadmium”. Today, the sulfur dioxide recovery rate at the zinc plant is 99.95%. As a result technical re-equipment and the launch of a Waelz kiln with the organization of a new dust cleaning room, the dust captured in the filter is returned to production. Implementation this project improves industrial and sanitary conditions in the workshop working area, minimizes emissions of pollutants into the atmosphere. Installation costs amounted to 4.5 million rubles.

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For operational monitoring of the state of atmospheric air on the border of the sanitary protection zone, a mobile environmental monitoring laboratory at CZP has been operating since 2010. To create an effective emission control system in Chelyabinsk, the plant transmits measurement results during NMU periods to email at the municipal unitary enterprise "GorEcoCenter". The cost of acquiring the laboratory amounted to 1.3 million rubles. Air samples are taken at seven points, two of them in a residential area - in the area of ​​Aralskaya and Volkhovskaya streets. The station can detect 15 ingredients in the air: in addition to sulfur dioxide, nitrogen dioxide, carbon monoxide, lead, zinc, cadmium and other substances.

According to a comprehensive report on the state of the environment of the Chelyabinsk region in 2016, published on the website of the Ministry of Ecology for the Chelyabinsk region in 2016, emissions from CZP PJSC amounted to 0.4% of emissions in the Chelyabinsk region or 1.7% of emissions in the city. Chelyabinsk.

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— Open environmental policy has been carried out at the enterprise since 2009,” sums up Pavel Izbrecht, General Director of CZP PJSC. — During this time, sulfuric acid systems were replaced and reconstructed, which make it possible to utilize sulfur dioxide formed during the roasting of the concentrate. In addition, the newest Waelz kiln was put into operation in 2016. This is the largest unit worth one and a half billion rubles, which allows us to process not only the waste that is generated at our enterprise, but also waste from other enterprises. We have begun implementing a project to build local treatment facilities and plan to complete it in 2020. The implementation of this project will completely eliminate the discharge of industrial wastewater into the Miass River. The implementation of the above measures allows us to gradually reduce the negative impact of production on the environment.

“The more enterprises that are involved in the projects of Rosprirodnadzor and the Ministry of Telecom and Mass Communications on the territory of Chelyabinsk and Magnitogorsk and, in principle, the region, the easier and clearer it will be for us to work with violators,” Vitaly Kuryatnikov, head of the Rosprirodnadzor department for the Chelyabinsk region, shares his impression of visiting the workshops .

The next step of Rosprirodnadzor will be to check the reliability of the sensor readings transmitted to the supervisory authorities. The information will be made public in order to dispel the veil hanging over the information space and remove mistrust in relation to the data provided on paper. As a result, when the department’s idea is fully implemented, supervisory authorities and ordinary citizens will be able to see the real picture of air pollution from a particular enterprise, and it will become easier to stop the actions of violators.

Can be considered conditionally environmentally friendly. Conditionally - because there is not a single industrial production that does not release into the environment substances that cannot be utilized by nature. Indeed, in this production there are also gas emissions - both from burners (NOx) and from surface preparation baths (volatile acids). Accidental spills of surface preparation substances are possible, usually leading to the release of these substances into either storm drains or municipal wastewater.

Nevertheless, this production is ready to ensure that these emissions do not exceed the maximum permissible parameters, and the planned production waste is either disposed of to obtain useful products, or is converted into non-toxic sludge suitable for storage in household waste landfills with minimal damage to the environment.

The main production wastes at the stage of dipping products into the melt are ash, hardzinc and fugitive dust, which is formed when dipping products into the melt as a result of decomposition of the flux.

The easiest way to dispose of the first two components is to sell them. The fact is that ash contains up to 90%, and hartzink - about 96% of metallic zinc. Until recently, the paint and varnish industry and the production of zinc white were a fairly large consumer of zinc and its compounds. However, at present, zinc white is being intensively replaced from production by other types of white paints, mainly based on titanium dioxide.

Another way to dispose of this waste is to send it to plants for the production of zinc metal. Abroad, there is a certain tax on this waste - approximately 30 and 70% of the price of zinc metal, respectively. However, this method of disposal is acceptable for Western Europe (due to the small transportation distance), somewhat less acceptable for the New World and, probably, unacceptable for Russia due to the small mass of the transported cargo and long distances.

But even in Western Europe, people are thinking about reducing zinc losses and returning at least part of it back into the process. For this purpose they come up with various ways, but they are all based on the physical state of the waste. Let's consider all types of waste separately.

Zolka

Appearance of this waste is depicted on rice. 13.19. Cinder occurs as a result of workers using scrapers to remove the oxide film from the surface of the bath before immersing the products in the melt. In this case, the scraper captures not only zinc oxide (ash itself), but also metallic zinc. This metallic zinc is found in the ash in the form of small drops ranging in size from fractions of a millimeter to several millimeters.

The possibility of the process of returning a significant part of metallic zinc through the following operations was investigated: grinding the ash, sifting into separate fractions and returning part of the fractions to the melt bath. This method has been shown to be cost-effective.

It was also proposed to slightly change the conditions for raking the ash. The ash is not raked outside the bath, but into a special device (ash collector), located at one end of the bath above the melt. Under these conditions, particles of metallic zinc, being under the temperature influence of the melt, flow back into the melt, as a result of which the ash’s chemical composition is increasingly approaching zinc oxide (64% zinc in the compound).

Rice. 13.19. Appearance of ash - one of the main recycled wastes from the hot-dip galvanizing process.

It is also possible that ash may periodically spill onto the surface of the bathtub when the latter is inoperative; in this case, the same processes occur as in the previous case.

The disadvantage of these methods is the presence on the surface of zinc metal droplets of an oxide layer, which does not melt at the bath temperature, and therefore prevents the rapid adhesion of molten particles into larger aggregates. Therefore, special mixtures such as flux-zinc have been proposed, small additions of which significantly speed up the process of processing the ash and make it possible to return up to 80% of the metallic zinc found in the ash to the bath. The chemical composition of the mixtures is not reported, but it can be easily determined chemically. As a rule, this is ammonium chloride or ammonium nitrate, to which some substances have been added to prevent caking and spontaneous explosion.

Installations for mechanically separating zinc droplets from zinc oxide are also offered. According to these methods, the technical product is ground and then sifted into fractions. Zinc oxide, as a more brittle product, turns into a dust fraction, and larger particles become metallic zinc.

Recently, in our opinion, a more progressive method of processing ash in specially designed furnaces has been widely advertised ( rice. 13.20). It has been experimentally shown that during general galvanizing the ash contains up to 70% metallic zinc, and during galvanizing of pipes and galvanizing using centrifuges - up to 80% zinc. At the same time, it has been shown that up to 90% of zinc metal can be recovered from this waste. Practice confirms these conclusions. To operate such a furnace, 10 cubic meters are required. m of combustible gas per hour, the furnace is serviced by one worker, and the cost of regenerated zinc is $0.125/kg, which is more than an order of magnitude cheaper than purchased zinc.

Hartzink (dross)

Hartzinc is an iron-zinc alloy of the approximate formula FeZn 7 with a density of about 7, with a melting point of about 530°C. The ways of its formation are obvious - this is the interaction of molten zinc with iron, which is part of the flux dried on the surface of the product; this is also the interaction of zinc with iron coming out from the surface of the product during the formation of an iron-zinc alloy; this is also the result of the interaction of zinc with the walls of the bath. The resulting hartzinc, being heavier than the zinc melt, settles to the bottom of the bath. In order to more effectively remove hartzink from the bottom of the bath, a lead pad is placed on its bottom. In this case, removing hartzinc using a grab is quite effective. In addition, hartzink does not adhere to the bottom of the bath.

The available manuals do not focus the reader’s attention on the fact that hartzinc crystals, which originate small, continuously grow, and only after reaching a certain size do they begin to sink to the bottom. Different baths, being equipped with burners of different designs, create liquid flows in the baths in different ways. As a result, hartzinc sediment of varying sizes is formed at the bottom of baths that differ in the heating method.

The hartzinc extracted from the bath, being poured into ingots for subsequent disposal, is external signs not much different from zinc metal pigs ( rice. 13.21 ). If you examine its section under a microscope, you can see ( rice. 13.22) that particles of hartzinc “float” in zinc, that is, along with hartzinc, pure zinc also goes into waste. Since waste in the form of hartzinc is a good starting material for obtaining metallic zinc from it again, buyers pay real money for this waste. They usually indicate that they accept harzinc for processing with a concentration of the target product (zinc) of 92-96%. Let's calculate how much excess zinc, still capable of serving technological purposes, is given away at the cost of waste.

Rice. 13.20. External view of the device for processing ash at the galvanizing site and obtaining the final product.

Calculations show that pure hartzinc of the formula FeZn 7 should contain 11.1% iron. In real waste, the iron content ranges from 4 to 8%. Elementary calculations show that with an iron content in hartzinc of 4 and 8%, the proportion of hartzinc in pigs is 36 and 72%, respectively, that is, the content of pure zinc is 64 and 28%.

The latter value is, in principle, equal to the fraction of voids between the dense packing of hartzinc crystals, if the latter are taken to be spherical particles, and a better result can only be achieved using heat treatment waste (more on that later). However, a value of 64% suggests that at least half of the zinc from the waste could have been retained for production. Firstly, it is necessary to take measures to increase the completeness of deposition of hartzinc in the bath - they are being carried out special events– melt bubbling.

There are patent solutions that propose heating hartzinc in a special crucible (similar to the above-mentioned ash solution), as a result of which hartzinc crystals settle to the bottom of the crucible, and metallic zinc appears on top, which can be returned to the bath. It is unknown, however, whether the economic side of the issue has been worked out.

Rice. 13.21.

Rice. 13.22.

At the beginning of April, the head of the city of Belovo, E.A. Panov, held a meeting at which his fate was finally and irrevocably decided zinc plant. True, this was largely facilitated by the fact that the regional governor A.G. Tuleyev, who had visited the city a little earlier, at a press conference expressed himself in the spirit that the zinc plant, which had spoiled a lot of blood for the townspeople, must certainly be closed. And at the meeting it was decided main question: where to get money for salaries and severance pay, where and how to employ able-bodied team members.
No one paid attention to the complaints of the representative of the Maglyuk group of companies, German Lalayan, who organized the processing of lead batteries at the zinc plant without any licenses in primitive Chinese smelting furnaces, about what a good business was conceived and how much money was invested for this. . The bankruptcy manager of the plant, Viktor Vasilyevich Markelov, outlined the difficult situation, saying that 6.8 million rubles are needed for all payments. It is unlikely that they will be able to scrape together without selling industrial facilities.

The zinc plant was put into operation in May 1932. The country needed zinc and it received it. Already in 1935, its production amounted to more than 12 thousand tons. Years passed, volumes grew, the area near the plant within a radius of several kilometers became so saturated with salts heavy metals, which has become unsafe for living. Emissions of harmful substances covered residential areas. However, in a planned economy they did not pay much attention to this.
Along with the restructuring, difficult times began for the plant. In March 1998, the production of zinc and sulfuric acid was stopped here, and a year later it was introduced external control. Since then, the company has gone downhill.

They tried to save it by organizing the recycling of zinc batteries. For these purposes, the Maglyuk group of companies bought the plant, establishing primitive production here. The batteries were broken manually with sledgehammers, and rough lead was smelted from them in workshops in the complete absence of windows, doors and partly a roof. As mentioned earlier, without licenses and other necessary documents.

On December 10 last year, for example, four female workers of Belgos LLC (Belovsky treatment facilities, which are located almost next to the plant) were urgently sent to the intensive care unit of City Hospital No. 8 as a result of emissions from the zinc plant. Such emissions occurred here periodically; not only the workers of the treatment plants located in the sanitary zone of the plant, but also the residents of nearby houses suffered from them.

The zinc plant is bankrupt, the new owners explained, and with the process of its liquidation, construction of a new enterprise is underway - the Belovsky Lead-Zinc Plant. Therefore, primitive processing of raw materials is a necessary measure, because people need to be paid wages. And then we will establish an environmentally friendly, highly profitable enterprise.

The raw material used was recycled lead from used lead-acid batteries, which were supplied here from almost all over the country by the Maglyuk Group of Companies as a customer-supplied raw material. She took it finished products, and the plant received money for remelting services. The group specializes in the production of commercial lead and alloys and owns three enterprises: in the Moscow region, Krasnoyarsk Territory and Belov. In January 2004, the zinc plant produced 120 tons of rough lead, in April – 370 tons and continued to increase volumes. This is despite the fact that Belovo occupies one of the first places in Russia in terms of contamination with heavy lead salts. Everyone knew about it, but preferred to keep quiet. True, after a collective complaint from treatment plant workers about emissions, after which they began to experience nausea, dizziness, and poor health (it was signed by more than 30 treatment plant workers last year), the city council held a press conference dedicated to the problems of the plant. But the specific position of the people’s representatives was never stated. Yes, production is harmful, but it’s a pity for the team, who will take care of the factory veterans, will the city really lose another enterprise - this was approximately the point of view of the deputies. The statement of the doctor of the Center for Sanitary and Epidemiological Inspection V. Gunin that the plant can only operate if there is a project, a license, an environmental assessment and other things, somehow passed by the parliamentary attention.

The city prosecutor's office took up the collective complaint of wastewater treatment workers, and involved relevant specialists in the inspections. It was revealed that three workers had already been taken away " ambulance“- they began to have convulsions. It turned out that in smelting shops lead aerosols exceed the permissible limit by 10 times, and phenol vapors by 1.4 times. According to the State Sanitary and Epidemiological Supervision authorities, under such working conditions the development of severe forms of occupational diseases is very likely.

The prosecutor's office appealed to arbitration court, which appoints bankruptcy trustees with a request to relieve V.V. Markelov from his position, and also prepared a corresponding submission on the closure of the proceedings. The owners of the plant wrote a complaint to the regional prosecutor's office against the actions of prosecutor Belov V.S. Chernykh and continued to recycle batteries.
The actions of the prosecutor's office did not go unnoticed - it issued a decision on August 12, and 5 days later, by order No. 55 of the manager of the zinc plant, V.V. Markelov, lead processing was stopped. On paper. On September 27, a criminal case was opened regarding the release of harmful substances into the atmosphere under Article 251. Part 1 of the Criminal Code, which implies a fine of up to 80 thousand rubles for the guilty person, or corrective labor for up to one year, or deprivation of the right to hold office for a period of 5 years.

Nevertheless, the new executive director of the plant, D.S. Stepanov, by his order, overturned the decision of the bankruptcy trustee and, from November 1, allowed the recycling of batteries. And on December 10, not only four sewage treatment workers were poisoned. Many residents of nearby houses, workers of enterprises and organizations felt unwell that day. On this day there was severe frost and emissions spread across the ground. The results of analyzes and samples showed that in the premises the maximum permissible concentration of formaldehyde and phenols was 32-38 times higher than the norm, and lead aerosols – 313.5 times! This aerosol belongs to the first class of danger, negatively affects the entire body, including the nervous system, protein balance of cells, immune, cardiovascular systems and is very difficult to remove from the body.
The city prosecutor's office opened a criminal case under Article 251.2 on the fact of the release of harmful substances into the atmosphere, causing harm to human health. It involves punishing the perpetrator with imprisonment for up to two years. Executive Director D.S. Stepanov was prosecuted under Article 19.20 of the Code of Administrative Offenses.

The public's outrage at the shameless attitude towards their health on the part of the Maglyuk Group of Companies and the persistent actions of the city prosecutor's office were supported by the authorities. The result was the final closure of the zinc plant. They also found the money needed to pay salaries and severance pay. Today, the company is selling machines and equipment, remaining building materials, and industrial facilities are being put up for auction. In the future, it is also planned to clean the plant area from harmful substances. The 73-year history of the zinc plant is finally and irrevocably completed.

Nikolaev Alexander

Zinc and its impact on the environment

1. Anthropogenic sources of entry into the environment

The main source is the release of zinc into the atmosphere at high temperatures technological processes. In this way, plus losses during transportation, enrichment, and sorting, from 1995 to 2005, 700 thousand tons of zinc were dispersed throughout the world. As a result of burning coal in 1980 137.5 thousand tons entered the atmosphere, by 2000 this figure increased to 218.8 thousand tons. The zinc content in the air in the area of ​​the non-ferrous metals recycling plant is: within a radius of 300 m -0.350 mg/m 3; 500m - 0.285 mg/m3, 1000m - 0.148 mg/m3, 2000m - 0.52 mg/m3. Metallic zinc is oxidized by atmospheric oxygen and precipitates in the form of ZnO oxide. On average, 72 kg of zinc falls annually on 1 km2 of the Earth's surface with atmospheric precipitation - three times more than lead, and 12 times more than copper. Significant amounts of zinc enter the soil with solid waste from brown coal power plants. In the area of ​​one of the zinc smelters, within a radius of 0.8 km, the zinc content in the surface layer of soil reached 80 mg/g. Within a radius of 1 km from the zinc plant, the zinc content in the green parts of vegetables is 53 -667 mg/kg, in root vegetables - 3.5 -65 mg/kg, in the soil -42 -40 mg/kg of dry residue.

Wastewater containing zinc is not suitable for irrigating fields. Failure to comply with hygiene standards led in Japan to an outbreak of severe musculoskeletal disease in the population who consumed rice grown in irrigation fields, where irrigation water was used that was heavily contaminated with zinc sulfide and cadmium.

Sludge poses a particular danger to the oceans waste water and the wastewater itself from chemical, woodworking, textile, paper, cement production, as well as mines, mining and smelting plants, and metallurgical plants. The threshold concentration of zinc, which reduces the efficiency of wastewater treatment by 5%, is 5-10 mg/l. A serious source of zinc entering water is its leaching with hot water from galvanized water pipes up to 1.2-2.9 mg from a surface of 1 dm2 per day. Summing up all anthropogenic sources, the total volume of zinc entering the environment is 314 thousand tons per year.

. Chemical and physical properties of zinc and its compounds

Zinc (Zincum) Zn is a chemical element of the 12th (IIb) group of the Periodic table<#"603625.files/image001.gif">

9. Methods for purifying emissions produced into the atmosphere from zinc and its compounds (selected ZnO compound)

Since the selected zinc compound - zinc oxide - is a fine powder - medium-fine dust, methods for purifying gases from solid particles will be considered.

Modern gas dust removal devices can be divided into four groups:

) mechanical dust removal devices in which dust is separated under the influence of gravity, inertia or centrifugal force.

) wet or hydraulic apparatus in which solid particles are trapped in a liquid.

) porous filters on which the smallest dust particles settle.

) electric precipitators in which particles are deposited due to the ionization of gases and dust particles contained in it.

For emissions containing this zinc compound, the most suitable treatment methods to use are porous filters, because they have the highest dust collection efficiency and are suitable for this type of particles.

Filters. In dust collectors of this type, the gas flow passes through porous material of varying density and thickness, in which the bulk of the dust is retained. Cleaning from coarse dust is carried out in filters filled with coke, sand, gravel, nozzle various shapes and nature. To remove fine dust, filter material such as paper, felt or fabric of varying density is used. Paper is used to purify atmospheric air or gas with low dust content. In industrial conditions, fabric or bag filters are used. They take the form of a drum, cloth bags or pockets working in parallel.

The main indicator of a filter is its hydraulic resistance. The resistance of a clean filter is proportional to the square root of the radius of the fabric cell. The hydraulic resistance of a filter operating in laminar mode varies in proportion to the filtration speed. As the layer of dust deposited on the filter increases, its hydraulic resistance increases.

Wool and cotton were previously widely used as filter fabrics in industry. They allow you to purify gases at temperatures below 100ºС. Now they are being replaced by synthetic fibers - chemically and mechanically more resistant materials. They are less moisture-intensive (for example, wool absorbs up to 15% of moisture, and tergal only 0.4% of its own weight), do not rot and allow the processing of gases at temperatures up to 150ºC. In addition, synthetic fibers are thermoplastic, which allows them to be installed, fastened and repaired using simple thermal operations.

Filter bags Some synthetic fabrics are made in the form of an accordion using heat treatment, which significantly increases their filtering surface with the same filter dimensions. Fabrics made of glass fiber, which can withstand temperatures up to 250 0 C, began to be used. However, the fragility of such fibers limits the scope of their application.

The development of production of metal-ceramic products has opened up new prospects in dust removal. The FMK metal-ceramic filter is designed for fine purification of dusty gases and capturing valuable aerosols from waste gases of chemical industry enterprises, non-ferrous metallurgy and other industries. The filter elements, fixed in the tube sheet, are enclosed in the filter housing. They are assembled from metal-ceramic pipes. A layer of trapped dust forms on the outer surface of the filter element. To destroy and partially remove this layer, back blowing with compressed air is provided. Specific gas load 0.4-0.6 m 3 / (m 2. min). The working length of the filter element is 2 meters, its diameter is 10 cm. The dust collection efficiency is 99.99%. The temperature of the purified gas is up to 500 0 C. The hydraulic resistance of the filter is 50-90 Pa. Compressed air pressure for regeneration is 0.25-0.30 MPa. The period between blowings is 30-90 minutes, the duration of blowing is 1-2 s.

One of the industrially produced bag filters and its characteristics are presented below.

Bag filter with mechanical regeneration of bags FRM-S.

Bag filters with mechanical regeneration of bags of the FRM-S type are reliable and effective dust collecting devices designed to capture fine dust from the air and non-flammable gases.

Scope of application: in the production of building materials, woodworking, technological processes of ferrous and non-ferrous metallurgy, etc.

The filter element of bag filters is a sleeve made of a special material, which is selected based on the operating conditions of the Customer’s installations. Regeneration is carried out by shaking the sleeves using an electromechanical vibrator.

Design and principle of operation:

The principle of operation of the filter is based on the capture of dust by a filter cloth as dust-laden air passes through it. As the thickness of the dust layer on the surface of the hoses increases, the resistance to air movement increases and decreases throughput filter, to avoid which, regeneration of dusty hoses is provided using electromechanical vibrators.

Dusty air enters the filter (Fig. 1) through the air duct through the inlet pipe (1) into the dusty air chamber (2), passes through the sleeves (3), while dust particles are retained on their outer surface, and the purified air enters the clean air chamber. air (4) and through the outlet pipe (5) is removed from the filter.

Regeneration of dusty hoses is carried out by turning on an electromechanical vibrator (6) for a short time, mounted on a mounting frame (7) mounted on vibration isolators (8).

Dust shaken off the hoses falls into the hopper (9) and is removed from the filter by the sluice feeder (10).

Specifications

The ruins of the Electrozinc electrolysis workshop after the fire. Photo: Farniev Konstantin

It is no secret that emissions from factories and industrial enterprises are one of the main sources of air pollution, and wastewater discharges from them cause significant harm to the hydrosphere. However, when the work of one plant threatens the life and health of 300 thousand people, it is dangerous to remain indifferent.

"Electrozinc" is the largest industrial enterprise Republic of North Ossetia, occupying 70.2 hectares in the north-eastern part of the regional capital, Vladikavkaz, and one of the leading non-ferrous metallurgy enterprises in Russia, which has been producing and selling zinc, cadmium and sulfuric acid since 1904.

And “Electrozinc” is an air polluter, whose activities have caused acute dissatisfaction among Vladikavkaz residents for at least 9 years. Local residents still remember October 5, 2009, when a thick veil formed as a result of an industrial release of sulfur oxide at a plant above Vladikavkaz. Townspeople began to complain of severe headaches and sore throats. On the day of the accident, more than 500 people gathered for a spontaneous rally demanding a referendum on stopping the operation of the enterprise. By the end of the month, five more emergency emissions above the limit occurred at the plant. Since then, rallies for the closure of Electrozinc have been held regularly. Although the first protests against the work of the enterprise began back in 2003: soon after the Ural Mining and Metallurgical Company (UMMC) became its owner, local residents began to complain about harmful emissions into the atmosphere.

It should be added that the sanitary protection zone around the plant is only 300 meters - it is at this distance that residential development begins (by law, enterprises of the first hazard class, which is Electrozinc, must be at least 1000 meters away from residential areas) . Although the “zone of influence” of the enterprise is far from being limited to one kilometer, but extends to almost the entire Vladikavkaz.

The storage areas for production waste are also a serious problem: huge mounds located within the city are open to wind and rain.

The head of the Russian Ministry of Natural Resources, Dmitry Kobylkin, reported on November 7 that the Electrozinc plant complied with all environmental requirements. “According to our line of Rosprirodnadzor, there have never been any comments against him. He always fulfilled everything we asked and demanded,” the minister said.

This confirms fears that it will not be possible to close the plant and rehabilitate the surrounding areas or at least reduce its emissions to acceptable levels in the near future. Scientist and public figure Tamerlan Kambolov created a petition on the website Change.org addressed to the president Russian Federation with a request to immediately and permanently close Electrozinc. To date, the petition has been signed by more than 26 thousand people.