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Sulphuric Acid on the WebTM Technical Manual DKL Engineering, Inc.

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Acid Plant Database  July 17, 2014

Owner Lead-Zinc Complex AD - Kardjali (LZC AD - Kardjali)

LZC-AD-Kardjali-Logo.jpg (6360 bytes)


127 Boulevard Bulgaria
6600 Kardjali
Republic of Bulgaria


Also OTsK AD

Website www.ock-bg.com
Plant -
Coordinates* 41° 37' 43" N, 25° 24' 21" E
Type of Plant Metallurgical
Gas Source


Plant Capacity 300 MTPD, 93 to 98.5% H2SO4
Emissions SO2: <100 ppm
Status 2012 - Bankruptcy
Year Built -
Technology Outokumpu Technology (Outotec)
Contractor -

- Outokumpu Technology provided know-how, engineering and basic engineering of equipment for the roaster and sulphuric acid plant for €35 million.
- Acid plant occupies an area of 1680 m2  

Power Consumption
- Roaster: 1400 kWh/h, 112 kWh/tonne (acid)
- Gas cleaning and acid plant: 1300 kWh/h, 104 kWh/tonne (acid)

Pictures LZC AD - Kardjali 1.jpg (150770 bytes)
General 1955 – Production begins on the site with 5000 tons zinc and 7000 tons sulphuric acid
Reference -
News March 27, 2014 - The construction of the new zinc plant in Kardzhali Bulgaria is set to begin in a Canadian-Spanish and German cooperation. The involved companies will be Canadian SNC-Lavalin, German Outotek and Spanish Asturiana, announced Harmony 2012 , the new owner of the metallurgical plant. John Elkin , the director of Harmony 2012 explained that the principal activities of the manufacturing plant will begin within two months, which will make room for new facilities, Standart wrote.The project includes the construction of an entirely new roasting plant, a new plant for the production of sulfuric acid and a new electrolyte facility. The new factory is to be built according to world standards and will meet all environmental standards and requirements, the management says.The construction of new plants is necessary due to the full amortization of the existing industrial buildings, installations and equipment. American Chamber of Commerce, Bulgaria

December 7, 2013 - The construction works for the new zinc plant at the site of bankrupt lead and zinc smelter OTZK Kardzhali are to start in June 2014.  The clearing of the production site is to start in early 2014, according to Kardzhali District Governor Biser Nikolov.  Nikolov, as cited by the BGNES news agency, presented the plans on Saturday, expressing hopes that the municipal authorities would make sure that the necessary permits were issued as soon as possible.
  "The Canadian company which signed a contract for the construction of the plant with the new owner of the lead and zinc smelter, Harmony 2012, is a representative of the Bloomberg Holding," Nikolov said.  In early November, Harmony 2012 announced that Canadian company SNC Lavalin had been selected as the main contractor for the project for the overall renovation and upgrade of the zinc plant at the site of OTZK in Kardzhali.  Harmony 2012 plans to conduct a large-scale reconstruction and modernization of the factory buildings, to replace all of the machines and equipment, and to build a modern lead and zinc smelter by Bulgarian and Balkan standards.  The company has assured that the new plant will be in line with environmental standards.  Offshore company Harmony 2012 was registered at the time when the news broke out that the previous owner of the lead and zinc smelter, Valentin Zahariev, would have to sell the heavily indebted plant.  In September 2012, Harmony 2012 bought the plant, which had run up debts of BGN 350 M, for BGN 8.6 M.  Harmony 2012 has been largely associated with Bulgaria's First Investment Bank, which is one of the biggest creditors of OTZK.  The debt of OTZK to First Investment Bank amounts to EUR 30 M.  In end-November 2013, the Kardzhali District Court declared OTZK bankrupt due to huge debts of the previous owner to creditors, partners, etc.

November 30, 2012 - Lead-Zinc Complex AD - Kardzhali (LZC AD - Kardzhali) has made 520 redundancies due to bankruptcy. Up to 30 employees will remain in the company, according to statements from the new CEO, Valentin Minev. The few employees that will remain on the insolvent firm’s payroll will facilitate the sale of certain assets and the changeover to the new owner Harmony 2012.  Most employees have left the company in the last couple of weeks, so this month the labour inspectorate was informed of only 72 official dismissals on 7 December 2012. The workers had been striking for months due to long-overdue wages. Many of them decided to resign, while others were made redundant. According to reports the unions have criticized that the company proceeded without formally consulting them.  LZC Kardzhali is the second biggest zinc smelter in Bulgaria. The company’s biggest competitor in the country is Plovdiv-based KCM. LZC Kardzhali exports 85 percent of its output, mostly to Italy, Germany, Austria and Turkey. It is not clear when the new owner, Harmony 2012 will resume production.

September 14, 2012 - After more than a year of uncertainty over the future of the country’s largest non-ferrous metal producer LZC, reported in previous newsletters, the Kardzhali plant was sold this month to Harmony 2012 Ltd. While four hours before the bidding deadline no offers had been submitted, three bids emerged last minute. The plant was sold for 8.6 million Lev (4.4 million euro) and includes the plant’s premises and land but not its machines. The total debt of the plant under its current owner is estimated at 350 million Lev (179 million euro).

June 1, 2012 - The Polish consortium Silesia and the majority owner of the troubled Lead and Zinc Complex (LZC; OTZK) in Bulgaria's Kardzhali will sign a 3-year management contract.  The news emerged after a meeting of the Control Board of the Complex and the Board of Directors of Intertrust Holding, which is the majority owner.  In a statement to the Bulgarian Stock Exchange, the Holding grounds the decision to finalize negotiations with Silesia on the lack of real investor's interest, social and public tensions, and the opinion of bank lenders.  The largest Bulgarian producer of non-ferrous metals, the Lead and Zinc Complex (LZC; OTZK) in the southern city of Kardzhali has been in trouble for at least several months now, with many fearing that the heavily indebted LZC, which has been out of operation in the past four months, will have the fate of Kremikovtzi, the behemoth steel mill near Sofia, which no longer operates as a result of years of mismanagement.  The creditors and trade unions have agreed to seek a way to fuel the Lead and Zinc Complex in Kardzhali again.

On April 12, after 40-day protests over delayed salaries, the workers at the Lead and Zinc Complex received some of their money, totaling BGN 500 000, which were distributed on as a result of the sale of another troubled company, the Gorubso-Madan mining firm.  Both the LZC and Gorubso-Madan were part of Intertrust Holding owned by Bulgarian tycoon Valentin Zahariev.  However, both have descended into debt, leading to workers' protests, and an intervention by the state arranging the sale of both companies by Intertrust Holding.  Zahariev owes a total of BGN 1.4 M in unpaid salaries to the Lead and Zinc Complex workers, and the payment of the January salaries came after 42-day protests by the plant workers which started in Southern Bulgaria and reach the capital Sofia.  Zahariev has raised the needed cash through the sale of the Gorubso mines in the southern town of Madan.

Bulgaria's government has indicated that the LZC in Kardzhali is also for sale, and that there are three bidders – one Bulgarian and two foreign – vying for it. However, Bulgaria's Finance Minister and Deputy PM in charge of the economy Simeon Djankov never specified which the bidders were, with the news about the interest expressed by the Polish consortium first emerging on April 20.  Initial data indicate that Zahariev's debts already amount to BGN 360 M, and are way beyond the earlier known figure of BGN 320 M.

A total of 519 employees of the Lead and Zinc Complex in Kardzhali, the leading Bulgarian non-ferrous metals producer, had not received salaries for half a year.  In early April, the workers filed personal claims in Court against the owner of the plant, Bulgarian oligarch Valentin Zahariev, who is also known for mismanagement of what used to be the largest steel-maker in Bulgaria, the now bankrupt Kremikovtzi plant near Sofia. They demand the replacement of the entire management, starting with him.  The Lead and Zinc Complex is still owned by Zahariev, the now-former owner of the Gorubso Madan metal mines. Gorubso Madan miners finally received their overdue wages after they had been staging protests for two weeks.Businessman Nikolay Valkanov has taken over the concession of the Gorubso Madan metal mines from Valentin Zahariev. Valkanov is a former VP of Multigroup, the company of Bulgarian tycoon Iliya Pavlov, who was shot dead in 2003. Valkanov currently owns "Minstroy" and Gorubso Zlatograd, another mining company in Southern Bulgaria, and has a concession of the "Varba" mine.  It was reported on May 20th that Valkanov has created jobs for 60 workers from the OTZK.

September 26, 2011 - The Administrative Court in Kardzhali has confirmed a fine of BGN 60 000 imposed on Bulgarian lead and zinc smelter, OTZK, over its noncompliance with the integrated environmental permit.  Viktor Atanasov, head of the administrative court in the Southeastern Bulgarian town, announced Monday that this was the biggest penalty upheld so far in the region.  Among the breaches committed by OTZK-Kardzhali are the uncontrolled release of harmful gas emissions as part of the production process and the impermissible content of dust and sulfur dioxide around the chimneys of the plant.  The company owned by Valentin Zahariev's Intertrust Holding explained its failure to observe the environmental standards with the insufficient time it had been given to select an external contractor to build a cleaning facility and the inability of the company to allocate money for such programs due to intercompany indebtedness and the financial crisis.  Kardzhali's Administrative Court, however, did not accept the motives, stating that OTZK had had plenty of time to ensure compliance, given that the Ministry of Environment and Water issued the permit back in 2006.  The fine was imposed after a check of the Haskovo Regional Inspectorate of Environment and Water carried out after multiple reports of industrial air pollution.  In 2010, OTZK broke air pollution norms 88 times, and in 2009 it breached legal limits 203 times, compared to the EU cap of 24 instances of pollution per spot per year.  The serious environmental violations exposed Bulgaria to the threat of a new infringement procedure launched by the European Commission.  As a result, OTZK announced a halt of lead production in April 2011.  The Kardzhali-based lead and zinc smelter is to unveil a new lead plant.  Valentin Zahariev has threatened to sue Bulgaria for missed profits amounting to BGN 46 M due to the excessively delayed procedures for evaluating environmental impact.  The company has already lodged a claim for BGN 7 M with the Administrative Court in Kardzhali. 

April 18, 2011 - Olovno Tzinkov Komplex AD, a Bulgarian lead and zinc smelter run by Intertrust Holdings AD, was ordered to close its lead unit because of excessive pollution.   The Kardjali-based smelter exceeded its annual limit of 24 lead and sulphur dioxide emissions above a specified level by April 12, the Environment Ministry said on its website.   “About 350 people will be laid off and we need to coordinate this with government authorities,” Roberto Mladenov, Intertrust’s executive director, said in a phone interview today. “The order to close the lead unit was issued this morning.”  Intertrust seeks $70 million to upgrade the unit by 2013, to meet European Union anti-pollution requirements, Intertrust Chairman Valentin Zahariev said in a March 15 interview.  The closure won’t affect zinc production, Mladenov said. Intertrust is investing 50 million euros ($72 million) to expand the zinc smelter. It plans to have a new electrolyte unit in operation by the end of the year and to re-equip two more zinc units next year, Zahariev said. Zinc output will be 20,000 tons this year, the same as in 2010, he said.  Bulgaria is recovering from its first recession in more than a decade after foreign investment dried up during the global credit crisis. The EU’s poorest country in terms of per- capita GDP is counting on demand for its exports, including metals and machinery, to boost growth to 3.6 percent this year after 0.2 percent in 2010.  Intertrust runs five metal, tool and engineering plants in neighboring Serbia, and the Gorubso mines at Madan, in Bulgaria. The company exports 85 percent of its output, mostly to Italy, Germany, Austria and Turkey, Zahariev said. The company’s biggest competitor in Bulgaria is Plovdiv-based KCM.

November 25, 2009 - The southern Bulgarian city of Kardzhali has once again seen increased levels of sulfur dioxide (SO2) pollution.  The Regional Environment and Waters Directorate in the city of Haskovo has announced that Kardzhali suffered sulfur dioxide levels well above the legal limit in the afternoon and early evening hours on Tuesday.  The sulfur dioxide concentration was 534 micro grams per cubic meter of air at 3 pm, 1 104 micro grams at 4 pm, and 938 micro grams at 5 pm on Tuesday, according to the Environment Directorate; the legally allowed limit is 500 micro grams per cubic meter of air.  According to the BGNES news agency, a number of local people with chronic diseases such as asthma, lung and heart problems have complained over the pollution, which caused their condition to deteriorate.  The Environment Directorate informed the local authorities immediately but has failed to use the specially installed siren warning system in order to alert the population.  The Directorate did send a recommendation to the Lead & Zinc Complex Plc to stop immediately the output of one of its divisions which is believed to have caused the pollution.  The management of the lead and zinc plant is reported to have complied immediately with the prescriptions of the environment watchdog but the high levels of sulfur dioxide in the air above Kardzhali remained for more than three hours. This is believed to have been the result of the meteorological conditions at the specific moment.  At 6 pm Monday night, the sulfur dioxide levels dropped down to 142 micro grams per cubic meter of air.  A similar increase of sulfur dioxide levels was registered in Kardzhali on November 19, 2009, when for two hours they were above the 500 micro gram threshold in the early afternoon hours.  Kardzhali has been having problems with sulfur dioxide pollution for a long time with critical air levels being reached about every other month.

September 25, 2007 - Outotec has been awarded a contract for the supply of a new zinc roaster with gas cleaning and sulphuric acid plant for OZK Kardzhali, the second biggest zinc smelter in Bulgaria. The contract value is approximately €25 million. Outotec’s scope of delivery covers engineering and supply of the roasting, gas cleaning and acid technology as well as supervision services for the erection and commissioning of the plant. The mechanical completion of the project is scheduled for mid 2009.  The new zinc roaster is part of OZK Kardzhali’s €68 million investment program, which will double the production of high-grade zinc by 2009. The roaster train supplied by Outotec will replace the existing 50-year-old roasters of Russian design. Outotec’s process not only increases the efficiency but also improves the energy recovery and environmental conditions of the smelter by reducing dust and sulfur dioxide gas emissions.

MTPD - Metric Tonne per Day           STPD - Short Ton per Day
MTPA - Metric Tonne per Annum      STPA - Short Ton per Annum
SA - Single Absorption
DA - Double Absorption

* Coordinates can be used to locate plant on Google Earth