Our aim is to build a profitable plant to produce high-purity manganese products that will also respect the principles of sustainability.
We are planning to open the new production plant of MANGAN Chvaletice in the industrial premises of EP Chvaletice in 2027. The plant will utilize state-of-the-art technologies for waste material recycling and for the production of high-purity manganese. It is an innovative technological procedure based on commercially used technologies, tailored to the production of high-purity manganese products from the Chvaletice deposits. We have consulted with experts in relevant fields worldwide on each phase of our project. The production technology will be tested in the verification unit: a pilot plant to be opened in the spring of 2023 at the EP Chvaletice industrial site.
Obtain high-purity manganese products by recycling the tailings
Stop groundwater contamination
Reclaim the locality
The process starts by removing the waste material, gradually taken from only a small portion of a pile each time. A hydraulic excavator will be used to load the waste material onto trucks. The trucks will transport the waste material to a storage area near the pulping station. The storage area and the pulping station will be situated in the free space between two tailings. The waste material will be transferred using an automatic crane from the storage area to a coarse screen to separate the larger impurities (roots, stones, etc.).
This roughly cleaned waste material will enter pulping tanks where it will be stirred in circulating water to obtain a suspension with the consistency of thin yoghurt.
The suspension will be pumped through a pipeline located in the pipeline bridge crossing the railway corridor and the road between Chvaletice and Přelouč, into a stack in the processing part of the plant.
An intense magnetic field will be used to increase the concentration of manganese compounds, resulting in an enriched waste material containing approximately 15% manganese, and a non-magnetic share with a minimum residual content of manganese. The waste concentrate will then undergo leaching – in closed and centrally ventilated leaching tanks, after the addition of sulphuric acid. Gases resulting from the process will be scrubbed on a continuous basis in a unit designed to clean industrial gases by water spraying. The water will be treated in an industrial water circuit purifier and reused after cleaning.
The washed and dewatered non-magnetic tailings will be transported across the pipeline bridge, back to the tailings pile area using a closed tubular conveyor.
Here it will be stacked into a pre-prepared deposition area. Water from pressure filters will be pumped back to the pulping station in the area of the piles where it will be reused to prepare a fresh suspension of the waste material.
As the leaching process dissolves a number of compounds contained in the tailings, it is necessary to remove unwanted soluble salts before further processing of the manganese sulphate solution. The resulting filtrate – a cleaned solution of manganese sulphate – is ready for electrowinning. In the electrowinning step, manganese metal, one of the target products, is deposited from the solution onto the stainless steel cathodes. The depleted solution after electrowinning (anolyte) still contains a certain amount of manganese, and is therefore returned to the leaching tanks. This reduces manganese losses as well as the amount of waste or by-products.
In order to protect the environment and the workers, a modern electrowinning method where selenium is not used as an additive will be applied. Ammonium sulphite will be used instead of selenium compounds. For the same reason, no hexavalent chromium compounds will be used to stabilize the deposited manganese metal; instead, hot water will be used, followed by hot air drying. The electrowinning cells will be centrally ventilated and gases will be scrubbed on a continuous basis. The water used for scrubbing will be treated in an industrial water circuit purifier and reused after cleaning.
A layer of the manganese metal settles on the cathodes during the electrowinning step. The cathodes are then transported to a “peeling machine”. This machine mechanically separates the fragile layer of manganese from the flexible electrode. This process results in manganese flakes 0.5 – 0.7 mm thick. The manganese flakes are packed in barrels and dispatched to customers, or are used in the second production step to make manganese sulphate monohydrate. The dewatered material from the leaching step still contains a considerable amount of manganese sulphate and other salts. These salts need to be recovered and returned to the production process. Residual manganese is precipitated from the solution and the precipitate is returned to the leaching step. This minimizes any losses of manganese.
Approximately 30% of manganese obtained by electrowinning should be dispatched directly to customers. The rest will be processed to manganese sulphate monohydrate. The manganese metal flakes obtained in the previous production step will be dissolved in a closed reactor in diluted sulphuric acid at about 60 °C for several hours. The chemical reaction between the manganese and the sulphuric acid will produce a manganese sulphate solution and gaseous hydrogen. The manganese sulphate solution will be purified in the next step to remove any trace amounts of certain metals, particularly zinc and iron. Additionally, the purified manganese sulphate solution will pass through several treatment steps to obtain dry crystals. The hydrogen will be scrubbed and dried for further use – for example, for steam production.
Washed waste material from the production process will be stacked in a pre-prepared deposition area, in the area of the former tailings. The dry-stacking piles will be designed in accordance with applicable regulations: upper and lower isolation of the material, drainage to collection tanks, and a stable slope of the sides to eliminate any possibility of slippage. The purpose of these measures is to minimize any negative impacts on the groundwater and on the surroundings of the dry-stacking piles. Once the design height of the dry-stacking piles is reached, continuous reclamation work will be carried out.
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