Vacuum Technology for Soil Demercurization
Development of Vacuum Technology and Equipment for Demercurization of the Mercury-Polluted lands of the "Pavlodar Chemical Plant" OJSC
Tech Area / Field
- ENV-SPC/Solid Waste Pollution and Control/Environment
8 Project completed
Senior Project Manager
Zalouzhny A A
Institute for Metallurgy and Ore Concentration, Kazakstan, Almaty
- Pavlodar Chemical Plant, Kazakstan, Pavlodar reg., Pavlodar\nThe S. M. Kirov Machine Building Plant OJSC, The Science and Technology Center “Lama”, Kazakstan, Almaty\nJSC "KK Interconnect", Kazakstan, Almaty\nNational Nuclear Center of the Republic of Kazakstan / Institute of Nuclear Physics, Kazakstan, Almaty
- Center for Advanced Mineral & Metallurgical Processing, USA, MT, Butte\nBrookhaven National Laboratory, USA, NY, Upton
Project summaryThe aim of the project is a creation and implementation of ecologically safe vacuum-thermal technology and apparatus for the demercurization of the wastes and lands of electrolysis shop №31 from OJSC "Pavlodar Chemical Plant" in such away that not only to clean contaminated materials, but also to produce more than 800 tons of mercury contained in lands.
During electrolytic production of chlorine and caustic soda on OJSC "Pavlodar Chemical Plant" as cathode was used metallic mercury. For 19 years of work in walls, concrete floors and in lands under shop has been collected more than 900 tons of mercury, which is gradually moving to the river Irtysh and endangers with global contamination of the North Arctic Ocean.
In the recommendations of the International Technical Conference by the problems of the Northern region of Kazakhstan on May 1998, the task of demercurization of the materials of OJSC "Pavlodar Chemical Plant" was introduced in to the list of the top-priority works (project № 6). The main quantity of mercury ( more than 800 tons) is situated in the lands under shop № 31 (mean contents 4,2 % Hg).
Vacuum technology is one of the most ecologically clean and effective methods of processing of natural and industrial raw materials, containing mercury, arsenic and other toxic elements, because of the speeding up of all the sublimation processes, dust entrainment, improvement of the process of condensation of vapor and metals selection.
Study of the mercury sublimation process and its compounds from lands with allow to find out the peculiarities of metals vaporization in vacuum from porous bodies and to specify the constructive peculiarities of the apparatus for this process.
Theoretical bases and technologies of vacuum-thermal extraction of mercury from mercury, mercury-antimony concentrates from dust of agglomeration mills of lead production are developed by Institute of Metallurgy and Ore Beneficiation. Basic blocs of continuously-working equipment for mercury sublimation from solid products are worked off and tested. It was shown by the plant tests in Khaidarkan Mercury Plant (KMP, Kirgizija), that at 350-4500С, pressure 30-50 mm of Hg during 10-15 minutes is sublimated 99-99,8 % of mercury from concentrates specific productivity of apparatus is 5-8 t/m2-during 24 hours, the mercury discharges with gases were cut in 400-1000 times at the expense of the decrease of gases volume in 30-70 times and decrease of concentration in them of mercury in 10-20 times. In 1990 this developed vibro-vacuum equipment was put into industrial exploitation on KMP.
Technology is developed, vacuum apparatus with periodic action for the deep sublimation of mercury from gold-containing schlocks is implemented into exploitation on Stepnogorsk GMZ.
2 monographs, more than 20 articles are published, 1 doctoral thesis and 6 candidate theses are defended, 6 patents are received in Kazakhstan and Russia by the results of studies done.
In the result of fulfillment of the project it will be purified all the lands in the amount of OJSC "Pavlodar Chemical Plant" in the amount of 12000 m3 and will be produced 800 tons of commercial mercury onto the sum of 2,8 millions US$.
3 doctors, 6 candidates of sciences and 20 qualified engineers and designers -specialist in the field of metallurgy and development of the new technologies are participating in the fulfillment of the project.
This project foresees:
1. Conducting of enlarged tests in vacuum-thermal processing of mercury-polluted lands and preparation of information for the industrial apparatus development.
2. Preparation of design-technological documentation and development industrial vibro-vacuum equipment with the productivity 25 tons per 24 hours for demercurization of mercury-polluted lands.
3. Testing, implementation of the industrial equipment and processing of mercury-polluted lands (12 000 m3) with the production of commercial mercury (800 tons).
Processing of the offers in industrial processing of other kinds mercury-containing industrial row materials.
Work on the project will be done during 3 years by the scientists and specialists in the field of creation and rocket technique, and future it would be possible to include here considerably more number of specialists indicated during designing and making of the equipment, development of the technologies and organization of industrial processing of new types mercury-containing industrial row materials. The fulfillment of this project will allow to prevent ecological catastrophe and to solve the important social problem in creation of the new working places.