Development of a complex of technologies for processing 3-5 hazard class wastes to produce useful products
Summary
Industrial wastes of 3-5 hazard classes are: slags and ash from boiler houses and thermal power plants, slags of ferrous and non-ferrous metallurgy, calcium sulfate (gypsum), thermophosphoric slags, pyrite (pyrite) stubs, waste of ferrous and non-ferrous metals in mechanical engineering, electronics and electrical industry, as well as waste of polymer composite materials including rubber products and others.
Air protection from harmful and toxic substances is one of the central problems of modern science and technology. As a rule, waste gases contain from 0.05 to 0.4 vol.% of toxic compounds that, according to sanitary standards, should not be emitted into the atmosphere without an additional purification. In many branches of chemical, metallurgical, electronic, fuel and other industries primarily associated with high process temperatures, mixtures of gases containing nitrogen oxides and, in some cases, nitric acid vapors, come out of reactors. The capture of these gases and vapors by conventional sorbents to the required degree of purification requires a long time of contact between the contaminated gases and sorbents, which requires a large volume of sorbent used each time. The cost of the sorbent is relatively high, which results in the high cost of gas purification in general. In addition, it is necessary to dispose of or bury the spent sorbent, which involves additional equipment and energy costs. Of particular importance is the purification from nitrous gases generated in industrial and household waste incineration plants that have recently been actively used.
The total amount of nitrogen oxides produced annually is 70 million tons per year.
The method for capturing nitrous and oxide compounds from industrial gases analyzed in the project allows to reduce the required volume of equipment for purifying industrial gases from nitrous compounds. The spent absorbent solution of manganese nitrate is a valuable market product with a high cost. The project plans to develop a technological process for the separation of pure commercial manganese nitrate and its purification.
In addition, it seems highly important to develop a flexible universal technology for creating block catalysts for purifying waste gases with a reduced content of precious metals. Reduction and, in some cases, complete exclusion of precious metals is possible due to the introduction into the structure of the catalyst compounds of compositions of transition metal compounds, which occur in significant (for catalyst production) quantities in various man-made waste.
Undoubtedly, it is promising to create a database of man-made waste that can become raw material for the production of gas purification catalysts. The relevance of the above is also due to the fact that presently there is an increase in the already existing shortage of carriers, sorbents, and catalysts – especially those intended for special purposes. This shortage is not only in quantity but also in quality and, above all, in assortment. The problem is exacerbated by the destruction or reprofiling of most of the few experimental industrial centers producing catalysts over the past decade. These centers used to be able to produce small-scale and experimental products of a diverse range with specific properties and guarantee their reliability.
To solve this problem, the project plans to:
- develop a technology of metal catalysts with oxide film and porous coating of foil of metals and alloys, including waste from machine-building industries (wire, chips, tapes), as well as block catalysts of cellular structure based on them;
- investigate the processes of extraction of catalytically active metals (Co, Ni, Mn, W, etc.) from spent industrial catalysts and man-made waste containing transition metal compounds and creation of thin-layer catalytic coatings based on them.
During the operation of non-ferrous metallurgy, petrochemical and chemical industry enterprises, waste containing such valuable components as rare, non-ferrous or precious metals is generated in quantities often exceeding their content in primary ores and concentrates that undergo processing. The volumes of some of these wastes can be very large. This allows to consider the waste mentioned above as promising raw materials for obtaining additional quantities of scarce and valuable metals. Simultaneously, a significant environmental problem of disposing of waste often occupying large spaces can also be solved.
In order to solve the problem, the project plans to develop the following technological processes:
- extraction of molybdenum, nickel or cobalt from spent catalysts of hydrotreating oil with simultaneous utilization of the catalyst base – aluminum oxide;
- extraction of rhenium and platinum from spent oil reforming catalysts;
- extraction of rhenium from copper-nickel production dusts;
- extraction of vanadium from iron-containing waste of vanadium production;
- additional extraction of platinum metals from spent noble metal refining solutions;
- processing of sludge from grinding of carbide blanks into pure tungsten and cobalt compounds in order to return them to the production cycle;
- utilization of cubic residues of dehalogenation processes to obtain commercial zinc compounds.
As reported by the Federal State Statistics Service, about 40 billion tons of solid and liquid industrial waste has been to date accumulated on the territory of the Russian Federation. According to expert estimates, the waste occupies from 4 to 7 million hectares of land. The rate of industrial waste generation is 5–7% per year or 6.0–7.0 billion tons/g.
More than 90–93% of the waste generated at the enterprises of the extractive sector of the economy is generated during the extraction of minerals: carbonates, natural gypsum, granite rubble, sand and clay, phosphorus fertilizers, alumina, oil shale, coal, oil, gas, diamonds, iron oxides and non-ferrous and polymetallic ores, etc.
The remaining 7-10% of waste is generated in processing industries: metallurgical, machine-building, electronic, electrical, chemical, petrochemical, agro-industrial complex, construction, transport, etc.
The proposed solutions to the urgent problem of processing industrial waste and the use of valuable components in industrial production fully comply with the priority areas delineated in the "Strategy of Scientific and Technological Development of the Russian Federation" approved by Decree of the President of the Russian Federation No. 642 of December 01, 2016, as well as the main provisions of the Decree of the President of the Russian Federation No. 204 of May 7, 2018: "On national goals and strategic objectives of the development of the Russian Federation for the period up to 2024" and "Industrial development strategies for the processing, disposal and disposal of production and consumption waste for the period up to 2030" (Decree of the Government of the Russian Federation No. 84-r dated 25.01.2018), as well as the goals and priorities of National Projects “Ecology” and “Digital Economy”.
