8«Инновационные аспекты развития науки и техники» UDC 67.08
Geraybeyli Samira Aslan qizi Герайбели Самира Аслан кызы
Senior laboratory assistant Старший лаборант Azerbaijan State Oil and Industry University
Азербайджанский государственный университет нефти и промышленности
TREATMENT AND DISPOSAL OF SOLID WASTE CONTAINING
USEFUL SUBSTANCES
ОБРАБОТКА И УТИЛИЗАЦИЯ ТВЕРДЫХ ОТХОДОВ, СОДЕРЖАЩИХ ПОЛЕЗНЫЕ ВЕЩЕСТВА
Abstract: The method is based on the treatment of slags formed during the combustion of solid household waste using natural minerals as modifying components. This paper discusses the results of studies conducted using two modifiers-natural dolomite and phosphogypsum, formed during the production of phosphoric acid.
Аннотация: Способ основан на обработке шлаков, образующихся при сжигании твердых бытовых отходов с использованием природных минералов в качестве модифицирующих компонентов. В настоящей работе рассматриваются результаты исследований, проведенных с использованием двух модификаторов -природного доломита и фосфогипса, образующихся в процессе производства фосфорной кислоты.
Key words: solid waste, slag, modifier, phosphogypsum, dolomite, phosphorus.
Ключевые слова: твердые отходы, шлак, модификатор, фосфогипс, доломит, фосфор.
Population growth, rapid economic growth, rapid urbanization and an increase in the standard of living in communities have significantly accelerated the rate of solid waste generation. At the same time, improper handling and disposal of solid waste is a serious problem: they lead to the deterioration of the urban environment in the form of air, water and land pollution, which creates risks for human health and causes a number of environmental problems [1].
XIIIМеждународная научно-практическая конференция
The continuous growth of the population has significantly increased the demand for building materials. The increased demand for building materials causes a number of problems. Only 55-65% of the extracted minerals are used in the construction sector. The rest of the past of them remains unused. As a result, a huge amount of solid waste is released into the environment, disrupting the ecological balance. One of the ways to solve the problem of solid household waste is their incineration for the purpose of obtaining energy. According to calculations, when burning about 1500-1700 tons of solid waste, a certain amount of ash and slag residues is formed, including 300-350 kg of bottom ash and 30-35 kg of fly dust [2].
They have not found their purposeful application to date. It should be noted that there are some factors that limit the use of these spent slags, regardless of the method of their production and the volume of reserves. One of these factors is that many of them do not contain enough nutrients. The problem can be solved by improving their quality by processing compounds or waste that has an inexhaustible supply.
Phosphogypsum is a huge and burdensome waste for the production of concentrated simple and complex fertilizers. As the production of phosphorus-containing fertilizers develops, the problem of phosphogypsum utilization becomes more and more urgent for many reasons, including transportation of phosphogypsum to landfills and its storage, which causes great environmental damage. 0.1% of fluorine is released when phosphogypsum is introduced into landfills. It is well known that phosphorus (P) is the second important key plant nutrient after nitrogen (N), which strongly affects the overall growth of plants, affecting key metabolic processes such as cell division and development, energy transport (ATP, ADP), signal transduction, macromolecular biosynthesis, photosynthesis and plant respiration [3]. Thus, the demand for phosphogypsum both in the construction industry and in agriculture reaches 20 million tons per year.
«Инновационные аспекты развития науки и техники» During the production of phosphoric acid, phosphogypsum is formed by the following reaction:
CaF(PO4)3 + 5H2SO4 + mH2O ^ (n+3) H3PO4 + 5CaSO4 . mH2O
+ HF
During the production of 1 ton of phosphoric acid, 3.5-4.2 tons of phosphogypsum are formed. Another waste used in research is sulfuric acid, which is formed at oil refineries. Phosphogypsum, natural dolomite and sulfuric acid are used for processing slags formed during the incineration of solid household waste. The main goal when using dolomite mineral was to increase the Mg content in the final product intended for use in agriculture to increase soil fertility. Sulfuric acid is used to provide the product with sulfur, which is one of the important macronutrients for plants in the soil [4, 5]. The slag samples used in the research were collected at the Baku Balakhan incineration plant. The content of 2 slag samples is shown in table 1.
Table 1. Results of analyses of slags obtained during the incineration of
solid household waste (mass%)
Sampl es Na2 O Mg O A12O 3 SiO 2 P2O 3 K2 O Ca O TiO 2 Mn O Fe2O 3 YTI x
1 5,82 2,42 4,12 14,8 2,12 2,2 7 32, 5 0,83 0,21 10,3 19,5
2 2,92 1,26 1,52 6,53 0,94 7,1 4 34, 6 0,98 0,24 3,90 21,1
*Note: The content of the components changes at 6000C.
Phosphogypsum formed during the production of phosphoric acid has the following content (mass%): Ca0-33.0; S03-47.0; P2O5total-1.6; P205prod-0.6; P203- 0.6; Fe203-0.2; Mg0-0.5; F-0.34; residue after calcination-17.9. The content of spent sulfuric acid was (mass%): H2S04-66.5; H3P04- 9.5 and the rest consists of water. A surfactant, alkylarylbenzenesulfonate (CAA), was used to dilute sulfuric acid.
XIIIМеждународная научно-практическая конференция
The content of another modifier-natural dolomite of Azerbaijani deposits was as follows (mass%): CaO- 30,1; MgO- 21,56; CO2- 42,75; CuO- 0,10; Fe203-0,12; MnO- 0,10; Al2O3- 0,11; NiO- 0,11; ZnO- 0,13; H20- 3,0.
In the case of non - condensing gaseous fuels (mass%): CaO - 55,97; MgO - 2,33; CO2 - 32,48; Al2O3 - 2,0; Fe2O3 - 0.2; Na2O - 0.5; SiO2-3.0; sodium -5.0.
The first sample was used in our experiments. The experiments were carried out as follows: 20 ml of an aqueous solution of CAA and 50 ml of sulfuric acid were added to a glass reactor with a capacity of 50 ml. Then 100 g of slag, 25 g of phosphogypsum and 25 g of dolomite were added to the reactor for 30 minutes, gradually stirring for 60 minutes. The process was stopped and dried and crushed shells were added to the product until a pH of 6.0-6.5 was reached. The solid phase was separated from the liquid phase. Both the solid and liquid phases were analyzed. To select the optimal process conditions, experiments were carried out with different contents of acid, phosphogypsum, dolomite and a surfactant containing water [6]. The amount of slag remained unchanged. The results of the experiments are shown in
table 2.
Table 2. The amount of the resulting product depending on the amount
of raw materials (kg)
Experiment number The material used Products Degra dation rate %
Slag Phospho gypsum Dolomit e H2SO 4 CAA solution Solid Liquid
1 100 25 25 50 20 65 155 92
2 100 20 20 60 20 70 150 93
3 100 30 15 55 20 64 156 90
4 100 35 15 50 20 60 160 94
5 100 40 10 45 25 52 168 91
6 100 24 26 45 25 47 173 90
7 100 40 10 50 20 57 163 87
Fig. 1. Technological installation for the production of fertilizers, meliorants and plant protection products based on slag, sludge and natural mineral compounds:1-a bunker of slag formed during the combustion of solid waste; 2-a container for nitric acid; 3-a bunker for oil well sludge; 4-a bunker for phonolite rock; 5-a bunker for lime solution; 6-a dispenser; 7-a screw; 8-a granulator; 9-a drying apparatus; 10-an elevator; 11-sieves; 12-a retort line; 13-a shredder;
14-a line of finished products.
The slag obtained during the incineration of solid household waste is filled into the hopper (1). Spent nitric acid is poured into the container (2). First, the lower lid of the hopper (1) opens, and the slag located there falls
21
XIIIМеждународная научно-практическая конференция on the auger (7), acid is also fed here from the container (2). After a short time, oil well sludge from the hopper (3) and phonolite from the hopper (4) enter the auger. After that, crushed and dried news from the container (5) is added to the porridge located on the auger (3). All the materials on the screw first enter the dispenser (6), and from there to the granulator (8), the drying apparatus (9), then to the elevator (10), and the sieves (11). In sieves, it is divided into three parts: a part with a size of 0.5-1.0 mm enters the retort line (12) into the granulator, a part with a size of 1.0-5.0 mm enters the consumer as a finished product (14), and the part with a size exceeding 5.0 mm enters the shredder (13). Large parts b are crushed in a shredder and returned to the process.
Conclusions. The analysis of the slags formed during the combustion of solid household waste showed that they contain a certain amount of batteries. It is established that both phosphogypsum formed during the production of sulfuric acid and sulfuric acid formed at oil refineries are inexhaustible sources of P and S for plants in the soil. Processing of these wastes together with natural dolomite mineral will make it possible to provide agriculture with high-quality fertilizers, so that plants can consistently absorb nutrients. Taking into account the research results, it can be concluded that waste incineration cannot be a solution to the problem. For more effective waste management, new technological options should be developed and applied.
List of literature
1. Mineral resources of the Krasnoyarsk territory, the Inventory of mineral deposits /ed. by S.S. Cardiaca Krasnoyarsk TERRITORY, 2002, p.582.
2. Pozin M.E., Kopyshev, A.B., Alosmanov S M. Technology of mineral salts. Ed. Chemistry, Leningrad, 1989, P.81.
3. Bruce F. // Chem. Eng. News, 2016, v.53, № 27, P.9-15.
4. Kononov A.V. Sterlin V. N., Evdokimova L. I. fundamentals of the technology of complex fertilizers. M., "Chemistry", 1988, P.307.
5. Pozin M. E. Technology of mineral salts. Ed. L., "Chemistry", 1991, P.1326 - 1327.
6. Karmashov V. F. Chemical processing of phosphate rock. M.: CHEMISTRY, 1983, p.300.
