UDK:629.4.016./66.01.02. 08./ 661.862.666.32

TECHNICAL AND ECONOMIC ASSESSMENTS OF THE TECHNOLOGY OF PRODUCTION OF UNPURIFIED AND PURIFIED COAGULANT FROM KAOLIN CLAYS OF THE DEPOSIT « CHASHMA-SANG »

* Naimov N.A., ** Rajabzoda N.Kh., *** Mirsaidov U.M.

*Research Institute of the Tajik National University

**JSC "Tajik Aluminum Company"

** *Chemical, Biological, Radiation and Nuclear Weapons Agency

security of the National Academy of Sciences of Tajikistan

It is obvious that the progress and development of technology and engineering definitely require an improvement in the quality of life, one of the aspects of which is the improvement of the supply of clean drinking water. However, the provision of high-quality drinking water is becoming increasingly difficult and thus there is a need to increase the capacity of water treatment systems using various coagulants and flocculants [1,2].

Aluminum sulfate is one of the most common coagulants for clarification and preparation of drinking water [3-6], it is traditionally obtained from bauxite-containing and other alumina-containing ores using the Bayer process [7].

However, our republic does not have bauxite deposits that would have industrial significance. But Tajikistan has a huge potential for the presence of deposits of low-quality alumina-containing ores, such as the deposits of kaolin clays " Ziddi ", muscovite -staurolite shales " Kurgovad ", nepheline syenites " Turpi ", etc. In this article, kaolin clay of the deposit " Chashma-Sang " was used as an example. According to geological studies, the total reserves of kaolin clays of the deposit " Chashma-Sang " in the Republic of Tajikistan in categories C, + C ₂ are 1958892 tons, including category C, - 478190 tons and C ₂ – 1,480,702 tons [8].

Based on this, using kaolin clays from the Chashma-Sang deposit, a method of sulfatization was previously studied and tested in laboratory and pilot-industrial conditions with the aim of obtaining unrefined and purified coagulants [9-11].

Sulfatization process depends on various process parameters. For example, the sulfatization process of kaolin clays from the Chashma-Sang deposit occurs at a temperature of 200-280 ºС, a process duration of 60-90 min., a sulfuric acid concentration of 95-98%, and a sulfuric acid dosage of 100-110% of stoichiometry. With such parameters, the degree of aluminum sulfate extraction reaches more than 90%.

Based on laboratory studies, a general equipment and technological scheme for the complex processing of alumina-containing ores by the sulfatization method was developed (Fig. 1).

Fig. 1. Apparatus-technological scheme of sulphatization line of aluminum-containing ores

As can be seen from Figure 1, the technology of complex processing of alumina-containing ores by the sulfatization method consists of 7 positions in 4 variants , which covers the production of several important products.

Based on this, first of all, the chemical composition of kaolin clays of the Chashma-Sang deposit was determined ( wt.% ): SiO ₂ – 67.1, Al ₂ O ₃ – 22.8, Fe ₂ O ₃ – 2.5, K ₂ O – 0.5, CaO – 1.8, MgO – 0.8, Na ₂ O – 0.6, P.P.P. – 0.8.

During sulfation of kaolin clays, the following chemical reactions may occur:

            (1)

             (2)

                                        (3)

                                      (4)

                                                   (5)

                                                       (6)

This article examines the technical and economic assessment (TEA) of the production of unrefined and refined coagulants from kaolin clays of the Chashma-Sang deposit according to the material balance (reaction 1-6) and positions A, B, C and I of the general equipment and process flow diagram in Fig. 1.

According to position A of the general process flow diagram (Fig. 1), the following equipment is planned to be used in the production of crude coagulant (Fig. 2):

Fig. 2. Apparatus-technological scheme of crude coagulant production

• Jaw crusher brand APZh-1525E, with a productivity of 4 t/h and a power of 5.5 kW/h;
• Drum-type ball mill type F1200×3000, with a capacity of 4 t/h and a power of 37 kW/h;
• Screw conveyor brand LVT159, with a capacity of 12 t/h and a power of 5 kW/h ;
• Hopper-dispenser brand UZHIM 597.15.00.000, with a volume of 12 m3 and a power of 5.5 kW/h.
• Sulfuric acid flow meter US-800, 5 W/h.
• Vertical screw mixer LVGran-10, with a volume of 10 m3 ^, a power of 11 kW/h and a loading capacity of 7 tons;
• Tunnel conveyor furnace (in the gas cleaning shop), gas consumption 45 m3 /h, productivity 10 t/h ^;
• Furnace conveyor with a capacity of 4 kW/h;
• Smoke exhaust engines 49.5 kW/h (9 pieces*5.5=49.5 kW/h);
• Blower fan motor 33 kW/h (first 15 + second 18=33 kW/h);
• Drum-type ball mill type F1200×3000, with a capacity of 4 t/h and a power of 37 kW/h;

In accordance with the technological regulations for the implementation of chemical technologies in industry, one of the main factors in the process of implementation in production is the implementation of technical and economic calculations [12-14].

It is important to note that most of the above-mentioned equipment is installed in the gas cleaning shop of  OJSC TALCO and the implementation of this technology is possible at this enterprise. Therefore, the feasibility study was carried out in accordance with the productivity and technical capabilities of the equipment involved in the gas cleaning shop.

The conveyor furnace capacity is 10 t/h of products, for the sulfatization process approximately 5 t/h of kaolin clay and 4.4 t of sulfuric acid (in total 9.4 t of charge) will be needed. Based on this, a stoichiometric calculation of the sulfatization process was carried out . According to laboratory studies, during the sulfatization of 10 g of kaolin with 8.8 g of sulfuric acid (in total 18.8 g of charge) approximately 17 g of sulfated sinter . Based on this, during the sulfatization of 9.4 tons of charge, 8.5 tons/hour of sinter should be formed ( ), which, according to the stoichiometric calculation, contains 3.435 tons of anhydrous aluminum sulfate and 0.265 tons of anhydrous iron sulfate (in total 3.7 tons/hour).

Thus, we will calculate the corresponding expenses. The price of sulfuric acid is 1000 somoni/t. If the carrying capacity of the acid carrier is 30 tons, the fuel consumption is 30 liters of diesel fuel (10 somoni/l) per 120 km, then the cost of transportation from the city of Yavan to the city of Tursunzade will be 300 somoni. Based on this, if the cost of 30 tons of sulfuric acid with transportation is 30300 somoni, then the cost of one ton of acid with transportation is 1010 somoni/t. The consumption of natural gas for 1 hour is 45 m3 ^at a cost of 1000 m3 taking into account transportation to OJSC TALCO is 1640 c (150 dollars). Table 1 shows the costs and prices of reagents and fuel.

Table 1. Consumptions of reagents and fuel at sulfatization of kaolin

clay 5 t/h

No.	Name of expenses	Unit of measurement	Expenses	Price, somoni
1.	Sulfuric acid 95%	t/h	4.4	4444
2.	Kaolin clay	t/h	5	1100
3.	Natural gas consumption	m3 / h	45	73.8
4.	Amount of expenses	-	-	5617.8

 

Let's calculate the energy consumption for the process of sulfation of 5 t/h of kaolin clay. If 5.5 kW/h is consumed for crushing 4 t/h of raw material, then for crushing 5 t = 6.87 kW/h, for grinding 4 t of raw material 37 kW/h, then for 5 = 46.25 kW/h, for transferring 12 t of raw material using a screw conveyor 2.5 kW/h is consumed , then for 5 t = 1.04 kW/h, for transferring 12 t of raw material from a dosing bin 5.5 kW/h, then for 5 t = 2.3 kW/h, for mixing 5 t/h of the mixture in a vertical mixer 11 kW/h, then for mixing 9.4 t/h (5 + 4.4 = 9.4 t/h) = 20.68 kW/h, with a furnace conveyor capacity of 10 t/h 4 kW/h is consumed, then for 9.4 t/h = 3.76 kW/h, engines smoke exhausters have a total capacity of 49.5 kW/h, the blower fan motor 33 kW/h, a ball mill with a capacity of 4 t/h consumes 37 kW/h, then for 8.5 t = 78.62 kW/h. Table 2 shows the electricity consumption taking into account the cost (1 kW of electricity = 0.20 somoni).

Table 2. Electricity consumption in the process of obtaining 8.5 t/h of crude coagulant while sulphatising 5 t/h of kaolin

No.	Name of equipment	Consumption, kW/h.	Price, somoni
1.	Jaw crusher	6.87	1.37
2.	Drum type ball mill	46.25	9.25
3.	Screw conveyor	1.04	0.208
4.	Hopper-dispenser	2,3	0.46
5.	Vertical auger mixer	20.68	4,136
6.	Furnace conveyor	3.76	0.752
7.	Smoke exhauster engines	49.5	9.9
8.	Blower fan motor	33	6.6
9.	Drum type ball mill	78.62	15.72
10.	Total consumption	242.32	48,46

 

Thus, taking into account the data given in tables 1 and 2, the total cost of obtaining 8.5 tons of unrefined coagulant is 5617.8 + 48.46 = 5666.26 somoni.

            The results of the technical and economic calculations for the production of 1 ton of unrefined coagulant obtained from kaolin clays of the Chashma-Sang deposit by the sulfatization method are presented in Table 3.

Table 3. Technical and economic calculation of production of 1 tonne of untreated coagulant

No.	Name of expenses	Unit measured .	Raw material consumption per 1 ton of product	Price per 1 ton of product
				somoni	dollar
1	Raw materials with transportation	kg	526	115.5	10.6
2	Concentrated sulfuric acid	kg	517	522.2	47.9
3	Natural gas for sulfation	m 3	5.3	8.7	0.8
4	Electricity	kW/h.	Total: 28.5	5.7	0.52
5	Total	-	-	625.1	57.34
6	World price	T	-	5450	500

 

According to the calculations, if up to 8.5 t/h of unpurified coagulant can be obtained per hour, then 204 t of unpurified coagulant can be obtained per day (24 hours). Thus, the annual productivity of the workshop for the production of unpurified coagulant, without taking into account the number of non-working days, the necessary repair work, etc., can be 74460 t.

Next, we will calculate the feasibility study for the production of purified coagulant from 8.5 tons of sulfated sinter according to the highlighted part (Pos. B and C in Fig. 3) from the general hardware and process flow diagram (Fig. 1).

Fig. 3. Apparatus-technological scheme of purified coagulant production

 

According to the technology, the process of aqueous treatment of sulfated Sintering is carried out at a temperature above 60 °C, for 30 minutes and a solid:liquid ratio of 1:3. Table 4 shows the equipment used in the water treatment process.

 

Table 4. Name of equipment used

No.	Name of equipment	Unit of measurement	Performance	Consumption, kW/h	Price, somoni
1.	Reactor-stirrer	m3 / h	6	5.5	1,1
2.	Stirred reactor steam generator	-	-	30	6
3.	Drum vacuum filter BOR5-1.75	t/h	14-18	4.4	0.88
4.	Total consumption	-	-	39.9	7.98

 

When processing 1 ton of sinter with water , approximately 3 m3 of water is consumed ^, the approximate price of which is 3 somoni/m3..

If the reactor capacity is 2 t/h of sinter and 6 m3 ^/ h of water, then the power consumption for processing 8.5 t of sinter is 150.8 kW/h (8.5*35.5/2=150.8). Based on this, the cost of electricity for processing 8.5 t of sinter is 30.19 somoni (150.8*0.20=30.16). Also, if 3 m3 of water is consumed to process 1 ton of sinter , then 25.5 m3 (8.5*3/1=25.5 m3) is needed to process 8.5 t , the cost of which is about 76.5 somoni (1m3 ^– 3 somoni). In addition, if the productivity of a drum vacuum filter is up to 18 t/h (with a power of 4.4 kW/h), then the power consumption for filtering 34 t of pulp (8.5 + 25.5 = 34 t) is 8.31 kW/h (34 * 4.4 / 18 = 8.31).

Thus, the amount of consumed electricity will be 159.11 kW/h (150.8 + 8.31 = 159.11 kW/h) and the cost will be 14.11 somoni (159.11 * 0.20 = 31.82 somoni). According to the stoichiometric calculation, when processing 1 ton of kaolin clay, taking into account 10% losses, 0.687 tons of anhydrous aluminum sulfate and 0.053 tons of anhydrous iron sulfate are formed.

Based on this, when sulfatizing 5 tons of kaolin, 3.435 tons of aluminum sulfate (5*0.687 = 3.435 tons) and 0.265 tons of iron sulfate are formed, totaling 3.7 tons of anhydrous coagulant.

Considering the water consumption for water treatment of 8.5 tons of sinter (25.5 m3)  without taking into account losses, it is possible to produce 25.5 m3 liquid coagulant containing 134.7 g/l of aluminum sulfate ( ) and 2.078 g/l of iron sulfate ( ).

Also, as a by-product, finely ground (less than 0.1 mm) quartz sand remains in the amount of 4.8 tons (8.5 - 3.7 = 4.8 tons).

The costs of water treatment of 8.5 tons of unrefined coagulant and the cost of liquid purified coagulant are given in Table 5.

Table 5. Costs for processing 8.5 tons of sinter and cost of liquid purified coagulant

No.	Name of costs	Unit of measurement	Expenses	Price
				somoni	dollar
1.	Water	m 3	25.5	76.5	7.01
2.	Electricity	kW/h	159.2	31.84	2.92
3.	Unpurified coagulant	T	8.5	5666.26	519.8
4.	Cost of liquid coagulant	m 3	25.5	5774.6	529.7
5.	The amount of finely ground quartz sand remaining as a by-product is 4.8 tons (100*4.8=480 somoni)

 

According to stoichiometric calculations, 5 tons of kaolin (8.5 tons of sinter ) produce 3.435 tons (5*0.687/1=3.435 tons) of anhydrous aluminum sulfate and 0.265 tons of iron sulfate, for a total of 3.7 tons of anhydrous coagulant. Aluminum sulfate is a hygroscopic substance, i.e., under normal conditions, aluminum sulfate absorbs up to 18 water molecules and iron sulfate up to 9 water molecules. Based on this, according to calculations with the inclusion of water molecules, from 5 tons of kaolin, taking into account 10% losses, it is possible to obtain approximately 6.689 tons of aluminum sulfate crystal hydrate (Al ₂ (SO ₄ ) ₃ •18H ₂ O) and 0.372 tons of iron sulfate crystal hydrate (Fe ₂ (SO ₄ ) ₃ •9H ₂ O) in total 7.061 tons of mixed coagulant crystal hydrate. That is, from 25.5 m ³ of a sulfate mixture containing 134.7 g/l of aluminum sulfate and 2.078 g/l of iron sulfate, it is possible to obtain 7.061 tons of crystal hydrates with natural evaporation.

Let us calculate the costs of obtaining 1 ton of purified mixed coagulant from kaolin clays. According to the calculations, 25.5 m3  of sulfate solutions are consumed to obtain 7.061 tons of mixed coagulant crystal hydrate, and 3.611 m3 of solutions  are consumed for 1 ton . The crystallization process of the sulfate-containing solution is carried out naturally, using solar heat. The results of the calculations for obtaining 1 ton of purified coagulant are given in Table 6.

Table 6. Technical and economic calculations of the process of obtaining 1 tonne of coagulant crystalline hydrate

No.	Name of costs	Unit measured .	Expenses	Price for 1 ton of products
				Somoni	dollar
1.	Water	m 3	3.06	9.18	0.84
2.	Electricity	kW/h	22.54	4.5	0.41
3.	Unpurified coagulant	T	1,2	802.46	73.62
5.	Cost of coagulant	-	-	816.1	74.87
6.	World price	T	-	5450	500
7.	The amount of finely ground quartz sand remaining as a by-product is 0.68 tons (100*0.68=68 somoni)

 

Also, according to the calculations, if more than 7 t/h of aluminum and iron sulfate crystal hydrates (mixed coagulant) can be obtained per hour, then 168 t of mixed coagulant can be obtained per day (24 hours). Thus, the productivity of the workshop for the production of purified mixed coagulant from kaolin clays per year can be 61,320 t, without taking into account the number of non-working days, the necessary repair work, etc.

According to previously conducted laboratory tests at the State Unitary Enterprise “ Dushanbevodokanal ”, the produced (unpurified and purified) coagulants can be used in the purification of drinking and waste water, and the introduction of this technology through the use of local mineral raw materials and domestic sulfuric acid gives a significant economic effect.

Technical and economic calculations show that the cost of 1 ton of unrefined coagulant obtained using this technology is approximately 625 somoni ($57), and the cost of 1 ton of purified coagulant is 816 somoni ($75).

At the same time, the cost of 1 ton of coagulant produced using imported aluminum hydroxide at TALCO Chemical LLC is approximately 2,800 somoni ($250), while on the world market the cost of 1 ton of coagulant is 5,000 somoni ($458).

Thus, the calculations carried out show that the cost of purified kaolin coagulant, excluding wages and existing taxes, is almost 3 times lower than the cost of local coagulant and more than 5 times lower than imported coagulant.

REVIEWER: Samikhzoda Sh.R.,

Doctor of Technical Sciences, Professor

REFERENCES

1. Farhaoui, M. Optimization of Drinking Water Treatment Process by Modeling the Aluminum Sulfate Dose / Farhaoui, L. Hasnaoui, M. Derraz / British Journal of Applied Science & Technology. – 17(1). – 2016. – Pр. 1-14. DOI:10.9734/BJAST/2016/26840
2. Zapolsky, A. K. Coagulants and flocculants in water treatment processes: Properties. Preparation. Application / A.K. Zapolsky, A.A. Baran // – L.: Khimiya. – 1987. – 208 р.
3. Koohestanian, A. The Separation Method for Removing of Colloidal Particles from Raw Water / Koohestanian, M. Hosseini, Z. Abbasian // American-Eurasian Journal of Agriculture and Enviromental Science. – 2008. – Vol. 4. – No. 2. – Pр. 266-273.
4. Ismail, A.K. Energy saving during alum production from kaolin with coproduction of alumina-silica composites from process silica wastes / K. Ismail // in Mineral Processing Technology. – 2010. – Pр. 781-787.
5. Arnoldsson, E. Assessment of drinking water treatment using Moringa oleifera natural coagulant / E. Arnoldsson, M. Bergman, N. Matsinhe, K. M. Persson. – Vatten. – Vol. 64. – 2008. – Pр. 137-150.
6. Apostol, G. Optimization of coagulation-flocculation process with aluminum sulfate based on response surface methodology / Apostol, R. Kouachi // I. Constantinescu. – UPB Scientific Bulletin. – Vol. 73. – No. 2. – 2011. – Pр. 1454-2331.
7. Pehlivan, A. Alumina extraction from low grade diasporic bauxite by pyro-hydro metallurgical Process / Pehlivan, A. O. Aydin, A. Alp // – SAÜ Fen Bilimleri Enstitüsü Dergisi. – Vol. 16. – No. 2. – 2012. – Pр.982-987.
8. Yorov, Z.YO. Mineral raw material base of chemical and metallurgical industry of Tajikistan / Z.YO. Yorov, Sh.O. Kabirov, A. Murodiyon, N.M. Sirodjev // – Dushanbe, 2012. – Rep. in “Mega Basym”, Istanbul, Turkey. – 416 р.
9. Naimov, N.A. Production of pilot batch of crude and purified coagulant from kaolin clays of “Chashma-Sang” deposit by sulfatisation / N.A. Naimov, U. Mirsaidov, J.R. Ruziev, A. Murodiyon, H.A. Mirpochaev, H. Safiev // – Bulletin of Technological University. – 2024. – Vol. 27. – No. 2. – Pр. 50-56.
10. Ruziev, J.R. Complex processing of kaolin clays of Tajikistan by sulfatisation method / J.R. Ruziev, N.A. Naimov // – Collection of articles of the Republican Scientific and Practical Conference “Prospects for the development of innovative technologies of production of inorganic substances and materials in the conditions of globalization” (with the participation of foreign scientists). – Tashkent, 9-10 November. – 2023. – Pр. 202-204.
11. Naimov, N.A. Technology of processing kaolin clays deposit “Chashmasang” by sulfatisation / N.A. Naimov, J.R. Ruziev, F.D. Ibrohimzoda, G. Aminjoni // – Proceedings of the International Scientific and Methodological Conference on the theme: “Progress Science Chemistry, Technology and Ecology” dedicated to the 20th anniversary of the Department of “Chemical Technology and Ecology” and “Twenty years of study and development of natural-mathematical and exact disciplines in the field of science and education”. – Dushanbe, 12-13 May 2023. – Pр. 37-39.
12. Boitsova, E.L. Feasibility study of designing a chemical production shop / E.L. Boitsova, F.A. Voroshilov, E.V. Menshikova // – Textbook, Tomsk Polytechnic University, Tomsk: Izd-vo Tomsk Polytechnic University. – 2019. –85 р.
13. Dybina, P.V. Calculations on technology of inorganic substances / P.V. Dybina, S. Solovyova, Y.I. Vishniak // – M.: Higher School. – 1967. –524 р.
14. Naimov, N.A. Feasibility study of production of crude coagulant from kaolinite-containing clays of “Ziddi” deposit / N.A. Naimov // Polytechnic Bulletin. Series: Engineering Research. – № 1 (57). – – Pр. 107-110.

TECHNICAL AND ECONOMIC ASSESSMENTS OF THE TECHNOLOGY OF PRODUCTION OF CRUDE AND PURIFIED COAGULANT FROM KAOLIN CLAYS OF THE

CHASHMA-SANG DEPOSIT

In article presents a feasibility study of the process of obtaining crude and purified coagulant for the treatment of wastewater and drinking water from kaolin clays in the deposit «Chashma-Sang» by sulfatisation. The process of sulfatisation of kaolin clays proceeds at temperature 200-280 °С, duration 60-90 min, concentration of sulphuric acid 95-98%, dosage 100-110% of stoichiometry. At the same time the degree of extraction of aluminium sulphate is more than 90%. On the basis of laboratory studies, a pilot test was carried out to produce pilot batches of crude and purified coagulants with further testing of their coagulation ability in laboratory conditions. The feasibility study was carried out on the basis of the results of pilot tests and existing equipment at the gas treatment plant of JSC «Tajik Aluminium Company». According to the calculations, the cost of one tonne of crude coagulant excluding wages and existing taxes is 625 somoni (57.3 $) and the cost of purified coagulant is 816 somoni (74.8 $). On the basis of carried out laboratory researches and technical and economic calculations it is possible to draw a conclusion about efficiency of technology of reception of crude and purified coagulants and possibility of its introduction in manufacture.

Keywords: feasibility study, kaolin clay, Chashma-Sang deposits, sulphatisation, crude coagulant, purified coagulant.

 

Information about the authors:  Naimov Nosir Abdurahmonovich – Tajik National University, candidate of technical sciences, doctoral candidate at the Scientific Research Institute. Address: 734025, Dushanbe, Tajikistan, Rudaki Avenue, 17. Phone: (+992) 901-11-65-12. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..

Rajabzoda Najibullo Habibullo – JSC “Tajik Aluminium Company”, Chairman of the Board of Directors. Address: 734024, Dushanbe, Tajikistan, Aini St., 48. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..

Mirsaidov Ulmas – Сhemical, biological, radiological, and nuclear safety and security agency of NAST, Doctor of Chemical Sciences, Professor, Academician of NANT, Consultant, Head Researcher. Address: 734025, Dushanbe, Tajikistan, Rudaki Ave, 33. Phone: (+992) 37 2258005. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..       

 

Article received 10.01.2024

Approved after review 13.04.2024

Accepted for publication 17.09.2024

UDC: 541. 123.6                             

SOLUBILITY AND PHASE EQUILIBRIUM OF AN WATER SYSTEM - POTASSIUM, MAGNESIUM, CALCIUM SALTS CARBONATES AT A TEMPERATURE OF 25°C

(K⁺,Mg²⁺,Ca²⁺//CO₃^2--H₂O)

Umaralii S., Usmonov M.B.

Tajik State Pedagogical University named after S. Ayni

Multicomponent water-salt systems are the composition of many natural and technical objects that are the subject of research in the field of chemistry, mineralogy and technology. The main method for studying chemical systems is physicochemical analysis, which can be used to determine the laws of interaction of their components and construct their state or solubility diagrams. State diagrams of chemical systems are an expression of the relationship between the properties of substances (melting, solubility, etc.) and the influence of external factors (temperature, pressure, etc.) [1]. The founder of this discipline, N.S. Kurnakova, played a great role in developing the theory of the foundations of physicochemical analysis [2]. N.S. Kurnakov was the first to define the main tasks of physicochemical analysis as a scientific theory. N.S. Kurnakov determined that physicochemical analysis is one of the parts of chemistry that studies the relationship between the composition and measurable properties of chemical systems, as a result of which a state and a basic diagram are created. N.S. Kurnakov became Yakusin and proposed the basic principles of physicochemical analysis, the principles of compatibility and consistency. The schematic method of studying the structure of facies diagrams played a very important role in the further development of the theory of the foundations of physical and chemical analysis. The study of multicomponent chemical systems is primarily due to the fact that existing methods do not allow for a visual display of the studied multicomponent systems using existing three-dimensional geometric figures, the implementation of experimental work requires a large amount of effort, time and chemical materials, since the determination of solid phases in equilibrium is difficult, etc.

 Yu. G. Goroshchenko proposed the third principle of physicochemical analysis - the compatibility principle, according to which the displacement of the geometric elements of the component (n-component) in the direction of the general system (n+1-component) should be justified from a scientific and theoretical point of view [3]. Based on this principle, L. Soliev developed a new method for studying multicomponent chemical systems, called the translation method. It was proposed and accepted by specialists as one of the universal methods for studying multicomponent chemical systems [1].

The purpose of monitoring phase equilibria and solubility in chemical systems is to identify their interactions based on test results and create conditions for creating a real diagram of their phase equilibria. Only on the basis of such diagrams can we obtain complete information about the chemical systems under study. The four-component system K+, Mg2+, Ca2+//CO32--H2O is one of the components of the five-component system K+, Mg2+, Ca2+//SO42-, CO32--H2O, which is part of industrial waste, including liquid waste from the aluminum industry [4-7]. The process of crystallization of these salts in an aqueous solution of waste is determined by the laws of phase balance of the six-component system Na+, Ca2+ //SO42-, CO32-, HCO3-, F--H2O and its five- and four-component system.

In this article, the solubility of a system consisting of potassium, magnesium and calcium carbonates formed with water at a temperature of 250C is investigated. Previously [8,9] we determined the phase equilibria of this system using the translation method and constructed a phase equilibria diagram.

The components of this chemical system consist of potassium, magnesium and calcium carbonates, which at a temperature of 250C in the form of CaSO3 – calcite (Cs); K2CO3 1.5-(K∙1.5); СаСО3 MgСО3-dolomite (Ca∙Mg) MgСО3 3H2O-magnesite (Mg 3); K2CO3 СаСО3-(K∙Са) crystallize. The following salts were used for the experiment: СаСО3 (chemically pure); MgСО3 3H2O (by chemical purity); K2SO3 (pure); the experiment was carried out using the saturation method [10-11].

Based on literature data [12,13], we previously prepared a solution for the invariant points of the following three-component systems of this four-component system at a temperature of 25 °C: K +, Mg2 +, // CO32 -- H2O, K +, Ca2 + // CO32 -- H2O and Mg2 +, Ca2 + // CO32 -- H2O. Then, using the translation method, the invariant points of the three-component level are transferred to the four-component level [8], their high solubility at a temperature of 25 °C is established, and then they are separated. The solution was stirred using a magnetic stirrer and the temperature was controlled by a contact thermometer connected to a U-8 thermostat, the accuracy of which is ±0.10 °C. Mixing was carried out for 80-120 hours. Crystallization of solid phases was observed using a Micromed C 11 microscope, and after equilibration, the solid phases were photographed using a SONY-DSC-S500 camera.

 

Fig. 1. Photomicrograph of the equilibrium solid phase of the system

K⁺, Mg²⁺,Ca²⁺//CO₃^2--H₂O,, for a temperature of 25^o

Separation of the solid and liquid phases was carried out through a Buchner funnel connected to a vacuum pump. Then the solid phase was washed with 96% ethyl alcohol and dried at 120°C. Chemical analysis was carried out using known methods [14-17]. Optical analysis of crystals [18] with their solid phases is shown in Figure 1, and the result of chemical analysis of the native solution is presented in Table 1.

 

 

Table 1. Solubility of nonvariant points of the K⁺, Mg²⁺,Ca²⁺//CO₃^2--H₂O

system at a temperature of 25^oC

 

	Liquid phase composition. with %				Equilibrium solid phases
	K2CO3	CaCO3	MgCO3	H2O
L1	52,740	-	-	42,260	К∙1,5
L2	-	0,004	-	99,995	Сс
L3	-	-	0,022	99,977	Mg∙3
	-	0,007	0,024	99,968	Сс + Ca∙Mg
	-	0,004	0,038	99,957	Ca∙Mg+ Mg∙3
	46,786	0,005	-	53,209	Сс+ К∙Сa
	57,916	0,004	-	42,079	К∙Сa+ К∙1,5
	55,930	-	0,012	44,058	К∙1,5+ Mg∙3
	61,110	0,007	0,018	38,700	Сс+ Ca∙Mg+ К∙Сa
	45,764	0,004	0,025	54,206	Ca∙Mg+ К∙1,5+ Mg∙3
	60,108	0,005	0,025	39,860	Ca∙Mg+ К∙1,5+ К∙Сa

 

Based on the obtained data, a solubility diagram of the K+, Mg2+, Ca2+//CO32--H2O system for a temperature of 25 °C was constructed, which is shown in Figure 2 (a) water-salt part b) salt part).

 

 

Figure 2. Solubility diagram of the K⁺,Mg²⁺,Ca²⁺//CO₃^2--H₂O system at a temperature of 25^oC a) water-salt part b) salt part

 

The mass-centric method was used to determine the location of the non-variant points of the three-component () and four-component () levels, where n is the number of digits. Due to the low solubility of salts, its ratio with water is 1:5. The positions of the three- and four-component non-variant points on the diagram are determined based on solubility data using the mass-centric method [19] by the following calculations.

1.For a point  with equilibrium solid phases Сс+Сa·Mg

       

2.For a point  with equilibrium solid phases Сa·Mg+Mg·       

3.For a point  with equilibrium solid phases Сс+K·1,5

       

4.For a point  with equilibrium solid phases K·Ca+K·1,5

 

    

5.For a point  with equilibrium solid phases K·1,5+Mg·3

 

         

6.For a point  with equilibrium solid phases Сс+K·Ca +Ca·Mg

           

7.For a point  with equilibrium solid phases K·1.5+Ca·Mg+ Mg·3

 

             

8.For a point  equilibrium solid phases K·Ca+ K·1,5 + Сa·Mg             

 

Fig. 2 shows the general part (a) and the salt part (b) of the solubility diagram of the K+, Mg2+, Ca2+//CO32--H2O system at a temperature of 25°C, which reflects the position of crystallization of the corresponding equilibrium phases. As can be seen from Fig. 2, for this four-component system at a temperature of 25°C, the region of crystallization of calcite (CaCO3) occupies most of it, which shows the low solubility of this salt under these conditions. Its geometric shapes (squares, dots and lines) are presented in Table 2.

 

Table 2. List of geometric forms of the K⁺,Mg²⁺,Ca²⁺//CO₃^2--H₂O

 diagram for a temperature of 25^oC

Geometric elements	Decoding the signs
е1	Solubility of potassium carbonate in water
е2	Solubility of calcium carbonate in water
е3	Solubility of magnesium carbonate in water
	Crystallization point Сс+Сa·Mg in the system   Mg2+,Ca2+//CO32--H2O
	Crystallization point Сa·Mg+ Mg·3  in the system  Mg2+,Ca2+//CO32--H2O
	Crystallization point Сс+K·1,5 in the system   K+,Ca2+//CO32--H2O
	Crystallization point K·Ca+K·1,5 in the system  K+,Ca2+//CO32--H2O
	Crystallization point  K·1,5+Mg·3 in the system K+,Mg2+//CO32--H2O
	The co-crystallization point of K·Ca+Сс+ Сa·Mg in the system K+,Mg2+,Ca2+//CO32--H2O
	The co-crystallization point of K·1,5+Mg·3+ Сa·Mg in the system K+,Mg2+,Ca2+//CO32--H2O
	The co-crystallization point of K·Ca+ K·1,5 + Сa·Mg in the system K+,Mg2+,Ca2+//CO32--H2O
е1 -	Crystallization point K·1,5 in the system  K+,Ca2+//CO32--H2O
е1 -	Crystallization point K·1,5 in the system  K+,Mg2+//CO32--H2O
е2 -	Crystallization point Сс in the system  Mg2+,Ca2+//CO32--H2O
е2 -	Crystallization point Сс in the system  K+,Ca2+//CO32--H2O
е3 -	Crystallization point Mg·3 in the system Mg2+,Ca2+//CO32--H2O
е3 -	Crystallization point Mg·3 in the system  K+,Mg2+//CO32--H2O
-	The co-crystallization point of Сс+ Сa·Mg дар системаи Mg2+,Ca2+//CO32--H2O
-	The co-crystallization point of Сa·Mg+ Mg·3  in the system Mg2+,Ca2+//CO32--H2O
-	The co-crystallization point of  K·Ca+ K·1,5 in the system K+,Ca2+//CO32--H2O
-	The co-crystallization point of  K·Ca+ Сс in the system  K+,Ca2+//CO32--H2O
-	The co-crystallization point of  Mg·3 + K·1,5 in the system K+,Mg2+//CO32--H2O
е1- - - - -е1	Field of crystallization K·1,5
е2- - - -е2	Field of crystallization Сс
е3- - - -е3	Field of crystallization Mg·3
- - -	Field of crystallization K·Cа
- - - - -	Field of crystallization Сa·Mg

 

CONCLUSION

1.First, the solubility of the K+,Mg2+,Ca2+//CO32--H2O system was studied at a temperature of 25oC, and a diagram of its solubility was created for this temperature.

2. The list of coordinates of the geometric forms of the K+,Mg2+,Ca2+//CO32--H2O system is established at the given temperature.
3. The micrograph of the equilibrium solid phases of this system for a temperature of 25oC is given.
4. It was determined experimentally that two new phases СаСО₃·MgСО₃ -dolomite (Ca∙Mg) and К₂CO₃·СаСО₃-(К∙Сa) are formed for this system at this temperature.

REVIEWER: Davlatshoeva J.A.,

Candidate of Chemical Sciences,

Associate Professor

 

REFERENCES

1. Soliev, L. Basics of physico-chemical analysis / L. Soliev //. - Dushanbe, –2020. –151 p.
2. Kurnakov, N.S. Introduction to physical and chemical analysis / N.S. Kurnakov // –M. –L. :Ed. Academy of Sciences of the USSR. –1940. –Р. 562.
3. Goroshchenko, Ya.G. Main directions of methodology of physical and chemical analysis of complex and multicomponent systems / Ya. G. Goroschenko, L. Soliev // Journal of Inorganic Chemistry. –1987. –T.32 –No.7. – Pp. 1676-1681.
4. Ermatov, A.G. Utilization of aluminum production waste / A.G. Ermatov, U.M. Mirsaidov, H.S. Safiev, B. Azizov. // –Dushanbe, Donish. –2006. –62 р.
5. Mirsaidov, U.M. Ecological problems and complex processing of raw materials and production waste / U.M. Mirsaidov, M.E. Ismatdinov, H.S. Safiev //. –Dushanbe, Donish. –1999. –53 р.
6. Usmonov, M. Solubility in the CaSO₄-CaCO₃-CaF₂-H₂O system at 25⁰C / M. Usmonov, L. Soliev, I. Nizomov. // Dokl. AN Republic of Tajikistan. –2012. –T.55. –No. 10. – Pp.811-817.
7. Avloev, Sh. Phas Eqilibria in the Na,K // SO₄,CO₃,F-H₂O system at 25⁰С / Sh. Avloev, L.Soliev // Russian Journal of inorganic chemistry. – 2007. –Vol 52. –№ 10. – Pp.1612-1616.
8. Umarali, S. Phase equilibria of the K₂CO₃-MgCO₃-CaCO₃-H₂O system at a temperature of 25⁰C / С. Umaralii // Message of the Educational University (Department of Natural Sciences). –2021. – No. 1 (10-11). – Pp. 230-235.
9. Umaralii, S. Phase equilibria of the five-component system K,Mg,Ca // SO₄, SO₃ - H₂O at a temperature of 25°C / С. Umaralii // Message of DMT, Department of Natural Sciences. –2022. – No.1. – Pp. 223-233.
10. Goroshchenko, Y.G. Determination of the position of non-variant points and diagrams of solubility by the method of donation / Y.G. Horoshchenko, L. Soliev, Yu.I. Gornikov // Ukr. chem. Journal. –1987. –T.53. –No. 6. –Pp. 568-571.
11. Nizomov, I.M. Phase equilibrium and solubility of the Na,K||CO₃,HCO₃,F-H₂O system at 0 and 25⁰C / I.M. Nizamov // Autoref. Candidate of Chemical Sciences. –Dushanbe. –2009. –22 р.
12. Gulomikbol, G. Phase equilibria and solubility in the Na,Ca||CO₃,НCO₃,F-H₂O system at 0 and 25⁰С / Г. Gulomikbol // Autoref. Candidate of Chemical Sciences / –Dushanbe. –2018. –59 р.
13. Handbook of experimental data on solubility of multi-component water-salt systems. –T.1., kn. 1-2. – SPb.: Khimizdat. –2003. –1151 р.
14. Handbook of experimental data on the solubility of multi-component water-salt systems. – T. II., kn. 1-2. –SPb. Khimizdat. –2004. –1247 р.
15. Kreshkov, A. P. Basic analytical chemistry/A. P. Kreshkov. // -Izd. – Chemistry. –1970. –T.2. – 456 р.
16. Analysis of mineral raw materials (under general editors. Knipovich Yu. N., Morachevskogo Yu. V.). Izd. "Goshmindat". –L.: –1959. –947 р.
17. Reznikov, A. A. Methods of natural water analysis / A.A. Reznikov, E.P. Mulikovskaya, I. Yu. Sokolov. // –Izd. – Nedra. –M. –1970. –488 р.
18. Tatarsky, V. B. Crystal optics and immersion method of substance analysis / V.B. Tatarsky. // - L.: –LGU. –1948. –149 р.
19. Goroshchenko, Y.G. Mass-centric method of imaging multi-component systems/Y.G. Goroshchenko// – Kyiv: Naukova dumka, – 1982. –264 р.     

SOLUBILITY AND PHASE EQUILIBRIUM WATER-SALT SYSTEMS OF POTASSIUM, MAGNESIUM, CALCIUM CARBONATES FOR TEMPERATURE 25°C (K⁺,Mg²⁺,Ca²⁺//CO₃^2--H₂O)

The article presents the results of studying the solubility of the K⁺, Mg²⁺,Ca²⁺//CO₃^2--H₂O system at a temperature of 25°C using the translation method. It is very necessary to know the laws of the structure of the phase diagram in it for the processing of natural mineral substances and industrial waste containing salts of potassium, calcium and magnesium carbonates. One of the current environmental problems in our country is the presence of various wastes, including wastes from industrial enterprises, which have a negative impact on the environment. Therefore, studying the solvability of such systems is not only of theoretical importance, but also of great scientific and practical importance. The solubility of the K⁺,Mg²⁺,Ca²⁺//CO₃^2--H₂O system at a temperature of 25⁰C was studied experimentally, based on the obtained evidence, for the first time. It is shown in Figure 2. a) presented water-salt part, b) salt part.

Key words: phase equilibria, translation method, industrial waste, temperature 25^oC, curves, fields, pointsInformation about the authors:

 

Information about the authors: Umarali Safarali – Tajik State Pedagogical University named after Sadriddin Ayni, Senior lecturer of the Department of Chemical technology and ecology.  Address: 734003, Dushanbe, Tajikistan, Rudaki Avenue, 121. Phone: (+992) 917861226. E-mail: safarali.umarali91.

    Usmonov Muhammadsalim Bozorovich – Tajik State Pedagogical University named after Sadriddin Ayni, candidate of chemical sciences lecturer of the Department of Chemical technology and ecology. Address: 734003, Dushanbe, Tajikistan, Rudaki Avenue, 121. Phone: (+992) 918887812. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..

 

Article received 19.02.2024

Approved after review 11.05.2024

Accepted for publication 30.08.2024