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AZERBAIJAN CHEMICAL JOURNAL № 1 2023 ISSN 2522-1841 (Online)
ISSN 0005-2531 (Print)
UDC 669.712:669.21
DEVELOPMENT OF AMMONIA-ALKALINE METHOD OF COMPLEX PROCESSING
OF ALUNITE ORE
R.G.Gamidov\ E.A.Teymurova1, Y.I. Jafarov2, A.A.Ibragimov1, F.S.Ibragimova1,
A.N.Mammadov1'3, N.LAbdullaev4
M.Nagiev Institute of Catalysis and Inorganic Chemistry, Ministry of Science and Education
of the Republic of Azerbaijan 2Azerbaijan State University Azerbaijan Technical University 4Institute of Geology and Geophysics, Ministry of Science and Education of the Republic
of Azerbaijan
Received 18.04.2022 Accepted 01.06.2022
The results of research in the field of development of complex processing of alunite ore from the Zaglig deposit of Azerbaijan are presented. An ammonia-alkaline ore processing method is proposed, which provides for the extraction of alkali metal sulfates (K2SO4, Na2SO4) at the beginning of the technological process during the leaching of alunite ore. To recover alkali metal sulfates from dehydrated ore to ammonia processing, the dehydration product is leached with a slightly alkaline (0.5% NaOH) solution. After extraction of alkali sulfates from the ore, the solid insoluble residue is subjected to ammonia leaching. In this case, only ammonium sulfate passes into the solution, which is used as a fertilizer. Thus, the separation of alkali metal sulfates from the ore at the beginning of processing improves the conditions for subsequent hydrochemical processes. the following average values of the degrees of extraction of alkali metals and aluminum into the solution from leaching were determined, (%): Na+ = 90.93; K+ = 96.42; Al+3 = 0.055. Aluminum oxide, which is part of alunite, remains in the sediment under optimal leaching conditions. Aluminum oxide, which is not part of the alum part of alunite, that is, associated with silicate in kaolinite, is also not extracted and remains in the undissolved precipitate.
Keywords: alunite ore, Zaglig depozit, dehydrating roasting, ammonia-alkaline leaching.
doi.org/10.32737/0005-2531-2023-1-122-128
Introduction
In world practice, the production of alumina is based mainly on the Bayer technology [1], which provides for the processing of high-quality bauxite, the industrial reserves of which are depleted. Due to the growing demand for aluminum for the further growth of the aluminum industry, it is now necessary to expand research in the direction of prospecting, exploration and development of alunite, nepheline and other aluminum-containing ores. The Zaglig alunite ore deposit, located on the territory of Azerbaijan, is a complex raw material for the chemical and metallurgical enterprises of the country, which makes it possible to obtain alum, alumina, aluminum sulphate, sulfuric acid, potassium fertilizers
(K2SO4) and other valuable products [2-9]. Alunite ores of the Zaglig deposit are promising materials for obtaining pure aluminum oxide [10-13]. For the complex processing of alunite ores, several methods have been proposed: alkaline, closed alkaline, acid, reductive-alkaline, sulfate-alkaline ammonia-alkaline [14-17]. According to the ammonia-alkaline method of Labutin [15], dehydrated ore is subjected to leaching with a weak ammonia solution. At the same time, along with the obtained ammonium sulfate, alkali metal sulfates also pass into the solution, and the oxide, aluminum hydroxide and barren steam remain in the insoluble residue, which are further processed by the alkaline method according to the Bayer method [1]. The mixture of sulfates obtained is unsuitable for use as a fertilizer due to the content
of sodium sulfate in them. A lot of research has been devoted to the problem of rational technology for processing alunite ores. However, all of them have a number of disadvantages: the bulkiness of technological schemes, the difficulty of cleaning sulfuric acid solutions from iron, the difficulty of separating alkali metal sulfates from aluminum and iron sulfates, high energy costs, and others. Therefore, overcoming these difficulties and developing effective methods for processing alunite ores is a priority task for the modern aluminum industry.
The aim of the work is to develop the ammonia-alkali method of alunite ore for the extraction of alkali metal sulfates K2SO4 and Na2SO4 at the beginning of the technological process and to obtain ammonium sulfate and ore residue enriched with aluminum oxide.
The object of study is the Zaglig alunite ore of Azerbaijan.
Experimental part
To recover alkali metal sulfates from
the dehydration product is leached with a slightly alkaline (0.5% NaOH) solution. After extraction of alkali sulfates from the ore, the solid insoluble residue was subjected to ammonia leaching. In this case, only ammonium sulfate passes into the solution, which is used as a fertilizer. Thus, the separation of alkali metal sulfates from the ore at the beginning of processing improves the conditions for subsequent hydrochemical processes.
The chemical analysis of the ore (Table 1) was carried out by X-ray method on X-ray spectrometer RFA, Universal S8 Tiger from Bruker (Germany).
The mineralogical composition of the studied ore was studied using X-ray phase analysis. It has been established that the main mass of alunite ore is made up of: silica represented by quartz (SiO2) ~ 53.4%, alunite (Na,K)2SO4-Al2(SO4)3-2Al2O3-6H2O ~ 35.5%, kaolinite [AbSi2O5(OH)4] ~ 9.8% and hematite (Fe2O3) ~ 1.5% (Figure l).
dehydrated ore prior to ammonia processing, Table 1. Chemical composition of an average sample of alunite ore from the Zaglig deposit (wt %)
Na2O MgO M2O3 SiO2 P2O5 SO3 K2O CaO TiO2 MnO Fe2Os Cl lvc*
1.88 0.015 23.63 29.86 0.22 27.34 5.0 0.07 0.49 0.10 4.09 0.03 6.9
V Cu Sr Cr Zr Ni Co Zn Ba As
0.0124 0.0062 0.20 0.023 0.034 0.0034 0.0005 0.03 0.04 0.0050
Fig. 1. X-ray diffraction pattern of alunite ore from the Zaglig deposit.
X-ray phase analysis of the ore and products of its processing was carried out using a D2 phaser diffractometer manufactured by Bruker (Germany). 10 g crushed ore was subjected to dehydrating roasting in an air atmosphere under established optimal conditions (T = 5500C, t = 2 hours) under stationary conditions in a muffle furnace. Dehydrating roasting of alunite ore was carried out during its complex processing in order to remove constitutional water, which is one of the components of alunite. This breaks the bond between the individual components of the mineral and increases its solubility in the appropriate solvent. As a result of dehydrating roasting, alunite, which is part of the studied ore, decomposes to obtain a mixture of dehydrated normal and basic alums [18].
550°C
2(K,Na)SO4-Al2(SO4)3-2Al2O3-6H2O-->
(K,Na)SO4- Al2(SO4)3 + +(K,Na)SO4-Al2(SO4y4Al2O3+12H2O
At this temperature, the resulting alum readily dissolves in alkalis and acids. At the same time, the decomposition of sulfates does not occur and sulfur dioxide (SO2), which pollutes the environment, is not released [19]. The dehydrated rock was analyzed by X-ray diffraction (XRF) and scanning electron microscopy (SEM). The diffraction pattern (Figura 2) reveals the presence of quartz, potassium alum, kaolinite and hematite.
Due to the low content of aluminum sodium kvass, they were not identified on the derivatogram, but were noted on the scanogram of the studied rock sample (Figure 3c). Chemical analysis of a sample of dehydrated alunite ore is presented in Table 2.
Fig. 2. Diffraction pattern of alunite ore fired at 550 C from the Zaglig deposit. Table 2. Elemental composition of alunite ore dehydrated at 5500C from the Zaglig deposit
Element wt % Atomic % Compound% Formula
Na K 1.72 1.56 2.32 Na2O
Al K 15.44 11.93 29.18 Al2Os
Si K 15.11 11.22 32.33 SiO2
S K 10.99 7.15 27.45 SO3
K K 4.68 2.49 5.63 K2O
Ti K 0.20 0.09 0.33 TiO2
Fe K 2.14 0.80 2.75 FeO
O 49.71 64.77
Total 100.00
c
Fig. 3. Results of SEM analysis of alunite ore dehydrated at 5500C from the Zaglig deposit; a) electronic image x 170, b) energy spectrum of the elements that make up the dehydrated alunite ore; c) scan of dehydrated alunite ore.
Fig. 4. Diffractogram of the sediment from the leaching of dehydrated alunite ore.
SEM analysis of dehydrated ore and its leach products was carried out using a JSM 6610 LV scanning electron microscope from JEOL (Japan) and an X-MAX spectrometer from Oxford Insyruments (United Kingdom of Great Britain).
The burnt ore was subjected to leaching with a 0.5% alkali solution (NaOH) with stirring and heating on a magnetic stirrer under the following optimal conditions: T = 90-1000C, t = 60 min, S:L = 1:6
t
(K, Na) SO4-Al2(SO4k4Al2O3 + NaOH (0,5%)p_p ^
0.5K2SO4+0.5Na2SO4+Al2(SO4)3-4Al2O3+Al(OH)3|
Silica in the form of quartz under optimal conditions for hydrochemical aqueous alkaline treatment (0.5% NaOH) calcined at 5500C of alunite ore remains inert, as a result of which it mainly remains in the sediment from leaching. Hematite under these conditions also remains in the sediment [17]. Under the established optimal conditions, the following average values of the degrees of extraction of alkali metals and aluminum into the solution from leaching were determined, (%): Na+ = 90.93; K+ = 96.42; Al+3
= 0.055. Alumina, which is part of alunite, remains in the sediment under optimal leaching conditions. Aluminum oxide, which is not part of the alum part of alunite, that is, associated with silicate in kaolinite, is also not extracted [8] and remains in the undissolved precipitate. Using XRF analysis, the presence of quartz, kaolinite, hematite and aluminum oxide in the sediment from the leaching of dehydrated alunite ore was established (Figure 4).
Results and discussion
The results obtained indicate a fairly high recovery of alkali metal sulfates. Alkali metal sulfates can be separated from the solution in the form of potassium and sodium sulfates after evaporation and fractional crystallization, and so that sodium sulfate is obtained separately from potassium sulfate, since the presence of sodium sulfate degrades the quality of the fertilizer. After the separation of alkali metal sulfates, the ore residue is subjected to ammonia leaching, with the production of ammonium sulfate and an insoluble residue enriched in aluminum, which is further processed by the well-known Bayer method:
t
Al2(SO4)3 -4Al2O3+6NH3+6H2O^ 3(NH4)2 SO4+4AI2O3I+2А1(ОН)з |
The isolated mixture of sulfate salts of potassium and sodium is processed into potassium sulfate by converting the mixture of salts with a solution of potassium chloride to obtain potassium sulfate and sodium chloride according to the reaction: Na2SO4+2KCl ^ K2SO4+2NaCl.
This method is used when the solution does not contain vanadium, which contaminates sodium chloride. A patent [19] was obtained for the proposed ammonia-alkaline method for processing alunite ore.
Conclusion
Thus, an ammonia-alkaline method for the complex processing of Zaglig alunite ore was developed, characterized in that alkali metal sulfates (K2SO4 and Na2SO4) are extracted at the beginning of the technological process by leaching dehydrated crushed ore with a weak (0.5%) solution of caustic alkali (NaOH). After that, the ore residue is subjected to ammonia leaching to obtain ammoni um sulfate and an ore residue enriched in aluminum oxide, which is further processed in an alkaline way. The method involves obtaining useful products: alumina, potassium and ammonium sulphates.
References
1. Alessio A. S., Sonia N., Edgar G., Cornelis K., Andreas K. Energy in Alumina Refining: Setting New Limits. Light Metals. 2015. P. 131-136. doi:10.1007/978-3-319-48248-4_24.
2. Kashkaj M.A. Alunity, ih genezisy i ispol'zovanie. M.: Nauka, 1970. Т. 1. 400 s. Т. 2. 318 s.
3. Shakhtakhtinskiy G.B., Khalilov A.N., Aslanov G.A. Polucheniye alyuminiyevykh soley iz bednoalutinizirovannykh porod Zaglikskogo mestorozhdeniya. Baku: Elm, 1972. 128 s.
4. Tagiev E.M. Tekhnologiya kompleksnoj, bezothod-noj pererabotki alunitovyh rud. Баку.: Elm, 2006. 504 с.
5. israfilov T.D. Aluminium alinmasinin nazari asas-lari va texnologiyasi. Baki: Zaman 3. 2011. 456 s.
6. Alyshanly G.I, Geidarov A.A., Mammadov A.N, Kalantarova S.Sh. Modelling of the precipitation process of aluminium hydroxide from aluminate solutions based on fuzzy logic theory. Chemical Problems. 2022. No 2. V. 20. P. 183-190.
7. Patent 1 2019 0055.Az.R. Tamiz alüminium oksdin alinmasi üsulu. Samadzada Q.M. §arifova Ü.M., Ataki§iyev R.H., Qahramanov Q.S., §adlinskaya G.V. 08.10.2019.
8. Evrazijskij Patent. 201800630 (13) A2. Soda shchelochnoj sposob pererabotki alunitovoj rudy. Tagiev El'dar Ismail ogly, Tagiev El'shad El'dar ogly, Agaeva Lale Gejdar kyzy. 2018.12.24.
9. Tagiev E.M. Puti usovershenstvovaniya kompleksnoj pererabotki zaglikskih alunitov. M: 1970. C. 326.
10. Talibli LA., Samedzade G.M., Alieva J.M., Mammadov A.N., Gamidov R.G., Gasimova A.M., Shadlinskaya G.V. Sludge-free production of pure alumina from rocks containing iron oxides and silica. Azerbaijan Chemical J. 2022. No 1. P. 88-92. doi.org/10.32737/0005-2531-2022-1-68-72
11. Heydarov A.A., Kashkai Ch.M., Alyshanly G.I., Jabbarova Z.A. Processing of Zaglik alunite ore by heap and tank leaching. Azerb. Chem. J. 2021. No 2. P. 42-49. doi.org/10.32737/0005-2531-2021-2-42-49
12. Pat 1 2020 0087 BN 1029102021 "Alunit filizinin emali üsulu" Hamidov R.H., ibrahimov O.A., Teymurova E.A, Agayev A.i. 2020.
13. Pat i 2020 0072 "Alunit filizindan alüminium oksidin alinmasinin elektrokimyavi üsulu". Hamidov R.H, Tahirli H.M, Tagiyev D.B. 2020.
14. Trockij I.A., ZHeleznov V.A. Metallurgiya alyu-miniya. Moskva: Metallurgiya 1977. 392 s.
15. Labutin G.V. Alunity. M.: Metallurgiya, 1965. 100 s.
16. Layner A.I. Proizvodstvo glinozema. Uchebnoye posobiye. M.: Gosudarstvennoye nauchno-tekh-nicheskoye izdatel'stvo literatury po chornoy i tsvetnoy metallurgii, 1961. 620 s.
17. Layner Yu.A. Kompleksnaya pererabotka alyuminiy soderzhashchego syr'ya kislotnymi sposobami. M.: Nauka, 1982. 208 s.
18. Gamidov R.G., Talybly I.A., Halilova M.I., Salimova S.R. Izuchenie termicheskogo pove-deniya alunita. Tezisy dokladov nauchnoj konferencii. Ekaterinburg. 26-28 aprelya. 2017.
19. SHahtahtinskij G.B., Samedzade K.M. Izuchenie voprosa o vydelenii sernistyh gazov pri provedenii obzhiga alunita. Azerbajdzhanskij himicheskij zhurnal. 1979. No 1. S. 140-145.
20. Az. patent i 2021 0103. Sposob pererabotki alunitovoj rudy. Gamidov R.G., Tagiev D.B., Ibragimov A.A., Tejmurova E.A., Agaev A.I. 2021.
ALUNIT FÍLÍZÍNÍN KOMPLEKS EMALININ AMMONYAK-QOLOLÍ ÜSULUNUN ÍNKͧAF
ETDÍRILMOSÍ
R.H.Hamidov, E.A.Teymurova, Y.LCafarov, O.AJbrahimov, F.S.ibrahimova, A.N.Mammadov, N.Í.Abdullayev
Azarbaycanin Zagliq yatagi alunit filizinin kompleks emalimn içlanmasi sahasinda tadqiqatlarin naticalari taqdim olunur. Alunit filizinin içlanmasi zamani texnoloji prosesin baçlangicinda qalavi metal sulfatlarin (K2SO4, Na2SO4) çixarilmasini nazarda tutan ammonyak-qalavi filiz emali üsulu taklif olunur. Ammonyakla emaldan avval susuzlaçdinlmiç filizdan qalavi metal sulfatlari barpa etmak üçün susuzlaçdirma mahsulu bir qadar qalavi (0.5% NaOH) mahlulu ila içlanir. Qalavi sulfatlarin filizdan çixarilmasindan sonra bark hall olunmayan qaliq ammonyakla içlanmaya maruz qalir. Bu halda, mahlula yalniz gübra kimi istifada olunacaq ammonium sulfat keçir. Belalikla, emalin avvalinda qalavi metal sulfatlarin filizdan ayrilmasi sonraki hidrokimyavi proseslarin çaraitini yaxçilaçdirir. Qalavi metallarin va alüminiumun yuyulmadan mahlula çixarilmasi daracalarinin açagidaki orta qiymatlari müayyan edilmiçdir, (%): Na+ = 90.93; K+ = 96.42; Al+3 = 0,055. Alunit tarkibina daxil olan alüminium oksidi optimal emal çaraitinda çöküntüda qalir. Alunitlarin kvas hissasina daxil olmayan, yani kaolinitda silikatla alaqali olan alüminium oksidi da çixarilmir va hall olmamiç çöküntüda qalir.
Açar sözlzr: alunit filizi, Zaylikyatagi, susuzla§dmci qovurma, ammonyak-qalavi i^bnmasi.
РАЗВИТИЕ АММИАЧНОГО-ЩЕЛОЧНОГО СПОСОБА КОМПЛЕКСНОЙ ПЕРЕРАБОТКИ
АЛУНИТОВОЙ РУДЫ
Р.Г.Гамидов, Э.А.Теймурова, Я.И.Джафаров, А.А.Ибрагимов, Ф.И.Ибрагимова, А.Н.Маммадов,
Н.И.Абдуллаев
Представлены результаты исследований в области разработки комплексной переработки алунитовой руды Загликского месторождения Азербайджана. Предложен аммиачно-щелочной способ переработки руды, предусматривающий извлечение сульфатов щелочных металлов (K2SO4, Na2SO4) в начале технологического процесса при выщелачивании алунитовой руды. Для извлечения сульфатов щелочных металлов из дегидратированной руды до аммиачной переработки, продукт дегидратации подвергается выщелачиванию слабощелочным (0.5% NaOH) раствором. После извлечения щелочных сульфатов из руды твердый нерастворимый остаток подвергается аммиачному выщелачиванию. При этом в раствор переходит только сульфат аммония, который используется в качестве удобрения. Таким образом отделение сульфатов щелочных металлов из руды в начале переработки улучшает условия проведения последующих гидрохимических процессов. определены следующие средние значения степеней извлечения щелочных металлов и алюминия в раствор от выщелачивания, (%) : Na+ = 90.93; K+ = 96.42; Al+3 = 0.055. Оксид алюминия, входящий в состав алунита, остаётся в осадке при оптимальных условиях выщелачивания. Оксид алюминия не входящий в состав квасцовой части алунита, то есть связанный с силикатом в каолините, также не извлекается и остаётся в нерастворённом осадке.
Ключевые слова: алунитовая руда, Загликское месторождение, дегидратирующий обжиг, аммиачное-щелочное выщелачивание.
