The most important technologies of receiving barium sulfate from barite

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Department technology of inorganic substances and materials

Kazan national research technological university

The most important technologies of receiving barium sulfate from barite

Yermukhanova Svetlana Tasbolatovna - Graduate Student;

Russian Federation, Kazan

Abstract

The article deals with natural barite ores whose origin is associated with magmatic eruptions, the location of the most powerful deposits. The main methods for obtaining artificial barium sulfate, precipitation from aqueous solutions of barium salts with sulfuric acid or sulfuric acid, precipitation from chloride, sulfide and hydroxide with sodium sulfate or sulfuric acid, purified solutions of sodium sulfate. Processing of natural barite in various ways, purified barium sulfate can be obtained from natural barite by treating the finely ground mineral with sulfuric acid to remove impurities from it. Natural barite can also be purified by dissolving it in molten salts. Main applications of blanfixe, requirements to raw material for the production of barium sulfate.

Keywords: barite, blanfixe, barium sulfate, sedimentation, purification of barite, barite recovery, charge.

Аннотация

ВАЖНЕЙШИЕ ТЕХНОЛОГИИ ПОЛУЧЕНИЯ СУЛЬФАТА БАРИЯ ИЗ ПРИРОДНОГО БАРИТА

Ермуханова С.Т.¹, Хацринов А.И.² (Российская Федерация)

Ермуханова Светлана Тасболатовна - аспирант;

Хацринов Алексей Ильич - доктор технических наук, профессор, кафедра технологии неорганических веществ и материалов,

Казанский национальный исследовательский технологический университет, г. Казань

В статье рассматриваются природные баритовые руды, происхождение которых связано с магматическими извержениями, расположение наиболее мощных месторождений. Основные способы получения искусственного сульфата бария, осаждение из водных растворов солей бария серной кислотой или сернокислыми солями, осаждение его из хлорида, сульфида и гидроокиси сульфатом натрия или серной кислотой, очищенными растворами сульфата натрия. Обработка природного барита различными способами, очищенный сульфат бария может быть получен из природного барита обработкой тонкоизмельченного минерала серной кислотой с целью удаления из него примесей. Очистку природного барита можно производить также растворением его в расплавленных солях. Основные области применения бланфикса, требования, предъявляемые к сырью для получения сульфата бария.

Ключевые слова: барит, бланфикс, сульфат бария, осаждение, очистка барита, восстановление барита, шихта.

The atomic clarke of barium is 0.005%. It is a part of silicate and other rocks, but the raw materials for producing barium compounds are only the minerals barite or heavy spar BaSO₄ and viterite BaSO₃. The most important industrial deposits are barite, the origin of which is associated with magmatic eruptions. In such deposits, barite is one of the main minerals of the vein and is accompanied by quartz, fluorite, carbonates and heavy metal sulfides. Barite occurs as secondary accumulations in sedimentary rocks in the form of nodules, veins, and sometimes strata. Barium compounds are adsorbed by negatively charged particles of manganese hydroxides and are therefore satellites of colloidal manganese ores. barite magmatic blanfixe

The most powerful deposits of barite are concentrated in the Trans Caucasus (Kutaisi, Ganjin, Shamkhor, Katar-Kovart, Aktal, etc.), where the BaSO₄ content in ores sometimes reaches 97%, in Central Asia and in the adjacent areas of Western Siberia. There are also BaSO₄ deposits in the Urals. In the Altai, barite is found in deposits of polymetallic or lead- zinc ores, from which lead, zinc, copper, iron, and silver sulfides are extracted to form a barite concentrate (Zmeinogorskoye, Leninogorskoye, Belousovskoye, Berezovsky, Salairskoye, and other deposits). Sorting the ore of the Zmeinogorsky Deposit gives barite with a content of 98% BaSO₄.

Ground barite of all grades for the grading are divided into class a (filler) for which the sieve residue of 0.085 mm should be no more than 1% on a sieve 0,15 mm - not more than 0.1%, and class B (weighting), for which the sieve residue of 0.085 mm should be no more than 5%. The best grades of lump barite and high-quality ground barite are used in the paint industry. For the production of barium salts are usually used bulk barite of grades I and II and barite concentrate.

Artificial barium sulfate is produced as a fine powder in the following ways:

1) Precipitation from aqueous solutions of barium salts with sulfuric acids or sulfuric acid salts [3]. In addition, sulfur and sulfur anhydride can be used for precipitation. Barium sulfate in production is obtained mainly by precipitation of it from chloride, sulfate and hydroxide with sodium sulfate or sulfuric acid. When barium sulfate is deposited from aqueous solutions of its chloride, a product is obtained that is contaminated with sodium and calcium chlorides, and from the sulfide - with sulfur compounds chlorides, and from the sulfide - with sulfur compounds.

The best quality product is obtained when it is produced from aqueous solutions of barium hydroxide when precipitated with purified solutions of sodium sulfate. To get rid of the alkali, the resulting paste is acidified with pure sulfuric acid. In all cases, a better product is obtained when it is precipitated from water-soluble barium salts with sodium sulfate, rather than with sulfuric acid, since solutions of sodium sulfate are better purifying than sulfuric acid. More promising is the production of barium sulfate from aqueous solutions of its hydroxide by the absorption of sulfur anhydride or sulfur dioxide with a low content of SO₂.

2) Processing of natural barite in different ways. Purified barium sulfate can be obtained from natural barite by treating the finely ground mineral with sulfuric acid to remove impurities from it. Thus, when treating barite with oleum, BaSO4 is dissolved, and then, after separating the insoluble residue, it is released when the solution is diluted with water. When processing natural barite with hydrochloric acid, aluminum, iron, and calcium compounds pass into the solution, and BaSO₄ and SiO₂ remain in the sediment. For such processing, it is advisable to use rich barites. Thus, a product containing 99% BaSO₄ and 1% SiO₂ was obtained from a mineral containing 95-98% BaSO₄, 1-2% SiO₂ and 1-3% Cao, Al₂O₃, Fe₂O₃ after double treatment with hydrochloric acid with a density of 1.19 g/cm3, diluted with 1:10, for 2 hours during boiling with subsequent washing of chlorine ions with water. It was found that the admixture of inert SiO2 does not interfere with the use of the product for radioscopy.

Purification of natural barite can also be performed by dissolving it in molten salts-NaCl and CaCl2: after settling the impurities and decanting the melt, it is cooled, and after processing the solidified mass with water, pure BaSO₄ is obtained[3]. This way you can get BaSO₄ suitable for the paper and battery industry, only from first-class barite ore [6]. Seemingly simple at first glance, the method is associated with great difficulties in production. In addition, it does not provide a high quality product [4].

A method for extracting barium sulfate from natural barite is known by treating crushed natural barite with mineral acid in two stages at T:W=1: 10 with intermediate filtration, hydrolysis of the barium-saturated solution, separation and washing of the product [7]. The method is associated with a high consumption of concentrated sulfuric acid, low solubility of barium hydrosulfate in 96% sulfuric acid (103 g/l or 50 g/kg taking into account the density of 96% sulfuric acid equal to 1.83 g/cm3) and instability of reproduction of a high degree of whiteness of the resulting product.

In the invention of M. H. Akhmetov and et al., the main task is to ensure the stable reproducibility of a high degree of purity and whiteness of the resulting product by obtaining a homogeneous solution of barium sulfate in a salt melt when processing natural barite with a salt melt and complete removal of iron into the gas medium. In the claimed method for obtaining barium sulfate from natural barite by treating barite with molten salts followed by cooling the melt, dissolving in water, filtration, washing the product on the filter with water and drying, a molten salt mixture of sodium and potassium chlorides is used as a molten salt in a molar ratio of 1:1, barite is introduced into the melt with a mass of 25% or less of the mass of the molten salt, and through a mixed melt at a temperature of 700-800°with a flow of dry hydrogen chloride [8].

To convert barite, which is practically insoluble in water or acids, into a soluble compound, it is reduced to barium sulfurous. In the future, barium sulfur is easily processed into any barium compounds. Recovery of barite is carried out almost exclusively in tubular rotary kilns using coal and natural or generator gas.

Despite the fact that the charge consists of barite and coal, BaSO₄ is reduced mainly by carbon monoxide:

BaS0₄ + 4TO = BaS + 4TO₂

Cafbon dioxide is reduced by carbon to CO by the reaction of CO₂+C=2CO. Above 1000° in the composition of the equilibrium gas mixture in the presence of carbon, CO2 is practically absent. Therefore, the recovery of barite above 900-1000° proceeds by the total reaction

BaS0₄ + 4С = BaS + 4TO - 138,5 kcal (1)

and when 600-800° for the overall reaction:

BaS0₄ + 2С= BaS + 2TO,- 56,1 kcal (2)

Due to the endothermic nature of these reactions, heat supply is necessary, for which natural or generator gas is burned in the furnace, the components of which (CH4, H2, CO) also restore barite when they are not fully burned. From the point of view of coal consumption and heat costs, it is more profitable to conduct the recovery process at low temperatures, by reaction (2), but since it proceeds slowly, it is preferred to carry it out by reaction (1), which goes much faster, and for this purpose the temperature in the "hot" end of the furnace is maintained above 1000°.

The rate of recovery of barite strongly depends on the temperature and grade of solid carbon reducing agent. In laboratory experiments, barite-containing (in%) was used:. BAO- 64.98, S0₃-34.13. CaO-0.26, Fe₂0₃-0.06, SiO₂-0.65, H₂0-0.08. Reducing agents contained; dried charcoal-18.8% volatile and 3.8% ash; coke-1% volatile, 0.6% moisture, 9.2% ash; anthracite -5.4% volatile, 2.6% moisture, 2.7% ash, coal -27.4% volatile, 1.2% moisture, 7.5% ash. The dispersion of barite and reducing agent is 0.13 mm. The amount of reducing agent was taken with a 60-55% excess of carbon. Coal is a more active reducing agent than charcoal, coke, and anthracite. Therefore, they prefer to use coal, for example, the brand of PJ, despite the fact that its consumption is greater than lean coals (for example, anthracite), which contain little volatile substances.

Factory experiments have shown the feasibility of granulating the charge from flotation barite and coxic (with a grain size less than 3 mm) with the addition of an 8% solution of sulfite lye as a binder (8-10% of the weight of the charge) . Due to the porosity of granulated barite, its recovery is faster than crushed barite, and an equal degree of recovery is achieved at a temperature ~ 100° lower. The recovery of barite by electro thermal method in a laboratory single-phase furnace (d = 300mm) with a capacity of 25 kW was studied [3].

The recovery of barite by gases has great advantages. This results in a pure alloy that is not contaminated with coal and ash, which greatly facilitates its further processing.

When BaSO₄ interacts with CO in the range of 700-1000°, mainly Willows and only a few Vasoses are formed. The rate of recovery of barite by carbon monoxide is approximately equal to the rate of recovery by coke.

The equilibrium reaction

BaSO4 (sol) + 4TO (g)=BaS (sol) + 4

in the absence of free carbon, it is strongly shifted towards the formation of BaS even at high temperatures. Thus, at 1200°in an equilibrium gas mixture of 91 % C 0₂ [lg Kr = lg (p4 CO₂ = p4 CO) = - 7690T-1+ 1,2].

Recovery of BaSO₄ by hydrogen below 700° is very slow, at 850-900° - fast Recovery of BaSO4 by methane is slower than by hydrogen, and requires higher temperatures. The initial rate of reduction of BaSO₄ by hydrogen or carbon monoxide increases in proportion to the gas pressure (studied up to 600 mm Hg); the activation energy of these reactions is 47,000 and 56,000 cal/mol, respectively. For the reaction BaSO₄(sol) + 4^ (G) =BaS (sol) + 4^0 (g) in the range 800-1000° lg ^ = 5,447+697,5/r.

Recovery of barite by natural gas in fluidized bed furnaces is promising. At 900° for 3040 minutes, the recovery rate reaches 94%, and the use of reducing agent (gas) 32-36%. According to other data, when barite is reduced by products of incomplete combustion of natural gas (~ 13% H₂ and 10% CO) for 70-80 minutes at 800-900° and the height of the boiling layer of 1 m, a "Plav" is obtained containing 62-64% BaS and 10-12% BaSO₃. The degree of use of gases in the recovery process: CO-74% and H₂-52%. The granulometric composition of the alloy is approximately the same as the original barite [3].

Technical and economic and experimental studies show that the most economical methods are for producing barium compounds from barium sulfide (Fig. 1) [9].

Fig. 1. Schematic diagram of the production of barium compounds from barium sulfide

These methods ensure the production of high-quality products, high production culture, the best sanitary and hygienic conditions and the integrated use of raw materials.

References / Список литературы

1. Rynok barita. Tekushchaya situatsiya i prognoz 2017-2021 gg., 2015. 158 s.

2. Barit/ pod red. V.P. Petrova, I.S. Delitsina. M.: Nauka, 1986. 245 s. [in Russian].

3. Pozin M.Ye. Tekhnologiya mineral'nykh soley (udobreniy, pestitsidov, promyshlennykh soley, okislov i kislot). L.: Khimiya, 1974. 791 s [in Russian].

4. Akhmetov T.G. Khimiya i tekhnologiya soyedineniy bariya. M.: Khimiya, 1974. 152 s. [in Russian].

5. Shapiro I.S. Khim.prom. № 12,14. 1944 [in Russian].

6. PudovkinaI.O., Morgunova E.M. Trudy UNIKHIM. V. 3, 1955, Str 130 [in Russian].

7. A.s SSSR 1763371 Khabirov V.V., Petrov M.P., Agalakov I.P., 23.09.92. Byull. № 35 [in Russian].

8. Pat. № 23337880 RF 10.11.2008 Sposob polucheniya sul'fata bariya iz prirodnogo barita [in Russian].

9. Akhmetov T.G., Busygin V.M., Gaysin L.G., Porfir'yeva R.T. Khimicheskaya tekhnologiya neorganicheskikh veshchestv. M., 1998. 488 s. [in Russian]

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