RU2434956C2 - Procedure for zircon processing with production of zircon dioxide - Google Patents

Abstract

FIELD: metallurgy. ^ SUBSTANCE: zircon is mixed with solution of magnesium chloride producing pulp subjected to spraying burning. There is formed gaseous mixture of steam and hydrogen chloride and solid mixture of zircon and magnesium oxide. Mixture is smelted at 12501300C producing pitch. Pitch is treated with hydrochloric acid with production of suspension heated at 1075C to value of pH equal to 6.57.0, There is produced solid product consisting of zircon dioxide, silicon and magnesium chloride which is leached with acidulous water producing solution of magnesium chloride and dissociated zircon - mixture of associated zircon and silicon dioxides. Mixture is washed with water, and further is treated with water solution of ammonia fluoride forming water solution of hexa-fluorine-silicate of ammonium, ammonia fumes and zircon dioxide non-soluble in solution of ammonia fluoride, which is washed and dried producing commodity product in form of commercial zircon dioxide. Filtrate is saturated with fumes of ammonia producing pulp consisting of water solution of ammonia fluoride and hydrated silicon dioxide washed and dried, producing commodity product in form of hydrated silicon dioxide. ^ EFFECT: complex zircon processing with production of commodity products - commercial zircon dioxide and hydrated silicon dioxide performed by closed process circuit. ^ 1 dwg, 3 tbl

Description

The invention relates to the fields of pyro- and hydrometallurgy, in particular to the decomposition of zircon by high-temperature sintering with alkaline earth metal oxides and to the hydrochemical processing of the pitch formed during sintering and can be used to produce both technical zirconium dioxide and synthetic hydrated silicon dioxide.

Existing technologies for producing zirconia from zircon, including sintering of zircon, with alkaline earth metal oxides to form a pitch containing zirconium dioxide, and hydrochloric acid leaching of the pitch do not provide the possibility of obtaining silicon dioxide from zircon, as well as the regeneration of alkaline earth metal oxides and hydrochloric acid.

A known method of producing zirconium dioxide (ZrO ₂ ), including sintering of zircon (ZrSiO ₄ ) with chalk (CaCO ₃ ) in a molar ratio of ZrSiO ₄ : CaCO ₃ = 1: 1 in the temperature range 1375 ± 25 ° C with the formation of pitch, containing in addition to ZrO ₂ , zirconate (CaZrO ₃ ), zirconosilicate (Ca ₃ ZrSi ₂ O ₉ ) and silicates (CaSiO ₃ , Ca ₂ SiO ₄ , Ca ₃ Si ₂ O ₇ , Ca ₃ SiO ₅ ) calcium [1]. The pitch is leached in two stages, first, calcium silicate is decomposed with diluted 3-8% hydrochloric acid, and then, after separation of the diluted solution containing calcium chloride and silicic acid, the solid residue is treated with 27% hydrochloric acid to separate acid-soluble CaZrO ₃ and Ca ₃ ZrSi ₂ O ₉ from zirconia. As a result of a 2-stage leaching, large volumes of a diluted solution of calcium, zirconium, and silicic acid chlorides are formed.

The disadvantages of this method are:

- a relatively high content of silicon dioxide (at least 5 wt.%) in the final product - zirconia, which determines its use only in the production of fused refractory bacores;

- impossibility: obtaining from zircon, in addition to zirconium dioxide, the second final product is silicon dioxide, since sintering produces pitch, which must be leached with diluted 3-8% hydrochloric acid (due to the qualitative composition of the pitch); regeneration of calcium and hydrochloric acid compounds; elimination of losses of zirconium due to the formation of acid-soluble compounds — zirconate and calcium zirconosilicate during sintering. It is not economically feasible to extract silicon as the target product, calcium compounds, hydrochloric acid and zirconium from diluted waste hydrochloric acid solutions;

- the formation of large volumes of environmentally hazardous hydrochloric acid diluted solutions, for the neutralization and disposal of which additional costs are required.

The closest set of essential features to the claimed invention is a method for producing zirconium dioxide from zircon [1].

A method of producing zirconium dioxide from zircon involves sintering zircon with dolomite (a natural mixture of calcium and magnesium carbonates) [1]. The resulting pitch contains mainly zirconia, as well as the following compounds, the presence of which and their mass fractions in the pitch depend on the ratio of the components of the charge, temperature and duration of sintering: calcium zirconate (CaZrO ₃ ); calcium zirconosilicate (Ca ₃ ZrSi ₂ O ₉ ); calcium silicates (CaSiO ₃ , Ca ₂ SiO ₄ , Ca ₃ Si ₂ O ₇ , Ca ₃ SiO ₅ ); solid solutions of calcium and magnesium siicates (CaMgSiO ₄ , Ca ₃ Mg (SiO ₄ ) ₂ , CaMgSi ₂ O ₆ , Ca ₂ MgSi ₂ O ₇ ) [1, p.32, 33].

To isolate zirconium dioxide from the pitch, the latter is leached with hydrochloric acid, and the multicomponent nature of the pitch determines the multistage mode of its leaching. First, the pitch is treated with 3-8% hydrochloric acid to break down: calcium silicates; solid solutions of calcium and magnesium silicates and conversion to a hydrochloric acid solution of calcium, magnesium in the form of chlorides, and silicon in the form of silicic acid. Then, the solid residue after the first leaching stage is treated with 27% hydrochloric acid to break down zirconate, calcium zirconosilicate and convert calcium, zirconium to hydrochloric acid solution. Silicon, especially in the initial period of leaching, when the concentration of hydrochloric acid is sufficiently high (from 18 to 27%), partially remains together with zirconium dioxide in the solid product in the form of a silica gel.

Hydrochloric solutions after leaching operations with a low content of zirconium, calcium, magnesium, silicon and unbound chlorine ion are environmentally hazardous waste products.

The disadvantages of the method are:

- a relatively high content of silicon dioxide (at least 5% by weight) in the final product - zirconia, which determines its use only in the production of fused refractory bacores;

- the need for the third stage of processing pitch with an aqueous solution of sodium hydroxide to purify zirconia from silica gel;

- the impossibility of obtaining from zircon, in addition to zirconia, the second final (commercial) product - silicon dioxide, since the pitch composition does not allow it to be leached in one stage with concentrated hydrochloric acid to obtain only two compounds in the solid residue: zirconia and silica gel precipitate . In the single-stage leaching mode, a pulp is formed with a jelly-like, bulk sediment, which is practically impossible to separate from the liquid phase and to wash from associated impurities;

- the inability to regenerate compounds of calcium, magnesium and hydrochloric acid, since it is not economically feasible to extract them from dilute hydrochloric acid solutions;

- irretrievable losses of zirconium due to the formation during sintering of acid-soluble compounds - zirconate and calcium zirconosilicate;

- the formation of large volumes of environmentally hazardous solutions, for the neutralization and disposal of which additional costs are required.

The technical result of the claimed invention is the ability to: obtain from zircon and technical zirconia, with a silicon dioxide content of less than 0.6 wt.%, And hydrated silicon dioxide; regeneration of magnesium oxide from the pitch, followed by the use of recycled magnesium oxide during the decomposition of zircon by sintering; regeneration of hydrochloric acid from a hydrochloric acid solution of magnesium chloride formed during the leaching of the pitch, followed by the use of reverse hydrochloric acid to leach the pitch; the practical exclusion of the formation of environmentally hazardous effluent solutions.

The claimed technical result is achieved in that in a method for producing zirconium dioxide from zircon, comprising sintering zircon with alkaline earth metal oxides to form a pitch containing zirconium dioxide, and hydrochloric acid leaching of the pitch according to the invention, before sintering, the zircon is mixed with a molar solution of magnesium chloride in molar ratio zircon to magnesium oxide 1: 2.2 ÷ 2.5 to obtain pulp, which is subjected to spray firing at a temperature of 850 ÷ 950 ° C with the formation of a vapor-gas mixture consisting of water and hydrogen chloride and a solid mixture consisting of zircon and magnesium oxide, the formed solid mixture is sintered and carried out at 1250 ÷ 1300 ° C for 2.0 ÷ 2.5 hours, hydrochloric acid leaching of the pitch is carried out with excess hydrochloric acid, taken in excess 20 ÷ 25% for hydrogen chloride, at 80 ÷ 90 ° C for 0.50 ÷ 0.67 hours to obtain a suspension, which is heated at a temperature of 107 ± 5 ° C to a pH value of 6.5 ÷ 7.0 s the formation of a solid product consisting of zirconia, silicon and magnesium chloride, which is leached with water, acidified hydrochloric acid to a pH value of 1.5 ÷ 2.0, with the formation of pulp containing a solution of magnesium chloride and dissociated zircon, consisting of a mixture of associated zirconium dioxide and silicon, the pulp is filtered to obtain a solution of magnesium chloride and dissociated zircon, which after washing with water acidified with reverse hydrochloric acid to a pH of 1.5–2.0, and then with water to a pH of 6.5–7.0, is treated with an aqueous solution of ammonium fluoride to form ammonia and pulp vapors consisting of from water a solution of ammonium hexafluorosilicate and zirconium dioxide, which is separated from the solution, washed with water to a pH value of 6.5 ÷ 7.0, and dried to obtain a commercial product in the form of technical zirconium dioxide, and a gas-vapor mixture of water and hydrogen chloride formed by spraying firing a circulating solution of magnesium chloride with zircon, condense to obtain circulating hydrochloric acid and use it to leach pitch, and a solution of magnesium chloride separated from dissociated zircon is purified from impurities, reduce its acidity, first with chemically active magnesium oxide, to a pH value of 4 ÷ 5, then ammonia water, to a pH value of 7.5, with the formation of a precipitate of hydroxides of impurity elements, which are separated from a solution of magnesium chloride and sent for disposal, and the purified solution of magnesium chloride is evaporated to a concentration of 415 ÷ 420 g / l of magnesium oxide and sent to prepare a mixture with zircon to obtain pulp for spray firing, an aqueous solution of ammonium hexafluorosilicate separated from zirconia is saturated vapors of ammonia to a pH value of 9.5 ÷ 10.0, to obtain a pulp consisting of an aqueous solution of ammonium fluoride and hydrated silicon dioxide, which is separated from an aqueous solution of ammonium fluoride, washed with water until a pH value of 6.5 ÷ 7.0, and dried to obtain a marketable product in the form of hydrated silicon dioxide, the aqueous solution of ammonium fluoride separated from hydrated silicon dioxide is adjusted to a pH value of 6.5 ± 0.5, and sent to the processing of dissociated zircon.

Mixing zircon with a circulating solution of magnesium chloride ensures, after spray pulping, the same chemical composition of the charge at any point. Mixing zircon with a circulating solution of magnesium chloride in a molar ratio of zircon to magnesium oxide in a solution of 1: 2.2–2.5 ensures the maximum degree of conversion of zircon to zirconia and magnesium orthosilicate during the subsequent sintering operation. Spray firing of pulp consisting of zircon with a circulating solution of magnesium chloride in a molar ratio of zircon to magnesium oxide in a solution of 1: 2.2 ÷ 2.5, at a temperature of 850 ÷ 950 ° C provides the maximum decomposition of a solution of magnesium chloride:

with the formation of a gas-vapor mixture consisting of water and hydrogen chloride, from which, during the subsequent condensation operation, circulating hydrochloric acid is formed, and a solid mixture consisting of zircon and magnesium oxide. Sintering of a solid mixture consisting only of zircon and magnesium oxide in a molar ratio of 1: 2.2 ÷ 2.5, at 1250 ÷ 1300 ° C for 2.0 ÷ 2.5 hours:

позволяет максимально преобразовать ортосиликат магния в кремнегель и солянокислый раствор хлорида магния. Нагревание суспензии, состоящей из диоксида циркония, кремнегеля и солянокислого водного раствора хлорида магния, при температуре 105÷110°С до величины рН, равной 6,5÷7,0, образующегося твердого продукта:allows you to get the pitch with the maximum converted zircon only to zirconium dioxide and magnesium orthosilicate and, subsequently, to leach the pitch in one stage. Processing the pitch with reverse hydrochloric acid with an excess of 20–25% in hydrogen chloride at 80–90 ° C for 0.50–0.67 hours to obtain a suspension:

allows maximum conversion of magnesium orthosilicate into silica gel and hydrochloric acid solution of magnesium chloride. Heating a suspension consisting of zirconia, silica gel and hydrochloric acid aqueous solution of magnesium chloride at a temperature of 105 ÷ 110 ° C to a pH value of 6.5 ÷ 7.0, the resulting solid product:

allows you to convert silica gel to silicon dioxide, insoluble in water, acidified with hydrochloric acid to a pH value of 1.5 ÷ 2.0, and eliminates the formation of magnesium chlorohydroxide, Mg (OH) Cl, insoluble in water, acidified with hydrochloric acid to a value a pH of 1.5 ÷ 2.0, which allows, in the subsequent leaching of a solid product consisting of zirconium dioxide, silicon dioxide and hydrated magnesium chloride, with water, acidified with reverse hydrochloric acid to a pH of 1.5 ÷ 2, 0, eliminate the loss of dioxide and silicon and to ensure maximum extraction of magnesium in hydrochloric acid aqueous solution of magnesium chloride. Leaching of a solid product consisting of zirconium dioxide, silicon dioxide and hydrated magnesium chloride with water, acidified with reverse hydrochloric acid to a pH of 1.5 ÷ 2.0, with the formation of a pulp containing a solution of magnesium chloride and dissociated zircon, consisting of a mixture of associated zirconia and silicon dioxide:

allows separating magnesium and impurity elements (iron, aluminum, etc.) from a mixture of associated zirconium and silicon dioxides in the form of an aqueous hydrochloride chloride solution. Filtration of the pulp to obtain a solution of magnesium chloride and dissociated zircon, washing the latter with water, acidified with reverse hydrochloric acid to a pH of 1.5 ÷ 2.0, and then with water to a pH of 6.5 ÷ 7.0, provides the necessary purification of dissociated zircon from magnesium, chlorine ion and impurity elements. Processing a mixture of associated zirconia and silicon dioxide with a circulating aqueous solution of ammonium fluoride:

with the formation of ammonia and pulp vapors, consisting of an aqueous solution of ammonium hexafluorosilicate and zirconium dioxide, which is separated from the solution, washed with water to a pH value of 6.5-7.0, and dried, it allows to obtain a commercial product in the form of technical zirconium dioxide, with a silicon content of less than 0.02 ÷ 0.60 wt.%. The condensation of a vapor-gas mixture of water and hydrogen chloride, formed during spray firing of a circulating solution of magnesium chloride with zircon, allows one to obtain circulating hydrochloric acid with an HCl content of at least 25 wt.% Suitable for treating pitch. Decreasing the acidity of a solution of magnesium chloride separated from dissociated zircon, first with reactive magnesium oxide, to a pH value of 4–5, then ammonia water, to a pH value of 7.5, with the formation of a precipitate of hydroxide impurity elements, which are separated from the solution magnesium chloride and sent for recycling, provides purification of a solution of magnesium chloride from impurity elements and compensation of magnesium losses. Evaporation of the purified solution of magnesium chloride to a concentration of 415 ÷ 420 g / l of magnesium oxide allows it to be used as a working solution for preparing a mixture with zircon in the form of pulp for spray firing and, subsequently, during spray firing of pulp, the formation of a gas-vapor mixture of water and chloride hydrogen with a content of the latter of at least 25 wt.%. Saturation of an aqueous solution of ammonium hexafluorosilicate separated from zirconium dioxide by ammonia recycled vapors formed by reaction (6) to a pH value of 9.5 ÷ 10.0:

allows you to get a pulp consisting of an aqueous solution of ammonium fluoride and hydrated silicon dioxide, separation from an aqueous solution of ammonium fluoride, washing with water to a pH value of 6.5 ÷ 7.0, and drying of which allows to obtain a marketable product in the form of hydrated silicon dioxide. The separation of an aqueous solution of ammonium fluoride from hydrated silicon dioxide and adjusting the pH of the solution to a value of 6.0 ÷ 7.0 allow it to be regenerated and used as a reverse solution for the treatment of dissociated zircon.

Thus, the use of the proposed method allows to ensure: complex processing of zircon with the receipt of marketable products in the form of technical zirconium dioxide and hydrated silicon dioxide; regeneration of magnesium oxide from the pitch in the form of a circulating aqueous solution of magnesium chloride, followed by its use in the decomposition of zircon; regeneration of hydrochloric acid from a hydrochloric acid aqueous solution of magnesium chloride formed during pitch leaching, followed by the use of reverse hydrochloric acid to pitch leach; the practical exclusion of the formation of environmentally hazardous effluent solutions.

Technical solutions that coincide with the totality of the essential features of the claimed invention have not been identified, which allows us to conclude that the claimed invention conforms to such a condition as "novelty."

The claimed essential features that predetermine the receipt of the specified technical result, does not explicitly follow from the prior art, which allows us to conclude that the claimed invention meets such a patentability condition as "inventive step".

The patentability condition "industrial applicability" is confirmed by an example of a specific implementation set forth in the "Information confirming the possibility of carrying out the invention" section.

The drawing shows a schematic flow diagram of the inventive method for producing zirconia and silicon dioxide from zircon.

To implement the method of producing zirconia and silicon dioxide from zircon, a zircon concentrate (zircon) of the Shokash deposit, the Republic of Kazakhstan, in the delivery state and pre-ground was used. The results of the analysis of zircon in the delivery state (grain) and crushed are presented in table 1

Table. one Zircon Grading Content, wt.% ZrO ₂ SiO ₂ HfO ₂ Fe ₂ O ₃ Al ₂ O ₃ TiO ₂ P ₂ O ₅ one 2 3 four 5 6 7 8 9 grain ≤50 μm≈23%; > 5≤100 μm≈60% 61.88 32.14 1.18 0.11 1.51 0.99 0.20 > 100≤130 μm≈17% shredded ≤50 μm = 85 ± 2%; <70 μm = 100%; 66.7 - - 0.02 1.13 0.70 -

Grain or crushed zircon weighing 100.0 ± 0.1 g is poured into an intensely mixed reverse solution of magnesium chloride with a content of 415 ÷ 420 g / l, mainly 420 g / l, in a molar ratio of zircon to magnesium oxide in a solution of 1: 2, 2 ÷ 2.5, mainly for grain - 1: 2.5, for crushed - 1: 2.2. The resulting pulp with stirring is fed to a laboratory spray firing unit, where the pulp at a temperature of 850 ÷ 950 ° C, mainly 900 ° C, is converted into a solid mixture consisting of zircon and magnesium oxide, and a gas-vapor mixture consisting of water and hydrogen chloride, which condensed in a downward refrigerator with the formation of circulating hydrochloric acid with a content of 26 ± 1 wt.% hydrogen chloride.

A mixture of zircon and magnesium oxide is placed in an alundum crucible and sintered in a laboratory furnace at a temperature of 1250 ÷ 1300 ° C, mainly for a mixture with grain zircon - 1300 ° C, - with ground zircon - 1250 ° C, for 2.0 ÷ 2, 5 hours, mainly 2.3 hours.

The pitch formed after sintering, consisting of zirconia, magnesium orthosilicate and unreacted zircon (≤1 wt.%), Is treated in a 1 L fluoroplastic reactor with a lid, with an electromechanical stirrer and a reflux condenser installed in a sand bath on an electric stove, reverse hydrochloric acid with an excess of 20 ÷ 25% for hydrogen chloride relative to the magnesium content in the pitch, mainly 24%, at 80 ÷ 90 ° C, mainly at 85 ° C, for 0.50 ÷ 0.67 hours, mainly 0.60 hours .

The resulting suspension is poured onto a baking sheet of fluoroplastic and heated at a temperature of 105 ÷ 110 ° C, mainly at 110 ° C, to a pH value of 6.5 ÷ 7.0, mainly 6.5, of the resulting solid product.

The solid product, consisting of zirconia, silicon dioxide and magnesium chloride, is placed in a fluoroplastic reactor (see above) and leached with water, acidified with reverse hydrochloric acid to a pH value of 1.5 ÷ 2.0, mainly 1.5, s the formation of pulp containing a solution of magnesium chloride and dissociated zircon, consisting of a mixture of associated zirconia and silicon dioxide.

The pulp is filtered on a laboratory nutsche filter to obtain a solution of magnesium chloride and dissociated zircon.

Dissociated zircon is washed with water, acidified with reverse hydrochloric acid to a pH of 1.5 ÷ 2.0, mainly 2.0, and then with water to a pH of 6.5 ÷ 7.0, mainly 6.5 and is treated in a fluoroplastic reactor (see above) with a circulating aqueous solution of ammonium fluoride to form: a pulp consisting of an aqueous solution of ammonium hexafluorosilicate and zirconium dioxide; as well as ammonia vapors. Ammonia vapors are used as a circulating reagent in the subsequent operation of separating hydrated silicon dioxide from an aqueous solution of ammonium hexafluorosilicate.

Zirconia is separated from a solution of ammonium hexafluorosilicate on a laboratory suction filter, washed with water to a pH value of 6.5-7.0, preferably 7.0, and dried to obtain a commercial product in the form of technical zirconium dioxide. The results of the analysis of the obtained samples of zirconium dioxide are presented in table 2.

table 2 Impurities ZrO ₂ Grain ZrSiO ₄ ZrO ₂ chopped. ZrSiO ₄ content ^* , wt.% SiO ₂ 0.27 ÷ 0.36 0.02 ÷ 0.11 Fe ₂ O ₃ 0.015 ÷ 0.10 0.007 ÷ 0.03 Al ₂ O ₃ 0.39 ÷ 0.47 0.21 ÷ 0.32 TiO ₂ 0.53 ÷ 0.64 0.58 ÷ 0.67 P ₂ O ₅ <0.05 <0.05 MgO 0.41 ÷ 0.50 0.33 ÷ 0.45 Wed particle size 1.0 ÷ 1.3 μm; 1.4 ÷ 4.1 μm; ≤6 μm = ≤2 μm = = 100% = 70% ^*) - minimum and maximum values in a series of 4 experiments.

The magnesium chloride solution is poured into a fluoroplastic reactor (see above) and with stirring, reactive magnesium oxide is loaded into it, lowering the acidity of the solution to a pH value of 4–5, mainly to 5, then ammonia water, to a pH value of 7, 5, with the formation of a precipitate of hydroxides of impurity elements.

The precipitate of hydroxides of impurity elements is separated by means of a laboratory suction filter from a solution of magnesium chloride and sent for disposal.

The magnesium chloride solution purified from impurities is evaporated in a fluoroplastic reactor (see above) to a concentration of 415 ÷ 420 g / l MgCl ₂ , mainly up to - 420 g / l, and sent to prepare the mixture with zircon in the form of pulp for spray firing.

The solution of ammonium hexafluorosilicate with stirring in a fluoroplastic reactor (see above) is saturated with ammonia working pairs to a pH value of 9.5 ÷ 10.0, mainly up to 10.0, to obtain a pulp consisting of an aqueous solution of ammonium fluoride and hydrated silicon dioxide .

Hydrated silicon dioxide is separated by means of a laboratory suction filter from an aqueous solution of ammonium fluoride and washed with water to a pH value of 6.5-7.0, preferably up to 7.0, and dried to obtain a marketable product in the form of hydrated silicon dioxide. The results of the analysis of the obtained samples of hydrated silicon dioxide are presented in table.3.

Table 3 The content ^{* of} impurities in SiO ₂ , wt.% Fe ₂ O ₃ Al ₂ O ₃ MgO F 0.014 ÷ 0.057 0.15 ÷ 0.32 0.03 ÷ 0.07 0.24 ÷ 0.55 ^*) - minimum and maximum values in a series of 4 experiments.

The aqueous solution of ammonium fluoride is adjusted to a pH value of 6.0 ÷ 7.0, mainly to 6.5, and sent to the processing of dissociated zircon.

Information sources

1. Metallurgy of zirconium and hafnium. Baryshnikov N.V., Heger V.E., Denisova I.D. et al. - Ed. Nekhamkina A.G. - M.: Metallurgy, 1979.-208 p.

Claims (1)

A method of processing zircon to obtain zirconia, comprising sintering with alkaline earth metal oxides to form a pitch containing zirconium dioxide and hydrochloric acid leaching of the pitch, characterized in that before sintering the zircon is mixed with a circulating solution of magnesium chloride in a molar ratio of zircon to magnesium oxide 1 : 2.2 ÷ 2.5 to obtain pulp, which is subjected to spray firing at a temperature of 850 ÷ 950 ° C with the formation of a vapor-gas mixture consisting of water and hydrogen chloride, and a solid mixture consisting of cir Kona and magnesium oxide, the formed solid mixture is sintered, and it is conducted at 1250 ÷ 1300 ° C for 2.0 ÷ 2.5 hours, the hydrochloric acid leaching of the pitch is carried out using reverse hydrochloric acid, taken in excess of 20 ÷ 25% in hydrogen chloride at 80 ÷ 90 ° C for 0.50 ÷ 0.67 h to obtain a suspension that is heated at a temperature of 107 ± 5 ° C to a pH value of 6.5 ÷ 7.0, with the formation of a solid product consisting of dioxide of zirconium, silicon and magnesium chloride, which is leached with water, acidified with reverse hydrochloric acid to a pH value of 1.5 ÷ 2.0, with a sample By calling pulp containing a solution of magnesium chloride and dissociated zircon, consisting of a mixture of associated zirconia and silicon dioxide, the pulp is filtered to obtain a solution of magnesium chloride and dissociated zircon, which after washing with water acidified with reverse hydrochloric acid to a pH value of 1.5 ÷ 2 , 0, and then with water to a pH value of 6.5 ÷ 7.0, it is treated with a circulating aqueous solution of ammonium fluoride to form ammonia and pulp vapors consisting of an aqueous solution of ammonium hexafluorosilicate and zirconium dioxide, which is separated from the solution, washed with water to a pH value of 6.5 ÷ 7.0, and dried to obtain a marketable product in the form of technical zirconium dioxide, and a gas-vapor mixture of water and hydrogen chloride formed by spray firing of a circulating solution of magnesium chloride with zircon is condensed to obtain reverse hydrochloric acid and used to leach pitch, and a solution of magnesium chloride separated from dissociated zircon is purified from impurity elements, its acidity is first reduced by reactive ox with magnesium to pH 4-5, then with ammonia water to pH 7.5, with the formation of a hydroxide precipitate of impurity elements, which are separated from the magnesium chloride solution and sent for disposal, and the purified magnesium chloride solution is evaporated to a concentration of 415 ÷ 420 g / l on magnesium oxide and sent to prepare a mixture with zircon to obtain pulp for spray firing, the aqueous solution of ammonium hexafluorosilicate separated from zirconia is saturated with ammonia by returning vapor to a pH value of 9.5 ÷ 10.0, to obtain m of pulp consisting of an aqueous solution of ammonium fluoride and hydrated silicon dioxide, which is separated from an aqueous solution of ammonium fluoride, washed with water to a pH value of 6.5-7.0, and dried to obtain a marketable product in the form of hydrated silicon dioxide, separated from hydrated silicon dioxide, the aqueous solution of ammonium fluoride is adjusted to a pH value of 6.5 ± 0.5, and sent to the treatment of dissociated zircon.