SU1212998A1 - Method of processing nephelite slime - Google Patents

Description

The invention relates to the technology of alumina production, mainly to the hydrochemical treatment of nepheline sludge from the complex aluminosigm processing waste.

Katnps ores.

The purpose of the invention is an intensification process.

According to the proposed method, nepheline sludge becomes an effective raw material for the production of other products. So, as the first stage, nepheline sludge causts up the solution and produces a solution of caustic potash with a silica content of 0.2-0.8 g / l. In the second stage, the resulting slurry is subjected to hydrochloric treatment with a potash solution in order to reduce the content of silicon dioxide in it to the amount corresponding to component Portland cement fir.

In the first stage, the obtained method nepheline

the sludge is treated with potash solution. At the same time, the degree of caustification of the potash solution reaches up to 80-85%. The concentration of silica in the final product, caustic potassium solution, ranges from 0.2 to 0.8 g / l. The amount of CO in the treated sludge increases to 15-20%.

In the second stage, the resulting nepheline sludge is again treated with a hydrochemically potash solution with a concentration of 450-500 g / l at W: T (8-9): 1 and 90-95 s for 1.5-2.0 hours. The resulting odiokpo - there is no portland cement mixture — the em ethos of CaO: SiOj 2.8–3.0.

Thus, the nepheline sludge from alumina production, after the proposed processing, becomes valuable raw material for the production of specified products, and silicon dioxide is precipitated from potash-potassium-silica solution and by dissolving in potassium hydroxide, obtaining similar valuable products like potassium

Indoor fertilizer, potassium zhidko glass, labeled-kremmezemis: guo mixture, etc.

The concentration of the potash solution of 175-185 g / l provides a degree

kaustifshsats and 85-87%, Its increase. 185 g / l leads to a decrease in the degree of caustification 85%, and sex

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In this stage, the product No. -...sh — potassium eaters becomes non-conditioned. Lowering the concentration is not advisable, since the ./ 1175 g / l degree of caustification almost does not exceed 85-87%. At the same time, steam consumption increases, which increases the cost of the process, and, in the long run. N increases the concentration of caustic potassium. Reducing the concentration of the solution i150 g / l KrjCO: leads to a decrease in the degree of caustification 85%. According to the proposed method, the process temperature is 110-115 C is optimal, because a decrease in the process temperature below 1 leads to: -1 decrease the degree of causticization up to 65-75%. An increase in the temperature of the process to 1 is not advisable, since it practically does not affect the degree of caustification, however, in the cured solution, it is higher. 1% silicon dioxide is up to 1.5 g / l SiOj.

The process of caustification is carried out at a VECO 5 ratio of F; T (2.5 - 3..0): 1. An increase in this ratio of Btiuie 3 leads to a decrease in the degree of kgg, a fit is lower than 85%. This is due to the fact that the solid-phase interaction proceeds in the external diffusion of the ultradiffusion stages and B1. The process of caustifesium proceeds: mainly in the external diffusion stage (at the superficialr). For the transition to the second stage, Ai S-iOj is necessary so that the dioxide does not go into pa.:; Creator. Increase the ratio W: T above. 3 leads to an increase in the amount of the liquid phase, i.e. potash, in this way, in the BOOM queue, dissolves evolved silicon dioxide and contributes to the transition of the process to the intradiffusional stadion, which reduces the degree of k austesting.

According to the predicted method, the low content of dioxide ffl and in the caus- tified solution is explained by barely boring.

Silica dioxide extracted from the solid phase partially passes into the solution, and the reverse reaction simultaneously proceeds — the production of calcium silicate, which delays the process of the process, i.e. This prevents the transition of the process into the intradiffusion sta- tion of EIGO. This occurs when the content of carbonate ion () in the liquid phase is low, which ensures the transition of the dioxide from the liquid to the solid phase. As is well known, a large concentration of carbonate ion in the liquid phase makes it possible to completely deprive the nepheline sludge. According to the proposed method, a potash solution of not a high concentration of 185 g / l is used, the degree of caustification reaches 85-87%, and the content of silicon dioxide is 0.2-0.8 g / l.

A decrease in the G: T ratio of 2.5 leads to a decrease in the amount of the liquid phase and an increase in the amount of nepheline sludge used for the caustification process, which is not advisable for the proposed technology of alumina production, as the amount of the obtained potassium hydroxide is reduced.

According to the proposed method, in the first stage, nepheline sludge is used to caustify the potash solution, and in the second, the treated sludge is again treated with a more concentrated potassium carbonate solution} 450-500 g / l, for W: T (8-9): and 90-95 C, to produce a single component portland cement raw meal. The liquid phase containing silicon dioxide is used to obtain these inorganic

substances.

The nepheline slurry in the second stage is treated with a more concentrated 450 × 500 g / l potash solution to decompose the calcium silicate that forms on the surface of the particles and dissolve the silica formed by the decomposition of the dicalcium silicate, thus partly causticizing the potassium solution;

Increasing the concentration of the potash solution over 500 g / l leads to a higher degree of desiliconization of the sludge, i.e. the molar ratio of CaO: SiO becomes higher than 3, a single-component portland cement mixture is not obtained. The resulting product contains a large amount of calcium carbonate. Portland cement obtained from this mixture is not conditional, and to obtain a conditional

212998

Portal need for additional correction of the charge by nepheline sludge, which leads to complication and cost of the process, IJWhen the concentration of the potash solution decreases below 450 g / l, the degree of silification decreases, the SiO content. in potash potassium solution also decreases, and the molecular ratio of 10 JWpHoe CaOcSiO becomes below 2.8,

In the second stage, the processing of nepheline sludge is carried out at 90-95 ° C. Increasing the temperature above 95 from 15 practically does not affect the degree of desalination, and lowering it below 90 ° C reduces the degree of desiliconization, taking into account the effect of temperature on diffusion processes. In the second stage, the descretion of nepheline sludge is carried out at F: T (8-9 ):one. Increasing the ratio of W: T above 9 leads to an increase in potash in the liquid phase, which accordingly increases the degree of sludge desaturation 25 and the molar ratio CaOrSiO becomes -. with more than 3 and the charge is not conditional.

The method is performed in the following jQ manner.

Example 1. 76.2 g of nepheline sludge are treated with 200 ml of a potash solution having a K.2 concentration. 75 g / l, at W: T 3: 1 and 115 s for 2.5 h in a reactor equipped with a stirrer (specific gravity of the solution is 1.14 g / cm), The resulting slurry is filtered and the precipitate is washed,

The filtrate (102 ml) has the following chemical composition, g / l: K Okomo, 98.5; ,one; SiO 0.26.

The precipitate (85.07 g dry) has the following chemical composition,%: SiOi 27.17, 2.7; 2.46; CaO 51.88; 1.52; p, p, p, 12.02; other 2.2.

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40

45

Then, 43 g of the precipitate obtained after caustification of the potassium solution is treated with 282 ml of a potash solution having a concentration of 500 g / l, at W: T 9: 1 and 95 C for 1.5 hours in a reactor equipped with a stirrer (the specific gravity of the solution 1.37 g / cm), The resulting slurry is filtered and the precipitate is washed.

The filtrate (210 ml) has the following chemical composition, g / l:

Kr0.ansg56, A; 282.3; SiO / U, 51.

The precipitate (45 g dry) has the following chemical composition,%; SiO, 18.67; A1, 29; 2.34; CaO 49.55; R, 0 1.45; ppt 23.31; other 2.32, and the molar ratio of CaOrSiOi 2.81.

Example 2, 69.5 g of nepheline sludge is treated with 150 ml of a potash solution having a concentration of CgSO3 175 g / l at W: T 2.5: 1 and IIO c for 3.0 hours in a reactor equipped with a stirrer (specific gravity

a solution of 1.14 g / cm). The resulting slurry is filtered and the precipitate is washed

The filtrate (70 ml) has the following chemical composition, g / l: K Omichs 103, KgOkar5 16.1; SiOz 0.5.

The precipitate (76.3 dry) has the following chemical composition,%: SiOi 27.52; A1.0E 2.43; GvGOz 2.50, CaO 52.54; RaO 1.54, ppt 10; 9; other 2.45.

Then 34 G of the precipitate obtained after caustification of the potash solution is treated with 200 ml of the potash solution having a KaCOj concentration of 500 g / l, at W: T 8: 1 and for 2 hours in a reactor equipped with a stirrer (the specific gravity of solution 1 , 32 / g / cm). The obtained navel is filtered. And the precipitate is washed.

The filtrate, (1, 45 ml) has the following chemical composition, g / l: KaOyayci 62.7; , K, OKO., B 277.1; SiOi 15.8.

The precipitate (36.3 g dry) has the following chemical composition,%:

SiOj.17,83; AljO, 2.86;., 2.32; CaO 49.87; R5o4,43, ppt 23.95; other 2.27, and the molar ratio of CaO: SiO 3. 2.93.

Example 3, 76 g of nepheline sludge is treated with 200 ml of a potash solution having a concentration of 185 g / l, at W: T 3: 1 and 115 for 3.0 hours in a reactor equipped with a stirrer (the specific gravity of the solution is 1.145 g / cm). The resulting slurry is filtered and the precipitate is washed.

The filtrate (98 ml) has the following chemical composition, g / l: 03, 92, 18.7; SiO 0.47.

The precipitate (85.15 g dry) has the following chemical composition ,,%: SiOa26.86, ABOz 2.37; 2.54;

CaO 51.28; 1.5; ppt 13, U.

other 2.39.

Then 30 g of sediment, obtained after caustification of the potash plant, Heyur, is treated with 200 ml of the potash solution having a concentration of 450 g / l, at W: T 9: 1 and 95 C for 2 hours in a reactor equipped with a stirrer (specific gravity a solution of 1.36 g / cm). The resulting slurry is filtered and the precipitate is washed.

The filtrate (150 ml) has the following chemical composition, g / l: K Okaust 35.75, K10kar5284,6; SiO 14.66.

The precipitate (32 g dry) has the following chemical composition, g / l: RLOi17,82-; ASTs 2.3; Fej.0j 2.35; CaO 49.87; 1.42; ppt 23.84; other 2.27, and the molar ratio CaO: S 1.0., 2,996.

The proposed method for processing nepheline sludge to produce caustic potash and a single-component Portland cement mixture is economical and, compared with the known process, reduces the cost of processing and the associated material costs and simplifies the causticization process of the potash solution for reducing the hardware design, which leads to a cheaper process. In addition, affordable and cheap raw materials are used to caustify potash solution — production waste, nepheline sludge instead of CaO, which creates waste-free production. Moreover, the heat costs that are spent on calcining limestone for obtaining CaO are cut off, respectively, reducing the instrumentation and cheapening the process, eliminating the consumption of natural raw materials - calcium carbonate. At the same time, the method is economical, since the cost of 1 ton of potassium hydroxide is reduced, the process of hydrochemical treatment of nepheline sludge proceeds more easily with the production of a one-component portland cement raw mixture; provides-. with the possibility of caustic. alkalis - caustic potash in the complex processing of alkali aluminosilicates, it is possible to use the resulting caustic potash

S, 71212998b

for organizing the production of non-chlorine, etc., using the available. potassium fertilizer (potassium s in nepheline sludge silica dioxide), potassium silicon water glass ..

Claims (1)

METHOD FOR PROCESSING NEPHELINE Sludge by treating nepheline sludge with potash solution, characterized in that, in order to intensify the process, the treatment is carried out in two stages: first, potash solution with a concentration of K _g CO ₃ 175-185 g / l at W: T = (2, 5-3): 1 and 110-115 ° С for 2.5-3.0 hours, and then with a potash solution with a concentration of K2.CO3 450-500 g / l at W: T = (8-9): 1 and 90-95 ° C for 1.5-2.0 hours SU w, 1212998