The method of obtaining alumina from nepheline raw materials

(57) Abstract:

The invention relates to ferrous metallurgy and can be used in the production of alumina by sintering. The method of obtaining alumina from nepheline raw materials includes batch preparation of alumina-containing material, soda solution and limestone, sintering the mixture in a rotary kiln and cooled. The mixture is prepared in three stages, the first stage in the alumina-containing material is injected waste production of aluminium by electrolysis in the form of sludge in the amount of 1-5% of the dry mass of the mixture and soda solution with a concentration of 40-60 g/l, the resulting mixture was milled in the first mill wet grinding, in the second stage in the limestone add soda solution with a concentration of 40-60 g/l, the resulting mixture was milled in the second mill wet grinding, in the third stage rodoslovnaya and staisfactory pulp dosalivaet in the third wet mill delivered and add soda solution with a concentration of 40-60 g/l, to obtain a mixture humidity 23-27%. The invention allows to increase the degree of extraction of alumina and alkalis, to reduce energy consumption and reduce environmental pollution. 3 table.

The invention relates to ferrous metallurgy and can be used for the raw material, comprising preparing a mixture of nepheline raw materials with the addition of kaolin clay as Malielegaoi aluminosilicate additive, limestone, sotoportego solution, sintering the mixture and leaching SPECA /1/.

The disadvantage of this method is the use as an additive expensive kaolin clay, leading to increased costs.

The closest technical solution is the method of processing aluminum-containing material, comprising preparing a mixture of aluminum-containing material, soda ash, limestone and fluorine-containing waste of the process of refining aluminum three-layer method in the amount of 1-5% and then sintering the mixture in a rotary kiln /2/.

The disadvantage of this method is the contamination of fluorine from fluorine-containing solid waste refining of aluminium waste water and gas emissions from the production of alumina. A high concentration of fluorine, chlorine and sodium in the waste lowers the melting point of SPECA, which can lead to the violation of technological mode of production of alumina due to failure of furnace sintering. Small amounts of these wastes make their use uneconomic.

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This object is achieved in that in the method of producing alumina from nepheline raw materials, comprising preparing a mixture of aluminum-containing material, soda solution and limestone, sintering the mixture in a rotary kiln and cooling, it is new that the mixture is prepared in three stages the first stage in the alumina-containing material is injected waste production of aluminium by electrolysis in the form of sludge in the amount of 1-5% soda solution with a concentration of 40-60 g/l, the resulting mixture was milled in the first mill wet grinding, in the second stage in the limestone add soda solution with a concentration of 40-60 g/l, the resulting mixture was milled in the second mill wet grinding, in the third stage rodoslovnaya and staisfactory pulp dosalivaet in the third wet mill delivered and add soda solution with a concentration of 40-60 g/l, to obtain a mixture humidity 23-27%.

The sludge in the production of aluminum by electrolysis contains aluminum and its compounds in the amount of 5-10% of dry weight of sludge and adding to the mixture allows uenishi reduce the introduction to the mixture of limestone.

A slurry containing coal 20-25%, organic compounds 15-25%, sodium 6-10%, potassium 2-3% and the fluorine 1-1,5% in dry weight of sludge are substitutes part of expensive fuel oil or coal fuel, and also serves as lagoonarium plasticizer to the mixture, allowing to save fuel, to increase the extraction of alumina and caustic soda from SPECA.

Example No. 1. Nepheline-staisfactory the mixture is prepared from the calculation of molar ratios:

PA₂O/Al₂O₃=1,05-1,1

(CaO+MgO)/(SiO₂+Fe₂O₃)=1,9-2,0

Stoneflies mixture having a ratio W:T=1:4 and using soda solution with a concentration of 40-60 g/l, subjected to wet grinding in a laboratory mill for 60 minutes. Then staisfactory mixture using soda solution with a concentration of 40-60 g/l is subjected to wet grinding in a mill for 60 minutes. Stoneflies and staisfactory pulp are mixed and subjected to joint the wet final grinding in a mill for 60 minutes. The resulting mixture of 0.5 l was adjusted to a moisture content of 25%, determine the fluidity of RASPLAV standard cone, after which the volume of the mixture was adjusted to a moisture content of 27% and determine its takuseshi mixture without the addition of sludge.

The mixture is poured into steel forms with a capacity of 0.5 l, which are then placed in a laboratory drying Cabinet, which produces dried samples of the charge of obtaining briquettes. These briquettes are placed in a laboratory muffle furnace, where they make their sintering speeds of 8-10°C per minute. Cooling the obtained SPECA carried out with the oven up to 600°C, and then in a desiccator. Sintering temperature 1100°C, 1150°C, 1200°C, 1250°C, heating time of 120 minutes, and the holding time is 30 minutes. To determine the optimum sintering temperature of the mixture without the addition of sludge in 1250°C. the Samples obtained SPECA ground in a laboratory mill wet grinding adding soda solution with a concentration of 40-60 g/l with a ratio of W:T=1:4, the resulting suspension is filtered and the resulting filtrate determine the concentration of aluminum and sodium. The results are shown in tables No. 1-3.

Example No. 2. Nepheline-staisfactory the mixture is prepared from the calculation of molar ratios:

PA₂O/Al₂O₃=1,05-1,1

(CaO+MgO)/(SiO₂+Fe₂O₃)=1,9-2,0

The additive is a sludge - the solid waste production of aluminum by electrolysis humidity 35% and contains wt.% in su the keys in stoneflies mixture, with the ratio of W:T=1:4 and using soda solution with a concentration of 40-60 g/l, in the form of pulp humidity 35% at 2% of dry mass, after which the mixture with the addition of the slurry is subjected to wet grinding in a laboratory mill for 60 minutes. Then staisfactory mixture, using soda solution with a concentration of 40-60 g/l, subjected to wet grinding in a mill for 60 minutes. Rodoslovnaya and staisfactory pulp are mixed and subjected to joint the wet final grinding in a mill for 60 minutes. The resulting mixture of 0.5 l was adjusted to a moisture content of 23%, determine the fluidity of RASPLAV standard cone, after which the volume of the mixture was adjusted to a moisture content of 25% and determine its fluidity, and further to a moisture content of 27% and 30%, resulting in determine the optimal humidity 27% rodoslovnaya-limestone mixture with 2% additive slurry. The mixture is poured into steel forms with a capacity of 0.5 l, which are then placed in a laboratory drying Cabinet, which produces dried samples of the charge of obtaining briquettes. These briquettes are placed in a laboratory muffle furnace, where they make their sintering speeds of 8-10°C per minute. Cooling the obtained custody carried out with the oven up to 600°C, and sate minutes. To determine the optimum sintering temperature of the mixture with the addition of 2% slurry in 1200°C. the Samples obtained guardianship ground in a laboratory mill wet grinding adding soda solution with a concentration of 40-60 g/l with a ratio of W:T=1:4, the resulting suspension is filtered and the resulting filtrate determine the concentration of aluminum and sodium.

The results are shown in tables No. 1-3.

Example No. 3. Nepheline-staisfactory the mixture is prepared from the calculation of molar ratios:

PA₂O/Al₂O₃=1,05-1,1

(CaO+MgO)/(SiO₂+Fe₂O₃)=1,9-2,0

The additive is a sludge - the solid waste production of aluminum by electrolysis humidity 35% and contains wt.% dry sludge: 30-39, Al - 5-10, F - 1,0-1,5, 13-21, Na - 6-10, 2-3, Si - 1.5 to 2.5, H - 6-10, Mg - 0,5-1,0, CA - 1,0-1,5, S - 3-5, Fe - 5-7.

The slurry is added to stoneflies mixture having a ratio W:T=1:4 and using soda solution with a concentration of 40-60 g/l, in the form of pulp humidity 35% 4% dry weight, after which the mixture with the addition of the slurry is subjected to wet grinding in a laboratory mill for 60 minutes. Then staisfactory mixture using soda solution, concentratie LPI mixed and subjected to joint the wet final grinding in a mill for 60 minutes. The resulting mixture of 0.5 l was adjusted to a moisture content of 23%, determine the fluidity of RASPLAV standard cone, after which the volume of the mixture was adjusted to a moisture content of 25% and determine its fluidity, and further to a moisture content of 27% and 30%, 9 resulting in determine the optimum moisture content of 25% rodoslovnaya-limestone mixture with 4% additive slurry. The mixture is poured into steel forms with a capacity of 0.5 l, which are then placed in a laboratory drying Cabinet, which produces dried samples of the charge of obtaining briquettes. These briquettes are placed in a laboratory muffle furnace, where they make their sintering speeds of 8-10°C per minute. Cooling the obtained SPECA carried out with the oven up to 600°C, and then in a desiccator. Sintering temperature 1100°C, 1150°C, 1200°C, 1250°C, heating time of 120 minutes, and the holding time is 30 minutes. To determine the optimum sintering temperature of the mixture with the addition of 4% of the sludge in 1150°C. the Samples obtained SPECA ground in a laboratory mill wet grinding adding soda solution with a concentration of 40-60 g/l with a ratio of W:T=1:4, the resulting suspension is filtered and the resulting filtrate determine the concentration of aluminum and sodium.

The results of the analyses are given in table>P CLASS="ptx2">Na₂O/Al₂O₃=1,05-1,1

(CaO+MgO)/(SiO₂+Fe₂O₃)=1,9-2,0

The additive is a sludge - the solid waste production of aluminum by electrolysis humidity 35% and contains wt.% dry sludge: 30-39, Al - 5-10, F - 1,0-1,5, 13-21, Na - 6-10, 2-3, Si - 1.5 to 2.5, H - 6-10, Mg - 0,5-1,0, CA - 1,0-1,5, S - 3-5, Fe - 5-7.

The slurry is added to stoneflies mixture having a ratio W:T=1:4 and using soda solution with a concentration of 40-60 g/l, in the form of pulp humidity 35% in the amount of 5% of dry mass, after which the mixture with the addition of the slurry is subjected to wet grinding in a laboratory mill for 60 minutes. Then staisfactory mixture, using soda solution with a concentration of 40-60 g/l, subjected to wet grinding in a mill for 60 minutes. Rodoslovnaya and staisfactory pulp are mixed and subjected to joint the wet final grinding in a mill for 60 minutes. The resulting mixture of 0.5 l was adjusted to a moisture content of 23%, determine the fluidity of RASPLAV standard cone, after which the volume of the mixture was adjusted to a moisture content of 25% and determine its fluidity, and further to a moisture content of 27% and 30%, resulting in determine the optimum moisture content of 23% rodoslovnaya-limestone mixture with 5% meets wardrobe, where produce drying samples of the charge of obtaining briquettes. These briquettes are placed in a laboratory muffle furnace, where they make their sintering speeds of 8-10°C per minute. Cooling the obtained SPECA carried out with the oven up to 600°C, and then in a desiccator. Sintering temperature 1100°C, 1150°C, 1200°C, 1250°C, heating time of 120 minutes, and the holding time is 30 minutes. To determine the optimum sintering temperature of the mixture with addition of 5% slurry in 1100°C. the Samples obtained SPECA ground in a laboratory mill wet grinding adding soda solution with a concentration of 40-60 g/l with a ratio of W:T=1:4, the resulting suspension is filtered and the resulting filtrate determine the concentration of aluminum and sodium.

The results are shown in tables No. 1-3.

Example No. 5. Nepheline-staisfactory the mixture is prepared from the calculation of molar ratios:

Na₂O/Al₂O₃=1,05-1,1

(CaO+MgO)/(SiO₂+Fe₂O₃)=1,9-2,0

The additive is a sludge - the solid waste production of aluminum by electrolysis humidity 35% and contains wt.% dry sludge: 30-39, Al - 5-10, F - 1,0-1,5, 13-21, Na - 6-10, 2-3, Si - 1.5 to 2.5, H - 6-10, Mg - 0,5-1,0, CA - 1,0-1,5, S - 3-5, Fe - 5-7.

Ø the acidity of 40-60 g/l, in the form of pulp humidity 35% in the amount of 6% of dry mass, after which the mixture with the addition of the slurry is subjected to wet grinding in a laboratory mill for 60 minutes. Then staisfactory mixture using soda solution with a concentration of 40-60 g/l, subjected to wet grinding in a mill for 60 minutes. Rodoslovnaya and staisfactory pulp are mixed and subjected to joint the wet final grinding in a mill for 60 minutes. The resulting mixture of 0.5 l was adjusted to a moisture content of 23%, determine the fluidity of RASPLAV standard cone, after which the volume of the mixture was adjusted to a moisture content of 25% and determine its fluidity, and further to a moisture content of 27% and 30%, resulting in determine the optimum moisture content of 23% rodoslovnaya-limestone mixture with 6% additive slurry. The mixture is poured into steel forms with a capacity of 0.5 l, which are then placed in a laboratory drying Cabinet, which produces dried samples of the charge of obtaining briquettes. These briquettes are placed in a laboratory muffle furnace, where they make their sintering speeds of 8-10°C per minute. Cooling the obtained SPECA carried out with the oven up to 600°C, and then in a desiccator. Sintering temperature 1100°C, 1150°C, 1200°C, 1250°C, heating time of 120 mm 6% slurry in 1075°C. Samples obtained SPECA ground in a laboratory mill wet grinding adding soda solution with a concentration of 40-60 g/l with a ratio of W:T=1:4, the resulting suspension is filtered and the resulting filtrate determine the concentration of aluminum and sodium.

The results are shown in tables No. 1-3.

Analyses of the obtained class of examples No. 1-5 show that the introduction of the charge in the composition of the sludge compounds of fluorine and alkali metals reduces the optimal sintering temperature required for the formation of porous quality SPECA /table no.1/. Introduction to the mixture of sludge increases the content of Al₂ABOUT₃and Na₂O in Speke, obtained by sintering the mixture slurry /table no.2/. Introduction to the mixture in the composition of the sludge compounds of aluminum and sodium increases the extraction of SPECA aluminum and sodium in terms of Al₂O₃and Na₂O /table no.3/.

As can be seen from table No. 3, increasing doses of sludge in the charge more than 5% (by dry weight of the charge) leads to a decrease in extraction Al₂ABOUT₃and Na₂O from SPECA due to the formation of low-melting sodium(potassium)calcium silicates formed in malabarista lingeriebrendan Speke, from which ill go into aluminate solution and is NACA in the charge. Thus, the use of the proposed method in comparison with the known allows to increase the degree of extraction of alumina 85,5 to 92,5%, alkalis Na₂O from 87.0 to 91,0% by introducing slurry to the mixture of aluminum and sodium compounds and by reducing rasshifrovka SPECA, also can reduce energy consumption by reducing the sintering temperature from 1250°C to 1100° due to the effect of the flux from cuttings and by reducing the moisture content of the mixture with the addition of sludge with 28-30% to 23-27%, reduce environmental pollution in the area of sludge compounds of fluorine and benzopyrene.

Sources of information

1. RF patent № 2165888, CL 01 F 7/38, 2001.

2. Auth. St. USSR № 1274999, class C 01 F 7/38, 1986.

The method of obtaining alumina from nepheline raw materials, comprising preparing a mixture of aluminum-containing material, soda solution and limestone, sintering the mixture in a rotary kiln and cooling, characterized in that the mixture prepared in three stages, the first stage in the alumina-containing material is injected waste production of aluminium by electrolysis in the form of sludge in the amount of 1-5% of the dry mass of the mixture and soda solution with a concentration of 40-60 g/l, the resulting mixture rasmol is 40-60 g/l, the resulting mixture was milled in the second mill wet grinding, in the third stage rodoslovnaya and staisfactory pulp dosalivaet in the third wet mill delivered and add soda solution with a concentration of 40-60 g/l, to obtain a mixture humidity 23-27%.