WO2001047809A1

WO2001047809A1 - Process for treating sodium aluminosilicate

Info

Publication number: WO2001047809A1
Application number: PCT/JP2000/009443
Authority: WO
Inventors: Yasuo Kawai; Isao Ishikawa; Yoshiyuki Takenaka; Hideya Saito; Mineo Nozaki
Original assignee: Showa Denko K. K.; Tsukishima Kikai Co., Ltd.
Priority date: 1999-12-28
Filing date: 2000-12-28
Publication date: 2001-07-05
Also published as: AU2231801A; JP4480317B2

Abstract

A process for treating sodium aluminosilicate which comprises adding a calcium compound to sodium aluminosilicate, heating the resultant mixture of sodium aluminosilicate and the calcium compound, subjecting the heated mixture to an elution treatment with water or an aqueous solution, to thereby solubilize and elute other sodium components in the sodium aluminosilicate, and recovering the sodium components while providing a useful product having a significantly reduced content of the sodium other than that in the sodium aluminosilicate. The process allows the other sodium components to be recovered almost completely from the sodium aluminosilicate, and also the production of a residue which has a content of the sodium other than that in sodium aluminosilicate of 1 % or less and thus can be effectively used. The percentage of the above elution can be enhanced by optimizing the conditions for heating and elution.

Description

Description Processing method of sodium aluminosilicate Technical field

The present invention relates to a method for treating sodium aluminosilicate.

According to the present invention, sodium aluminosilicate which is currently discarded or not effectively used, such as red mud and soda light generated during the production of alumina and aluminum, zeolite used in various applications, Alternatively, by separating sodium contained in naturally occurring zeolite and sodalite, the recovery and utilization of sodium and the removal of sodium-removed residue from semite are performed. It can be effectively used as a raw material for packaging. Background art

A typical example of sodium aluminosilicate is red hydroxide produced as a by-product of the production of aluminum hydroxide and alumina. About 800 kg of this red mud is produced for 1 ton of aluminum. Red _{_{mud, A 1 2 O 3, S}} i O, the aluminosilicate sodium and F e ₂ 〇 ₃ consisting of N a ₂ O as a main component, and the other, T i 0 _2, quartz, alumina Contains several percent of hydrates and lime compounds. Possible uses include cement raw materials and steelmaking raw materials. However, it has been considered difficult to use cement raw materials because it contains a large amount of Na and steel raw materials contain a large amount of A1. Therefore, red mud has been discarded as industrial waste without being used.

As a method for recovering useful components (F e, Na, A 1) from red mud, there is Japanese Patent Application Laid-Open No. 50-16608. This method The CaO-containing component is added to the red mud at a predetermined ratio, melted by reducing heat treatment, separated into iron and slag, and Na and A are extracted from the slag by alkaline elution. This is a method to recover one component. However, according to this method, Na can be recovered only in the amount of about 60 to 70% of the red mud content, and Na remains in the residue, and cannot be effectively used as a cement raw material. In addition, since the heat treatment is performed in a state that iron containing about 40% is contained in red mud, considerable heat load is applied.

Other sodium aluminosilicates include zeolite used in various applications. Zeolite is generally used as a catalyst supporting a metal catalyst and a noble metal catalyst, and for ion exchange. Some are recycled and used in most cases After removing harmful and useful components, the carrier zeolite is discarded as industrial waste.

As described above, some of the sodium aluminosilicate have been proposed for their effective use, but in practice, the residue after recovery of useful components or the sodium aluminosilicate itself is effectively used. Has been discarded. Therefore, a main object of the present invention is to recover a useful component of Na among the components contained in sodium aluminosilicate and further reduce the Na concentration of a substance discharged as a residue. The purpose is to propose a treatment method that can be effectively used as a cement raw material. Disclosure of the invention

The present invention recovers the Na component at a higher rate than various types of sodium aluminosilicate in order to effectively use the sodium aluminosilicate that has been discarded or not used without being used effectively at present. A method for treating sodium aluminosilicate to obtain a useful substance having a very low content, characterized by the following preferred features. (1) A calcium compound as a simple substance or a mixture of calcium oxide, calcium carbonate, calcium hydroxide, calcium sulfate, or the like, or a mixture containing them, particularly preferably calcium oxide, is added to sodium aluminosilicate. Add and mix.

At this time, the amount of the calcium compound added is such that the sodium component in the sodium aluminosilicate is expressed as Na ₂ O, and the silicon component is expressed as a molar ratio of Ca ON a ₂ O when expressed as Si 0 _2. Or (preferably “and”) C a 〇ZS i 0 ₂ force; ~ 5, preferably 2.0 ~ 4.0. The particle size of the sodium aluminosilicate and the calcium compound to be added is not particularly specified, but includes a particle size of 1 μm to 300 μm, more preferably a particle size of 60 μm or less. Things are good. The mixture may be either dry or wet, but is more preferably wet.

(2) The mixture of (1) is subjected to a heat treatment at 800 to 140 ° C., more preferably 100 to 135 ° C., using a heater such as a kiln. At this time, the mixture to be heat-treated may be in the form of a powder or a pellet, and the form is not particularly limited. The heat treatment time is from 5 minutes to 180 minutes, more preferably from 20 to 80 minutes.

(3) The high-temperature exhaust gas generated by the heater generates steam in a boiler, etc., recovers waste heat, and recovers energy.

(4) The heat-treated product obtained in (2) is eluted with water (or an aqueous solution) to elute and recover sodium. The amount of water (or aqueous solution) at this time is 1 to 30 times by weight, more preferably 10 to 20 times by weight, of the heat-treated product. Further, the elution temperature is 50 ° C or higher, more preferably 70 ° C or higher. The elution time is between 10 and 120 minutes, more preferably between 60 and 90 minutes.

(5) The slurry obtained in (4) is subjected to solid-liquid separation using a filter, etc. The cake is further washed well with water. The resulting separated solution and the washing filtrate are effectively used in equipment that requires an alkaline solution as a sodium-containing solution, and the cake (residue of sodium eluted is removed from the sodium). Collected residue is sometimes recycled.) Is recycled as cement raw material. Further, the washing filtrate may be used for elution of the heat-treated product obtained in (2). BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows an embodiment of the process of the present invention.

FIG. 2 shows an example (1) of an apparatus configuration for performing the process of the present invention.

FIG. 3 shows an example (part 2) of an apparatus configuration for performing the process of the present invention.

FIG. 4 shows an example (part 3) of an apparatus configuration for performing the process of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

The sodium aluminosilicate according to the present invention includes sodalite discharged in the production of aluminum hydroxide, aluminum, and metallic aluminum. Zeolites used in various applications, natural and synthetic zeolites and sodalites, etc. Either way.

The soda light emitted in the production of aluminum is generally Na ₂ O power; 18 to 25 weight ⁰ /. , A 1 ₂ O ₃ power s 3 1 ~ 3 8 weight ⁰ I, S i O ₂ 2 8-3 5 wt%, impurities such as F e ₂ O ₃ contains 5 wt% or less. Further, as a typical example of Zeorai bets, expressed in ionic _{formula, C a O · A 1 2} 0 3 · 4 S i 0 2 -. 6 5 H 2 _{〇, N a 2 O - A 1} 2 0 _{_{3 · 2 S i 0 2 -}} . 4 5 H 2 0, N a 2 O · A 1 2 0 3 - 2 5 S i 0 ₂ · 6 H ₂ O.

This sodium aluminosilicate may be obtained as red mud containing iron in bauxite treatment, but in the present invention, sodium aluminosilicate separated from iron is preferred. Preferred correct aluminosilicate soda in the present invention, aluminosilicate soda 9 0 wt% or more, good Ri rather preferably 9 5 those containing by weight% or more, or 1 0 weight iron content in the F e ₂ 〇 ₃ %, More preferably less than 5% by weight. A method of obtaining sodium aluminosilicate separated from iron in bauxite treatment is known. However, there is no particular problem if sodium aluminosilicate contains iron and other metal components. However, the more the soda light, the less the energy consumption per soda light.

As the calcium compound, calcium oxide, calcium carbonate, calcium hydroxide, calcium sulfate, and the like, and in some cases, a mixture thereof can be used. Calcium oxide is preferred. By mixing and heating the calcium compound with sodium aluminosilicate, the calcium compound and the sodium aluminosilicate react to convert the soda component into a compound that can be dissolved in water. it can. The product that can be eluted is probably a product containing sodium aluminate.

The amount of the calcium compound to be added is such that when the sodium component in the sodium aluminosilicate is represented by Na ₂ O and the silicon component is represented by Si 0 ₂ , the molar ratio is C a OZN a ₂ O or Z and C a OZ S i 0 ₂ is typically 1 or more, properly favored properly is preferred 1-5, yo Ri may range from 2-4. If these ratios are less than 1, it is not possible to make a compound capable of sufficiently eluting the soda content in the sodium aluminosilicate. If these ratios are too large, compounds that are difficult to elute may be formed, and the elution rate of soda may decrease. When the sodium aluminosilicate and the calcium compound are mixed, it is preferable that the sodium aluminosilicate and the calcium compound are ground to reduce the particle size. Preferably, but not limited to, those having a particle size in the range of 1 μm to 300 m, more preferably 80 / zm or less, especially 60 / im or less. is there. By making these particle sizes smaller, the soda elution rate can be increased. However, not all particles need to be within these ranges, at least 60% by weight, and more preferably at least 80% by weight, are within these ranges. Is effective. It has been found that adjusting the particle size is effective in increasing the soda elution rate and reducing the soda content in the residue to 1% or less. It is not necessary to reduce the particle size too much, and it would not be economical.

The sodium aluminosilicate and the calcium compound may be mixed in a dry state, but C a 一部 partially dissolves as C a (OH) _2, and the Na and C a of the sodalite in the liquid phase before firing. It is preferable that water is added and mixed in a wet state, since the mixture may undergo a substitution reaction.When mixed in a wet state, the mixture can be pelletized and pelletized. Is preferred. By forming pellets, generation of dust during firing is suppressed, and transfer is facilitated. When pelletizing, since the reactivity depends on the particle size of the original particles, it is desirable that the original particles have the above-mentioned particle size.

The mixture of the sodium aluminosilicate and the calcium compound is generally heated at a temperature of 800 to 140 ° C, particularly preferably 100 to 135 ° C. The heating temperature has a large effect on the soda elution rate after heating. It is considered that a heating temperature within a certain range is required to generate compounds that can be easily eluted. The heating atmosphere may be in the air. The heating time is not particularly limited, but is generally 5 to 180 minutes, and is preferably 20 to 80 minutes. Is preferred. Heating rate 'Although not limited, generally 10 to 30 ° C / min may be used. Cooling may be either rapid cooling or slow cooling. The heating device is not limited, but kilns and the like are industrially advantageous (a substance produced by this heat treatment may be referred to as a heat-treated product).

After the heat treatment, the heat-treated product is preferably ground to facilitate elution.

Elution is performed with water or an aqueous solution. The amount of water or aqueous solution is not particularly limited, but is preferably 1 to 30 times by weight, more preferably 10 to 20 times by weight of the heat-treated product. Elution can be promoted by using warm water. It is generally at least 50 ° C, preferably at least 70 ° C. The elution time is not particularly limited, but may be 5 to 120 minutes, preferably 60 to 90 minutes.

As described above, according to the present invention, sodium aluminosilicate and a calcium compound are mixed, heated, and soda is eluted, so that the amount of soda in the eluted residue can be extremely reduced. It is possible. By selecting appropriate conditions, the residual soda content can be reduced to 1% or less, further to 0.6% or less, 0.1% or less, and particularly to 0.01% or less. Thus, the solid of sodium recovered from sodium, which is mainly composed of calcium silicate, can be used as a cement raw material. Further, the recovery (extraction) rate of more than 95%, more preferably more than 99%, especially more than 99.9% is calculated as the recovery rate of soda in sodium aluminosilicate. It can be achieved. It has not been heretofore known that such a high soda recovery (extraction) rate can be achieved, and in particular, it is possible to reduce the soda content in the solids of sodium recovered to 1% or less. The fact that it can be practically used as a useful cement raw material greatly enhances the usefulness of the present invention.

When the heat-treated product is eluted with water or aqueous solution, Even if the noremina component is also eluted, this eluate can be reused for bauxite treatment (eg, the Bayer method) without the need to separate soda and alumina. On the other hand, if alumina remains in the elution residue, there is no problem in using it as a cement raw material, and an elution residue that does not contain alumina at all is preferable as a cement raw material. An embodiment of the process of the present invention will be described with reference to FIG. This treatment process is roughly divided into a baking step and an elution step.

(Firing process)

Various kinds of sodium aluminosilicate are supplied through line 11 and the additive CaO is supplied through line 12 to a mixing device 1, for example, a double kneader. Mix O well. This mixture is supplied from line 13 to heating device 2, for example, a kiln, and is calcined at 100 ° C. to 135 ° C. Next, the calcined product is sent through line 14 to a cooling device 3, for example, a rotary cooler or a steel belt cooler, where it is cooled, and then, through line 15, a crushing device 4, for example, a hammer. It is supplied to a mill and pulverized.

(Elution process)

The pulverized material pulverized by the pulverizing device 4 in the firing step is supplied to the elution device 5 via the pipe 16 together with the water (or aqueous solution) from the pipe 17 and is stirred at 50 ° C. Elution is performed at ~ 100 ° C. The slurry of the elution device 5 is extracted from the pipe 18 and separated into solid and liquid by a solid-liquid separation device 6, for example, a horizontal belt finoletter or a rotary drum finoletter. The filtrate containing the useful component sodium is withdrawn through line 20 and reused. The separated cake is washed by the washing water supplied from the pipe 19, and discharged from the pipe 21. This sodium recovery residue is mainly composed of calcium and silica. Since the rubber content is less than 1%, it is effectively used as a cement raw material. Also, the washing filtrate at this time is extracted from the pipe 20 and reused.

FIGS. 2 to 4 disassemble and show a configuration example of the apparatus more specifically for performing the process of the present invention. In these figures, sodalite is supplied to a mixer 31 via a sodalite storage tank 32, and a Ca〇 storage tank 33, a Ca〇 pulverizer 34, and a CaO quantitative feeder 3 are provided. After the mixture is fed into the kiln 37 via the kiln charging device 36, the mixture is injected into the kiln 37 via the kiln charging device 36 Fired at temperature. After the calcined product is cooled by a cooler 38, it is pulverized by a crusher / pulverizer 39, and then subjected to elution treatment with warm water in an elution tank 40. The slurry subjected to the elution treatment is separated into a filtrate and a cake by a filter 41, and the filtrate passes through a filtrate tank 42, passes through an evaporative concentrator 43, and is used in an alumina treatment process such as a Bayer method. Is done. On the other hand, the cake after filtration is passed through a cake receiving tank 44, a dryer 45, and a drying cake receiving tank 46, and is used as a cement raw material. 47 is a bug fino letter. Example

(Example 1 )

Table 1 shows the analytical values of sodalite obtained from the desiliconization process added to the Bayer method for the production of aluminum hydroxide and alumina. This soda light, CaO having a particle size of 53 ^ xm or less, and water in such an amount that the total water content of the mixture becomes 40% are put into a mixing device and mixed. C a O mixing amount at this time, when expressed the Kei-containing components in Sodarai preparative S i 0 _2, was added to the power sale by a C a O / S i 0 ₂ molar ratio = 3. The mixture is calcined in a kiln at 1200 ° C. for a residence time of 30 minutes, and then cooled. And cooled, and then pulverized by a pulverizer.

The pulverized product was put into an elution tank, water was added at 20 times the weight of the calcined product (pulverized product), and the mixture was mixed well at 90 ° C for 60 minutes to perform elution. Next, the elution slurry was supplied to a filter to perform solid-liquid separation, and the separated cake was thoroughly washed with water.

The obtained recovered liquid and cake were chemically analyzed for the sodium component concentration, and the recovery ratio of the sodium component and the remaining sodium concentration in the cake were determined. As a result, a high sodium recovery rate of 99.9% was obtained, and the sodium concentration of the insoluble residue was also very low at 0.01% dry%. A useful material that can be used as a raw material was obtained. Soda light analysis value

(Example 2)

Into the same soda light as in Example 1, CaO having a particle size of more than 300 / zm is charged into a mixing device and mixed. At this time, as in Example 1, the CaO mixed amount was added so that the molar ratio of CaO / SiO2 = 3. This mixture was calcined in a kiln at 1200 ° C. for a residence time of 60 minutes, then put into a cooling device, cooled, and then ground by a grinding device.

The obtained recovered liquid and cake were chemically analyzed for the sodium component concentration, and the recovery rate of the sodium component and the sodium remaining concentration in the cake were determined. I asked. As a result, the recovery rate of sodium was 22.5%, and the sodium concentration of the insoluble residue was 8.81 dry%.

(Example 3)

Into the same sodalite as in Example 1, C a の with a particle size of 53 μπι or less is charged into a mixing device and mixed. C a O mixing amount at this time, in the same manner as Example 1, was added to the power sale by a C a O Bruno S i O ₂ molar ratio = 3. This mixture was calcined in a kiln at 800 ° C. for a residence time of 30 minutes, then put into a cooling device, cooled, and then pulverized by a pulverizer.

The sodium concentration of the obtained recovered liquid and cake was chemically analyzed to determine the sodium component recovery rate and the sodium concentration remaining in the cake. As a result, the sodium recovery was 61.8%, and the sodium concentration of the insoluble residue was 4.33 dry ⁰ /. Met.

(Example 4)

An experiment was performed using used synthetic zeolite 4A. Table 2 shows the analysis values of synthetic zeolite 4A. The zeolite and CaO are charged into a mixing device and mixed. C a 〇 mixing amount at this time, when expressed the Kei-containing components in the Soviet one Dalai preparative S i 0 _2, was added to the power sale by a C a O / S i 〇 ₂ molar ratio = 3. This mixture was calcined in a kiln at 1200 ° C. for a residence time of 60 minutes, then put into a cooling device, cooled, and then pulverized by a pulverizer. The pulverized product was put into an elution tank, water was added at 20 times the weight of the calcined product (pulverized product), and the mixture was mixed well at 90 ° C for 60 minutes to perform elution. Next, the elution slurry was supplied to a filter to perform solid-liquid separation, and the separated cake was thoroughly washed with water. The obtained recovered liquid and The sodium component concentration in the cake was chemically analyzed to determine the sodium component recovery rate and the residual sodium concentration in the cake. As a result, a high sodium recovery of 93.4% was obtained, and the sodium concentration of the insoluble residue was extremely low at 0.66 dry%. Useful materials that can be used as cement raw materials were obtained. Table 2 Analytical values of zeolite (used synthetic zeolite 4A)

As described above, according to the present invention, the following effects can be obtained.

(1) From waste or unused natural resources of sodium aluminosilicate

However, it is possible to almost completely recover sodium, which is a useful component.

(2) Cement raw materials with very low sodium content can be produced from waste or sodium aluminosilicate, an unused natural resource. Industrial applications

According to the present invention, sodium aluminosilicate which is currently discarded or not effectively used, such as red mud and soda light generated during the production of alumina and aluminum, zeolite used in various applications, Alternatively, by separating sodium contained in naturally occurring zeolite and sodalite, sodium can be recovered and sodium-removed residue can be cemented. It can be effectively used as a raw material.

Claims

The scope of the claims

1. Add calcium compound to sodium aluminosilicate,

Heat-treating a mixture of sodium aluminosilicate and a calcium compound, eluting the resulting heat-treated product with water or an aqueous solution to elute sodium in the sodium aluminosilicate, and

The elution sodium is recovered from the elution-treated product, and a useful substance having a very low sodium content is obtained.

A method for treating sodium aluminosilicate including a process.

2. The sodium aluminosilicate according to claim 1, wherein the calcium compound is calcium oxide, calcium carbonate, calcium hydroxide, calcium sulfate alone, or a mixture of two or more thereof, or a mixture containing them. Processing method.

3. The mixing ratio of sodium aluminosilicate and calcium compound is such that the sodium component in sodium aluminum silicate is represented by Na ₂ O, the silicon component is represented by Sio ₂ , and the calcium content in calcium compound is 3. The method for treating sodium aluminosilicate according to claim 1, wherein the components have the following molar ratio when expressed as C a O.

C a OZN a ₂ 0 = l~5 or C a 〇_ZS i 〇 ₂ = l to 5

4. The calcium compound to be added to and mixed with sodium aluminosilicate and sodium aluminosilicate has a particle diameter of at least 60% by weight or more and 300 μm or less. The method for treating sodium aluminosilicate according to any one of the above.

5. The method for treating sodium aluminosilicate according to any one of claims 1 to 4, wherein the mixing of the sodium aluminosilicate and the calcium compound is performed in a wet state of the mixture.

6. Heat treatment of the mixture of sodium aluminosilicate and calcium compound The aluminum according to any one of claims 1 to 5, wherein the heat treatment temperature is 100 to 135 ° C and the heat treatment time is 5 to 180 minutes. How to treat sodium silicate.

7. In the elution of sodium from the mixed heat-treated product of sodium aluminosilicate and calcium compound, the above mixed heat-treated product is crushed or pulverized, and water or an aqueous solution added to the crushed or pulverized material. Is 1 to 30 times the weight of the heat-treated product, the elution temperature is 50 ° C. or higher, and the elution time is 5 to 120 minutes. Processing method of sodium aluminosilicate.

8. The slurry (a suspension of the sodium eluate and the elution residue) obtained by the above-mentioned elution treatment is subjected to solid-liquid separation, and the obtained cake is sufficiently washed with water. 8. The method for treating sodium aluminosilicate according to claim 7, wherein a sodium recovery residue having a sodium content of 1% or less is obtained.

9. The content of sodium obtained by removing all or part of sodium from the sodium-recovered residue, that is, the mixed and heat-treated product of sodium aluminosilicate and a calcium compound is 1. /. The method for treating sodium aluminosilicate according to any one of claims 1 to 8, wherein the following residue is used as a raw material for cement production.

10. The method according to any one of claims 1 to 9, wherein the aqueous solution from which the sodium has been recovered is reused by equipment requiring an alkali solution or sodium hydroxide, for example, by a Bayer method. Treatment of sodium aluminosilicate.