JP2916172B2 - Method for recovering valuable components from inorganic powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention relates to a method for producing Si, Al, Fe, Ti, etc. from coal ash, various mineral substances, clay, etc. containing Al ₂ O ₃ or SiO ₂ as a main component. The present invention relates to an improvement in a method for efficiently separating valuable components and effectively using resources. Hereinafter, in this specification, a method for recovering valuable components from coal ash will be described as a representative example, but the present invention is not limited to this.

[Prior Art] With the diversification of energy resources after the oil crisis, the role of coal along with nuclear power, natural gas, solar energy and the like has been significantly increased. As a result, the amount of coal ash emitted from coal-fired power plants, etc., is expected to increase sharply, from about 3.8 million tons / year in 1986 to 10 million tons / year or more in the 1990s. . Attempts have been made to effectively use the coal ash discharged in such an enormous manner as fine aggregate for civil engineering and construction, as a raw material for cement, etc., but the effective utilization rate is only about 45% at most, and most of it is on land. It is only used for landfill and sea reclamation. However, in addition to the problem of environmental pollution due to scattering and the like, problems such as shortage of landfills and soaring disposal costs are increasing year by year, and the necessity of utilizing coal ash as a secondary resource is gradually increasing. .

That is, coal ash is not only Si and Al, but also Fe, Ti,
It contains Ba, Sr, alkali metals, etc., and if these metals can be separated and recovered as a single substance, the value as a secondary resource is expected to be significantly increased.

Typical methods for chemically recovering valuable elements from coal ash under these expectations include the direct dissolution method (using acid or alkali), the sinter (sintering) dissolution method, and the chloride / fluoride volatilization method. HNO ₃ method, which is classified as
The HCl method and the HF-HSiF ₅ method seem to be quite effective methods as described in detail below. However, some disadvantages have been pointed out.

(I) HNO ₃ method is (e.g. U.S. Pat. No. 4,243,640. No.) is a method of recovering by eluting the valuable components by HNO _3, to conserve HNO ₃ The amount of the time, and decarburization advance coal ash To reduce the C content to 2% or less,
The Fe content is reduced to 4% or less by a deironing treatment, and then washing and dissolving are performed stepwise with HNO ₃ .

That is, the coal ash that has been decarburized and deironed is first washed with a HNO ₃ solution at a low temperature of about 70 ° C., and then HNO ₃ is removed.
Using HNO ₃ at a concentration of about 30 to 65% over multiple stages, 100
The dissolution treatment is performed at a temperature of 220 ° C. By this process 50
% And high purity Al ₂ O ₃ can be obtained.

However, this method only recovers Al ₂ O _{3 and} cannot recover other elements.Although the dissolution process is complicated, the dissolution rate of Al ₂ O ₃ is low, and a satisfactory recovery rate is obtained. Can not be obtained.

(Ii) HCl method of coal ash in addition to the aqueous HCl solution was heated to about 105 ° C., after separation of the iron (iron chloride) by ion-exchange resin from the solution, by blowing the HCl gas separated liquid AlCl ₃ · 6H ₂ O crystals are deposited. Sulfuric acid is added to the remaining liquid to replace Ca with gypsum, and other alkali components are separated as alkali sulfate. AlCl ₃ · 6H ₂ O crystals are recovered as calcined Al ₂ O _3. According to this method, the dissolution rate of the Al component is about 50%, and the dissolution rate of Fe is about 80%.

This method is simple in operation and economically advantageous, but has the disadvantage that the recovery rate of the Al component to be recovered is low. The present inventors have confirmed that 8N-HC
l, the dissolution rate is 100% C, the dissolution time is 6 hours, and the dissolution rate is 10% for the bulb concentration.
The Fe component is 45 to 81% and the Ti component is 6 to 55%. The dissolution rates of the Al component and the Ti component are low, and the dissolution rate varies significantly depending on the type of coal ash.

(Iii) HF-HSiF ₅ method (for example, US Pat. No. 4,539,187)
No.) Coal ash is sufficiently reacted with a sufficient amount of hydrofluoric acid and silicic hydrofluoric acid to produce fluorides and silicic fluorides of Fe, Al and Si, and the mixture is distilled at 90 to 110 ° C. to form a mixture of Al and Fe. Separate water-soluble SiF ₄ vapor from fluoride and silicon fluoride. The evaporated SiF ₄ is absorbed in water and then hydrolyzed to produce high-purity SiF.
Instead of O ₂ and HF, Al component ゃ Si substantially free of Fe component etc.
While recovering O ₂ , HF is used cyclically as the dissolving acid. The fluorides of Al and Fe and the silicon fluorides are separated from other impurity components by a centrifugal separator.

This method has a high dissolution rate of Si, Al, Fe, etc.
Since HSiF ₅ can be recycled as a dissolving agent, it is considered to be a very effective method. However, this method is not only complicated in operation, but also difficult to separate the fluorides of Al and Fe from the silicon fluoride, and it is considered that the purity of the recovered product cannot be sufficiently increased.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and its object is to convert Si, Al, F from inorganic powder such as coal ash.
An object of the present invention is to provide a technology capable of efficiently separating and recovering valuable components such as e and Ti by a simple operation.

[Means for Solving the Problems] The constitution of the valuable component recovery method according to the present invention, which has solved the above problems, is based on the use of hydrofluoric acid and hydrochloric acid in an inorganic powder containing SiO ₂ and Al ₂ O ₃ as main components. Add a mixed acid and heat to absorb the volatile Si-containing components into water or an aqueous alkali solution and collect them.On the other hand, remove the insoluble matter from the remaining liquid by filtration and extract Al and other components from the resulting solution by solvent extraction. The point is that the metal compound is extracted and separated.

[Action] In order to solve the problems pointed out by the above-mentioned conventional method, the present inventors used HF / HCl mixed acid having high dissolving power for coal ash and the like as a dissolving agent, Some Si, Al, Fe, T
Research was conducted to increase the dissolution rate of each compound including i and the like, and to separate and recover each component easily and with high purity from the solution. As a result, it is possible to dissolve valuable components in coal ash at a high dissolution rate if the HF / HCl mixed acid is added and then appropriately heated, and if the HF concentration of the dissolving agent is properly controlled, the insoluble β -Al ₂ O ₃ · 3H without generating the ₂ O, it may maximize the dissolution of the Al component, SiF ₄ to produce the lysate is volatilized by distillation, absorbing it in water or an alkali Insoluble matter (mainly Si component and C) is filtered off from the residual liquid after evaporating and removing SiF ₄ to obtain Al, Fe, Ti from the solution.
It has been found that valuable components such as can be easily separated and recovered at a high purity by a solvent extraction method, and have arrived at the present invention.

Hereinafter, the configuration, operation, and effect of the present invention will be described in detail, following the history of the experiment.

Table 1 shows the chemical composition of various coal ash obtained from domestic thermal power plants (average particle size of 7.0 to 13.5 μm).
m), and the SiO ₂ -based minerals contained in these coal ashes are mainly composed of quartz, mullite, and vitreous (solid solution with Al ₂ O ₃ ) according to the result of X-ray diffraction. Al ₂ O ₃
The minerals are mainly composed of mullite, corundum and vitreous (solid solution with SiO ₂ ). The ratio of the acid-soluble component among the Al ₂ O ₃ components contained in these five types of coal ash was determined by the method of Okuda et al. [“Meiko Takuho”, 4 (11), 510-514 (195)
5)] shows the results of the examination shown in FIG.

Table 2 shows the solubility of coal ash in HCl [pulp concentration: 10 wt / v% (meaning sample weight g / mixed acid solution ml ... the same applies hereinafter), dissolution temperature: 100 ° C, HCl concentration: 8N, dissolution time : 6 hours], and the solubility of the Si component in HCl is extremely low. On the other hand, among the Al components, corundum and mullite hardly dissolve, but it is considered that an acid-soluble component and a part of the vitreous are dissolved, which corresponds well to the results in FIG.

As is evident from these results, it is not easy to elute and separate the Al component contained in the mullite content of Blairsol coal ash or Warkworth coal ash by the HCl method.

When HF-HCl mixed acid is used as a dissolving agent in the above-mentioned HCl method, SiO ₂ and Al ₂ O _{3 in} coal ash dissolve well. Where H
Considering the dissolution reaction in consideration of both Cl and HF, the reaction becomes very complicated. Therefore, considering only the reaction with HF, the following is obtained.

That is, at a temperature of about 60 ° C. or higher, the SiO ₂ in the coal ash is SiO ₂ (solid) + 4HF (aq) → SiF ₄ (sol) + 2H ₂ O (liq) (1) SiF ₄ (sol) → SiF ₄ ( gas)… (2) SiO ₂ (solid) + 6HF (aq) → H ₂ SiF ₆ (sol) + 2H ₂ O (li)
q) (3) The dissolution reaction proceeds according to the above equations (1) and (3).
If the dissolution reaction proceeds according to equation (1), the stoichiometric ratio between the dissolved SiO ₂ and the HF used should be HF / SiO ₂ = 4, while if it proceeds according to equation (3), HF / SiO
₂ = 6. However, the actual stoichiometric ratio is H
F / SiO ₂ = 5-6 (refer to FIG. 2; however, experimental data at 70-90 ° C.), the reaction of formula (3) has priority over the reaction of formula (1), and SiO ₂ It is considered that the gas is mainly changed to H ₂ SiF ₆ rather than being directly gasified as SiF ₄ .

Next, FIG. 3 shows that the Si component in the solution (SiF ₄ , H ₂ SiF ₆ )
In the case of 70 ° C. and 80 ° C., the evaporation rate of the Si component decreases as the HF concentration increases.
In the case of ° C., 95% or more evaporates independently of the HF concentration.

However, the evaporation rate of the Si component and the distribution rate of the Si component described below are values determined by the following formula.

A: Si content in the residue B: Si content in the solution C: Si content in the precipitate deposited in the absorbing solution D: Si content dissolved in the absorbing solution H among the Si components ₂ SiF ₆ undergoes a decomposition reaction shown in the following formula (4) at a high temperature of 60 ° C. or more, and SiF ₄ (gas) and HF (g
as).

H ₂ SiF ₆ (sol) → SiF ₄ (gas) + 2HF (gas) (4) The boiling point of H ₂ SiF ₆ is 108.5 ° C./720 mmHg, which is −9 of SiF ₄
Since it is significantly higher than 5 ° C., it is advantageous to evaporate the Si component by increasing the processing temperature and proceeding with the reaction of the above formula (4), and the preferable dissolution temperature seems to be about 60 to 110 ° C.

When the evaporated SiF ₄ is absorbed in water, the following (5)
As shown in the formula, silicate colloid (SiO ₂ · 2H ₂ O: silicate colloid is generally represented by SiO ₂ · nH ₂ O, but here SiO ₂ · 2H
(Expressed as ₂ O) and H ₂ SiF ₆ (sol) are generated, so 3SiF ₄ (gas) + 4H ₂ O (liq) → 2H ₂ SiF ₆ (sol) + SiO ₂ 2H ₂ O (solid)… (5 The silicate colloid precipitated by this reaction is filtered and separated from the absorbing solution, and the filtrate is neutralized with ammonia or the like to form the silicate colloid according to the following formula (6). The components can be recovered in high yield.

H ₂ SiF ₆ (sol) + 6NH ₄ OH (sol) → SiO ₂ · 2H ₂ O (solid) + 6NH ₄ F (sol) + 2H ₂ O (liq) ... (6) Fig. 4 shows the solution, residue and absorption solution And a graph showing the relationship between the Si component distribution rate in the precipitate and the evaporation rate and the mixed acid concentration (however, pulp concentration: 15 wt / v%, dissolution temperature: 90 ° C, dissolution time: 4.5 hours, HF concentration: 3.8 N) ), Both the solubility and the evaporation rate of the Si component increase sharply when the HCl concentration is in the range of 1.0 to 2.0 N, and hardly increase at higher values. Therefore, it is considered that the preferable HCl concentration in the HF / HCl mixed acid is 1N or more, more preferably 2N or more.

Next, FIG. 5 is a graph showing the relationship between the dissolution rate of the Al component in the coal ash and the HF concentration (however, pulp concentration: 10 wt / v%, HCl
Concentration: 6N, dissolution temperature: 60-90 ° C, dissolution time: 6 hours), and if the HF concentration is properly adjusted, the dissolution rate of the Al component is 10
It reaches 0%, indicating that the Al component in corundum as well as aluminosilicate (glassy or mullite) can be completely dissolved. The HF concentration at which the Al dissolution rate becomes 100% is 5.8N at 60 ° C.
On the other hand, when the temperature is higher than that, the concentration shifts to the low HF concentration side of 3.8 N, but in any case, when the HF concentration becomes higher than that, the Al dissolution rate rapidly decreases. The reason can be considered as follows. That is, the dissolution reaction of Al ₂ O ₃ in coal ash by HF is represented by the following equation (7): Al ₂ O ₃ (solid) + 6HF (sol) + 3H ₂ O (sol) → 2AlF ₃ · 3H ₂ O (α type) (7) Alternatively, H ₂ SiF ₆ (sol) generated by the above equation (3)
Reaction of the following formula (8) with Al ₂ O ₃ (solid) + H ₂ SiF ₆ (sol) + 3H ₂ O (liq) → 2AlF ₃
・ 3H ₂ O (α type) + SiO ₂・ 2H ₂ O (solid)… (8) It is thought that the reaction proceeds by soluble α-type AlF ₃ .3H ₂ O generated by these reactions. Together with the reaction of the following formula (9) to produce insoluble β-type AlF ₃ .3H
Changes to ₂ O.

AlF ₃ .3H ₂ O (α type) → AlF ₃ .3H ₂ O (β type) (9) The reaction of equation (9) can be considered from the tendency shown in FIG.
It is determined that the higher the HF concentration or the higher the dissolution temperature, the more accelerated. Therefore, increasing the dissolution rate of the Al component, so as not to generate is β-type AlF ₃ · 3H ₂ O is insoluble in the dissolution reaction step, while suppressing the lowering the HF concentration of the mixed acid, is possible to the melting temperature to be lower desired.

FIG. 6 is a graph showing the relationship between the dissolution rate of each component of Al, Fe and Ti in coal ash and the HF concentration (however, pulp concentration: 10 wt / v%, HCl concentration: 6N, dissolution temperature: 90 ° C.) , Dissolution time: 6
Al) is dissolved almost 100% when the HF concentration is 4N, but at higher HF concentrations, the insoluble β-type AlF ₃ .3H ₂ O is generated, and the dissolution rate decreases. On the other hand, the dissolution rate of the Fe component shows a high value regardless of the HF concentration. The Ti component has a high dissolution rate in the HF concentration range of 3 to 6N.

From these results, it is considered that the preferable HF concentration for increasing the dissolution rate of each component of Al, Ti, and Fe is 2.5 to 5N, more preferably 3 to 4N.

In any case, if an appropriate concentration of HF / HCl mixed acid is used and an appropriate dissolution condition is set, a high dissolution rate can be obtained for each component of Al, Ti, and Fe. Therefore, the Si component in the solution is separated by evaporation and the insoluble residue is removed, and then the Al component, the Ti component and the Fe component are successively extracted and separated from the solution. . The extraction method used in this step includes, for example, a kerosene diluent (organic phase) and a dissolving solution (aqueous phase) of an extractant (di-2-ethylhexyl phosphate, -n-tributyl phosphate, methyl isobutyl ketone, etc.). ), The Al component is transferred to the aqueous phase and extracted, and then the Fe and Ti components in the organic phase are separated by back-extraction with varying oxalic acid concentrations. The extraction method and the like are not limited to the above method.

FIG. 7 is a schematic flow chart showing an embodiment of the present invention.
This process is mainly a mixed acid dissolving step I such as coal ash,
Si component recovery step II, Al, Fe, Ti component solvent extraction step III,
And an oxide production step IV.

First, in the mixed acid dissolving step I, a predetermined amount of water is put into the acid dissolving tank 7 from the tank 1 through the liquid feed pump 4, and the coal ash is fed from the coal ash hopper 9 through the feeder 10 while being stirred by the stirrer 8. . Thereafter, predetermined amounts of hydrochloric acid and hydrofluoric acid are supplied from tanks 2 and 3 to dissolution tank 7 through liquid feed pumps 5 and 6. At this time, a considerable amount of heat is generated, but when the temperature does not reach a predetermined melting temperature, the temperature is adjusted by heating with steam or the like. After reacting at a predetermined temperature for a predetermined time, the dissolving tank 7 is cooled with water. Vapors such as SlF ₄ and HF generated in the dissolving reaction step are extracted by suction by an air pump 11 and guided to an absorption tower 12 to precipitate Si components as silicate colloid. After filtration 14
And then dried or fired in a drying furnace or firing furnace 16 to obtain SiO ₂ .

On the other hand, the solution (including Al, Fe, and Ti components) from which the Si component has been removed by evaporation is filtered to remove undissolved residues by a filter 18 and sent to a solvent extractor 20 by a liquid feed pump 19. Here, first, an organic solvent diluted solution (organic phase) and a solution (aqueous phase) of the extractant are used.
Fe and Ti components are extracted to the organic side. Next, the organic phase is sent to a back extractor 22 by a liquid feed pump 21, and further sent to a back extractor 24 by a liquid feed pump 23 to remove the Fe component and the Ti component dissolved in the organic phase by, for example, oxalic acid solutions having different concentrations. Etc. are sequentially separated by back extraction. Each of the solutions containing the Al, Fe, and Ti components separated in the solvent extraction step is a liquid feed pump 26, 2
The mixture is sent to neutralization tanks 29, 30, 31 by 7, 28, neutralized with ammonia water, etc., and precipitated as hydroxide.
After being sent to the filters 35, 36, 37 by the filters 33, 34 and filtered and separated, they are fired in the firing furnaces 41, 42, 43, and the respective oxides (Al ₂ O ₃ , Fe ₂ O
₃ , TiO ₂ ). In this case, a drying furnace may be used in place of the firing furnace, and each component may be recovered as a hydroxide.

Note that the flow chart of FIG. 7 shows a typical procedure for carrying out the present invention, but does not originally limit the present invention, and is within a range that can conform to the above and subsequent points. Changing the configuration of the equipment or changing the processing procedure is all included in the technical scope of the present invention.

[Example] Example 1 The following experiment was performed using a dissolution test apparatus equipped with a Teflon-lined dissolution tank (capacity 1.6), a stirrer, a mantle heater, and a Si component absorption tower.

Using 100 g of Blairsol coal ash as a sample, put it in a dissolution tank together with a predetermined amount of water, add a predetermined amount of hydrochloric acid and hydrofluoric acid with stirring, and heat to a predetermined temperature. Gases such as SiF ₄ and HF generated in the dissolving step are sucked by an air pump at a rate of 500 ml / min, sent to a water absorption tower cooled to 5 ° C. and absorbed. After performing the dissolution reaction for a predetermined time, for the Si component, the Si partition ratio is determined from the amount of Si contained in the dissolution solution, the dissolution residue and the absorption solution and the precipitates precipitated in the absorption solution, and the Al, Fe,
For the Ti component, the respective dissolution rates were determined from the contents in the solution and the residue.

First, regarding the solubility of the Si component, the pulp concentration: 10 wt / v
%, Dissolution time: 6 hours, HCl concentration: 6N, HF concentration 1.5
~ 6.5 N range, dissolution temperature in the range of 60 ~ 100 ℃,
The effects of each were examined.

Precipitates (SiO ₂ · 2H ₂ O) in the absorbing solution when the dissolving temperature was set to 70 ° C. and 90 ° C., absorbing solution (mainly H ₂ SiF ₆ -HF-HCl mixed solution), (mainly H ₂ SiF ₆ ) and the Si content in each residue were used to determine the Si distribution, and the results shown in FIGS. 8 and 9 were obtained.

As is clear from FIGS. 8 and 9, the Si content in the residue decreased as the HF concentration increased in each case.
Melts almost completely at 6.5N. When the dissolution temperature was set at 90 ° C. (FIG. 9), the Si distribution in the dissolution was extremely low, and the Si distribution (evaporation) between the absorbing solution and the precipitate was high. This confirms that the higher the temperature is, the more the reaction of the formula (4) is promoted and the evaporation of the Si component is accelerated, as described in FIG.

Example 2 Using the five types of coal ash shown in Table 1, a dissolution test was performed using a bench-scale test facility equipped with a Teflon-lined dissolution tank (volume of 144), a pressure filter, and a neutralization tank. Was performed.

In the test, a predetermined amount of water is put into a dissolution tank, and 10 kg of a sample charcoal ash is charged with stirring. Next, a predetermined amount of hydrochloric acid and hydrofluoric acid are added, and the concentration is adjusted by heating with steam. Thereafter, the solution is filtered and washed with water to separate into a solution and a residue, and the residue is dried and weighed to obtain a sample for analysis.

Pulp concentration: 10wt / v%, dissolution temperature: 90 ° C, HF concentration: 4N, H
Table 3 shows the dissolution rate of each component of the above five types of coal ash when Cl concentration: 1.5 N and dissolution time: 1 hour.

As is apparent from Table 3, according to the present invention, Al: 80 to 94%, Fe: 70 to 90%, T:
A high dissolution rate of i: 64 to 91% and Si: 61 to 71% was obtained, indicating that the present invention can be effectively used regardless of the type of coal ash.

Example 3 An experiment of recovering valuable components was performed according to the flow chart of FIG. 7 by using Blairsol coal ash having the lowest dissolution rate in Example 2 described above. However, dissolution condition, Al component extraction condition, Fe
The conditions for back extraction of Ti and Ti components were as follows.

(Dissolution conditions) Pulp concentration: 10wt / v%, HF concentration: 3.8N, HCl concentration: 1.5N,
Dissolution time: 4.5 hours, dissolution temperature: 90 ° C (Al component extraction conditions) After evaporating and separating the Si component in the dissolution reaction step, the insoluble matter (residue) is filtered off, and the extractant di-2-ethylhexyl phosphate is extracted from the solution. The Fe and Ti components were extracted and separated to the organic side using the kerosene solution.

(Conditions for back extraction of Fe and Ti components) The Fe components transferred to the organic phase in the Al component extraction step and
The Ti component was back-extracted with 0.2N oxalic acid to extract the Fe component, and then back-extracted with 1N oxalic acid to extract the Ti component. FIG. 10 shows the obtained recovery rates of the valuable components as oxides. No. 10
In the figure, the numerical values in the upper column indicate the recovery rate for each process, and the numerical values in the lower column indicate the integrated recovery rates.

As is apparent from FIG. 10, according to the present invention, Al, Si,
Each component of Fe and Ti can be recovered as an oxide in a high yield. The SiO ₂ purity of the silicate colloid recovered as a precipitate from the absorption liquid of the Si component evaporated in the melting step was 99.9%
The particle shape is flat and the specific surface area is about 40 m ²
/ g.

The SiO ₂ purity of the silicate colloid recovered as a precipitate by neutralizing the absorbing solution is higher than that of the precipitate and 99.99% or more, and the particles are porous and have a high specific surface area of about 200 m ² / g. I was In addition, Al ₂ O ₃ , Fe ₂ O ₃ , and TiO ₂ were all recovered as fine powder having a purity of 99% or more.

[Effects of the Invention] The present invention is configured as described above. From coal ash having Al ₂ O ₃ or SiO ₂ as a main component, it is possible to obtain high purity not only Al component but also Fe component and Ti component. As a result, the coal ash could be effectively recovered as a secondary resource.
In addition, the present invention can recover the above valuable elements in the form of oxides in good yield from not only coal ash but also low viscosity as a mineral resource, and is of extremely high practical value.

[Brief description of the drawings]

FIG. 1 is a graph showing the component ratio of Al ₂ O ₃ contained in the coal ash used in the experiment, FIG. 2 is a graph showing the relationship between the stoichiometric ratio of HF / SiO ₂ and the dissolution rate of Si, and FIG. Fig. 4 is a graph showing the relationship between the concentration and the evaporation rate of the Si component, Fig. 4 is a graph showing the relationship between the HCl concentration and the distribution ratio of the Si component, Fig. 5 is a graph showing the relationship between the HF concentration and the dissolution rate of the Al component, FIG. 6 is a graph showing the relationship between the HF concentration and the dissolution rate of the Al, Fe, and Ti components. FIG. 7 is a schematic flow chart showing an embodiment of the present invention. FIGS. 8 and 9 are the HF concentration and the distribution ratio of the Si component. FIG. 10 is a graph showing the recovery of valuable components obtained in the examples. I: dissolution step, II: Si component recovery step III: extraction step, IV: oxide production step 7: dissolution tank, 12: absorption tower 14: filter, 20: solvent extractor 22 , 24 …… Reverse extractor, 29,30.31 …… Neutralization tank 35,36,37 …… Filter

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshifumi Kameoka 7-3-3-1-334 Takamaru, Tarumizu-ku, Kobe-shi, Hyogo (72) Inventor Genichiro Kamagaya 1845, Nagijincho, Takasago-cho, Takasago-shi, Hyogo (72) Inventor Nakamoto Tadashige 5-1-32, Komatsubara, Arai-machi, Takasago City, Hyogo Prefecture (58) Field surveyed (Int.Cl. ⁶ , DB name) 18

Claims (1)

(57) [Claims] 1. A mixed acid of hydrofluoric acid and hydrochloric acid is added to an inorganic powder containing SiO ₂ and Al ₂ O ₃ as main components, and the mixture is heated and volatilized.
An inorganic material characterized by extracting and separating Al and other metal compounds by solvent extraction from a solution obtained by filtering off insolubles from the remaining liquid while absorbing and recovering Si-containing components in water or an aqueous alkaline solution. A method for recovering valuable components from powder.