JPS5988319A - Method for recovering zinc carbonate from matter containing zn - Google Patents

Abstract

PURPOSE:To obtain zinc carbonate of high quality by bringing matter contg. Zn as well as Fe and Pb into contact with an aqueous soln. contg. NH4OH and (NH4)2CO3 to dissolve Zn, removing the remaining insoluble matter, and crystallizing zinc carbonate. CONSTITUTION:Matter contg. Zn as well as Fe, Pb, etc. recovered from kiln dust produced in the reduced iron equipment of an iron mill is brought into contact with an aqueous soln. contg. 5-40wt% NH4OH and 5-40wt% (NH4)2CO3 to dissolve Zn. It is preferable that NH4SCN is further contained in the soln. After removing the undissolved residue, zinc carbonate is crystallized from the filtrate. In order to crystallize zinc carbonate, the filtrate is heated to evaporate ammonia, or gaseous CO2 is blown. The crystallized zinc carbonate is taken out by filtration to obtain the desired zinc carbonate. This zinc carbonate is suitable for use as a starting material for zinc oxide for a pigment, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recovering zinc carbonate from Zn-containing materials.

Zinc oxide (ZnO), which is used as a pigment in paints and a vulcanization accelerator in tires, is generally obtained by the following manufacturing method.

(1) Dry method This dry method includes the French method using zinc metal as raw material,
There is an American method for producing zinc ore.The French method involves placing zinc ingots in a melting pot, heating them to about 1000°C, vaporizing them, and oxidizing them with hot air. On the other hand, American law
When a reducing agent such as coal is added to a low-volatile ore such as (ZnMn)Fe04 and roasted in a retort or reverberatory furnace, the zinc is reduced and evaporated as steam. (2) Wet method In this wet method, metallic lead is dissolved in hydrochloric acid, the temperature is set to 20 degrees Baumé, a sodium carbonate solution at 20 degrees Baumé is added to this, zinc carbonate is precipitated, and zinc carbonate is precipitated. After washing with water and drying, it is baked at about 600°C.

On the other hand, ZnO is being recovered as ZnO from kiln dust of steel works equipment, for example, reduced iron equipment. In the kiln dust, etc., +1ii, lead nia~50
It contains iron: 90 to 45 iron, lead: 2 to 8 d, and other components, all of which have a high proportion of oxides.

In the case of obtaining ZnO using this Zn-containing dust as a raw material, if the dry method described above is adopted, the iron in the dust becomes dust and scatters to the outside, and the lead evaporates and becomes mixed into the product by several thousand ppm. According to the wet method, when dust is dissolved in hydrochloric acid, iron is also dissolved, and the amount becomes tens of thousands of PPM and cannot be used as a commercial product. In general, even if the iron and lead content is several thousand PPM, it may cause problems depending on the application. Depending on the purpose, 100 PP may not be available.
In order to meet such demands, the present invention is designed to reduce F from Zn-containing materials containing at least Fe and Pb.
By obtaining zinc carbonate with as little e r P b as possible, ZnO
In order to achieve this objective, the first invention C provides a method for recovering raw materials such as F e +p.
5 to 40 w of each Zn-containing material containing at least b.
t % (7J) NH40H and (NH4) 2
Zn is dissolved by contacting with an aqueous solution containing at least C03, undissolved residue is removed, and the solution from which the undissolved residue has been removed is subjected to zinc carbonate crystallization means to recover zinc carbonate. be.

In addition, the second invention brings a Zn-containing material containing at least Fe and Pb into contact with an aqueous solution containing at least NH4OH and (NH4)2CO3 to dissolve Zn, remove undissolved residual material, and remove undissolved residual material. Zinc carbonate is partially extracted from the solution from which zinc carbonate has been removed, and most of the heavy metal ions dissolved as impurities in the solution are co-precipitated as hydroxide and/or carbonate or basic carbonate. The method is characterized in that the solution is separated and then main precipitation of zinc carbonate is performed on the solution.

In the third invention, a Zn-containing material containing at least Fe and PB is brought into contact with an aqueous solution containing at least NH40H and (NH4)2CO3 to dissolve Zn, remove undissolved residual lFj, and remove undissolved residual lFj. In the process of precipitating zinc carbonate to the solution from which the pickle has been removed, metal zinc is added to precipitate the heavy metal A and ions dissolved as impurities in the solution, and the precipitate is separated. .

The fourth invention is to dissolve Zn by contacting a Zn-containing material containing at least F e + P b with an aqueous solution containing at least NH4OH and (NH4) 2 C03, remove undissolved residue, and remove undissolved Zn. The method is characterized in that zinc carbonate is precipitated from the solution from which residual residue has been removed, the crystals are separated by fi, and the P solution is used as a solution for Zn.

As described above, the present invention is based on a wet method, and focuses on the fact that zinc is an amphoteric metal. The basic idea is to bring zinc carbonate into contact with the liquid to dissolve Zn, precipitate the zinc compound, and crystallize the P liquid from which the undissolved residue is removed.
C03) z[:2n(OH)z]3' and/or Z
The aim is to recover it as nCO3.

As mentioned above, the conventional wet method involved dissolution with hydrochloric acid. In the conventional wet method, since the starting material is only metallic zinc, there is no need to consider impurity treatment. However, since the present invention targets Zn-containing substances such as kiln dust of reduced iron equipment containing at least Fe and PB,
The greatest attention must be paid to how to remove mainly Fe and Pb to obtain zinc carbonate with few impurities.

Therefore, in the present invention, since Zn is fortunately an amphoteric metal,
This is based on the unprecedented knowledge that the Zn solution is an aqueous solution containing at least NH4OH and (NH4)2CO3. According to the present invention, the Zn-containing material is not brought into contact with the Zn solution without any holes. , Zn dissolution is performed. The contact between the Zn-containing material and the Zn solution is carried out, for example, by charging the Zn-containing material into a Zn solution tank and, if necessary, under stirring.

As a Zn solution, at least NH4OH and (NH4)2
An aqueous solution containing CO3 is used, which also contains rhodanammonium NH4SCN or ammonium sulfide (NH4).
nS may be added. Rodan ammonium or ammonium sulfide is suitable for removing Pb, and in particular, when rhodan ammonium is added, the Pb content can be reduced to almost zero, which is a suitable embodiment for applications where Pb gold content is not desired. The reason why both NH4OH and (NH4) 2 CO3 are used is that even if one of them is used, the solubility of Zn is low as described below.
H4) NH4OH and NH without using 2CO3,
Figure 9 shows the dissolution of Zn using a solution with 4S CN. When CO2 gas is blown into this, zinc carbonate is obtained, but it becomes jelly-like and impurities adhere to it, making it difficult to remove. This is because it is difficult to handle and is therefore not suitable for practical use. .

When dissolving Zn, the concentration of the solution is an important factor, and the respective concentrations of NH4OH and (NH4)2CO3 are preferably 5 to 10 wt%, particularly 10 to 30 wt%. This will be explained with reference to and 2.

<Experiment 1> Ammonia NJ-1, < OH(!: Solubility of Zn-containing dust in the form of Zn(OH)2 (unit: 9) by varying the concentration with ammonium carbonate (NH4)2C03
/l), the results shown in Table 1 were obtained.

Table 1 Also, the solubility at a solution temperature of 40° C. is shown in FIG.

Focusing on this Figure 1, NH40H = 17111/
11. In a solution of (NH4)z C03 = 100 ft/l, zinc is present in the form of Zn(OH)z at 140. ! 9/11
dissolve.

Therefore, considering the post-dissolution operation according to the present invention, the crystals obtained by heating and/or vacuuming the Zn solution to evaporate ammonia are basic zinc carbonate CZ n
COa )z[Z n (OH)2)3, and some of the zinc combines with carbonic acid and precipitates, so the concentration of ammonium carbonate (NH4)2C03 in the solution decreases, and the solubility state remains the same. Transitioning along the dotted line to Figure A-+B, Zn
The solubility of (OH)z decreases and (ZnCOs h(Zn
(OH)2]3 result can be obtained.

Also, when CO2 gas is blown into the solution at point A, it reacts with ammonium hydroxide NH40H and forms zinc carbonate (NH4).
2CO3, so the NH4OH concentration decreases, and on the other hand (
As the NH4)2CO3 concentration increases, the solubility state shifts along the dotted line to A-)C, the solubility of Zn(OH)z decreases and crystals of zinc carbonate can be obtained.

In order to obtain a large amount of crystals, it is advantageous to carry out the process at a location where the solubility of Zn(OH)z is the largest with respect to a change in NH40H concentration.
= 200 g/l and NH40H = 1719/l, indicating that it is best to precipitate zinc carbonate by evaporating ammonia. In addition, if the N H40H concentration is high, for example, exceeding 3009/l, or low, for example, 5
It can be seen that when it is less than 0 g/It, the amount of precipitation is small.

In this way, the amount of unused 509/l is low, making it uneconomical to use a large amount of chemicals, and even if too large a quantity is dissolved, the amount of ammonia evaporates will increase, making it uneconomical from a thermal standpoint. Not. Furthermore, according to Figure 1, NH
It can also be seen that the solubility of 4OH or (NH4)2CO3 alone is low, and that it is desirable to use both in combination.

<Experiment 2> NH4OH concentration 0 to 3oo, 9/l, (NH4)2C
Solution 2 with Os concentration changed from 0 to 4 o o g7i
Zn-containing dust was immersed in 01πl, and after dissolving the zinc,
[ZnC0a
:]2[Zn(OH)z)3 crystals were obtained, and the amounts of Fe and Pb as impurities contained therein were analyzed.

The results are shown in Table 2.

Table 2 (Note) Amount of crystals precipitated in the upper row Middle row = Fe content (PPM) Lower row = PB content (PPM) The crystals are N1 (40H = 200 g/ 12
It was found that the crystals under the conditions of H4)2 CO3-100.9/l were white in color and easy to control for yield. (N1(4
) Regarding the 2C03 concentration, the one under the condition of 200 g/l is Fe.

The content of Pb impurities is high, and the baked zinc white is also colored brown. (NH4)2CO3 concentration is 100g/l and 200g/l
g/l, the lower the NH4OH concentration, the higher the amount of iron impurities, while the lower the NH4OH concentration, the higher the amount of lead impurities.
There are many cases where the 4OH concentration is high.

Both NH4OH and (NH4)2 CO3 are 3oog
/I! Under the conditions, Fe=108PPM1Pb=11
It becomes 20PPM, which is less, (NH4)2CO3=4
Under the condition of 00g/1(7), (NH4)2CO3 is difficult to dissolve in the ammonia aqueous solution, and undissolved crystals remain at the bottom. Each concentration is selected depending on whether to focus on the presence of Fe or PB impurities, but in any case, 50 to 400 g of each.
/l, especially a concentration of 50 to 300 g/l.

On the other hand, as mentioned above, methods for crystallizing zinc carbonate include (1) evaporating ammonia from the undissolved residual solution by heating or vacuuming, or a combination thereof; (2) evaporating the ammonia from the solution; A method of directly blowing CO gas into
(3) After method (1), there is a method of blowing CO gas. In the case of (1), [ZnC0a)2(Zn(OH
)z) In the form of a, in the case of (2), in the form Z n COaQ,
In case (3), zinc carbonate can be obtained in both forms.

In connection with the second invention, depending on the application, the content of cine blunts may be extremely objectionable. In this case, the following method of partial crystallization prior to release of the product was found to be suitable. In the process of reaching this conclusion, the inventor found that (1) impurities are precipitated together with the crystals during crystal precipitation. (2) Or are the impurities dissolved in the solution and attached to the zinc carbonate crystals when the zinc carbonate is filtered? (3) What is the difference between when zinc carbonate crystals begin to appear and when do they finally appear? We investigated whether the amount of impurities is different, (4) whether the impurities can be removed by recrystallization, and (5) whether the impurities can be removed by electrolysis, but from the viewpoint of economy and operability, partial crystal It turned out that the method was the best one.

The partial crystallization method is specifically performed as follows. First, a Zn-containing material is brought into contact with the above-mentioned Zn solution, Zn is dissolved, and undissolved residue is removed. Partial extraction of zinc carbonate (
crystallization) operation. In this case, any of the zinc carbonate operations described above may be performed. For partial extraction of ammonia by evaporation, the solution is preferably heated to 40 DEG -85 DEG C. and/or vacuum is applied to partially evaporate the ammonia. At temperatures below 40°C, during the evaporation of ammonia,
The heating operation alone is impossible and requires a fairly high degree of vacuum, which is inappropriate. If the temperature exceeds 85°C, the yield of crystals decreases, and the result is the same as if only main crystallization was performed without partial crystallization, and no impurity removal effect could be found. CO2 gas may be blown in place of or in combination with this method.

After partial extraction is completed, the main crystallization is performed in the same manner on the r liquid obtained by filtration or the supernatant liquid obtained by static separation. If the ammonia evaporation method is used, heating is performed at a temperature exceeding 85° C. and/or under vacuum. Here, 8
The reason why the precipitation forms differ at 5°C is not clear, but from a phenomenon perspective, when heated to 85°C or higher, a large amount of crystals form, even though it does not seem that much ammonia has been blown away. Judging from the location of precipitation, it is assumed that there is some sort of thermal equilibrium relationship around 85°C.

Next, explanation will be given with reference to various experimental examples.

Experiment 3> In order to dissolve a large amount of p'e and Pb, the concentration was increased and N
H4OH'=200.97A! , (NH'4)2CO3
= Immersing zinc-containing dust in a 300 g/l aqueous solution,
The solution obtained by dissolving Zn and filtering the undissolved residue was
ml test tube and added 16,I NHs+S04 in different amounts to separate Zn, Fe, and P in the precipitated crystals.
When the content of b was analyzed, it was as shown in Table 3.

From the results in Table 3, it can be seen that the initial crystals contain a large amount of Fe, PB. Fe has a liquid pH of 8.5
~7, it stays constant at 160-270 PPM, and when it goes above 85 and below 2, it approaches 970 PPM.
860 PPM at PH=9 in solution, 130 PPM at PH=85
, at pH=8 or below, it is 50 PPM or less, which is contrary to the common belief that the first crystals are good crystals.

<Experiment 4> Fe + Zn content was measured by recrystallization and electrolysis. N H40H2 200 g/11. (N
H4) Zn-containing dust is immersed in an aqueous solution of 2CO3-10 [/// to dissolve Zn, the residue is separated from P, and the P solution is heated to 90°C.
to evaporate ammonia, precipitate zinc carbonate crystals, and separate into FFe-123PP, pb=1790PP.
Obtain a crystal of M, and convert this crystal to NH40H= 200f
J/I! , (NH4)2CO3 = 100.9/l solution and this liquid (Nl(4)2S = 100g/1llN
Recrystallization was performed using a solution of H45CN=100/41.

Also NH40H2200.9. /j? , (NH4)
After electrolyzing the solution containing Zn-containing dust immersion residue in a solution of 2CO3 = 100 g/l using a zinc electrode, the temperature was raised to 90°C, and crystals were collected. The analytical values for Pb are shown in Table 4.

The unit for the amount of impurities (Fe, Pb) is P P Mo. The upper row is the amount of impurities in the crystalline state, and the lower row is the amount of impurities in the P liquid.

Table 4 From these results, it appears that it is difficult to reduce the lead content even by recrystallization or electrolysis. Looking at the amount of FetPb dissolved in the f liquid, this is 8 to 3P.
This is because PML does not dissolve in r-liquid, so it comes out in the crystal. The one with NH4SCN added has a pb level of 10 or less and is dissolved in the F solution at 200 PPM, so it is possible to recrystallize it, but the NH4SCN attached to the crystal is about 2
If the temperature is not 00°C, it will decompose easily, so its applications are limited where its contamination is allowed.

<Experiment 5> As described above, the amount of impurities cannot be reduced even if the crystals that have been crystallized are treated once, so the impurities must be removed before the crystals are produced. Therefore, the following fractional crystallization experiment was conducted.

That is, since it is difficult to control the amount of ammonia evaporation, for example, the temperature, ammonia concentration, and partial pressure are constant at normal pressure of 760 mmH, @-abs, the temperature is raised to an intermediate temperature of 70 to 85 °C, and some of the crystals are removed. Precipitation filtration and P solution 9
When the temperature was raised to 0C, main crystallization was performed, and impurities were analyzed, the fifth
The results shown in the table were obtained. The numerical values in the “Treatment method” column in the same table are [Z n CO3]zCZ n (OH)2]3
tD crystal amount (unit, 9r).

According to this result, when the partial crystallization temperature is increased, the ratio of the amount of partial crystallization increases, so that F e + P
Since b precipitates, the amount of Fe and Pb in this crystal is 10
．． 3 and 645 PPM, and the JL without partial crystallization is li' e = 123 PPM.
vl.

Since pb=1790PPM, each about 1/
12 and 1/3, which shows that the method of the present invention is particularly effective for removing Fe.

In connection with the third invention, an extraction method using an organic solvent may be considered as a method for further reducing the Fe and Pb contents in zinc carbonate crystals, but according to the experimental results of the present inventor, heavy metals are extracted alone in an alkaline solution. No extraction solvent could be found.

With the dissolution of Zn-containing dust, Zn・li'e, Pb
is dissolved in the solution as an ammonia complex. That is, [Z nN1(4)z [CO3)3 , CFe
NH4][CO0)2, [PbN, H4)+[COa]
3 in the complex state becomes [ZnCO5]z[
Zn(OR)2:33, [Fe(CO3)23m[F
e (Olj)3:)3, [PbCO3]2[P b
(OH)z]s precipitates in an acid or a neutral single salt solution, depending on the ionization tendency, K, Na+ Ca, Mg+ Zn, Cr, Fe”e C
d, Co, NLS n + P b + Fe 3”
+ H+ Cu + A g + Hg + A u
In the order of υ, the first metal is base and has high solubility.Since the liquid in which the Zn-containing dust is currently being dissolved is alkaline, there are some points in which it is unclear whether the order will be in this order, but the next experiment will be conducted later. 6 etc., it became clear that the addition of metallic zinc was an extremely effective method.

<Experiment 6> Zn-containing dust, NH40H = 2009/l,
(NH4); COa = 1007j/l immersed in an aqueous solution, the undissolved residue was filtered, the liquid was heated to 90°C to crystallize, and the [ZnC0a]z[Zn(OH)+)a crystals were Filter, dissolve aqueous ammonia and ammonium carbonate in a solution of F, e = 2.5PPM, Pb = 70PPM, and add N
H4OH = 200g/7! , (NH4)2CO3=1
A solution of 00&/4 was prepared and the following four experiments were conducted. Please also refer to Figure 2 for the experimental procedure.

-1 150 g of dissolved solution 17KZn-containing dust was immersed, the undissolved residue was filtered, 5 g of metal zinc powder was added to this R solution, and after stirring well, it was filtered, Fe: 30 PPM, P b :
0. A P solution with a concentration of I PPM or less was obtained, heated to 90°C for crystallization, filtered, Fe: 820 PPM, Pb: 11 PP
M crystal, Fe: 3 PPM, Pb:
0.2 PPM, *&, eh. -2 Znn-containing soot 150. ! 9, add metal zinc powder, stir well, filter undissolved substances, add 5V11 metal zinc powder to this P solution, stir well, and perform ion exchange of Zn and Pb. The metallic zinc was filtered to obtain an r solution of Fe: 17 PPM, PB: 0, 2 P PM, to which 5 g/13 of metallic zinc was again added, heated to 80°C, and basic zinc carbonate was added. The crystals were partially crystallized, filtered, heated to 90° C., filtered, and Fe: 33
0PPM, Pb: 10PPM crystal and Fe:
A P solution of 2 PPM and 2 PPM of Pb was obtained.

6-3 The Δ solution obtained by Zn and Pb ion exchange in the experiment of 6-2 was heated to 90°C to precipitate crystals, filtered, and Fe:5
Crystal containing 50PPM, Pb:11PPM and Fe:
An r liquid containing 3 PPM and Pb: 0.2 PPM was obtained.

-4 The liquid obtained by adding metal zinc powder in the 6-2 experiment to dissolve and filter the zinc dust was crystallized by heating to 90°C, filtered through f1, and
:1l100PP, Pb:470PPM crystal and F
A liquid f containing e: 4 PPM and Pb: 0.6 PPM was obtained.

-5 The r solution obtained by adding metallic zinc powder from the 6-2 experiment and dissolving and filtering the zinc dust was air oxidized, and the dissolved iron ions were separated as ferric hydroxide precipitate. If heated to ℃ and stirred, black iron and lead will be deposited on the surface of the metal zinc particles.If this is transferred and stirred, the black precipitate will peel off and the white surface of the zinc will come into contact with the liquid. However, black precipitate was deposited again, so the same operation was repeated several times until no black precipitate appeared and filtered. The P solution was heated to 90°C and crystallized and filtered to obtain Fe:5PPM.

Pb: 3PPM crystal and Fe: 3PPM, Pb
: 0.2 PPM P solution was obtained.

From these four experiments, it was found that adding metallic zinc powder was effective when it was added to the solution after dissolving the Zn-containing dust.
It was found that the content of impurity Pb was the lowest in those that were partially crystallized while still in the tank. And at least Zn
If metal zinc powder is added to the solution in which the contained dust has been dissolved and filtered, and it comes into good contact with the stirring and crushing solution, the PB content can be reduced to 11P.
It has been found that this is an extremely effective method that can reduce the amount to PM.

Figure 2 shows a possible addition process for metallic zinc, along with the above experiments and their results. Of course you can go. Also, the amount of zinc added is 20 to 20% of the liquid.
It is desirable to add 50%.

In relation to the fourth invention, the fourth invention attempts to reduce the Pb content by reusing the P solution from which the crystals have been separated from P as a part of the Zn solution.

For example, new NH40H without zinc = 200
g/l, (NH4)2CO3=1009/11 (7)
In the crystal obtained by crystallizing basic zinc carbonate from a solution containing dissolved Zn-containing dust, Fe = 123 PPM.

Pb=1790PPM. On the other hand, aqueous ammonia and ammonium carbonate were dissolved in the R solution after crystallization and 1 filtration, and 9 Zn-containing dust was immersed in this solution. Basic zinc carbonate was crystallized from the filtered liquid, and the impurity content was Fe: 1l 100PP, Pb: 470PPM,
It was found that pb was reduced to about 1/4.

The reason for this is that if zinc is already in the solution, the dissolution rate of PB in the Zn-containing dust will be suppressed, and even though the dissolution rate of zinc will be slow, since zinc is already dissolved,
It is considered that the amount of Pb and Fe dissolved in the solution eventually reaches the same amount in the same amount of time, and the amount of Pb and Fe dissolved in the solution decreases.

The flow sheet of the fourth invention is shown in FIG. 3.0 Note that it is preferable to reuse all of the P solution, fill it with ammonia and carbon dioxide gas, and use it as a dissolving solution. Also, the more zinc is dissolved, the less iron and lead are dissolved.

As detailed above, according to the present invention, F e +pb
It is possible to obtain zinc carbonate with few impurities such as, and it can be used as a high-purity raw material for ZnO.

[Brief explanation of the drawing]

Figure 1 is a relationship diagram showing Zn solubility in the Zn solution of the present invention, Figure 2 is a flow sheet showing an example of the process of the present invention together with experimental results, and Figure 3 is a flow sheet showing an example of reusing the P solution. . Procedural amendment (voluntary) November 2, 1980 Kazuo Wakasugi, Commissioner of the Japan Patent Office 1. Case description Method for recovering zinc carbonate from Zn-containing materials 3. Relationship with the case of persons making amends 4! fRevision Applicant Address Name: Tsukishima Kikai Co., Ltd. 4, Agent: 13 [1] Address: 505 Hubby Heights New Kameido, 1-42-14 Kameido, Koto-ku, Tokyo Telephone: 03 (881) 17136 7. Subject of amendment: Specification Detailed Description of the Invention Column 8, Contents of Amendment Specification, page 8, line 3; “Aqueous solution has reached”

Claims (9)

[Claims] (1) Zn-containing materials containing at least Fe and Pb are mixed with 5 to 40 wt% of NH4OH and (NH4)2, respectively.
Zn is brought into contact with an aqueous solution containing at least CO3 to dissolve Zn, undissolved residue is removed, and the solution from which undissolved residue has been removed is subjected to zinc carbonate crystallization means to recover zinc carbonate. Method for recovering zinc carbonate from contained materials. (2) The method for recovering zinc carbonate from a Zn compound according to claim 1, further comprising NH4SCN in the aqueous solution. (3) A method for recovering zinc carbonate from a Zn compound according to claim 1, wherein ammonia is evaporated as a means for crystallizing zinc carbonate. (4) The method for recovering zinc carbonate from a Zn-containing material according to claim 1, wherein CO2 gas is blown in as a means for crystallizing zinc carbonate. (5) Zn-containing material containing at least Fe and Pb is
Contact with an aqueous solution containing at least H4OH and (NH4)2C03 to dissolve Zn, remove undissolved residue,
Partial extraction of zinc carbonate is performed on the solution from which undissolved residue has been removed, and most of the heavy metal ions dissolved as impurities in the solution are co-precipitated as hydroxide and/or carbonate or basic carbonate. A method for recovering zinc carbonate from a Zn-containing material, the method comprising: separating the precipitate, and then subjecting the solution to main precipitation of zinc carbonate. (6) A method for recovering zinc carbonate from a Zn-containing material according to claim 5, wherein ammonia is evaporated as a means for precipitating zinc carbonate. (7) For partial precipitation of zinc carbonate, the undissolved residue removal solution is heated to 40 to 85°C to partially evaporate ammonia, and for main precipitation of zinc carbonate, the precipitate fractionated solution is heated to 85°C. Zinc carbonate recovery method 0 from a Zn-containing material according to claim 5, in which ammonia is evaporated by heating to a temperature exceeding (8) Zn-containing material containing at least Fe and Pb is
Zn is dissolved by contacting with an aqueous solution containing at least H4OH and (NH4)2CO3, undissolved residue is removed, and metal zinc is added in the process of precipitating zinc carbonate to the solution from which undissolved residue has been removed. A method for recovering zinc carbonate from a Zn-containing material, which comprises precipitating heavy metal ions dissolved as impurities in a solution and separating the precipitate. (9) Iron ions in the solution from which the undissolved residues have been removed,
Aerate or add an oxidizing agent to precipitate and separate the liquid as 31′ [1i iron hydroxide. Heat the liquid to 40 to 85°C, add metallic zinc, and stir to precipitate heavy metal ions dissolved as impurities. A method for recovering zinc carbonate from a Zn-containing material according to claim 8. (Zn-containing material containing at least 10Fe and Pb is
Dissolving Zn by contacting with an aqueous solution containing at least OH and (NI(4)2CO3) and removing undissolved residue;
A method for recovering zinc carbonate from a Zn-containing material, comprising precipitating zinc carbonate from a solution from which undissolved residues have been removed, separating the crystals, and using an r solution as a solution for Zn. 01) IP liquid new L-I NH4OH Oyobi (NH
4) The method for recovering zinc carbonate from a Zn-containing material according to claim 10, which is used as a Zn solution after adjusting the concentration of 2 COa.