JP2006037125A - Method for recovering metal from acidic bleeding water and resource circulation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal recovery method where useful metals are recovered from acidic bleeding water. <P>SOLUTION: The above problem is solved by a metal recovery method comprising: an adsorption stage 11 where metals M comprised in acidic bleeding water W are adsorbed with an adsorbent material; a first metal recovery stage 12 where the metals M adsorbed into the adsorbent material by the adsorption stage 11 are separated from the adsorbent material using acidic water or alkaline water and are recovered. Further, in the case the acidic bleeding water W comprises sulfuric acid ions, the above problem is solved by a metal recovery method comprising: a neutralization stage 21 where calcium carbonate or calcium hydroxide is added to the acidic bleeding water W; a separation stage 22 where a liquid L2 and precipitates P2 produced by the neutralization stage 21 are separated; and a second metal recovery stage 23 where the metals M are recovered from the precipitates P2 separated by the separation stage 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for recovering metal from acidic spring water and a resource circulation system for effectively using metal resources.

  In various regions, a wide variety of waters with different temperatures, components, pH, etc. spring out. Among such spring waters, the strong acid spring water has a negative effect on the human body and living organisms because the pH of the water of the river is lowered when it flows directly into the river. Therefore, in Kusatsu-cho, Gunma Prefecture, where strong acid water springs out, the spring water is acidic and contains sulfate ions, so the calcium carbonate is crushed and dissolved in water. By adding the solution made to this spring water, the spring water is neutralized to about pH 5-6.

  At this time, calcium sulfate salt (precipitate) is generated from the spring water by neutralization. The spring water excluding the deposit is used as drinking water, power generation water, and the like. Moreover, the spring water containing the deposit by neutralization is returned to the river. In this way, even if the spring water is strongly acidic, it is neutralized and used, so that the ecosystem is not destroyed so as not to affect the human body and fish.

  Here, the precipitate separated from the spring water used as hot spring bathing water and the like is dehydrated and then buried in a predetermined place. Moreover, since the deposit in the spring water returned to the river is deposited on the dam, the deposit containing the deposit is dredged and dehydrated, and then buried in a predetermined place.

  The inventors of the present application have found that such acidic spring water and calcium sulfate salt (precipitate) obtained by neutralizing the acidic spring water contain many kinds of metals. However, these metals are reclaimed together with the calcium sulfate salt as described above without being used elsewhere.

  Then, this invention makes it a subject to provide the metal collection | recovery method from an acidic spring water, and a resource circulation system so that the metal currently buried can be utilized effectively.

  In order to solve the above problems, a first metal recovery method of the present invention includes an adsorption step of adsorbing a metal contained in acidic spring water with an adsorbent, and the metal adsorbed on the adsorbent by the adsorption step. And a first metal recovery step of separating and recovering from the adsorbent using acidic water or alkaline water.

  According to this invention, the metal contained in acidic spring water can be directly recovered and can be used effectively. In addition, when sulfate ions are contained in the spring water, the spring water after metal recovery is neutralized with calcium carbonate as before and used for drinking water, power generation water, etc. Can be shed as

  In order to solve the above-mentioned problems, the second metal recovery method of the present invention is characterized by adding calcium carbonate or calcium hydroxide to the acidic spring water when the acidic spring water contains sulfate ions. A neutralization step for summing, a separation step for separating the precipitate and liquid generated by the neutralization step, and a second metal recovery step for recovering metal from the precipitate separated by the separation step It is characterized by that.

  According to this invention, the metal contained in the acidic spring water containing sulfate ions can be recovered from the precipitate generated by neutralization, and can be used effectively. Moreover, the spring water after neutralization excluding the sediment can be used for drinking water, power generation water, etc., and can be made to flow as river water as before.

  In the second metal recovery method, the second metal recovery step includes, as one method, a dehydration step of dehydrating the precipitate, a drying step of drying the precipitate dehydrated by the dehydration step, The metal can be recovered by including a recovery step of recovering the metal by metal refining treatment from the precipitate dried by the drying step.

  The drying in the drying step is performed by using the spring water that is 70 ° C. or higher before neutralization in the neutralization step.

  According to the present invention, the load on the environment can be reduced by using the heat of the hot spring water for drying the precipitate.

  Furthermore, the calcium carbonate or calcium hydroxide generated by the metal refining treatment is recovered and used in the neutralization step.

  According to this invention, the metal can be recovered from the spring water as described above, and calcium carbonate or calcium hydroxide that has been buried in the land can be circulated and used, thereby reducing the burden on the environment.

  In the second metal recovery method, the second metal recovery step includes, as other methods, a dehydration step of dehydrating the precipitate, a dissolution step of dissolving the precipitate dehydrated by the dehydration step in an acid, The metal can be recovered by having a separation step of separating bubbles generated by the dissolution step from a liquid and a recovery step of recovering metal from the bubbles separated by the separation step by metal refining treatment. .

  In the second metal recovery method, the second metal recovery step includes, as yet another method, a dehydration step of dehydrating the precipitate, and a dissolution step of dissolving the precipitate dehydrated in the dehydration step in an acid. A separation step of separating bubbles generated by the dissolution step from the liquid, an adsorption step of adsorbing a metal contained in the liquid separated by the separation step with an adsorbent, and an adsorption step adsorbing the metal to the adsorbent The metal is recovered by having a recovery step of separating and recovering the metal from the adsorbent using acidic water or alkaline water.

  Further, the acid used in the dissolving step is hydrochloric acid or nitric acid.

  According to the present invention, by using hydrochloric acid or nitric acid as the acid for dissolving the precipitate, the precipitate mainly composed of calcium sulfate and containing the metal can be effectively dissolved in the liquid consisting of the acid. As described above, the metal can be efficiently recovered from the generated bubbles or solution.

  In order to solve the above problems, the resource circulation system of the present invention comprises a neutralizing means for neutralizing an acidic spring water containing sulfate ions by adding calcium carbonate or calcium hydroxide, and the neutralizing means. Separation means for separating the generated precipitate and liquid, dehydration means for dehydrating the precipitate separated by the separation means, drying means for drying the precipitate dehydrated by the dehydration means, and the drying means Metal recovery means for recovering metal from the precipitate dried by metal refining treatment, and drying in the drying means is at least 70 ° C. before neutralization by the neutralization means It is characterized by using water.

  According to this invention, the metal contained in the acidic spring water containing sulfate ions can be recovered from the precipitate generated by neutralization, and can be used effectively. Moreover, the spring water after neutralization excluding the sediment can be used for drinking water, power generation water, etc., and can be made to flow as river water as before. Moreover, the environmental load can be reduced by utilizing the heat of the hot spring water for drying the precipitate.

  In the resource circulation system of the present invention, calcium carbonate or calcium hydroxide generated by the metal refining treatment is recovered and used for the neutralization means.

  According to the present invention, the metal can be recovered from the spring water as described above, and calcium carbonate or calcium hydroxide that has been buried in the land can be circulated and used, thereby reducing the burden on the environment.

  In the resource circulation system of the present invention, the deposit generated by the adding means is provided with an adding means for adding a part of the precipitate dehydrated by the dehydrating means to the acidic spring water containing sulfate ions. And liquid are used as the acidic spring water containing the sulfate ions for the neutralization means.

  According to the present invention, by adding a part of the precipitate dehydrated by the dehydrating means to the acidic spring water containing sulfate ions, the metal contained in the precipitate can be recovered again by various methods. Can do. In addition, since the dehydrated precipitate contains calcium carbonate or calcium hydroxide remaining without reacting, the precipitate is added to the acidic spring water containing sulfate ions to neutralize it. The amount of calcium carbonate or calcium hydroxide to be used can be reduced, and resources can be effectively utilized.

  According to the metal recovery method of the present invention, the metal contained in the acidic spring water can be recovered from the spring water or the precipitate generated by neutralization, and neutralization excluding the precipitate generated by neutralization. Later spring water can be used for drinking water, power generation water, etc., and can be made to flow as river water as before. Therefore, the metal that has not been used conventionally can be used effectively, and the spring water can be used as drinking water, water for power generation, river water, etc. after neutralization as usual.

  According to the resource circulation system of the present invention, the metal contained in the acidic spring water can be recovered from the precipitate generated by neutralization, and the neutralized spring water excluding the precipitate has been used so far. Similarly, it can be used for drinking water, power generation water, etc., and can be made to flow as river water. Therefore, the metal that has not been used conventionally can be used effectively, and the spring water can be used as drinking water, water for power generation, river water, etc. after neutralization as usual. Moreover, since resources such as spring water, calcium carbonate, or calcium hydroxide are circulated and used, the load on the environment can be reduced.

  Below, with reference to drawings, the metal recovery method and resource circulation system of this invention are demonstrated concretely.

  FIG. 1 is a flowchart for explaining the metal recovery method of the present invention.

  The metal recovery method and the resource circulation system of the present invention are intended to treat acidic spring water W.

  The target acidic spring water W will be described.

  As the acidic spring water W, water in a range of acidity is usually used, and water having a pH of 1.0 or more and less than 7.0 is used.

  The acidic spring water W to be treated preferably contains sulfate ions. For example, water containing a sulfate ion concentration of about 600 to 1700 mg / L (ppm) is used.

  Acidic spring water W, in particular, acidic spring water W containing sulfate ions, is, for example, Kusatsu-machi, Gunma Prefecture, etc., and has many spring qualities in Japan, and springs in many areas. The acidic spring water W is referred to as spring water, hot springs, etc., and is water that springs from the ground and is at least acidic, and preferably is not particularly limited as long as it contains sulfate ions. It is not limited to the water that springs in the area.

  Moreover, it is preferable that the metal M is contained in the acidic spring water W at a concentration of 0.001 mg / L or more, and more preferably about 0.005 to 50 mg / L.

  Examples of the metal M contained in the spring water W include lithium, beryllium, magnesium, aluminum, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, selenium, Rubidium, strontium, yttrium, zirconium, niobium, molybdenum, palladium, silver, cadmium, indium, antimony, cesium, barium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, Examples thereof include ytterbium, lutetium, tungsten, platinum, gold, mercury, thallium, lead, bismuth, thorium, and uranium.

  Hereinafter, the first metal recovery method (metal recovery 1) and the second metal recovery method (metal recovery 2 to 4) will be sequentially described. The first metal recovery method is also used when the spring water W contains a large amount of sulfate ions as described above, but is useful when the content of sulfate ions in the spring water W is small. The second metal recovery method is useful when the spring water W contains a large amount of sulfate ions as described above.

  First, as shown in the leftmost flow (metal recovery 1) in FIG. 1, the first metal recovery method of the present invention includes an adsorption step 11 for adsorbing metal M contained in acidic spring water W with an adsorbent. And a first metal recovery step 12 for separating and recovering the metal adsorbed on the adsorbent in the adsorption step 11 from the adsorbent using acidic water or alkaline water.

  In the adsorption step 11, a conventionally known adsorbent that adsorbs the metal M can be used. For example, a chelate resin adsorbent, an ion exchange resin, or the like is used.

  The acidic water used for separating the metal M from the adsorbent is, for example, hydrochloric acid, nitric acid, sulfuric acid, formic acid, or a solution obtained by diluting these acids with water. The pH of the acidic water is, for example, about 1.0 to 6.5. As the alkaline water used for separating the metal M from the adsorbent, for example, a solution in which sodium hydroxide, potassium hydroxide or the like is dissolved is used. The pH of the alkaline water is, for example, about 10-12. Of these acidic water or alkaline water, hydrochloric acid (hydrochloric acid solution) or sodium hydroxide solution is preferably used to separate the metal M from the adsorbent.

  Each metal M separated from the adsorbent is separated and purified by a method such as solvent extraction or electrolysis and recovered.

  The spring water from which the metal M has been recovered by the first metal recovery method described above is neutralized to about pH 5-6 by adding calcium carbonate or calcium hydroxide (13), and the resulting precipitate P1 And the liquid L1 are separated (14), and then the liquid L1 is used as drinking water, power generation water, etc., and flows as river water (15).

Next, in the second metal recovery method of the present invention, as shown in the flow on the right side in FIG. 1 (metal recovery 2, 3 and 4), when the acidic spring water W contains sulfate ions, the acidic spring Neutralization step 21 in which calcium carbonate (CaCO ₃ ) or calcium hydroxide (Ca (OH) ₂ ) is added to water W for neutralization, and the precipitate P2 and liquid L2 generated in the neutralization step 21 are separated. It has the separation process 22, and the 2nd metal collection | recovery process 23 which collect | recovers the metal M from the deposit P2 isolate | separated by the separation process 22, It is characterized by the above-mentioned.

  In the neutralization step 21, a solution in which calcium carbonate or calcium hydroxide is dissolved in water is added to the spring water W, and neutralization is performed by a conventionally known method. In the separation step 22, the liquid L2 and the precipitate P2 are separated by a conventionally known method such as filtration or centrifugation.

  The second metal recovery step 23 specifically has the following three modes (metal recovery; 2, 3, 4).

  As the metal recovery 2 (27) in FIG. 1, the second metal recovery step 23 includes a dehydration step 24 for dehydrating the precipitate P2, a drying step 25 for drying the precipitate P2 dehydrated by the dehydration step 24, and a drying step. And a recovery step 27 for recovering the metal M by the metal refining process 26 from the precipitate P2 dried by 25.

  In the dehydration step 24, the precipitate P2 is dehydrated using an apparatus such as a filter press, a belt press, or a centrifuge. At this time, the moisture content of the precipitate P2 is not particularly limited, but is usually about 40%.

  In the drying step 25, for example, the precipitate P2 is dried using an apparatus such as a steam dryer.

  The metal refining process 26 performs a metal refining process from the dried precipitate P2 by a method such as electrolysis and melting using a dry metal refining apparatus, a melting furnace, and the like. Further, a known refining technique can be used for the metal refining process 26 according to the metal to be recovered. Note that, at the stage of the metal refining process 26, the metal may be recovered using the above-described adsorbent.

  Here, it is preferable to recover calcium carbonate or calcium hydroxide generated by the metal refining treatment 26 and use it in the neutralization step 21 described above.

  Moreover, the temperature of the spring water W is not specifically limited, There can exist the temperature of the range of 0-100 degreeC. When the spring water W is at a high temperature of, for example, 70 ° C. or higher, the heat of the spring water W can be used for the drying process 25 of the precipitate P2. When the heat of the spring water W is used for the drying process 25, as described above, the process 11 for adsorbing the metal M with the adsorbent or neutralization so that more heat can be used at a higher temperature. It is preferably used in the previous stage of the step 21 to be performed.

  Next, in the second metal recovery step 23, as the metal recovery 3 (34) in FIG. 1, a dehydration step 24 for dehydrating the precipitate P2, and a dissolution step 31 for dissolving the precipitate P2 dehydrated in the dehydration step 24 in an acid. And a separation step 32 for separating the bubbles B generated in the dissolution step 31 from the liquid L3, and a recovery step 34 for recovering the metal from the bubbles B separated in the separation step 32 by a metal refining process 33.

  It is preferable to use hydrochloric acid, nitric acid, or the like as the acid for dissolving the precipitate P2 in the dissolving step 31 in order to dissolve the precipitate P2 well. The pH of this acid is about 1-2, and it is possible to use a stock solution, but it is preferable to use the acid diluted to about 3-4 times. Further, the mass ratio of the precipitate P2 and the acid is not particularly limited. For example, the precipitate P2 can be dissolved in the acid at a mass ratio of the precipitate P2: acid = 1: 1.

  By dissolving the precipitate P2 in the acid in the dissolution step 31, bubbles B are generated. Since the metal B is contained in the bubble B, the bubble B is separated from the liquid L in the separation step 32.

  In the separation step 32, in order to separate the bubbles B from the liquid L3, for example, a plate having an appropriate size is used, and the bubbles B are separated from the liquid L3 by attaching the bubbles B to the plate.

  The metal refining process 33 is a process for recovering the metal M from the separated bubbles B. The metal refining process is performed from the bubbles B by the same method as the metal refining process 26 in the aspect of the metal recovery 2 described above. be able to. Note that, at the stage of the metal refining process 33, the metal may be recovered using the above-described adsorbent.

  Next, in the second metal recovery step 23, as the metal recovery 4 (36) in FIG. 1, a dehydration step 24 for dehydrating the precipitate P2, and a dissolution step 31 for dissolving the precipitate P2 dehydrated in the dehydration step 24 in an acid. A separation step 32 for separating the bubbles B generated by the dissolution step 31 from the liquid L3, an adsorption step 35 for adsorbing the metal M contained in the liquid L3 separated by the separation step 32 with an adsorbent, and an adsorption step 35 A recovery step 36 for separating and recovering the metal M adsorbed on the adsorbent from the adsorbent using acidic water or alkaline water.

  In the aspect of the metal recovery method according to this metal recovery 4, each step of the dehydration step 24, the dissolution step 31 and the separation step 32 is the same as each step according to the metal recovery 3 described above.

  The adsorbent used in the adsorption step 35 is the same as that used in the adsorption step 11 related to the metal recovery 1 described above.

  The acidic water and alkaline water used in the recovery process 36 are the same as those used in the first metal recovery process 12 according to the metal recovery 1 described above. Further, in the recovery step 36, the step of recovering the metal M is the same as that in the first metal recovery step 12 related to the metal recovery 1 described above.

  In addition, in the 2nd metal collection | recovery process 23, a part of deposit P2 after the dehydration process 24 can also be added to the acidic spring water W containing the sulfate ion before a process (refer arrow 41 in FIG. 1). Thereafter, similarly to the above-described spring water W, the metal M contained in the precipitate P2 can be recovered again by each of the metal recovery methods 1 to 4. Furthermore, in the case of each method of metal recovery 2-4, unreacted calcium carbonate or calcium hydroxide contained in the precipitate P2 can be used for the neutralization step 21, and resources can be effectively utilized. .

  Next, the resource circulation system will be described.

  This resource circulation system mainly corresponds to the metal recovery method described as the metal recovery 2 among the metal recovery methods described above.

  That is, the resource circulation system of the present invention includes a neutralizing means for neutralizing by adding calcium carbonate or calcium hydroxide to an acidic spring water W containing sulfate ions, and a precipitate P2 and liquid generated by the neutralizing means. Separation means for separating L2, dehydration means for dewatering the precipitate P2 separated by the separation means, drying means for drying the precipitate P2 dehydrated by the dehydration means, and the precipitate P2 dried by the drying means And a metal recovery means for recovering the metal by a metal refining treatment, and drying in the drying means is performed by using spring water W that is 70 ° C. or higher before neutralization by the neutralization means. And

  In addition, calcium carbonate or calcium hydroxide is generated by the metal refining treatment. This calcium carbonate or calcium hydroxide is preferably recovered and used as calcium carbonate or calcium hydroxide in the neutralization means.

  Furthermore, in this resource circulation system, as shown by an arrow 41 in FIG. 1, an adding means for adding a part of the precipitate P2 dehydrated by the dehydrating means to the acidic spring water W containing sulfate ions. In addition, it is preferable to use the precipitate and liquid generated by the adding means as the acidic spring water W containing sulfate ions for the neutralizing means.

  When the sediment P2 is added to the spring water W, the mass ratio is not particularly limited. For example, the ratio of the sediment P2: spring water W = 1: 2000 can be set. Thus, by adding the precipitate P2 to the spring water W, the metal M contained in the precipitate P2 together with calcium sulfate can be recovered again by the above-described methods 1 to 4 for metal recovery.

  In addition, the precipitate generated by the adding means contains calcium carbonate or calcium hydroxide that has not been reacted in the neutralizing means. When this precipitate is added to water, Therefore, the amount of new calcium carbonate or calcium hydroxide to be added for neutralization can be reduced by using these precipitates and liquid as neutralization means. Thereafter, the metal M can be recovered from the spring water W treated by the neutralizing means by the metal recovery methods 2 to 4.

Here, the spring water W used as bathing water for hot springs in Kusatsu-machi, Gunma Prefecture has an average of 94.5 ° C. when springing, and is springing out at a speed of 6.2 m ³ / min. This spring water W whose temperature is lowered to about 52 ° C. by tap water is used as hot spring bathing water. And it is used for river water etc. after neutralizing the spring water W used as bathing water with calcium carbonate. At this time, the amount of calcium carbonate necessary for neutralizing the spring water is about 60 t (tons) per day.

Calcium carbonate (CaCO ₃ ) was added to acidic spring water containing sulfate ions springed from the soil in Kusatsu-machi, Gunma Prefecture, and calcium sulfate (CaSO ₄ ), which is a neutralized product, was precipitated. Table 1 shows the concentration (unit: mg / kg) of each metal contained in the neutralized product. The symbol <DL indicates the case where the value is below the detection limit value of each metal, and the same applies to the symbol <DL in the table below.

  Also, in Table 1, each of the same spring water used as hot spring bathing water and river water flowing into the river, in the state before neutralization, the pH value and each metal contained The concentration (unit: mg / L) is shown.

  10 g of the neutralized product described above was dissolved in 10 mL of hydrochloric acid (HCl). Table 2 shows the pH value and the concentration A (unit: mg / L) of each metal contained in a liquid that was filtered and diluted with water to 100 mL.

  In addition, bubbles were generated when 10 g of the neutralized product was dissolved in 30 mL of hydrochloric acid. The bubbles are collected on a plate, washed with water, filtered, and diluted with water to make 100 mL. The pH value and the concentration B (unit: mg / L) of each metal contained are measured. It shows in Table 2. From this, the collection rate (unit:%) of each metal by air bubbles was as shown in Table 2.

  Further, 10 g of the neutralized product described above was diluted 50 times in mass with acidic spring water having the same pH of 1.97 as above, stirred and centrifuged to obtain a liquid (supernatant liquid). ) Only. Table 3 shows the concentration (unit: ppm) of each metal contained in the supernatant. The supernatant was passed through a metal adsorbent made of a chelate resin having iminodiacetic acid groups fixed thereon, and the metal was recovered. Table 3 shows the concentration (unit: ppm) of each metal contained in the supernatant after passing through the metal adsorbent. From this, the adsorption rate (unit:%) of each metal by the metal adsorbent was as shown in Table 3.

Moreover, about the hot spring water in Table 1, ₂ g of calcium hydroxide (Ca (OH) ₂ ) was added to 1 L of hot spring water (raw water) to precipitate a neutralized product. Table 4 shows the pH of the supernatant (raw water) of the precipitated neutralized product, the concentration of the contained metal (unit: mg / L), and the proportion of the metal remaining in the raw water.

  Moreover, about the hot spring water in Table 1, 4 g of calcium carbonate was added to 1 L of hot spring water (raw water) to precipitate a neutralized product. Table 4 shows the pH of the supernatant (raw water) of the precipitated neutralized product, the concentration of the contained metal (unit: mg / L), and the proportion of the metal remaining in the raw water.

  Further, in the same manner as in Table 4, calcium hydroxide or calcium carbonate is added to hot spring water (raw water), and the concentration of metal contained in each neutralized product (precipitate) (unit: mg / L) Table 5 shows the degree of concentration (= metal concentration in the precipitate / metal concentration in the raw water).

  As shown in Table 1, various metals are contained in the acidic spring water, and by recovering the metal, each metal that has been landfilled in the past can be used effectively. Further, as shown in Tables 2 to 4, each metal can be recovered by various methods. In particular, from Tables 4 and 5, calcium carbonate and calcium hydroxide can be used to neutralize acidic spring water, but calcium carbonate is more preferred from the point of recovering metal.

It is a flowchart explaining the metal collection | recovery method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 35 ... Adsorption process 12, 23, 27, 34, 36 ... Metal recovery process 13, 21 ... Neutralization process 22 ... Separation process 24 ... Dehydration 25 ... Drying 26, 33 ... Metal refining process 31 ... Dissolution process to acid 32 ... Separation step 41 ... Step of adding precipitate to added spring water W ... Spring water M ... Metal P1, P2 ... Precipitate L1, L2, L3 ... Liquid B ... Bubble

Claims (11)

An adsorption process for adsorbing metal contained in acidic spring water with an adsorbent;
A first metal recovery step of separating and recovering the metal adsorbed on the adsorbent by the adsorption step from the adsorbent using acidic water or alkaline water;
A metal recovery method characterized by comprising: When the acidic spring water contains sulfate ions, a neutralization step of neutralizing the acidic spring water by adding calcium carbonate or calcium hydroxide;
A separation step of separating the precipitate and liquid generated by the neutralization step;
A second metal recovery step of recovering metal from the precipitate separated by the separation step;
A metal recovery method characterized by comprising: The second metal recovery step includes
A dehydration step of dehydrating the precipitate;
A drying step of drying the precipitate dehydrated by the dehydration step;
From the precipitate dried by the drying step, a recovery step of recovering metal by metal refining treatment,
The metal recovery method according to claim 2, comprising:   The metal recovery method according to claim 3, wherein the drying in the drying step is performed by using the spring water that is 70 ° C. or higher before neutralization in the neutralization step.   5. The metal recovery method according to claim 3, wherein calcium carbonate or calcium hydroxide produced by the metal refining treatment is recovered and used in the neutralization step. The second metal recovery step includes
A dehydration step of dehydrating the precipitate;
A dissolution step of dissolving the precipitate dehydrated in the dehydration step in an acid;
A separation step of separating bubbles generated by the dissolution step from the liquid;
A recovery step of recovering metal from the bubbles separated by the separation step by a metal refining process;
The metal recovery method according to claim 2, comprising: The second metal recovery step includes
A dehydration step of dehydrating the precipitate;
A dissolution step of dissolving the precipitate dehydrated in the dehydration step in an acid;
A separation step of separating bubbles generated by the dissolution step from the liquid;
An adsorption step of adsorbing a metal contained in the liquid separated by the separation step with an adsorbent;
A recovery step of separating and recovering the metal adsorbed on the adsorbent by the adsorption step from the adsorbent using acidic water or alkaline water;
The metal recovery method according to claim 2, comprising:   The metal recovery method according to claim 5 or 7, wherein the acid used in the dissolution step is hydrochloric acid or nitric acid. Neutralizing means for neutralizing by adding calcium carbonate or calcium hydroxide to acidic spring water containing sulfate ions,
Separation means for separating the precipitate produced by the neutralization means and the liquid;
Dehydrating means for dehydrating the precipitate separated by the separating means;
Drying means for drying the precipitate dehydrated by the dehydrating means;
Metal recovery means for recovering metal by metal refining treatment from the precipitate dried by the drying means;
Have
Drying in the drying means is performed by using the spring water that is 70 ° C. or higher before neutralization by the neutralization means.   The resource circulation system according to claim 9, wherein calcium carbonate or calcium hydroxide generated by the metal refining treatment is collected and used for the neutralization means. While having a means for adding a part of the precipitate dehydrated by the dehydrating means to the acidic spring water containing the sulfate ions,
The resource circulation system according to claim 9 or 10, wherein the precipitate and liquid generated by the adding means are used as the acidic spring water containing the sulfate ions for the neutralizing means.

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