JPH06127946A - Treatment of iron chloride base waste liquid - Google Patents

Abstract

PURPOSE:To provide a method for treating iron chloride base waste liquid where iron powder is added to strong acid waste liquid contg. copper chloride or nickel cupric chloride, etc., and the waste liquid is purified and regenerated in a continuous process and simultaneously valuable metal is recovered. CONSTITUTION:The iron power 15 is added into iron chloride strong acid waste liquid 10 no reduce residual ferric chloride to ferrous chloride, causing dissolved copper chloride to be deposited by substitution. The iron powder 15 and iron chloride waste liquid 10 are mixed in the mixed waste liquid 10b after copper removing in the ratio of 10-30% to the copper removed liquid. The pH of the obtained mixed waste liquid 10c is adjusted to 1.3-2.5 and the iron ion concentration is controlled to >=280g/ l to form ferric hydroxide. Suspensible impurities 40 of the mixed waste liquid 10c are adsorbed on and included in the ferric hydroxide and further coagulant solution 50 is added to form coagulated floc which is large to some degree and easy to separate and then the coagulated floc is separated and removed by a solid-liquid separator 53.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating iron chloride-based waste liquid, more specifically, in a continuous process by adding iron powder to a strong acid waste liquid containing copper chloride or copper chloride / nickel. The present invention relates to a method for treating an iron chloride waste liquid in which a waste liquid is regenerated into a purified liquid and valuable metals are recovered.

[0002]

2. Description of the Related Art For example, a lead frame for IC or LSI may be processed by photoetching. The etching liquid used at that time usually contains highly pure ferric chloride. By the way, after the use of the etching solution, since the components of the lead frame are eluted into the solution and the concentration of ferric chloride in the solution is lowered to deteriorate the etching efficiency, it is necessary to replace the etching solution at regular intervals. Has been done. However, this etching waste liquid contains a considerable amount of valuable copper ions and nickel ions in addition to high-concentration iron ions. Therefore, Japanese Patent Laid-Open No. 1-1672
As disclosed in Japanese Patent Publication No. 35-35, a method is known in which iron waste is added to the etching waste liquid to adjust the pH in the waste liquid, copper and nickel are recovered, and the etching liquid is reused. .

[0003]

However, in the above-described conventional iron chloride waste liquid treatment method, the grade of recovered copper and nickel is low, and the value of a valuable metal is low. Further, as a means for enhancing the quality of recovered metal from the past, as in the method for treating a metal-containing carbon-containing powder described in JP-A-51-120902, a powder containing a valuable metal is made into a slurry. , It is known to wet classify this before flotation, but since it is physically beneficiated, if the specific gravity of the impurities to be separated is large,
It is difficult to perform flotation processing. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for treating an iron chloride-based waste liquid capable of recovering a valuable metal of high quality at the same time as the purification of the waste liquid.

[0004]

A method for treating an iron chloride waste liquid according to the above-mentioned object is to add iron powder to an iron chloride strong acid waste liquid containing copper, nickel and a small amount of chromium to remove residual chloride. Dissolved copper chloride is replaced and precipitated by reducing 2 iron to ferrous chloride, and iron powder and the iron chloride waste liquid are contained in the liquid thus decoppered in a proportion of 10 to 30% with respect to the decoppering liquid. The pH of the mixed waste liquid thus obtained was mixed with 1.3 to 2.
5, and the ferric ion concentration was controlled to 280 g / liter or less to produce ferric hydroxide, and the ferric hydroxide was allowed to adsorb and entrap the suspending impurities of the mixed waste liquid, and further aggregated. The agent solution is added to form a large amount of agglomerate flocs that are easily separated, and then the agglomerate flocs are separated and removed. As the iron chloride-based strong acid waste liquid,
Examples thereof include an etching waste liquid containing ferric chloride as a main component or an etching waste liquid and a hydrochloric acid pickling waste liquid.

As the iron powder, for example, spherical converter refined iron powder can be used, and the size thereof is 44 to 250 μm.
m, especially 44 to 150 μm is preferable. If it is less than 44 μm, the specific surface area is too large and the reaction occurs rapidly.
If control is not possible (rapid increase), and if it exceeds 250 μm, the specific surface area of the spherical iron powder becomes small, and the reaction active area is small, resulting in insufficient reaction. Further, the iron ion concentration in the strong acid waste liquid to which the iron powder has been added is preferably 280 g / liter or less, and particularly preferably 240 to 270 g / liter,
If it is less than 240 g / liter, it is too thin to be suitable as a product for etching. If it exceeds 280 g / liter, the iron ion concentration is too high and the nickel substitution reaction is suppressed.

Furthermore, the oxidation-reduction potential of the strong acid waste liquor to which the iron powder is added is -520 to -400 mV, especially -4.
60 to -430 mV is preferable, and if less than -520 mV, the amount of iron powder added becomes excessive and the stirrer is overloaded, making it impossible to operate. If it exceeds -400 mV, the nickel substitution reaction (cementation) proceeds slowly. Further, the PH value of the strong acid waste liquid to which the iron powder has been added is 1.3 to 2.
5, especially 1.5 to 1.7 is preferable, and when the pH is less than 1.3, the hydrolysis of chromium is less likely to occur in the low PH region and the amount of hydroxide generated is reduced, so that chromium hydroxide and ferric hydroxide are used. Co-precipitation does not occur, and when the pH exceeds 2.5, the amount of hydroxide generated increases too much, iron powder consumption increases, and the load on the solid-liquid separator used in the next step is large. Becomes Further, the hydroxide clings around the iron powder and inhibits contact between the solution and the iron powder, resulting in poor reaction (particularly, poor reaction of nickel cementation).

Further, the amount of ferric hydroxide produced in the waste liquid is preferably from 13 to 30 g / liter, particularly preferably from 15 to 20 g / liter. Below 13 g / liter is insufficient for coprecipitating chromium hydroxide. However, suspended impurities (C, S
Insufficient to entrap insoluble solids (SS) such as iO ₂ . On the other hand, if it exceeds 30 g / liter, the hydroxide clings to the periphery of the iron powder and inhibits contact between the solution and the iron powder, resulting in poor reaction (particularly nickel cementation). Further, since the amount of hydroxide is too large, the separation in the solid-liquid separation step, which is the next step, becomes poor, and SS in the product liquid increases. Furthermore, examples of the suspending impurities include carbon and silicon dioxide in the case of etching waste liquid.

[0008]

In the iron chloride waste liquid treating method according to the present invention, iron powder is added to the iron chloride strong acid waste liquid containing copper, nickel and a small amount of chromium to remove residual ferric chloride. It is reduced to 1 iron and the dissolved copper chloride is deposited by substitution. Next, iron powder and an iron chloride waste liquid are mixed in the decoppered liquid at a ratio of 10 to 30% with respect to the decoppered liquid, and the pH of the obtained mixed waste liquid is set to 1.3 to 2.5. By adjusting and controlling the iron ion concentration to 280 g / liter or less, ferric hydroxide is produced. After that, the ferric hydroxide is allowed to adsorb and entrap the suspending impurities in the mixed waste liquid, and a coagulant is further added to form a cohesive floc which is easy to separate to some extent. Separated and removed by solid-liquid separator.

[0009]

Embodiments of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is an overall process diagram showing a method for treating an iron chloride waste liquid according to an embodiment of the present invention.

The method for treating an iron chloride waste liquid according to the present invention comprises a copper removal process, a nickel removal process, and a suspending impurity (SS) removal process for an iron chloride strong acid waste liquid. First, the etching waste liquid 10 which is a kind of iron chloride-based strong acid waste liquid was stored 10
The waste liquid 10 is supplied from the 0 m ³ waste liquid tank 11 into the decoppering reaction tank 12 by the slurry pump 13 at 0.9 to 1.3 m ³ / Hr. The decoppering reaction tank 12 is supplemented with dilution water as needed. In the waste liquid 10, in addition to ferric chloride as a main component, a metal such as copper, nickel or chromium is dissolved and ionized in the etching process to divalent iron ion and divalent iron ion is reduced. Is mixed in.

Next, from the 2 m ³ OGP hopper feeder 14 into the decoppering reaction tank 12, a particle size of 1 m, which is a kind of iron powder, is introduced.
m or less (250 to 44 μm: 90 to 100%, 150 to
74 μm: 50-70%) spherical converter refined iron powder 15 (hereinafter, referred to as OGP iron powder), while stirring device 16
Stir by. At this time, the addition amount of the OGP iron powder 15 is adjusted so that the iron ion concentration in the waste liquid 10 is 280 g / liter or less, the oxidation-reduction potential (ORP) is −300 to −100 mV, and the PH is 0.5 to 1.5. Adjust. As a result, the following reactions occur and copper powder is deposited. 2FeCl ₃ + Fe → 3FeCl ₂ (1) CuCl ₂ + Fe → FeCl ₂ + Cu ↓ (2) 2HCl + Fe → FeCl ₂ + H ₂ ↑ (3) The OGP iron powder 15 contains Fe ³⁺ , Cu
²⁺ , HCl equivalent to solid content, solid flow 70-120kg
/ Hr is added to the waste liquid. Further, the temperature of the waste liquid 10 rises to 70 to 100 ° C. due to its own heat of reaction, so that the reaction positively occurs and copper is deposited on the surface of the OGP iron powder 15.

The mixed liquid 10a of the waste liquid 10 and the OGP iron powder 15 overflowing from the decoppering reaction tank 12 is temporarily stored in the corn tank 17, and then the slurry pump 18 is used.
Is pumped up and supplied with the upper wet cyclone 19 and the cyclone 20. This wet cyclone 19
Is set to the concentration (coarse particle classification) condition, so that the unreacted OGP iron powder 15 and the O particles to which the reaction-produced copper particles adhere
The GP iron powder 15 and the largely grown copper particles are separated and returned to the decoppering reaction tank 12. The solid flow rate here is 120
~ 150kg / Hr, copper occupies 80% or more, the rest is a few percent of iron, and a trace amount of suspended impurities such as carbon and silicon dioxide (hereinafter sometimes referred to as SS), and the particle size is 60. ˜150 μm.

Next, the medium-grained powder and fine-grained solids that cannot be captured by the wet cyclone 19 are further sent to the next wet cyclone 20 via the corn tank 21 and the slurry pump 22. Since this wet cyclone 20 is set to a collection (fine particle classification) condition of a collection particle size of 20 μm or more, medium-sized unreacted OGP iron powder 15 and OGP to which reaction-produced copper particles adhere The iron powder 15 and the copper particles that have grown into medium particles are separated and returned to the decoppering reaction tank 12. The solid flow rate here is 10-40 kg / Hr, 70% copper
It occupies the above, the rest is a few% of iron and a trace amount of SS, and the particle size is 20 to 80 μm. In addition, since the OGP iron powder 15 to which the copper particles adhere and the grown copper particles are returned to the decoppering reaction tank 12 again, the reactions of the reaction formulas (1), (2), and (3) are promoted, By continuing this decoppering treatment continuously for 6 hours or more (usually about 10 hours), the
The GP iron powder 15 disappears and copper with large grains is generated.

After that, as shown by the broken line in FIG. 1, the produced copper is drained by a draining akins 23, and then washed by showering clean water by a cleaning akins 24 and collected in a recovery box 25. To be done. The recovered copper particles 26 are dried and commercialized. The recovered copper particles 26 have a quality (purity) of 80 to 95%.

Next, mixed waste 10b containing particulate solids 5~19μm which is copper removal process is sent to the de-nickel reaction vessel 27 of 12m ^3. The solid flow rate here is 6-10
kg / Hr, copper 30-70%, iron 15% or less, SS
It is a few percent. The nickel removal reaction tank 27 has a stirring device 2
No. 8 is provided and steam piping is provided to keep the liquid temperature at 70 to 100 ° C.

In the denickel reaction tank 27, a small amount of etching waste liquid in the waste liquid tank 11 (a ferric chloride new liquid may be used because trivalent iron ions in the waste liquid are useful) 10,
The OGP iron powder 15 recovered from the converter in the 2 m ³ OGP hopper feeder 29 is charged to form the mixed waste liquid 10c. At this time, the liquid temperature in the tank is 40 ° C or higher (70 to 10
ORP of the mixed waste liquid 10c is -52 while keeping it at 0 ° C.
Nickel is deposited by adjusting the amounts of the etching waste liquid 10 and the OGP iron powder 15 added so that the pH is 0 to -400 mV, the PH is 1.3 to 2.5, and the iron ion concentration is 280 g / liter or less. NiCl ₂ + Fe → FeCl ₂ + Ni ↓ (4) At this time, the OGP iron powder 15 was added in an excessive amount as a bed material (several tens of equivalents of the content Ni to be treated) from the initial stage, and further during continuous treatment. Decopperized mixed waste liquid 10b
The content of Ni and the small amount of Fe ³⁺ , Cu ²⁺ , HCl, and Ni contained in a small amount of the etching waste liquid 10 are added to the OGP iron powder 15 in an amount of 1.5 to several times. The solid flow rate at this time is usually 60 to 120 kg / Hr, and the maximum is 300 kg.
/ Hr.

In this case, a nickel coating is deposited on the surface of the iron powder of the OGP iron powder 15, but the unreacted portion of the iron powder surface is formed when the hydroxides described later adhere or when hydroxide is generated. The resulting hydrochloric acid becomes passivated by the attachment of hydrogen gas generated when it further reacts with the iron powder, which hinders the progress of the reaction. Therefore, a small amount of trivalent iron ions is mixed and this portion is subjected to a chemical conversion treatment to be activated to promote a smooth reaction. Although it is possible to add a small amount of hydrochloric acid instead of the etching waste liquid 10, the surface of the iron powder is similarly passivated due to the attachment of hydrogen gas generated when the hydrochloric acid reacts with the OGP iron powder 15.

When chromium ions are contained in the waste liquid and the content thereof is a small amount of 2 g / liter or less, the above-mentioned conditions (PH may be 2 or less in the denickel reaction tank 27). Therefore, chromium ions can be generated as hydroxides by the following reaction formula simultaneously with the precipitation of nickel. The generation of chromium hydroxide is promoted by the generation of ferric hydroxide described below. CrCl ₃ + 3H ₂ O → Cr (OH) ₃ + 3HCl (5) CrCl ₃ + 2H ₂ O → CrOOH + 3HCl (6) 2HCl + Fe → FeCl ₂ + H ₂ ↑ (7)

Next, in the reaction when a small amount of trivalent iron ions is mixed in the denickeling reaction tank 27, the pH is 1.
It becomes as follows under the condition of 3 to 2.5. Reaction rate when PH = 1.3 (8) 70%; (9),
(10) Reaction rate when 30% PH = 2.0 (8) 50%; (9),
(10) Reaction rate when 50% PH = 2.5 (8) 40%; (9),
(10) 60% 2FeCl ₃ + Fe → 3FeCl ₂ (8) FeCl ₃ + 3H ₂ O → Fe (OH) ₃ + 3HCl (9) 2HCl + Fe → FeCl ₂ + H ₂ ↑ (10) In other words, when PH is 2.0 Approximately half of the trivalent Fe ions are activated by a chemical conversion reaction between the passivated OGP iron powder 15 and the surface of the iron powder to accelerate the nickel deposition reaction. On the other hand, the other half of the trivalent Fe ions form a ferric hydroxide precipitate. By producing a small amount (appropriate amount) of this starch, a coagulant effect of adsorbing / entrapping SS or coprecipitating and capturing chromium hydroxide can be obtained.

The mixed waste liquid 10c overflowing from the denickel reaction tank 27 is temporarily stored in the cone tank 30, pumped up by the slurry pump 31, and sent to the wet cyclone 32 and further to the wet cyclone 33. At this time, as in the decoppering step, the wet cyclone 32 is set under the conditions of condensation (coarse-grain classification), so that unreacted O
GP iron powder 15, O to which nickel particles produced by reaction are attached
The GP iron powder 15 is separated and returned to the denickeling reaction tank 27. The solid flow rate here is usually 40 to 90 kg / H.
At r, the iron content occupies half, the rest is nickel and copper and a trace amount of SS, and the particle size is 60 to 150 μm.

Next, the medium-sized powder and fine-grained solids that cannot be captured by the wet cyclone 32 remain in the corn tank 34,
The second stage wet cyclone 3 via the slurry pump 35
Sent to 3. Wet cyclone 33 is collected (fine particle classification)
Since the conditions are set and the collection particle size is 20 μm or more, the unreacted OGP iron powder 15 of medium particles and the OGP iron powder 15 to which the nickel particles produced by reaction are attached are separated,
It is returned to the lower portion of the nickel-free reaction tank 27. The solid flow rate here is 5 to 15 kg / Hr, the iron content is half, the balance is nickel and copper, and a small amount of SS, and the particle size is 10
-60 μm.

At this time, the unreacted OGP iron powder 15 and the OGP iron powder 15 to which nickel particles adhere are returned to the denickeling reaction tank 21 again, so that the reactions (4) to (10) are promoted. 12 hours or more continuously (about 24 hours)
By continuing this treatment process, the nickel quality is improved. In this nickel removal process, the stirring device 28
Alternatively, the phenomenon of mechanical peeling and grinding due to recycling using the wet cyclones 32 and 33 has not occurred.

After performing the above steps for about 24 hours, the continuous supply of the waste liquid is stopped, and the nickel iron powder is taken out together with the mixed waste liquid 10c from the discharge port at the bottom of the denickeling reaction tank 27 for draining. The mixture is sent to an Akins (classifier) 36, and the supernatant liquid is once stored in a corn tank 37 and then returned to the nickel-free reaction tank 27 by a slurry pump 38.
On the other hand, the drained nickel iron powder is sent to the next cleaning Akins 39. Here, the nickel iron powder 40 (wet powder) is washed in a shower ring of purified water and drained, and the nickel iron powder 40 (wet powder) is collected in the collection box 41. After that, the wet nickel-iron powder 40 is dried and commercialized. The obtained nickel iron powder 40 has a quality of 10 to 20%. In addition, the supernatant of the cleaning Akins 39 is the corn tank 4
After being temporarily stored in No. 2, it is returned to the washing tank (not shown) by the pump 43.

Next, SS and hydroxide of the insoluble solid substance overflowing from the cyclone 33 (mainly the hydroxide second
(Iron) mixed solution containing 5 to 19 μm fine solid matter 10d
Is a high speed stirring tank 44 and a low speed stirring tank 4 to which a flocculant is added.
Sequentially sent to 5. A stirring device 4 is provided in each stirring tank 44, 45.
6 and 47 are provided, and in this high-speed stirring tank 44, a flocculant dissolving tank 49 stirred by a stirring device 48 is provided.
The coagulant solution 50 therein is added by the pump 51. The solid flow rate here is 30 to 50 kg / Hr, most of which is ferric hydroxide precipitate, and the rest is nickel, copper, M-
Fe is several%, SS is several%.

By the way, in the liquid of the mixed waste liquid 10d that has overflowed the wet cyclone 33, hydroxide precipitate and SS adsorbed / entrapped therein and a small amount of nickel particles, copper particles, iron particles in a fine particle state. Contains. This mixed waste liquid 1
0d is sent to the high-speed stirring tank 44, the flocculant solution 50 (concentration 1,000 mg / liter) is added from the flocculant dissolution tank 49, and the flocculant solution 50 is diffused throughout the mixed waste liquid 10d, and then The low-speed agitation tank 45 carefully forms the floc. If the shape of this flocculation floc is too fine, the solid-liquid separation ability decreases, so a flocculation floc that is large to some extent and easy to separate is used. Next, a suspending impurity removing step for removing suspending impurities in the denickeled mixed waste liquid 10e containing the aggregated flocs will be described.

The denickelized mixed waste liquid 10e is 2
It is divided and is evenly supplied to a pair of solid-liquid separators (decanters) 53 driven by a motor 52. Here, the mixed waste liquid 10e is separated into a hydroxide precipitate 54 (hereinafter referred to as SS precipitate) in which suspended impurities such as carbon and silicon dioxide are adsorbed and entrapped and a supernatant liquid 10f, and solid SS precipitate is obtained. The object 54 is recovered in the recovery box 55.
In this way, the SS precipitate 54 in which the suspending impurities, such as carbon and silicon dioxide, are adsorbed and included in the etching waste liquid 10 can be effectively recovered. By the way, since the pH of the separated supernatant liquid is about 2, there is a possibility that hydroxide may be generated as it is. Therefore, it is necessary to set the pH to 1 or less. Therefore, the supernatant liquid 10f is temporarily stored in the cushion tank 56, and the hydrochloric acid tank 57
From the pump 58, add some hydrochloric acid 59 and add PH
After the adjustment, the pump 60 stores the product in a 100 m ³ product tank 61. The product liquid 62 in the product tank 61 is taken out by the pump 63 and reused.

The present invention is not limited to the above-mentioned embodiments, and any modification within the scope of the present invention is included in the present invention.

[0028]

The method for treating an iron chloride waste liquid according to the present invention comprises adding iron powder to a strong acid waste liquid containing nickel,
Valuable metals such as copper and nickel in the iron chloride waste liquid can be recovered in high quality. Moreover, ferric hydroxide is produced by adjusting the pH of the strong acid waste liquid to which the iron powder has been added to 1.3 to 2.5, and carbon or silicon dioxide in the strong acid waste liquid is generated in the ferric hydroxide. Adsorbs suspended impurities such as
It can be included and separated and removed.

[Brief description of drawings]

FIG. 1 is an overall process diagram of a method for treating an iron chloride waste liquid according to an embodiment of the present invention.

[Explanation of symbols]

 10 etching waste liquid 10a mixed waste liquid 10b mixed waste liquid 10c mixed waste liquid 10d mixed waste liquid 10e mixed waste liquid 10f supernatant liquid 11 waste liquid tank 12 decoppering reaction tank 13 slurry pump 14 OGP hopper feeder 15 OGP iron powder 16 stirrer 17 cone tank 18 slurry pump 19 Wet cyclone 20 Wet cyclone 21 Cone tank 22 Slurry pump 23 Akins for draining 24 Akins for cleaning 25 Recovery box 26 Copper particles 27 Denickel reaction tank 28 Stirrer 29 OGP hopper feeder 30 Cone tank 31 Slurry pump 32 Wet cyclone 33 Wet cyclone 34 Cone Tank 35 Slurry Pump 36 Akins for Draining 37 Cone Tank 38 Slurry Pump 39 Akins for Cleaning 40 Nicke Iron powder 41 Recovery box 42 Cone tank 43 Pump 44 High speed stirring tank 45 Low speed stirring tank 46 Stirring device 47 Stirring device 48 Stirring device 49 Coagulant dissolving tank 50 Coagulant solution 51 Pump 52 Motor 53 Solid-liquid separator 54 Hydroxylated starch Item 55 Collection box 56 Cushion tank 57 Hydrochloric acid tank 58 Pump 59 Hydrochloric acid 60 Pump 61 Product tank 62 Product liquid 63 Pump

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hideyoshi Sasahara 1-1 1-1 Toibata-cho, Tobata-ku, Kitakyushu, Kitakyushu, Fukuoka Inside Nippon Steel Co., Ltd. Yawata Works (72) Inventor Tadao Kitazawa Yawata-higashi, Kitakyushu, Fukuoka 1-3-1 Otani Astec Irie, Inc. (72) Eiji Inoue 1-3-1 Otani, Yawatahigashi, Kitakyushu, Fukuoka Prefecture Astec Irie, Inc.

Claims (1)

[Claims] 1. Dissolved copper chloride is added by adding iron powder to an iron chloride-based strong acid waste liquid containing copper, nickel and a small amount of chromium to reduce residual ferric chloride to ferrous chloride. The iron powder and the iron chloride-based waste liquid are mixed in the liquid thus precipitated and decopperized in a proportion of 10 to 30% with respect to the decoppered liquid, and the pH of the obtained mixed waste liquid is 1.3 to 2 0.5 and the iron ion concentration is controlled to 280 g / liter or less to produce ferric hydroxide, and the ferric hydroxide is allowed to adsorb and entrap the suspending impurities of the mixed waste liquid, and A method for treating an iron chloride waste liquid, which comprises adding a flocculant solution to form a large amount of floc that is easy to separate and then removing the floc.