JP3593726B2 - Method for treating wastewater containing sulfuric acid and copper - Google Patents

Description

【００４０】
実験例２
表２に示す濃度の実廃水（銅箔製造廃水）と合成廃水（硫酸銅＋硫酸）に消石灰を添加してｐＨ９〜１０とし、生成汚泥を１００℃で１時間加熱し、３時間静置した後の汚泥濃度の測定及び外観の観察を行った。結果を表２に示す。
【００４１】
表２より、銅の初濃度が低い場合でも、ＳＯ_４ ／Ｃｕ重量比が大きくなると脱水縮合が起きにくくなることが分かる。
【００４２】
【表２】

【００４３】
実施例１
図１に示す方法に従って、下記水質の原水の処理を行った。
【００４４】
原水水質
ｐＨ ：１．６
Ｃｕ ：５２０ｍｇ／ｌ
ＳＯ_４ ：３５００ｍｇ／ｌ
Ｚｎ ：２０ｍｇ／ｌ
Ｃｒ ：１．５ｍｇ／ｌ
即ち、まず、第１中和槽１にて、原水にＣａ（ＯＨ）_２ を２０００ｍｇ／ｌ添加してｐＨを４に調整した後、第１凝集槽２において、ポリマー（ポリアクリルアミド系高分子凝集剤「クリフロックＰＡ３６２」栗田工業（株）製）を１ｍｇ／ｌ添加し、第１沈殿槽３で固液分離した。なお、第１中和槽１には、この分離汚泥を原水／汚泥＝５／１の割合で返送した。
【００４５】
第１沈殿槽３の上澄水は、石膏の析出、分離により、そのＳＯ_４ ／Ｃｕ比が４．２となっていた。
【００４６】
次いで、第１沈殿槽３の上澄水を第２中和槽４に送り、アルカリ汚泥を添加した。このアルカリ汚泥は、返送汚泥と第１沈澱槽３の上澄水を中和するためのＣａ（ＯＨ）_２ とを混合してなるものであり、Ｃａ（ＯＨ）_２ は上澄水に対して７００ｍｇ／ｌに相当する量が混合される。第２中和槽４においては、このアルカリ汚泥を原水／汚泥＝６／１の割合で添加し、ｐＨ８．５〜９に調整した。その後、ポリマー（クリフロックＰＡ３６２）を２ｍｇ／ｌ添加し、第２沈殿槽６で固液分離し、汚泥の一部は汚泥反応槽７に返送し、残部を系外に排出した。
【００４７】
得られた汚泥濃度は２１重量％であり、この汚泥をフィルタープレスで脱水したところ、２７．７ｋｇ／ｍ^２ ・ｈｒの処理速度で含水率３８重量％の脱水ケーキを得ることができた。
【００４８】
なお、フィルタープレスの脱水条件は次のとおりとした。
【００４９】
圧力：１５ｋｇ／ｃｍ^２
濾過時間：２分
圧搾時間：１５分
比較例１
実施例１で処理した原水と同水質の原水を直接第２中和槽に導入したこと以外は実施例１と同様にして処理を行った。ただし、第２中和槽に添加するアルカリ汚泥の量を調整してｐＨを実施例１と同様に８．５〜９とした。また、ポリマー添加量は２ｍｇ／ｌとした。
【００５０】
得られた汚泥濃度は７．２重量％であり、この汚泥を実施例１と同様にフィルタープレスで脱水したところ、処理速度は５．２ｋｇ／ｍ^２ ・ｈｒであり、得られた脱水ケーキの含水率は６６重量％であった。
【００５１】
実施例２
図２に示す方法に従って、下記水質の原水の処理を行った。
【００５２】
原水水質
ｐＨ ：１．６
Ｃｕ ：５２０ｍｇ／ｌ
ＳＯ_４ ：３５００ｍｇ／ｌ
Ｚｎ ：２０ｍｇ／ｌ
Ｃｒ ：１．５ｍｇ／ｌ
即ち、まず、第１中和槽１にて、原水にＣａ（ＯＨ）_２ を２０００ｍｇ／ｌ添加してｐＨを４に調整した後、第１凝集槽２において、ポリマー（クリフロックＰＡ３６２）を１ｍｇ／ｌ添加し、第１沈殿槽３で固液分離した。なお、第１中和槽１には、この分離汚泥を原水／汚泥＝５／１の割合で返送した。
【００５３】
第１沈殿槽３の上澄水は、石膏の析出、分離により、そのＳＯ_４ ／Ｃｕ比が４．２となっていた。
【００５４】
次いで、第１沈殿槽３の上澄水を第２中和槽４に送り、Ｃａ（ＯＨ）_２ を７００ｍｇ／ｌ添加して、ｐＨを８．５〜９に調整した。次いで、ポリマー（クリフロックＰＡ３６２）を２ｍｇ／ｌ添加し、第２沈殿槽６で固液分離し、分離された汚泥を熟成槽８において、６５℃で４時間加熱処理した後、排出した。
【００５５】
得られた汚泥濃度は１６重量％であり、この汚泥を実施例１と同様にフィルタープレスで脱水したところ、２１ｋｇ／ｍ^２ ・ｈｒの処理速度で含水率４５重量％の脱水ケーキを得ることができた。
【００５６】
比較例２
実施例２で処理した原水と同水質の原水を直接第２中和槽に導入したこと以外は実施例２と同様にして処理を行った。ただし、第２中和槽に添加するアルカリ汚泥の量を調整してｐＨを実施例２と同様に８．５〜９とした。また、ポリマー添加量は２ｍｇ／ｌとした。
【００５７】
得られた汚泥濃度は５．７重量％であり、この汚泥を実施例１と同様にフィルタープレスで脱水したところ、処理速度は２．５ｋｇ／ｍ^２ ・ｈｒであり、得られた脱水ケーキの含水率は７０重量％であった。
【００５８】
【発明の効果】
以上詳述した通り、本発明の硫酸と銅とを含む排水の処理方法によれば、硫酸と銅とを含む排水を容易かつ効率的に処理して高濃度汚泥を得ることができる。従って、この高濃度汚泥を効率的に脱水して低含水率の脱水ケーキを得ることができ、この脱水ケーキから、有価金属である銅を高い回収効率で回収することが可能とされる。
【図面の簡単な説明】
【図１】本発明の硫酸と銅とを含む排水の処理方法の一実施例を示す系統図である。
【図２】本発明の硫酸と銅とを含む排水の処理方法の他の実施例を示す系統図である。
【符号の説明】
１ 第１中和槽
２ 第１凝集槽
３ 第１沈殿槽
４ 第２中和槽
５ 第２凝集槽
６ 第２沈殿槽
７ 汚泥反応槽
８ 熟成槽[0001]
[Industrial applications]
The present invention relates to a method for treating wastewater containing sulfuric acid and copper, and more particularly, to a method for separating sludge containing copper insolubilized product generated by adding alkali to wastewater containing sulfuric acid and copper and treated water. The present invention relates to a method for increasing the concentration of copper-containing sludge to be used to improve the copper collection efficiency.
[0002]
[Prior art]
Since copper is a valuable metal, sludge containing a large amount thereof is generally recovered and used as a copper raw material.
[0003]
However, sludge containing copper insolubilized material (copper hydroxide) obtained by adding an alkali to wastewater containing copper has poor concentration properties, and usually has a concentration of about 1 to 3% by weight. The water content of a dewatered cake obtained by dewatering such sludge by a filter press is usually 70 to 80% by weight, and in such a dewatered cake having a high water content, the transportation efficiency from the generation source to the recovery plant is poor. In addition, when crude copper oxide is produced from a dehydrated cake by a dry method, a large amount of energy is required for evaporating water. Therefore, in order to improve the copper recovery efficiency, it is necessary to reduce the water content of the dewatered cake as much as possible.
[0004]
As described above, the concentration of the copper-containing sludge obtained by the ordinary treatment is 1 to 3% by weight. When the concentration of the sludge is increased to about 10% by weight, a dewatered cake having a water content of about 50% by weight is obtained. Has been confirmed empirically.
[0005]
Conventionally, as a method for increasing the sludge concentration, there is the following method.
[0006]
(1) HDS method: A method in which separated sludge is returned to a wastewater neutralization step, and copper hydroxide in the sludge is reformed into a dehydrated condensate (Cu (OH) ₂ → CuO).
[0007]
{Circle around (2)} Heating method: A method in which the separated sludge is heated at 60 to 100 ° C. to convert copper hydroxide in the sludge into copper oxide.
[0008]
[Problems to be solved by the invention]
However, when treating the wastewater containing sulfuric acid and copper, even if the HDS method or the heating method is applied, it may not be possible to increase the sludge concentration.
[0009]
The present invention solves the above-mentioned conventional problems, and in a method of separating sludge containing copper insolubilized product generated by adding alkali to wastewater containing sulfuric acid and copper and treated water, the obtained copper-containing sludge It is an object of the present invention to provide a method for improving the copper collection efficiency by increasing the concentration.
[0010]
[Means for Solving the Problems]
The method for treating wastewater containing sulfuric acid and copper according to claim 1 is a method for separating sludge containing copper insolubilized product generated by adding alkali to wastewater containing sulfuric acid and copper and treated water, Is added to the wastewater as a mixture obtained by mixing with the separated sludge. First, a gypsum produced by adding a calcium compound to the wastewater to adjust the pH to 3 to 5 is separated , _{After the} weight ratio of ₄ / Cu is set to 6 or less , the mixture is added, and solid-liquid separation is performed into sludge containing copper insolubilized product and treated water.
[0011]
The method for treating wastewater containing sulfuric acid and copper according to claim 2 is a method for separating sludge containing copper insolubilized product generated by adding alkali to wastewater containing sulfuric acid and copper and treated water, Gypsum produced by adding a calcium compound to the mixture to adjust the pH to 3 to 5 and separating the SO ₄ / Cu weight ratio to 6 or less , adding an alkali, and forming a sludge containing a copper insolubilized product. It is characterized by solid-liquid separation with treated water and heat treatment of the separated sludge.
[0012]
[Action]
Generally, wastewater containing copper is often sulfuric acid acid wastewater. However, even if the HDS method or the heating method is applied to such wastewater, the sludge concentration cannot be increased. Revealed by research.
[0013]
That is, gypsum is generated when an inexpensive slaked lime is used as an alkali in treating wastewater containing sulfuric acid and copper by adding an alkali. Gypsum becomes an impurity when recovering copper, and therefore it is not desirable to mix it into the dehydrated cake. However, if gypsum is present in a certain ratio or more with respect to copper, even if the HDS method or the heating method is applied, the following will occur. Thus, it was found that the sludge concentration could not be increased.
[0014]
In the HDS method and the heating method, the reaction in which dehydration and condensation of copper hydroxide in sludge occurs is based on the following formula. A so-called ordinary hydroxide has water of crystallization, but when dehydration and condensation occurs, as in formula (1), Since the water of crystallization is separated, sludge having a high concentration property is generated.
[0015]
Cu (OH) ₂ .nH ₂ O → CuO + (n + 1) H ₂ O (1)
However, when the copper-containing wastewater containing a large amount of sulfate ions is neutralized with slaked lime, such a dehydration-condensation reaction does not occur, so that the sludge concentration does not increase. When dehydration condensation occurs, the liquid changes from bluish white of Cu (OH) ₂ to black of CuO, so that the appearance of the reaction can be easily estimated from the appearance.
[0016]
It is considered that the reason why dehydration condensation does not occur is that gypsum is mixed into copper hydroxide to hinder the dehydration condensation reaction for some reason. However, as a result of the experiment, the solubility of gypsum (CaSO ₄ : 2080 mg / l (25 C)), the following contamination is hindered depending on the copper concentration, and Ca (SO) ₄ is detected in the precipitate of copper hydroxide in a substantially equal relationship, so that Cu (OH) ₂ and CaSO ₄ are detected. It was estimated that ₄ compounds would be formed.
[0017]
Therefore, in the present invention, in treating wastewater containing sulfuric acid and copper, gypsum is first deposited and separated at pH 3 to 5 in a region where copper hydroxide is not precipitated by a calcium compound, and the weight of SO ₄ / Cu is increased. The ratio is set to 6 or less, and sulfate ions, which are factors that hinder the dehydration-condensation reaction of copper hydroxide, are removed from the system. Thereafter, by applying the HDS method or the heating method, a high-concentration sludge having a sludge concentration of 10% by weight or more is obtained.
[0018]
With such a high-concentration sludge, efficient dehydration is performed at a dehydration rate five times or more higher than the conventional sludge, and the water content is lower by about 20 to 30% by weight than the conventional sludge. A dehydrated cake can be easily obtained, and the copper recovery efficiency is greatly improved.
[0019]
【Example】
Hereinafter, a method for treating wastewater containing sulfuric acid and copper according to the present invention will be described in detail with reference to the drawings.
[0020]
1 and 2 are system diagrams showing one embodiment of the method for treating wastewater containing sulfuric acid and copper of the present invention.
[0021]
1 and 2, 1 is a first neutralization tank, 2 is a first coagulation tank, 3 is a first sedimentation tank, 4 is a second neutralization tank, 5 is a second coagulation tank, 6 is a second sedimentation tank, 7 is a sludge reaction tank, 8 is an aging tank provided with a heater 8A, and reference numerals 11 to 26 indicate pipes.
[0022]
The method shown in FIG. 1 is an embodiment method according to claim 1 of the present invention, in which raw water (effluent containing sulfuric acid and copper) is first introduced from a pipe 11 into a first neutralization tank 1. In the neutralization tank 1, slaked lime (Ca (OH) ₂ ) is added as a calcium compound from a pipe 19 and is treated under a pH condition of pH 3 to 5. Thereby, sulfuric acid precipitates as gypsum. The effluent from the first neutralization tank is then subjected to a coagulation treatment in the first coagulation tank 2 by adding a polymer (polymer coagulant) from the pipe 20. The effluent of the first flocculation tank 2 is introduced into the first sedimentation tank 3 through the pipe 12, and is separated into solid and liquid. Thereby, the sludge containing gypsum is separated.
[0023]
The separated sludge is extracted from the pipe 21. In the present embodiment, a part of the separated sludge is returned to the first neutralization tank 1 from the pipe 23. By thus circulating the sludge, the precipitation rate of gypsum can be increased. The remainder of the separated sludge is discharged out of the system through the pipe 22.
[0024]
In this gypsum precipitation treatment, calcium chloride may be used in combination with calcium chloride as a calcium compound in order to increase the Ca ion implantation efficiency. Further, hydrochloric acid may be used together with slaked lime for pH adjustment.
[0025]
The supernatant of the first sedimentation tank 3 is then introduced from a pipe 13 into a second neutralization tank 4, where the alkali in the sludge reaction tank 7 and the second sedimentation tank 6 from the second stage are separated. A mixture with the returned sludge (hereinafter sometimes referred to as “alkaline sludge”) is added from the pipe 25, and a precipitation treatment of copper and other metals is performed.
[0026]
The effluent from the second neutralization tank 4 is then subjected to a coagulation treatment in a second coagulation tank 5 by adding a polymer from a pipe 26. The effluent of the second flocculation tank 5 is introduced into the second sedimentation tank 6 from the pipe 14, and is separated into solid and liquid. Thereby, the sludge containing the copper insolubilized material is separated.
[0027]
The separated sludge is withdrawn from the pipe 16, and a part of the sludge is sent to the sludge reaction tank 7 from the pipe 18 as returned sludge and mixed with alkali (Ca (OH) _{2 in} this embodiment) injected from the pipe 24. Is done. The remainder of the sludge is discharged out of the system through the pipe 17. The supernatant water of the second sedimentation tank 6 is discharged as treated water from the pipe 15 to the outside of the system.
[0028]
The sludge obtained by the method of the present embodiment is obtained by applying the HDS method after removing sulfuric acid, which is an inhibitor of the dehydration-condensation reaction of copper hydroxide, in advance. It is a highly concentrated sludge that has progressed smoothly.
[0029]
The method shown in FIG. 2 is an embodiment method according to claim 2 of the present invention. The step of depositing and separating gypsum-containing sludge from raw water is the same as the method shown in FIG. The difference is that alkali is added to the second neutralization tank 4 without returning the separated sludge.
[0030]
That is, Ca (OH) ₂ is added from the pipe 24 in the second neutralization tank 4, and then the supernatant water is discharged out of the system through the second flocculation tank 5 and the second precipitation tank 6 as treated water.
[0031]
On the other hand, the sludge separated in the second sedimentation tank 6 is sent from the pipe 16 to the maturation tank 8, which is heated in the maturation tank 8 to dehydrate and condense the copper hydroxide in the sludge, and then discharged out of the system from the pipe 17. I do.
[0032]
The sludge obtained by the method of the present embodiment is obtained by applying a heating method after previously removing sulfuric acid, which is an inhibitor of the dehydration-condensation reaction of copper hydroxide. It is a highly concentrated sludge that has progressed smoothly.
[0033]
In the method of the present invention, in order to increase the concentration of the obtained sludge, the sulfate ions in the wastewater are previously precipitated and separated as gypsum, so that the water after the separation of the gypsum, that is, in FIG. supernatant water of 1 sedimentation tank 3 _must be disposed as sO 4 / Cu weight ratio is 6 or less. When this ratio exceeds 6, the inhibition of the dehydration-condensation reaction of copper hydroxide by sulfate ions is remarkable, and it is not possible to obtain high-concentration sludge.
[0034]
Such a method of the present invention is particularly effective for treating wastewater containing sulfuric acid and copper having a sulfate ion concentration of 2000 ppm or more.
[0035]
Hereinafter, the present invention will be described more specifically with reference to experimental examples and specific examples and comparative examples.
[0036]
Experimental example 1
Slaked lime was added to synthetic wastewater prepared by adding copper sulfate and sulfuric acid to the Cu and SO ₄ concentrations shown in Table 1 to adjust the pH to 9 to 10, and the generated sludge was purified with pure water to 3 to 10 mL. Washed 4 times. The purpose of this cleaning is to remove the remaining Ca ions and SO ₄ ions. It is presumed that some CaSO ₄ .2H ₂ O crystals were also eluted by the washing.
[0037]
The sludge after washing was heated at 60 ° C. for 3 hours, and the sludge concentration after standing for 24 hours, the CaSO ₄ concentration in the sludge were measured, and the appearance of the sludge was observed. Table 1 shows the results.
[0038]
The following is clear from Table 1. That is, No. As shown in 1, the solubility of the _{CaSO 4 (2080mg / l (25} ℃)) in the following, CaSO ₄ 17% in the sludge are also detected, CaSO ₄ and Cu _{(OH) 2} forms a double salt You can see that. On the other hand, No. of conditions that CaSO ₄ is precipitated Dehydration condensation also occurs in Nos. 2, 3, and 4, but No. 2 of SO ₄ / Cu = 7. In No. 5, dehydration condensation did not occur, and the sludge concentration was 10% by weight or less.
[0039]
[Table 1]

[0040]
Experimental example 2
Slaked lime was added to actual wastewater (copper foil production wastewater) and synthetic wastewater (copper sulfate + sulfuric acid) at the concentrations shown in Table 2 to adjust the pH to 9 to 10, the resulting sludge was heated at 100 ° C. for 1 hour, and allowed to stand for 3 hours. The subsequent measurement of the sludge concentration and observation of the appearance were performed. Table 2 shows the results.
[0041]
From Table 2, it can be seen that even when the initial copper concentration is low, the dehydration condensation hardly occurs when the SO ₄ / Cu weight ratio increases.
[0042]
[Table 2]

[0043]
Example 1
According to the method shown in FIG. 1, raw water having the following quality was treated.
[0044]
Raw water quality pH: 1.6
Cu: 520 mg / l
SO ₄ : 3500 mg / l
Zn: 20 mg / l
Cr: 1.5 mg / l
That is, first, in the first neutralization tank 1, Ca (OH) ₂ was added to raw water at 2000 mg / l to adjust the pH to 4, and then the polymer (polyacrylamide polymer aggregation) was added in the first aggregation tank 2. 1 mg / l of an agent “Cryfloc PA362” manufactured by Kurita Water Industries Ltd. was added, and solid-liquid separation was performed in the first settling tank 3. The separated sludge was returned to the first neutralization tank 1 at a ratio of raw water / sludge = 5/1.
[0045]
The supernatant water of the first settling tank 3 had a SO ₄ / Cu ratio of 4.2 due to precipitation and separation of gypsum.
[0046]
Next, the supernatant water of the first settling tank 3 was sent to the second neutralization tank 4, and alkali sludge was added. This alkaline sludge is a mixture of returned sludge and Ca (OH) ₂ for neutralizing the supernatant water of the first settling tank 3, and Ca (OH) ₂ is added to the supernatant water at a concentration of 700 mg / ml. An amount corresponding to 1 is mixed. In the second neutralization tank 4, the alkaline sludge was added at a ratio of raw water / sludge = 6/1 to adjust the pH to 8.5 to 9. Thereafter, 2 mg / l of a polymer (Cryfloc PA362) was added, and solid-liquid separation was performed in the second sedimentation tank 6, a part of the sludge was returned to the sludge reaction tank 7, and the remaining part was discharged out of the system.
[0047]
The obtained sludge concentration was 21% by weight, and when this sludge was dewatered by a filter press, a dewatered cake having a water content of 38% by weight could be obtained at a treatment speed of 27.7 kg / m ² · hr.
[0048]
In addition, the dehydration conditions of the filter press were as follows.
[0049]
Pressure: 15 kg / cm ²
Filtration time: 2 minutes Squeezing time: 15 minutes Comparative Example 1
The processing was performed in the same manner as in Example 1 except that the raw water treated in Example 1 and the raw water having the same quality were directly introduced into the second neutralization tank. However, the pH was adjusted to 8.5 to 9 as in Example 1 by adjusting the amount of alkaline sludge added to the second neutralization tank. The amount of the polymer added was 2 mg / l.
[0050]
The obtained sludge concentration was 7.2% by weight, and when this sludge was dewatered with a filter press in the same manner as in Example 1, the processing speed was 5.2 kg / m ² · hr. The water content was 66% by weight.
[0051]
Example 2
According to the method shown in FIG. 2, raw water having the following quality was treated.
[0052]
Raw water quality pH: 1.6
Cu: 520 mg / l
SO ₄ : 3500 mg / l
Zn: 20 mg / l
Cr: 1.5 mg / l
That is, first, in a first neutralization tank 1, Ca (OH) ₂ was added to raw water at 2000 mg / l to adjust the pH to 4, and then in a first flocculation tank 2, 1 mg of a polymer (Cryfloc PA362) was added. / L, followed by solid-liquid separation in the first precipitation tank 3. The separated sludge was returned to the first neutralization tank 1 at a ratio of raw water / sludge = 5/1.
[0053]
The supernatant water of the first settling tank 3 had a SO ₄ / Cu ratio of 4.2 due to precipitation and separation of gypsum.
[0054]
Next, the supernatant water of the first precipitation tank 3 was sent to the second neutralization tank 4, and 700 mg / l of Ca (OH) ₂ was added to adjust the pH to 8.5 to 9. Next, 2 mg / l of a polymer (Cryfloc PA362) was added, and solid-liquid separation was performed in the second sedimentation tank 6. The separated sludge was heated in an aging tank 8 at 65 ° C. for 4 hours, and then discharged.
[0055]
The obtained sludge concentration was 16% by weight, and when this sludge was dewatered by a filter press in the same manner as in Example 1, a dewatered cake having a water content of 45% by weight was obtained at a processing speed of 21 kg / m ² · hr. did it.
[0056]
Comparative Example 2
The treatment was carried out in the same manner as in Example 2, except that the raw water treated in Example 2 and the raw water having the same quality were directly introduced into the second neutralization tank. However, the pH was adjusted to 8.5 to 9 as in Example 2 by adjusting the amount of alkaline sludge added to the second neutralization tank. The amount of the polymer added was 2 mg / l.
[0057]
The obtained sludge concentration was 5.7% by weight, and when this sludge was dewatered with a filter press in the same manner as in Example 1, the treatment speed was 2.5 kg / m ² · hr. The water content was 70% by weight.
[0058]
【The invention's effect】
As described in detail above, according to the method for treating wastewater containing sulfuric acid and copper of the present invention, wastewater containing sulfuric acid and copper can be easily and efficiently treated to obtain high-concentration sludge. Therefore, the high-concentration sludge can be efficiently dewatered to obtain a dewatered cake having a low water content, and from this dewatered cake, copper as a valuable metal can be recovered with high recovery efficiency.
[Brief description of the drawings]
FIG. 1 is a system diagram showing one embodiment of a method for treating wastewater containing sulfuric acid and copper of the present invention.
FIG. 2 is a system diagram showing another embodiment of the method for treating wastewater containing sulfuric acid and copper of the present invention.
[Explanation of symbols]
Reference Signs List 1 First neutralization tank 2 First coagulation tank 3 First sedimentation tank 4 Second neutralization tank 5 Second coagulation tank 6 Second sedimentation tank 7 Sludge reaction tank 8 Ripening tank

Claims (2)

A method for separating sludge containing copper insolubilized product produced by adding an alkali to wastewater containing sulfuric acid and copper and treated water, wherein the alkali is mixed as a mixture obtained with the separated sludge. In the method of adding to wastewater,
First, gypsum produced by adding a calcium compound to the waste water to adjust the pH to 3 to 5 is separated , and the SO ₄ / Cu weight ratio is adjusted to 6 or less, and then the mixture is added to produce the copper insolubilized product. A method for treating wastewater containing sulfuric acid and copper, comprising performing solid-liquid separation into sludge containing water and treated water. In a method of separating into sludge and treated water containing copper insolubilized product generated by adding alkali to wastewater containing sulfuric acid and copper,
First, gypsum produced by adding a calcium compound to the waste water and adjusting the pH to 3 to 5 is separated , and the SO ₄ / Cu weight ratio is adjusted to 6 or less, and then alkali is added to produce a copper insolubilized product. A method for treating wastewater containing sulfuric acid and copper, comprising subjecting the separated sludge to solid-liquid separation into treated sludge and treated water, and subjecting the separated sludge to heat treatment.

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