JPH0369515A - Method for recovering high-purity iron sulfate from waste sulfuric acid pickling solution for stainless steel - Google Patents
Method for recovering high-purity iron sulfate from waste sulfuric acid pickling solution for stainless steelInfo
- Publication number
- JPH0369515A JPH0369515A JP20477689A JP20477689A JPH0369515A JP H0369515 A JPH0369515 A JP H0369515A JP 20477689 A JP20477689 A JP 20477689A JP 20477689 A JP20477689 A JP 20477689A JP H0369515 A JPH0369515 A JP H0369515A
- Authority
- JP
- Japan
- Prior art keywords
- sulfuric acid
- soln
- stainless steel
- concentration
- iron
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 title claims abstract description 77
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 title claims abstract description 12
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 12
- 239000010935 stainless steel Substances 0.000 title claims abstract description 12
- 229910000358 iron sulfate Inorganic materials 0.000 title claims abstract description 9
- 239000002699 waste material Substances 0.000 title claims description 21
- 238000005554 pickling Methods 0.000 title claims description 19
- 238000000034 method Methods 0.000 title claims description 18
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 37
- 229910052742 iron Inorganic materials 0.000 claims abstract description 17
- 239000000706 filtrate Substances 0.000 claims abstract description 7
- 238000001816 cooling Methods 0.000 claims abstract description 6
- 238000009792 diffusion process Methods 0.000 claims abstract description 5
- 239000012452 mother liquor Substances 0.000 claims abstract description 5
- 238000010438 heat treatment Methods 0.000 claims abstract 2
- 239000007788 liquid Substances 0.000 claims description 21
- 239000013078 crystal Substances 0.000 claims description 9
- 238000000502 dialysis Methods 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 238000001914 filtration Methods 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 2
- 239000012535 impurity Substances 0.000 claims 1
- 230000001737 promoting effect Effects 0.000 claims 1
- 229910000859 α-Fe Inorganic materials 0.000 abstract description 4
- 229910000359 iron(II) sulfate Inorganic materials 0.000 abstract description 3
- 239000000049 pigment Substances 0.000 abstract description 3
- 150000002500 ions Chemical class 0.000 abstract description 2
- SURQXAFEQWPFPV-UHFFFAOYSA-L iron(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+2].[O-]S([O-])(=O)=O SURQXAFEQWPFPV-UHFFFAOYSA-L 0.000 abstract 1
- 230000029219 regulation of pH Effects 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 15
- 239000002253 acid Substances 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 5
- 239000002244 precipitate Substances 0.000 description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 3
- 238000006722 reduction reaction Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 235000014413 iron hydroxide Nutrition 0.000 description 2
- XBDUTCVQJHJTQZ-UHFFFAOYSA-L iron(2+) sulfate monohydrate Chemical compound O.[Fe+2].[O-]S([O-])(=O)=O XBDUTCVQJHJTQZ-UHFFFAOYSA-L 0.000 description 2
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 235000011149 sulphuric acid Nutrition 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910017060 Fe Cr Inorganic materials 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 101100324822 Neurospora crassa (strain ATCC 24698 / 74-OR23-1A / CBS 708.71 / DSM 1257 / FGSC 987) fes-4 gene Proteins 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 239000011550 stock solution Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/36—Regeneration of waste pickling liquors
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
Description
本発明は、ステンレス鋼の硫酸酸洗廃液から低Ｃｒの高
純度硫酸鉄を回収する方法に関するものである。The present invention relates to a method for recovering low-Cr, high-purity iron sulfate from a waste solution from sulfuric acid pickling of stainless steel.
現在、ステンレス鋼の表面処理法として硫酸による酸洗
処理が行われている。酸洗により鋼材中のＦｅ、Ｃｒが
Ｈ２ＳＯ，に溶解し、これらの濃度が高くなると酸洗速
度が著しく低下するため、系外に排出し新酸と入れ替え
ねばならない。従って、比較的Ｈｚ Ｓ○４濃度の高い
廃硫酸液が大量に排出されている。
一方、普通鋼の場合の硫酸酸洗廃液は減圧濃縮により水
分を華発せしめ、ｒ ｒ ｅ ｅ−Ｈ２ＳＯ４濃度を４
５〜６０％に高めることにより溶存しているＦｅ５Ｏａ
を硫酸鉄−水塩として析出せしめた上、これをＨ２ＳＯ
４液と分離し、Ｈ２Ｓ○４液は酸洗槽に戻して再使用す
る方法が行われている。また分離された硫酸鉄−水塩中
にはＣｒその他の重金属が殆ど含まれていないので、顔
料やフェライト用等の原料として利用されている。（特
公昭５０−２８７９号公報参照）
また別法として、廃硫酸をそのまま、或いは予Ｖａ縮若
しくは濃硫酸を添加する等の手段によりＨ２ＳＯ，濃度
を調整した上、これを２０℃以下に冷却することにより
ＦｅＳＯ４・７ｌ−Ｉ２０を析出せしめた後これを分離
し、その分離液は水を添加してＨ２Ｓ Ｏａ濃度を調整
した上、回収酸として繰り返し酸洗に利用されている。
（特公昭４７−４０６２９号公報参照）Currently, pickling treatment with sulfuric acid is used as a surface treatment method for stainless steel. Pickling dissolves Fe and Cr in the steel into H2SO, and as their concentrations increase, the pickling speed drops significantly, so they must be discharged from the system and replaced with fresh acid. Therefore, a large amount of waste sulfuric acid solution with a relatively high concentration of Hz S*4 is discharged. On the other hand, in the case of ordinary steel, the waste liquid from sulfuric acid pickling is concentrated under reduced pressure to exude moisture, and the concentration of r.e.e.H2SO4 is reduced to 4.
Dissolved Fe5Oa by increasing to 5-60%
was precipitated as iron sulfate-hydrate salt, and this was heated with H2SO
A method is used in which the H2S○4 liquid is separated from the H2S4 liquid and returned to the pickling tank for reuse. Furthermore, since the separated iron sulfate hydrate contains almost no Cr or other heavy metals, it is used as a raw material for pigments, ferrite, etc. (Refer to Japanese Patent Publication No. 50-2879) Alternatively, the waste sulfuric acid may be used as it is, or the concentration of H2SO may be adjusted by means such as pre-condensation with Va, or addition of concentrated sulfuric acid, and then cooled to below 20°C. After FeSO4.7l-I20 is precipitated by this method, it is separated, and the separated liquid is added with water to adjust the H2SOa concentration, and then used as recovered acid for repeated pickling. (Refer to Special Publication No. 47-40629)
しかるに、ステンレス鋼の硫酸酸洗廃液中にはＦｅの外
にＣｒが多量に含まれており、これを前記方法にて処理
する場合は、濃縮法、冷却法の何れの場合においても硫
酸鉄が析出する。この中に含まれるＣｒ量は当初は微量
であるが、時間の経過とともに缶内母液中のＣｒ濃度が
上昇し、これにつれて結晶中に含まれるＣｒ濃度が増大
するばかりでなく、母液を酸洗槽に再利用する場合は酸
洗速度が低下する等の問題があるので、回収酸として再
利用出来ないため回収装置を設置する例は見当たらない
。従って、石灰中和によって処理する方法が行われてい
るが、生成する水酸化鉄中にＣｒの水酸化物が混入し公
害上からそのままでは廃棄できないため、セメントによ
る固化等不溶性化したり、中和時に空気酸化してフェラ
イト化し無害化した上で廃棄する方法が現在行われてい
る。
そこで、特開昭６３−２９５４４２号公報に記載されて
いるように、高純度酸化鉄又は水酸化鉄を製造する際の
鉄塩水溶液の効率的精製法として、廃酸に鉄や塩基を添
加しＰＨ３〜７に調整し生成する水酸化物を自然沈降、
濾過、又は遠心分離等により分離除去する方法が提案さ
れている。
この方法の場合、Ｃｒとして１１００ｐｐ以下を含有す
る廃硫酸を鉄や塩基を用いて中和しＰＨを５．０以上と
し、Ｃｒを水酸化物として分離除去した場合濾液中のＣ
ｒ濃度はｉｏｐｐｍに低下する。
ただし、廃硫酸中のＣｒ濃度が数百ｐｐｍ以上ではＰ
Ｈを５．０以上に中和しても残留Ｃｒは８ｏｐｐｍ以上
となる。ＰＨを６．０以上としても２０ｐｐｍ以上のＣ
ｒが残留する。
しかしながら、ステンレス鋼を硫酸にて酸洗する際に排
出される廃硫酸中のＣｒは４０００ｐ ｐ ｍ以上と格
段に高いため、塩基による中和、或いは鉄屑及び塩基併
用による中和では脱Ｃｒが有効的且つ充分には行われな
いという問題がある。
本発明はこの問題を解決するためなされたものである。However, the waste solution from sulfuric acid pickling of stainless steel contains a large amount of Cr in addition to Fe, and when this is treated by the above method, iron sulfate is removed in both the concentration method and cooling method. Precipitate. Initially, the amount of Cr contained in this is very small, but as time passes, the Cr concentration in the mother liquor inside the can increases, and as a result, not only does the Cr concentration in the crystals increase, but the mother liquor is pickled. If it is reused in a tank, there are problems such as a decrease in the pickling speed, so it cannot be reused as recovered acid, so there are no examples of installing a recovery device. Therefore, a method of treatment by lime neutralization is used, but since Cr hydroxide is mixed in the iron hydroxide produced and cannot be disposed of as it is due to pollution, it may be hardened with cement or otherwise made insoluble, or neutralized. The current method is to oxidize it in the air to turn it into ferrite, render it harmless, and then dispose of it. Therefore, as described in JP-A No. 63-295442, as an efficient method for purifying an aqueous iron salt solution when producing high-purity iron oxide or iron hydroxide, iron or a base is added to waste acid. Adjust the pH to 3-7 and let the generated hydroxide settle naturally.
A method of separating and removing it by filtration, centrifugation, etc. has been proposed. In the case of this method, waste sulfuric acid containing 1100 pp or less as Cr is neutralized using iron or a base to raise the pH to 5.0 or higher, and when Cr is separated and removed as hydroxide, the carbon in the filtrate is
The r concentration drops to ioppm. However, if the Cr concentration in the waste sulfuric acid is several hundred ppm or more, P
Even if H is neutralized to 5.0 or higher, residual Cr remains at 8 oppm or higher. C of 20 ppm or more even if the pH is 6.0 or more
r remains. However, since the Cr content in the waste sulfuric acid discharged when pickling stainless steel with sulfuric acid is extremely high at over 4000 ppm, it is not possible to remove Cr by neutralizing with a base or a combination of iron scraps and a base. The problem is that it is not carried out effectively and satisfactorily. The present invention has been made to solve this problem.
本発明においては、まずＣｒ濃度の高い廃硫酸を拡散透
析装置にて処理し、遊離硫酸の大部分を除去することに
より残留硫酸濃度数％以下の脱酸液を得る。この脱酸液
に金属鉄又はミルスケールを投入し、これを５０〜１０
０℃に加熱し、撹拌、混合、振盪等の機械的手段により
固液間の接触作用を強力に行い、置換還元反応を行わし
めＣｒを金属物として析出させる。これを濾過又は遠心
分離等によって分離除去した後、硫酸を添加しＰ Ｈを
２以下に調整し、この調整脱Ｃｒ液をそのまま或いは濃
縮によりＦｅＳ○４濃度を例えば２０％以上にした後、
２０’Ｃ以下に冷却し硫酸鉄結晶を析出せしめ、これを
母液と分離することによって、低Ｃｒ高純度ＦｅＳ○４
・７Ｈ２Ｓ○４をステンレス鋼の硫酸酸洗廃液より回収
するものである。In the present invention, waste sulfuric acid with a high Cr concentration is first treated with a diffusion dialysis device to remove most of the free sulfuric acid, thereby obtaining a deoxidized solution with a residual sulfuric acid concentration of several percent or less. Add metallic iron or mill scale to this deoxidizing solution, and add 50 to 10
The mixture is heated to 0° C., and strong solid-liquid contact action is performed by mechanical means such as stirring, mixing, and shaking to cause a substitution-reduction reaction and precipitate Cr as a metal substance. After separating and removing this by filtration or centrifugation, sulfuric acid is added to adjust the pH to 2 or less, and the adjusted Cr-removal solution is used as it is or after concentration is made to have a FeS4 concentration of, for example, 20% or more,
By cooling to below 20'C to precipitate iron sulfate crystals and separating them from the mother liquor, low Cr high purity FeS○4 is produced.
・7H2S○4 is recovered from the waste solution of sulfuric acid pickling of stainless steel.
【作用】
以下に本発明の各工程における作用について詳述する。
廃硫酸を拡散透析装置にかけることにより廃硫酸中のｆ
ｒｅｅ−ＨｚＳ○４の大部分を分離除去し、透析廃液側
にＦｅ、Ｃｒ等のそのまま取り残されたｆ ｒ ｅ ｅ
−Ｈ２ＳＯ４濃度の低い脱酸液を得ることができる。次
いで、これに金属鉄又はミルスケールを添加し、液温を
５０〜１００℃に加温して撹拌、混合、振盪等の機械的
手段により固液の間の接触作用を促進させ、Ｃｒイオン
を添加した金属鉄又はミルスケールと置換、還元し金属
物として析出沈澱させて脱Ｃｒを有効に行うものである
。この場合、添加する金属鉄又はごルスケールは充分過
剰にしておくことが好ましい。
主な反応機構は
（］）Ｆｅの溶解によるＰ Ｉ（の上昇２Ｈ’＋Ｆｅ→
Ｆｅ”＋Ｈ２↑
（２）ＦｅによるＣｒ３＋の還元
Ｃｒ”＋Ｆ ｅ →Ｆ ｅ”＋Ｃｒ
が考えられる。
（２）の反応は酸濃度に関係なくＰＨの低い時にも起こ
るが、硫酸濃度が高いと析出したＣｒの再溶解が起こる
ので、（１）の反応が進行してＰＨが上がってからでな
いと実質的に進行しない。従って、第一工程に於ける脱
酸率はＰ Ｈ値で１〜２に近づけることが望ましいが、
脱酸率を上げることは透析装置の膜面積の増加を必要と
し、設備費の上昇につながるので、ＰＨ１以下でもよい
。
脱酸液中のＣｒは金属鉄又はミルスケールによる置換還
元反応より殆ど全部が析出するが、Ｃｒ濃度は上記の反
応機構よりして、単にＰ Ｈだのでは決定できないが、
Ｐ Ｈの下限は一応４を目安とする。
脱Ｃｒされた処理液中には金属鉄又はミルスケール及び
Ｃｒ等の沈澱物が含まれているので、これらを濾別した
後、その濾液にＨｚ Ｓ Ｏａを添加してＰ Ｈを２以
下に調整する。これは処理液をそのまま放置すると、溶
存中のＦｅ”が酸化されてＦｅ３゛となりＦｅ（ＯＨＬ
＋の沈澱が析出され易いので、これを防止するためであ
る。Ｐ Ｈ調整液は、これをそのまま１０℃以下に冷却
するか、或いは濃縮してＦｅＳＯ４２０％以上、好まし
くは３０％以上とした上で２０℃以下に冷却することに
より、高純度硫酸鉄結晶を析出回収し得られるが、結晶
の析出量を多くしたい場合には１０’Ｃ以下に冷却する
とよい。
一方、回収液側には廃硫酸中のｆｒｅｅ−Ｈ２ＳＯ４の
大部分が移行しているが、Ｆｅ、Ｃｒ等はわずか（原液
中濃度の３〜４％）しか含まれていないので、これに補
給硫酸を添加し濃度調整することにより酸洗に再利用し
得るメリットがある。
また第三工程における残留Ｃｒ濃度はＰ Ｈ４の場合２
０ｐｐｍ、ＰＨ５の場合ｌｐｐｍとなり、残留ＣｒＱ度
２０ｐｐｍの脱Ｃｒ溶ｌ夜から晶析分離したＦ ｅ Ｓ
０４ ・７ ＨｚＯ中のＣｒ含有量はｌｐｐｍ以下、
また残留Ｃｒ濃度ｌｐｐｍの脱Ｃｒ液から晶析分離した
ＦｅＳＯ４・７Ｈ２０中のＣｒ含有量は０、ｌｐｐｍ以
下になる。[Function] The function of each step of the present invention will be explained in detail below. f in waste sulfuric acid by applying it to a diffusion dialysis device
Most of the ree-HzS○4 is separated and removed, and Fe, Cr, etc. are left as they are on the dialysis waste liquid side.
- A deoxidizing solution with a low concentration of H2SO4 can be obtained. Next, metal iron or mill scale is added to this, the liquid temperature is raised to 50 to 100°C, and the contact action between the solid and liquid is promoted by mechanical means such as stirring, mixing, and shaking to remove Cr ions. It effectively removes Cr by substituting and reducing the added metal iron or mill scale to precipitate it as a metal substance. In this case, it is preferable that the amount of metallic iron or scale to be added be sufficiently excessive. The main reaction mechanism is (]) Increase in P I (2H'+Fe→
Fe"+H2↑ (2) Reduction of Cr3+ by Fe Cr"+F e →F e"+Cr is considered. The reaction (2) occurs even when the pH is low regardless of the acid concentration, but it precipitates when the sulfuric acid concentration is high. Since Cr is redissolved, it will not proceed substantially until the reaction (1) has progressed and the pH has increased.Therefore, the deoxidation rate in the first step is 1 to 2 in terms of pH value. It is desirable to get close to
Increasing the deoxidation rate requires an increase in the membrane area of the dialysis device, leading to an increase in equipment costs, so the pH may be lower than 1. Almost all of the Cr in the deoxidizing solution is precipitated by the substitution-reduction reaction with metallic iron or mill scale, but the Cr concentration cannot be determined simply from P H based on the reaction mechanism described above.
As a guideline, the lower limit of PH should be 4. Since the Cr-removed treatment liquid contains precipitates such as metallic iron or mill scale and Cr, after these are filtered out, Hz SOa is added to the filtrate to reduce the P H to 2 or less. adjust. This is because if the treatment solution is left as it is, the dissolved Fe'' will be oxidized and become Fe3゜Fe(OHL).
This is to prevent + precipitates from being easily deposited. The PH adjustment solution can be cooled as it is to below 10°C, or concentrated to have FeSO4 of 20% or more, preferably 30% or more, and then cooled to below 20°C to precipitate high-purity iron sulfate crystals. Although it can be recovered, if it is desired to increase the amount of crystals precipitated, it is preferable to cool it to 10'C or less. On the other hand, most of the free-H2SO4 in the waste sulfuric acid has migrated to the recovered liquid side, but since it contains only a small amount of Fe, Cr, etc. (3-4% of the concentration in the stock solution), this is replenished. There is an advantage that it can be reused for pickling by adding sulfuric acid and adjusting the concentration. In addition, the residual Cr concentration in the third step is 2 in the case of PH4.
0 ppm, 1 ppm in the case of pH 5, and the Fe S crystallized from the Cr removal solution with a residual CrQ level of 20 ppm.
04 ・7 Cr content in HzO is less than lppm,
Further, the Cr content in FeSO4.7H20 crystallized and separated from the Cr-removed liquid with a residual Cr concentration of 1 ppm is 0.1 ppm or less.
以下、本発明の実施例について述べる。
液組成： ｆ ｒ ｅ ｅ−Ｈ□Ｓ○ａ９１ｇ／ｌ、Ｆ
ｅ９０ｇ／ｌ、Ｃｒ ６ ｇ／／２の廃硫酸２６０ ｆ
ｆ ／ ｈを拡散透析装置（徳山ソーダ株式会社製、Ｔ
ＳＤ−５０−５５０型）に通液する。一方、これに見合
う量の水２６０ ｆ ／ ｈを通水することにより液組
成：ｆ ｒ ｅ ｅ−Ｈ２Ｓ○ａ ２２．４ｇ／ ＣＦ
ｅ７０ｇ／ ｎＣｒ４．７ｇ／ｅの脱酸液３２４ ｆ
ｆｉ ／ ｈが得られた。
同時に液ｍ威： ｆ ｒｅｅ−Ｈ２Ｓ○ａ ８３．２
ｇ ／ Ｅ 。
Ｆ ｅ ３．５ｇ／ Ｌ Ｃｒ ０．２ｇ／ ｆｌの
回収酸２００℃を得た。脱酸液には金属鉄１３０ｋｇを
加え、液温を８５℃に加熱しながらポンプ循環する。５
時間後ＰＨが４にて反応を中止した後、直ちにフィルタ
ープレスにて加圧濾過し３１６ｋｇの濾液が得られた。
第１鉄の酸化防止のためＣ０ｎＣ−Ｈ２Ｏ４５ｋｇを添
加した。濾液中の残留Ｃｒは２ｏｐｐｍであった。
次いでこの液を２等分し、その内の一部１５８ｋｇを０
℃まで冷却した後、析出した結晶を遠心分離し２３ｋｇ
のＦｅＳＯ４・７ Ｈ２Ｏを回収した。結晶中のＣｒ含
有量は０．９ＰＰｍであった。
前記濾液の残部１５８ｋｇをＦｅＳＯ４濃度３０％まで
濃縮した上、これを２０℃まで冷却した後、析出した結
晶を遠心分離し３１．ｋｇのＦｅＳＯ４・７Ｈ，０を回
収した。結晶中のＣｒ含有量は１．５ｐｐｍであった。
一方、回収酸には、Ｃｏｎｃ−Ｈ２Ｏ４５ｋｇ及びＨ２
Ｏ４５ｋｇを力Ｕえることにより、液組成：Ｈ２ＳＯ，
２４％、ＦｅＯ，２％、Ｃｒ０．０１％の調整硫酸液３
１５ｋｇが得られ、これを再び酸洗用に循環使用した。
実施例で判るように、本発明の方法によれば、ステンレ
ス鋼硫酸酸洗廃液中に６０００ｐ ｐ ｍ含まれていた
Ｃｒが、ＰＨ＝４の脱Ｃｒ液では２０ｐｐｍにまで低下
し、その脱Ｃｒ率は９９．７％である。
ちなみに、前記特開昭６３−２９５４４２号公報に開示
されている方法と比較すると、同公報における実施例４
では、ＰＨ＝４．２の場合、脱Ｃｒ率は４２．３％、Ｐ
Ｈ＝６．２の場合であっても、 脱Ｃｒ率は９４．３
％であり、本願発明の方法によれば極めて有効に脱Ｃｒ
されることが判る。Examples of the present invention will be described below. Liquid composition: fre e-H□S○a91g/l, F
e90g/l, Cr 6 g//2 waste sulfuric acid 260f
f/h using a diffusion dialysis device (manufactured by Tokuyama Soda Co., Ltd., T
SD-50-550 model). On the other hand, by passing a corresponding amount of water at 260 f/h, the liquid composition: fre e-H2S○a 22.4 g/CF
e70g/nCr4.7g/e deoxidizer 324f
fi/h was obtained. At the same time liquid m power: f ree-H2S○a 83.2
g/E. A recovered acid containing 3.5 g/L Fe and 0.2 g/fl Cr was obtained at 200°C. 130 kg of metal iron is added to the deoxidizing liquid, and the liquid is circulated through a pump while being heated to 85°C. 5
After a period of time, the reaction was stopped at pH 4, and immediately filtered under pressure using a filter press to obtain 316 kg of filtrate. 45 kg of C0nC-H2O was added to prevent oxidation of ferrous iron. The residual Cr in the filtrate was 2 oppm. Next, this liquid was divided into two equal parts, and part of it, weighing 158 kg, was
After cooling to ℃, the precipitated crystals were centrifuged and weighed 23 kg.
of FeSO4.7 H2O was recovered. The Cr content in the crystal was 0.9 PPm. After concentrating the remaining 158 kg of the filtrate to a FeSO4 concentration of 30% and cooling it to 20°C, the precipitated crystals were centrifuged. 31. kg of FeSO4.7H,0 was recovered. The Cr content in the crystal was 1.5 ppm. On the other hand, the recovered acid contains 45 kg of Conc-H2O and H2
By applying 45 kg of O, the liquid composition: H2SO,
Adjusted sulfuric acid solution 24%, FeO, 2%, Cr0.01% 3
15 kg was obtained, which was recycled again for pickling. As can be seen from the examples, according to the method of the present invention, 6000 ppm of Cr contained in the stainless steel sulfuric acid pickling waste solution was reduced to 20 ppm in the Cr removal solution at pH=4. The rate is 99.7%. By the way, when compared with the method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 63-295442, Example 4 in the same publication
Then, when PH=4.2, the Cr removal rate is 42.3%, P
Even when H=6.2, the Cr removal rate is 94.3
%, and according to the method of the present invention, Cr can be removed extremely effectively.
It turns out that it will be done.
本発明の方法によれば次のような効果がある。
（１）従来、石灰中和法により処理され廃棄処分されて
いたステンレス鋼の硫酸酸洗廃液よりフェライト用、顔
料用として有用でありメリットの高＜Ｃｒ含有量の低い
高純度硫酸鉄が得られる。
（２）新酸とほぼ同純度の硫酸が回収され酸洗工程にて
再利用することができ、資源の有効利用上、また公害防
止上、極めて有用である。
（３）従来技術に較べ、非常に高い脱Ｃｒ率が得られる
。The method of the present invention has the following effects. (1) High-purity iron sulfate with high merits and low Cr content, which is useful for ferrite and pigments, can be obtained from stainless steel sulfuric acid pickling waste, which was conventionally treated by lime neutralization and disposed of. . (2) Sulfuric acid with approximately the same purity as the new acid can be recovered and reused in the pickling process, which is extremely useful for effective use of resources and prevention of pollution. (3) Compared to the conventional technology, a very high Cr removal rate can be obtained.
Claims (2)
ｒ濃度の高い廃硫酸を、拡散透析装置にて処理し、ｆｒ
ｅｅ−Ｈ＿２ＳＯ＿４を除去すると共に、脱酸液を得る
第一工程と、 該脱酸液に金属鉄又はミルスケールを投入し、これを５
０〜１００℃に加熱し更に機械的手段により固液間の接
触作用を促進せしめることにより、Ｃｒを析出させる第
二工程と、 第二工程にて処理した液を濾過して析出したＣｒの不純
物を除去した後濾液に硫酸を添加してＰＨを２以下に調
整する第三工程と、 第三工程にて得たＰＨ調整脱Ｃｒ液を冷却し硫酸鉄結晶
を析出せしめこれを母液と分離する第四工程とからなる
、ステンレス鋼の硫酸酸洗廃液より高純度硫酸鉄を回収
する方法。1. C emitted when stainless steel is pickled with sulfuric acid
Waste sulfuric acid with a high r concentration is treated with a diffusion dialysis device, and fr
A first step of removing ee-H_2SO_4 and obtaining a deoxidizing solution; adding metal iron or mill scale to the deoxidizing solution;
A second step in which Cr is precipitated by heating to 0 to 100°C and further promoting contact between solid and liquid by mechanical means; and Cr impurities precipitated by filtering the liquid treated in the second step. A third step of adding sulfuric acid to the filtrate to adjust the pH to 2 or less after removing the A method for recovering high-purity iron sulfate from a waste solution from sulfuric acid pickling of stainless steel, which comprises a fourth step.
ＳＯ＿４濃度を２０％以上にした後、これを冷却し硫酸
鉄結晶を析出せしめ、これを母液と分離する第四工程と
からなる、請求項１記載のステンレス鋼の硫酸酸洗廃液
より高純度硫酸鉄を回収する方法。2. The pH-adjusted deCr solution after the third step is concentrated and Fe
High purity sulfuric acid from the sulfuric acid pickling waste liquid of stainless steel according to claim 1, comprising a fourth step of increasing the SO_4 concentration to 20% or more, cooling it to precipitate iron sulfate crystals, and separating this from the mother liquor. How to recover iron.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20477689A JPH085676B2 (en) | 1989-08-09 | 1989-08-09 | A method of recovering high-purity iron sulfate from the sulfuric acid pickling waste liquid of stainless steel |
| AU14754/92A AU636532B2 (en) | 1989-08-09 | 1992-04-09 | Remote monitoring system for containers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20477689A JPH085676B2 (en) | 1989-08-09 | 1989-08-09 | A method of recovering high-purity iron sulfate from the sulfuric acid pickling waste liquid of stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0369515A true JPH0369515A (en) | 1991-03-25 |
| JPH085676B2 JPH085676B2 (en) | 1996-01-24 |
Family
ID=16496161
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20477689A Expired - Lifetime JPH085676B2 (en) | 1989-08-09 | 1989-08-09 | A method of recovering high-purity iron sulfate from the sulfuric acid pickling waste liquid of stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH085676B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102653437A (en) * | 2011-09-20 | 2012-09-05 | 卢玉柱 | Method for treating yellow sludge obtained in neutralization of steel pickling waste water lime |
| CN104961214A (en) * | 2015-06-26 | 2015-10-07 | 开平市开物化工建材有限公司 | Preparing device for polymeric aluminum ferric sulfate |
| CN104961216A (en) * | 2015-06-26 | 2015-10-07 | 开平市开物化工建材有限公司 | Solidified polymeric aluminum ferric sulfate preparation device based on low-pressure boiling |
| CN113003545A (en) * | 2021-02-23 | 2021-06-22 | 佛山市景嘉机电设备有限公司 | Method for recycling and treating iron-containing mixed acid waste liquid in steel industry |
| CN113755852A (en) * | 2021-09-13 | 2021-12-07 | 浙江金洲管道科技股份有限公司 | Treatment system and method for reducing acid consumption and reducing emission of red mud in steel acid pickling and rust removing process |
-
1989
- 1989-08-09 JP JP20477689A patent/JPH085676B2/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102653437A (en) * | 2011-09-20 | 2012-09-05 | 卢玉柱 | Method for treating yellow sludge obtained in neutralization of steel pickling waste water lime |
| CN104961214A (en) * | 2015-06-26 | 2015-10-07 | 开平市开物化工建材有限公司 | Preparing device for polymeric aluminum ferric sulfate |
| CN104961216A (en) * | 2015-06-26 | 2015-10-07 | 开平市开物化工建材有限公司 | Solidified polymeric aluminum ferric sulfate preparation device based on low-pressure boiling |
| CN113003545A (en) * | 2021-02-23 | 2021-06-22 | 佛山市景嘉机电设备有限公司 | Method for recycling and treating iron-containing mixed acid waste liquid in steel industry |
| CN113755852A (en) * | 2021-09-13 | 2021-12-07 | 浙江金洲管道科技股份有限公司 | Treatment system and method for reducing acid consumption and reducing emission of red mud in steel acid pickling and rust removing process |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH085676B2 (en) | 1996-01-24 |
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