JPS59116339A - Recovering method of zn from zn-containing dust - Google Patents

Abstract

PURPOSE:To recover surely high purity Zn from the extraction residue by leaching Zn-contg. dust, contg. Fe and Pb with sulfuric acid, removing the Pb-component as an insoluble residue, then extracting the Fe<3+> obtd. by oxidizing Fe<2+> with an acidic extracting agent. CONSTITUTION:Zn-contg. dust, contg. Fe and Pb (i.e.; blast furnace dust) 1 is charged into a leaching tank 2 and is subjected to a leaching treatment with an aq. sulfuric acid soln. so that the Zn component and the Fe component are dissolved as ZnSO4 and FeSO4. On the other hand, PbSO4 having low solubility is settled as an insoluble residue 4. The residue 4 is filtered away by an insoluble residue removing tank 5. The filtrate is oxidized 6 by an oxidizing agent 7, such as HNO3 to oxidize Fe<2+> to Fe<3+>. The oxidized liquid is fed to a solvent extraction stage 8, where the liquid is subjected to solvent extraction by an acidic extracting agent 9, such as D-2EHPA. An alkali liquid 13, such as NH4OH, is added to the ZnSO4 soln. (residual liquid of extraction) to neutralize the soln. and the formed Zn(OH)2 14 is recovered by a solid-liquid sepn. 15. It is also possible to recover Zn in the form of ZnO 18 by subjecting Zn(OH)2 to drying and decomposing 17 according to need.

Description

【発明の詳細な説明】 本発明は、Ｆｅおよびｐｂを含むＺｎ含有ダストからＺ
ｎ（ＯＨ）ｚｔたはＺ　ｎ　Ｏ等の形で高純度Ｚｎを回
収する方法に関する０ 高炉ダストには、２〜４係程度のＺｎ、およびＰｂ、さ
らにかなり多量のＦｅ分も含有されてい乙。そこで、ダ
ストをその゛まま投棄するのではなく、上記Ｆｅ分を高
炉のＦｅ源として再利用することか行なわれている。DETAILED DESCRIPTION OF THE INVENTION The present invention provides Zn-containing dust containing Fe and PB.
0 Regarding the method of recovering high-purity Zn in the form of n(OH)zt or ZnO, etc. Blast furnace dust contains about 2 to 4 parts of Zn and Pb, as well as a considerably large amount of Fe. . Therefore, rather than dumping the dust as it is, attempts are being made to reuse the Fe content as an Fe source for blast furnaces.

この場合、Ｚｎ分を含んだままでＦｅ源とすることは、
高炉内においていわゆるＺｎアタックの問題があるため
、予めＺｎ分を分離せねはならない。In this case, using it as an Fe source while still containing Zn means:
Since there is a problem of so-called Zn attack in the blast furnace, it is necessary to separate the Zn component in advance.

そこで、ダスト中のＺｎの除去に際して、工業的に湿式
処理方法′１．たは乾式処理方法が採用されている。湿
式処理法の代表例は、ダストにＮａＯＨ水溶液を接触さ
せてＺｎ分をＺ　ｎ　（ＯＲ）４２−とじて溶解分離除
去するものであるが、設備コストのみならずＮ　ａ　Ｏ
Ｈを使用するためランニングコストが嵩み、さらにＺｎ
除去後の残漬を高炉原料として再使用する際にＮａが残
留して支障となる。湿式処理法の他の例として、ロダン
廃液抽出法もあるが、この方法もｖ１■記処理法と設備
において、具体的にはロータリーキルンにおいてＺｎ化
合物を還元して、Ｚｎを揮発除去するものである。しか
し、この方法は設備費および熱エネルギーが嵩むし、か
つＺｎの純度が５０％程度であり、このまま他の用途に
使用することは到底できない。さらに、ｐｂの除去率が
よくない問題もある。Therefore, when removing Zn from dust, wet treatment method '1. or dry processing methods are used. A typical example of a wet treatment method is to bring dust into contact with an aqueous NaOH solution to dissolve and separate the Zn component as Zn(OR)42-, but this not only increases the equipment cost but also the NaOH aqueous solution.
Running costs increase due to the use of H, and Zn
When the residue after removal is reused as blast furnace raw material, Na remains and becomes a problem. Another example of the wet treatment method is the Rodan waste liquid extraction method, which also uses the treatment method and equipment described in v1. Specifically, the Zn compound is reduced in a rotary kiln and the Zn is removed by volatilization. . However, this method requires high equipment costs and thermal energy, and the purity of Zn is about 50%, so it cannot be used as is for other purposes. Furthermore, there is also the problem that the removal rate of PB is not good.

本発明は、前記問題のある従来法に代えて、Ｆｅおよび
ｐｂ分を確実に除去して高純度Ｚｎとして回収すること
ができるＺｎ回収方法を提供するものである。The present invention provides a Zn recovery method that can reliably remove Fe and PB and recover high-purity Zn in place of the conventional method with the aforementioned problems.

本発明の要旨は、Ｆｅおよびｐｂを含むＺｎ含有ダスト
をＨ２ＳＯ４水溶液に浸出し、不溶解残漬としてｐｂ分
を除去し、その後酸化剤により　Ｆｅ２＋をＦｅ３＋に
転化し、続いてＦｅ３＋と親和力がある酸性抽出剤によ
りＦ　ｅ３＋を酸性抽出剤（１］＋１に移行させてＦｅ
分を抽出分１唯し、抽出残液から高純度Ｚｎ化合物を回
収することを特徴とするＺｎ含有ダストからのＺｎ回収
方法、にある。The gist of the present invention is that Zn-containing dust containing Fe and PB is leached into an H2SO4 aqueous solution, the PB content is removed as an undissolved residue, and then Fe2+ is converted to Fe3+ by an oxidizing agent, and then Zn-containing dust that has an affinity for Fe3+ is extracted. Transfer Fe3+ to acidic extractant (1]+1 using acidic extractant to obtain Fe
A method for recovering Zn from Zn-containing dust, characterized in that a high-purity Zn compound is recovered from an extraction residual liquid, with only one extraction fraction.

次に本発明法を図面を参照しながらさらに詳述すると、
少くともＦｅ、ｐｔ）を含むＺｎｎ含有スス１１、たと
えば高炉ダストもしくは前述のキルンから排出さ扛たキ
ルンダストあるいは両者の混合ダストを、浸出槽２に投
入１〜、Ｈ２Ｓ　０４水溶液３で浸出操作を行う。この
浸出によって、ＺｎおよびＦｅ分は、Ｚ　ｎ　Ｓ　０４
およびＦｅ５０．＋となって溶解するが、ＰｂＳＯ４は
溶解度が低いので、不溶解残漬となって沈澱するＯ ここで、他の酸、たとえばＨＣｌ−？　Ｈ，Ｎ０３の使
用も考えられるが、Ｚｎ、Ｆｅおよびｐｂ分の全てが溶
解してしまいｐｂ分を除去することができない。Ｈ，２
ＳＯ４水溶液による浸出に当って、勿論撹拌あるいは必
要ならば加温を加えることができる。次いで、不溶解残
漬４は、不溶解残漬除去槽５において１過除去するＯ その後、浸出ｒ液に対して、酸化工程６においてＨ，Ｎ
　Ｏ３等の酸化剤７により酸化させる０この酸化に当っ
て、過酸化水素やオゾンを用いることもできるけれども
、続く溶媒抽出工程８で酸性抽出剤９としてＤ−２ＥＨ
ＰＡを使用する場合には、その劣化があるため、酸化剤
としてはＨＮＯ３が望ましｖ′１０酸化によって、Ｆｅ
２＋はＦｅ３＋に酸化されるＯこの場合、浸出Ｐ液中の
溶解Ｆｅに対して通常２当量の硝酸が添加される。Next, the method of the present invention will be explained in more detail with reference to the drawings.
Znn-containing soot 11 containing at least Fe, pt), such as blast furnace dust, kiln dust discharged from the above-mentioned kiln, or a mixture of both, is charged into a leaching tank 2 1 - and leaching operation is performed with an H2S04 aqueous solution 3 . Through this leaching, the Zn and Fe contents are reduced to Zn S 04
and Fe50. However, since PbSO4 has low solubility, it remains undissolved and precipitates. Here, other acids, such as HCl-? Although it is possible to use H and N03, all of the Zn, Fe and PB components are dissolved, making it impossible to remove the PB component. H,2
During the leaching with the SO4 aqueous solution, it is of course possible to add stirring or heating if necessary. Next, the undissolved residue 4 is removed once in an undissolved residue removal tank 5. After that, the leaching solution is subjected to an oxidation step 6 in which H, N and
Oxidized with an oxidizing agent 7 such as O3 Although hydrogen peroxide or ozone can also be used for this oxidation, D-2EH is used as the acidic extracting agent 9 in the subsequent solvent extraction step 8.
When using PA, HNO3 is preferable as the oxidizing agent because of its deterioration.
2+ is oxidized to Fe3+. In this case, 2 equivalents of nitric acid are usually added to the dissolved Fe in the leached P solution.

次に、酸化滴液は、溶媒抽出工程８において、酸性抽出
剤９たとえばＤ　−２ＥＨＰＡ　（Ｄ　−２エチルへキ
／ルフォスフォリックアシッド）により溶媒抽出を行う
。Ｄ−２ＥＨＰＡの構造式は次の通りである。Next, the oxidized droplets are subjected to solvent extraction in a solvent extraction step 8 using an acidic extractant 9 such as D-2EHPA (D-2 ethylhexyl/phosphoric acid). The structural formula of D-2EHPA is as follows.

このＤ　−２ＥＨＰＡは３価のＦｅイオンときわめて高
い親和力を示し、Ｆｅ３＋との接触により、ＯＨ基のＨ
十がＦｅ３＋と置換され、次記の化合物となるＤ−２Ｅ
ＨＰＡ ／ Ｆｅ　　−Ｄ−２ＥＨＰＡ ＼ Ｄ−２ＥＨＰＡ そして、この化合物は比重の軽い酸性抽出剤１１１１に
移行するため、Ｚｎ５Ｏｎ溶液１０とＦｅ抽出液１１と
を分離できる。Ｆｅ抽出液は、その後の処理を経て高純
度のＦｅあるいはＦｅ２Ｏ３として回収される。This D-2EHPA shows an extremely high affinity for trivalent Fe ions, and upon contact with Fe3+, the OH group
D-2E in which 10 is replaced with Fe3+, resulting in the following compound
HPA / Fe -D-2EHPA \ D-2EHPA Since this compound transfers to the acidic extractant 1111 with a light specific gravity, the Zn5On solution 10 and the Fe extract 11 can be separated. The Fe extract is recovered as highly pure Fe or Fe2O3 through subsequent processing.

一方、回収したＺｎＳＯ４溶液（抽出残液）は、Ｚｎ系
のメッキ液あるいは電解亜鉛原料等にそのまま利用する
か、これを中和工程１２に移す０中和はＮＨ４ＯＨまた
はＮａＯＨのアルカリ液１３によシ行い、生成するＺｎ
（ＯＨ）ｚ　１４は固液分離機１５によジ分離回収する
。中和液１６、すなわち（ＮＨ４）２８０４またはＮａ
２ＳＯ４は肥料あるいはガラス原料等に使用可能である
。On the other hand, the recovered ZnSO4 solution (extraction residual liquid) can be used as it is as a Zn-based plating solution or electrolytic zinc raw material, or can be transferred to the neutralization step 12. Neutralization can be carried out using an alkaline solution 13 of NH4OH or NaOH. The Zn produced by
(OH)z 14 is separated and recovered by a solid-liquid separator 15. Neutralizing solution 16, i.e. (NH4)2804 or Na
2SO4 can be used as fertilizer or raw material for glass.

回収したＺｎ（ＯＨ）ｚは、必要ならば乾燥分解工程１
７を経て、ＺｎＯ１８として回収するとともできる。The recovered Zn(OH)z is subjected to dry decomposition step 1 if necessary.
7, it can be recovered as ZnO18.

このようにして、分離回収したＺｎは後述の実施例で示
すように、きわめて高い純度を示すばかりでなく、分離
の過程でｐｂを確実に除去できる。In this way, the separated and recovered Zn not only exhibits extremely high purity, but also ensures the removal of PB during the separation process, as shown in Examples below.

なお、酸性抽出剤としては、Ｆｅ３＋の親和力のある抽
出剤であれば、Ｄ−２ＥＨＰＡに限定されるものではな
い０ 次に実施例を示す０ （実施例） 製鉄所で発生する第１表の組成（ｗｔ　％　）のＺｎ含
有ダストからＺｎ回収の実験を行った。Note that the acidic extractant is not limited to D-2EHPA as long as it has an affinity for Fe3+0 Examples are shown below0 (Example) An experiment was conducted to recover Zn from Zn-containing dust having the following composition (wt %).

上記ダス）５０．！９をＨ２ＳＯ４水溶液（３１７ｎ）
３ＱＱｃｃで常温下で浸出した。このとき、マグネチッ
クスターラーで１時間撹拌した。浸出率係は、第２表の
通りであった。Das above) 50. ! 9 in H2SO4 aqueous solution (317n)
Leaching was carried out at room temperature using 3QQcc. At this time, the mixture was stirred for 1 hour using a magnetic stirrer. The leaching rate was as shown in Table 2.

第２表 て、浸出ＦｅＫ対する２当楽の硝酸をもって硝酸酸化し
た後、５０　Ｑ　ｃｃに調整した液に、３０％濃度のＤ
　−２Ｅｆ（ＰＡを５００ｃｃ添加し、常温で１０分間
据とうしてＦｅ”十の溶媒抽出を行った。Table 2 shows that after oxidizing the leached FeK with nitric acid using 20% nitric acid, 30% concentration of D was added to the solution adjusted to 50 Q cc.
500 cc of -2Ef (PA) was added and allowed to stand at room temperature for 10 minutes to perform solvent extraction of Fe''.

またこの抽出を３回まで繰返した。そのときの１ｉ’ｅ
除去率は、第３表の通りであった。This extraction was also repeated up to three times. 1i'e at that time
The removal rate was as shown in Table 3.

３回抽出まで行うと、Ｆｅをｉｏｏ　ｓ抽出除去できる
ことが判る。続いて各抽出回数のそれぞれの抽残液水相
にアンモニア水を加え、ｐＨ−６，５を終点として中和
処理した。そして生成したＺｎ（ＯＨ）２を脱水乾燥後
、５００℃の雰囲気に３時間保持し、ＺｎＯを得た。得
られたＺ　ｎ　Ｑの純度（ｐｐｍ）を調べたところ、第
４表の通９であった。It can be seen that if the extraction is performed up to three times, Fe can be extracted and removed by IOOS. Subsequently, aqueous ammonia was added to the raffinate aqueous phase of each extraction, and neutralization was performed with pH-6.5 as the end point. After dehydrating and drying the generated Zn(OH)2, it was held in an atmosphere at 500° C. for 3 hours to obtain ZnO. The purity (ppm) of the obtained Z n Q was examined and found to be 9 in Table 4.

そして、Ｆｅ　３回抽出時のＺｎＯ純度として９９９チ
を得た。Then, a ZnO purity of 999 was obtained when Fe was extracted three times.

このように、従来法によっては得られない高純度Ｚｎを
回収できるとともに、ｐｂおよびＦｅをそれぞれ確実に
分離できることが明らかとなった○ 以上の通り、本発明によれば、ｐｂの除去率が高くなる
とともに、Ｆｅと共に、高純度Ｚｎを回収でき、かつプ
ロセスとしても経済的となる０In this way, it has become clear that high-purity Zn, which cannot be obtained by conventional methods, can be recovered and that PB and Fe can be separated reliably. As described above, according to the present invention, the removal rate of PB is high. At the same time, high-purity Zn can be recovered together with Fe, and the process is also economical.

【図面の簡単な説明】[Brief explanation of the drawing]

図面は本発明法の工程例を示す説明図である。 ｎＯ The drawings are explanatory diagrams showing an example of the process of the method of the present invention. nO

Claims (1)

【特許請求の範囲】[Claims] （１）　　ＦｅおよびＰｂを含むＺｎ含有ダストをＨ２
ＳＯ４水溶液で浸出し、不溶解残漬としてＰｂ分を除去
し、その後酸化剤によりＦｅ２＋をＦｅ３＋に転化し、
続いてＦｅ３→−と親和力がある酸性抽出剤によりＦｅ
”＋を酸性抽出剤側に移行させてＦｅ分を抽出分離し、
抽出残液から高純度Ｚｎ化合物を回収することを特徴と
するＺｎ含有ダストからのＺｎ回収方法。(1) Zn-containing dust containing Fe and Pb was heated to H2
Leaching with SO4 aqueous solution to remove Pb as undissolved residue, then converting Fe2+ to Fe3+ with an oxidizing agent,
Next, Fe is removed using an acidic extractant that has an affinity for Fe3→-
"+" is transferred to the acidic extractant side to extract and separate the Fe component,
A method for recovering Zn from Zn-containing dust, which comprises recovering a high-purity Zn compound from an extraction residue.