JP2019181349A - Sulfurizing agent removal method, and wet-type method of refining nickel oxide ore - Google Patents
Sulfurizing agent removal method, and wet-type method of refining nickel oxide ore Download PDFInfo
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- 239000003795 chemical substances by application Substances 0.000 title claims abstract description 146
- 238000000034 method Methods 0.000 title claims abstract description 94
- 229910000480 nickel oxide Inorganic materials 0.000 title claims abstract description 40
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 title claims abstract description 40
- 238000007670 refining Methods 0.000 title abstract 3
- 238000002386 leaching Methods 0.000 claims abstract description 221
- 239000002002 slurry Substances 0.000 claims abstract description 129
- 239000007788 liquid Substances 0.000 claims abstract description 116
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 108
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 98
- 238000005987 sulfurization reaction Methods 0.000 claims abstract description 74
- 238000000926 separation method Methods 0.000 claims abstract description 67
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 52
- WWNBZGLDODTKEM-UHFFFAOYSA-N sulfanylidenenickel Chemical compound [Ni]=S WWNBZGLDODTKEM-UHFFFAOYSA-N 0.000 claims abstract description 24
- 230000003472 neutralizing effect Effects 0.000 claims abstract description 23
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 claims abstract description 21
- 239000002253 acid Substances 0.000 claims abstract description 20
- 235000014413 iron hydroxide Nutrition 0.000 claims abstract description 19
- 239000000243 solution Substances 0.000 claims description 120
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 72
- 238000006386 neutralization reaction Methods 0.000 claims description 70
- MSNWSDPPULHLDL-UHFFFAOYSA-K ferric hydroxide Chemical compound [OH-].[OH-].[OH-].[Fe+3] MSNWSDPPULHLDL-UHFFFAOYSA-K 0.000 claims description 65
- 238000005486 sulfidation Methods 0.000 claims description 43
- 238000004065 wastewater treatment Methods 0.000 claims description 42
- 229910052742 iron Inorganic materials 0.000 claims description 23
- 238000009854 hydrometallurgy Methods 0.000 claims description 21
- 239000012535 impurity Substances 0.000 claims description 17
- 238000005273 aeration Methods 0.000 claims description 15
- 229920002472 Starch Polymers 0.000 claims description 13
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 13
- 239000008107 starch Substances 0.000 claims description 13
- 235000019698 starch Nutrition 0.000 claims description 13
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 11
- 229910052782 aluminium Inorganic materials 0.000 claims description 11
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 11
- 239000011777 magnesium Substances 0.000 claims description 11
- 229910052749 magnesium Inorganic materials 0.000 claims description 11
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims description 9
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 3
- 239000003929 acidic solution Substances 0.000 claims description 3
- 229910052804 chromium Inorganic materials 0.000 claims description 3
- 239000011651 chromium Substances 0.000 claims description 3
- 229910001453 nickel ion Inorganic materials 0.000 claims description 3
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 abstract description 75
- 229910000037 hydrogen sulfide Inorganic materials 0.000 abstract description 75
- 230000008569 process Effects 0.000 abstract description 45
- 239000007787 solid Substances 0.000 abstract description 8
- 230000000694 effects Effects 0.000 abstract description 3
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 24
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 18
- 238000006243 chemical reaction Methods 0.000 description 15
- -1 iron ion Chemical class 0.000 description 15
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 13
- 239000000920 calcium hydroxide Substances 0.000 description 13
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 13
- 235000011116 calcium hydroxide Nutrition 0.000 description 13
- 229910017052 cobalt Inorganic materials 0.000 description 13
- 239000010941 cobalt Substances 0.000 description 13
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 13
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 12
- 238000011084 recovery Methods 0.000 description 10
- 238000003723 Smelting Methods 0.000 description 9
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 238000004140 cleaning Methods 0.000 description 7
- 235000019738 Limestone Nutrition 0.000 description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 6
- 229910000019 calcium carbonate Inorganic materials 0.000 description 6
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 6
- 239000006028 limestone Substances 0.000 description 6
- 150000002739 metals Chemical class 0.000 description 6
- 239000011593 sulfur Substances 0.000 description 6
- 229910052717 sulfur Inorganic materials 0.000 description 6
- 239000002562 thickening agent Substances 0.000 description 6
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 5
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000001784 detoxification Methods 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- 239000005083 Zinc sulfide Substances 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000004062 sedimentation Methods 0.000 description 3
- 239000011701 zinc Substances 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- 229910052984 zinc sulfide Inorganic materials 0.000 description 3
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 description 3
- 150000007514 bases Chemical class 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 230000003100 immobilizing effect Effects 0.000 description 2
- 150000002506 iron compounds Chemical class 0.000 description 2
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 2
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 2
- 229910001710 laterite Inorganic materials 0.000 description 2
- 239000011504 laterite Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- HYHCSLBZRBJJCH-UHFFFAOYSA-M sodium hydrosulfide Chemical compound [Na+].[SH-] HYHCSLBZRBJJCH-UHFFFAOYSA-M 0.000 description 2
- 229910052979 sodium sulfide Inorganic materials 0.000 description 2
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 239000000701 coagulant Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 229910052595 hematite Inorganic materials 0.000 description 1
- 239000011019 hematite Substances 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 230000033444 hydroxylation Effects 0.000 description 1
- 238000005805 hydroxylation reaction Methods 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 1
- SHXXPRJOPFJRHA-UHFFFAOYSA-K iron(iii) fluoride Chemical compound F[Fe](F)F SHXXPRJOPFJRHA-UHFFFAOYSA-K 0.000 description 1
- 229910001425 magnesium ion Inorganic materials 0.000 description 1
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 description 1
- 239000000391 magnesium silicate Substances 0.000 description 1
- 229910052919 magnesium silicate Inorganic materials 0.000 description 1
- 235000019792 magnesium silicate Nutrition 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 229910001437 manganese ion Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 150000004763 sulfides Chemical class 0.000 description 1
- 125000000101 thioether group Chemical group 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
Description
本発明は、ニッケル酸化鉱石の湿式製錬プロセスの硫化処理を経て得られた硫化後液中の硫化水素等の硫化剤を除去する硫化剤の除去方法及びそれを用いたニッケル酸化鉱石の湿式製錬方法に関する。 The present invention relates to a sulfidizing agent removal method for removing a sulfiding agent such as hydrogen sulfide in a liquid after sulfidation obtained through a sulfidizing treatment of a nickel oxide ore hydrometallurgical process, and a nickel oxide ore using the same. It relates to the smelting method.
ニッケル酸化鉱石の湿式製錬方法（ニッケル酸化鉱石の湿式製錬プロセス）として、硫酸を用いた高圧酸浸出法がある。この方法は、従来の一般的なニッケル酸化鉱石の製錬方法である乾式製錬方法と異なり、還元及び乾燥工程を含まず、一貫した湿式工程からなるので、エネルギー的及びコスト的に有利であることとともに、ニッケル品位を５０質量％程度まで上昇したニッケルを含む硫化物（以下「ニッケル硫化物」ともいう）を得ることができるという利点を有している。 There is a high pressure acid leaching method using sulfuric acid as a hydrometallurgical method of nickel oxide ore (a hydrometallurgical process of nickel oxide ore). Unlike the conventional dry smelting method, which is a conventional nickel oxide ore smelting method, this method does not include reduction and drying steps, and consists of a consistent wet process, which is advantageous in terms of energy and cost. In addition, there is an advantage that a sulfide containing nickel (hereinafter also referred to as “nickel sulfide”) whose nickel quality is increased to about 50 mass% can be obtained.
高圧酸浸出法に基づくニッケル酸化鉱石の湿式製錬方法は、例えば、下記工程を含む。
（ａ）ニッケル酸化鉱石のスラリーに硫酸を添加し、高温高圧下で浸出し、得られた浸出スラリーから浸出残渣スラリーを固液分離して、ニッケルとともにコバルト等の金属元素を含む浸出液を得る、浸出工程及び固液分離工程
（ｂ）浸出液に中和剤を添加して、不純物元素を含む中和澱物スラリーとニッケルを含む中和終液とを得る中和工程
（ｃ）中和終液に対し、硫化水素ガスにより硫化処理を施してニッケル硫化物と硫化後液とを得る硫化工程
（ｄ）ニッケル硫化物の分離後の硫化後液に中和処理を施して無害化する排水処理工程
The hydrometallurgical method of nickel oxide ore based on the high pressure acid leaching method includes, for example, the following steps.
(A) adding sulfuric acid to a slurry of nickel oxide ore, leaching under high temperature and high pressure, solidifying the leaching residue slurry from the obtained leaching slurry, to obtain a leaching solution containing a metal element such as cobalt together with nickel; A leaching step and a solid-liquid separation step (b) A neutralization step of adding a neutralizing agent to the leaching solution to obtain a neutralized starch slurry containing an impurity element and a neutralized final solution containing nickel (c) a neutralized final solution On the other hand, a sulfidation step for obtaining nickel sulfide and a post-sulfurization solution by performing a sulfidation treatment with hydrogen sulfide gas (d) A wastewater treatment step for neutralizing the post-sulfurization solution after separation of nickel sulfide to render it harmless
ニッケル硫化物分離後の硫化後液には硫化水素が溶存する。そこで、該硫化水素を除去するために、ニッケル硫化物分離後の硫化後液に、３価の鉄、例えば特許文献１に記載されるように、浸出スラリーを固液分離して得られた浸出液に中和処理及び硫化処理を施して得られた硫化後液を排水処理工程（中和処理工程）で無害化して得られる水酸化鉄（III）、又は、ヘマタイト（酸化鉄(III)）と、硫酸とを添加する。これにより、水酸化鉄（III）又は酸化鉄(III)と、硫化後液に溶存する硫化水素とを反応させることで、硫化水素を除去することができる。水酸化鉄（III）による硫化水素の除去反応を下記式（１）に示す。また、酸化鉄(III)による硫化水素の除去反応を下記式（２）及び（３）に示す。
Ｆｅ（ＯＨ）３＋１／２Ｈ２Ｓ＋Ｈ２ＳＯ４
→ＦｅＳＯ４＋１／２Ｓ０＋３Ｈ２Ｏ （１）
Ｆｅ２Ｏ３＋３Ｈ２ＳＯ４→Ｆｅ２（ＳＯ４）３＋３Ｈ２Ｏ （２）
Ｆｅ２（ＳＯ４）３＋Ｈ２Ｓ→２ＦｅＳＯ４＋Ｈ２ＳＯ４＋Ｓ０ （３）
Hydrogen sulfide is dissolved in the post-sulfurization solution after separation of nickel sulfide. Therefore, in order to remove the hydrogen sulfide, the leachate obtained by solid-liquid separation of the leaching slurry as described in Patent Document 1, for example, trivalent iron, for example, as described in Patent Document 1, after the separation of nickel sulfide. Iron hydroxide (III) or hematite (iron (III) oxide) obtained by detoxifying the post-sulfurization solution obtained by neutralizing and sulfidizing to the wastewater treatment process (neutralization process) Add sulfuric acid. Thereby, hydrogen sulfide can be removed by reacting iron hydroxide (III) or iron oxide (III) with hydrogen sulfide dissolved in the solution after sulfidation. The removal reaction of hydrogen sulfide with iron (III) hydroxide is shown in the following formula (1). Moreover, the removal reaction of hydrogen sulfide by iron (III) oxide is shown in the following formulas (2) and (3).
Fe (OH) 3 + 1 / 2H 2 S + H 2 SO 4
→ FeSO 4 + 1 / 2S 0 + 3H 2 O (1)
Fe 2 O 3 + 3H 2 SO 4 → Fe 2 (SO 4 ) 3 + 3H 2 O (2)
Fe 2 (SO 4 ) 3 + H 2 S → 2FeSO 4 + H 2 SO 4 + S 0 (3)
なお、このように硫化後液の溶存硫化水素を除去する際には、例えば特許文献２のように、曝気槽での撹拌と同時に、エアレーションを行うことで、溶存硫化水素ガスの除去を促進することが一般的である。 In addition, when removing the dissolved hydrogen sulfide in the solution after sulfidation in this way, for example, as in Patent Document 2, aeration is performed simultaneously with stirring in the aeration tank to promote removal of dissolved hydrogen sulfide gas. It is common.
硫化工程では、ニッケルの回収ロスを減らすために、硫化水素ガス添加量を増やしてニッケル硫化物の生成量を増やし硫化後液のニッケル濃度を下げることが望ましい。しかし、硫化水素ガスの添加量を増やすことによって硫化工程後の硫化後液に溶存する硫化水素ガス量が増加すると、硫化水素を除去しきれず、系外に排出する排ガス中の硫化水素ガス濃度が上昇してしまうという問題が生じる。したがって、硫化工程のニッケルの回収ロスを減らすこと及び排ガス中の硫化水素ガス濃度を低くすることを両立するために、硫化水素を効果的に低減できる方法が求められている。 In the sulfiding step, in order to reduce the recovery loss of nickel, it is desirable to increase the amount of hydrogen sulfide gas added to increase the amount of nickel sulfide produced and to lower the nickel concentration in the post-sulfurizing solution. However, if the amount of hydrogen sulfide gas dissolved in the post-sulfurization liquid after the sulfidation process is increased by increasing the amount of hydrogen sulfide gas added, hydrogen sulfide cannot be removed, and the concentration of hydrogen sulfide gas in the exhaust gas discharged outside the system The problem of rising. Therefore, a method capable of effectively reducing hydrogen sulfide is required in order to achieve both reduction in nickel recovery loss in the sulfiding step and reduction in hydrogen sulfide gas concentration in the exhaust gas.
本発明は、このような実情に鑑みてなされたものであり、ニッケル酸化鉱石の湿式製錬プロセスにて生じる硫化後液から硫化水素等の硫化剤を除去する硫化剤の除去方法であって、硫化剤を効果的に低減できる硫化剤の除去方法及びそれを用いたニッケル酸化鉱石の湿式製錬方法を提供することを目的とする。 The present invention has been made in view of such circumstances, and is a method for removing a sulfurizing agent that removes a sulfurizing agent such as hydrogen sulfide from a post-sulfurization solution generated in a hydrometallurgical process of nickel oxide ore, It is an object of the present invention to provide a method for removing a sulfurizing agent capable of effectively reducing the sulfurizing agent and a method for hydrometallizing nickel oxide ore using the same.
本発明者らは、上述した課題を解決するために鋭意検討を重ねた。その結果、硫化後液の溶存硫化水素等の硫化剤を除去する際に、ニッケル酸化鉱石の湿式製錬プロセスにおいて、酸浸出で得られる浸出スラリーのＦｅ３＋濃度を２．９ｇ／Ｌ以上にし、該浸出スラリーに中和処理を施して水酸化鉄（III）を生成させて水酸化鉄（III）を含む浸出スラリーを得て、該水酸化鉄（III）を含む浸出スラリーを固液分離処理して得られる水酸化鉄（III）を含む浸出残渣を用いて硫化水素等の硫化剤を固定化することで、硫化後液に含まれる硫化剤を効果的に低減することができることを知見し、さらに検討を重ね、本発明を完成させた。すなわち、本発明は、以下のものを提供する。 The inventors of the present invention have made extensive studies in order to solve the above-described problems. As a result, when removing the sulfurizing agent such as dissolved hydrogen sulfide in the liquid after sulfidation, the Fe 3+ concentration of the leaching slurry obtained by acid leaching is 2.9 g / L or more in the wet smelting process of nickel oxide ore, The leaching slurry is neutralized to produce iron (III) hydroxide to obtain a leaching slurry containing iron (III) hydroxide, and the leaching slurry containing the iron (III) hydroxide is subjected to solid-liquid separation treatment. It was found that the sulfiding agent contained in the liquid after sulfidation can be effectively reduced by immobilizing a sulfiding agent such as hydrogen sulfide using the leaching residue containing iron (III) hydroxide obtained in this way. The present invention was completed by further study. That is, the present invention provides the following.
（１）本発明の第１の発明は、ニッケル酸化鉱石を硫酸により高温高圧下で酸浸出して得られる浸出スラリーを固液分離してニッケルを含む浸出液と浸出残渣とを得て、該浸出液に対し硫化剤により硫化処理を施してニッケルの硫化物と硫化後液とを生成させる湿式製錬プロセスにおいて、該ニッケルの硫化物を分離して得られた硫化後液中に溶存する硫化剤を除去する硫化剤の除去方法であって、前記酸浸出では、得られる浸出スラリー中のＦｅ３＋濃度を２．９ｇ／Ｌ以上にし、前記固液分離では、前記浸出スラリーに中和処理を施して水酸化鉄（III）を生成させて水酸化鉄（III）を含む浸出スラリーを得た後、該水酸化鉄（III）を含む浸出スラリーを固液分離処理してニッケルを含む浸出液と水酸化鉄（III）を含む浸出残渣とを得、前記硫化後液に対して、前記水酸化鉄（III）を含む浸出残渣を添加することにより、該硫化後液に含まれる硫化剤を固定化し除去する硫化剤の除去方法である。 (1) According to a first aspect of the present invention, a leach slurry obtained by acid leaching of nickel oxide ore with sulfuric acid under high temperature and high pressure is subjected to solid-liquid separation to obtain a leach liquid containing nickel and a leach residue, and the leach liquid In a hydrometallurgical process in which nickel sulfide and a sulfidized liquid are produced by performing a sulfidizing treatment with a sulfidizing agent, a sulfiding agent dissolved in the post-sulfurized liquid obtained by separating the nickel sulfide is obtained. In the acid leaching, the Fe 3+ concentration in the obtained leaching slurry is set to 2.9 g / L or more, and in the solid-liquid separation, the leaching slurry is neutralized. After producing iron hydroxide (III) to obtain a leaching slurry containing iron (III) hydroxide, the leaching slurry containing iron (III) hydroxide is subjected to solid-liquid separation treatment and leaching liquid containing nickel and hydroxylation. Leaching residue containing iron (III) and obtained before This is a method for removing a sulfurizing agent, in which a leaching residue containing iron (III) hydroxide is added to the post-sulfurizing solution to fix and remove the sulfurizing agent contained in the post-sulfurizing solution.
（２）本発明の第２の発明は、前記浸出スラリーに対する固液分離により得られた前記水酸化鉄（III）を含む浸出残渣を、前記湿式製錬プロセスにおける、前記硫化後液に対して中和処理を施すことで無害化する排水処理に供し、前記硫化後液に対して、前記排水処理後の前記水酸化鉄（III）を含む浸出残渣を添加する第１の発明に記載の硫化剤の除去方法である。 (2) According to a second aspect of the present invention, the leaching residue containing the iron (III) hydroxide obtained by solid-liquid separation of the leaching slurry is applied to the post-sulfurization liquid in the hydrometallurgical process. Sulfurization according to the first aspect of the invention, which is subjected to wastewater treatment that is rendered harmless by performing neutralization treatment, and a leaching residue containing the iron (III) hydroxide after the wastewater treatment is added to the post-sulfurization solution. This is a method for removing the agent.
（３）本発明の第３の発明は、前記浸出スラリーに対する中和処理では、前記浸出スラリーのｐＨを２．５〜３．２にする第１又は第２の発明に記載の硫化剤の除去方法である。 (3) The third aspect of the present invention is the removal of the sulfurizing agent according to the first or second aspect, wherein the pH of the leaching slurry is 2.5 to 3.2 in the neutralization treatment of the leaching slurry. Is the method.
（４）本発明の第４の発明は、前記硫化後液に対して、前記水酸化鉄（III）を含む浸出残渣とともに硫酸を添加する第１〜第３の発明のいずれかに記載の硫化剤の除去方法である。 (4) A fourth invention of the present invention is the sulfide according to any one of the first to third inventions, wherein sulfuric acid is added to the post-sulfurized solution together with the leaching residue containing the iron (III) hydroxide. This is a method for removing the agent.
（５）本発明の第５の発明は、前記硫化後液は、ニッケルイオン濃度が０．０２〜０．１０ｇ／Ｌであり、鉄、マンガン、マグネシウム、アルミニウム及びクロムから選択される少なくとも一種を含む硫酸酸性溶液である第１〜第４の発明のいずれかに記載の硫化剤の除去方法である。 (5) According to a fifth aspect of the present invention, the post-sulfurization solution has a nickel ion concentration of 0.02 to 0.10 g / L, and at least one selected from iron, manganese, magnesium, aluminum and chromium. It is the removal method of the sulfurizing agent in any one of the 1st-4th invention which is a sulfuric acid acidic solution to contain.
（６）本発明の第６の発明は、前記硫化後液に対して、前記水酸化鉄（III）を含む浸出残渣を添加するとともに、エアレーションを行う第１〜第５の発明のいずれかに記載の硫化剤の除去方法である。 (6) A sixth invention of the present invention is any one of the first to fifth inventions in which the leaching residue containing the iron (III) hydroxide is added to the post-sulfurized solution and aeration is performed. It is the removal method of the sulfurization agent of description.
（７）本発明の第７の発明は、ニッケル酸化鉱石を硫酸により高温高圧下で酸浸出して浸出スラリーを得る浸出工程と、浸出工程で得られた前記浸出スラリーを固液分離してニッケルを含む浸出液と浸出残渣とを得る固液分離工程と、固液分離工程で得られた前記浸出液に中和剤を添加してニッケルを含む中和終液と不純物元素を含む中和澱物とを得る中和工程と、中和工程で得られた前記中和終液に対し硫化剤により硫化処理を施してニッケルの硫化物と硫化後液とを得る硫化工程と、前記ニッケルの硫化物を分離して得られた前記硫化後液に含まれる硫化剤を固定化し除去する硫化剤除去工程と、を有するニッケル酸化鉱石の湿式製錬方法であって、前記固液分離工程は、前記浸出工程で得られた前記浸出スラリーに中和処理を施して水酸化鉄（III）を生成させて水酸化鉄（III）を含む浸出スラリーを得る予備中和工程、及び、該予備中和工程で得られた前記水酸化鉄（III）を含む浸出スラリーを固液分離処理して浸出液と水酸化鉄（III）を含む浸出残渣とを得る分離工程を有し、前記浸出工程では、前記浸出スラリー中のＦｅ３＋濃度を２．９ｇ／Ｌ以上にし、前記硫化剤除去工程では、前記ニッケルの硫化物を分離して得られた前記硫化後液に対して、前記水酸化鉄（III）を含む浸出残渣を添加することにより、前記硫化後液に含まれる硫化剤を固定化し除去するニッケル酸化鉱石の湿式製錬方法にある。 (7) The seventh invention of the present invention is a leaching step in which nickel oxide ore is acid leached with sulfuric acid under high temperature and high pressure to obtain a leaching slurry, and the leaching slurry obtained in the leaching step is solid-liquid separated to obtain nickel A solid-liquid separation step for obtaining a leachate containing leaching residue and a leach residue, a neutralization final solution containing nickel by adding a neutralizing agent to the leachate obtained in the solid-liquid separation step, and a neutralized starch containing an impurity element, A neutralization step of obtaining a nickel sulfide and a post-sulfurization solution by subjecting the neutralized final solution obtained in the neutralization step to a sulfurization treatment with a sulfurizing agent, and a nickel sulfide. A sulfidizing agent removal step of fixing and removing the sulfiding agent contained in the post-sulfurized liquid obtained by separation, and a nickel oxide ore hydrometallurgy method, wherein the solid-liquid separation step is the leaching step The leaching slurry obtained in step 1 is neutralized and water A pre-neutralization step for producing iron (III) fluoride to obtain a leaching slurry containing iron (III) hydroxide, and a leaching slurry containing the iron (III) hydroxide obtained in the pre-neutralization step A separation step of obtaining a leaching solution and a leaching residue containing iron (III) hydroxide by liquid separation treatment, wherein in the leaching step, the concentration of Fe 3+ in the leaching slurry is set to 2.9 g / L or more, and In the agent removal step, sulfidation contained in the post-sulfurization solution is performed by adding a leaching residue containing the iron (III) hydroxide to the post-sulfurization solution obtained by separating the nickel sulfide. It is in the hydrometallurgical method of nickel oxide ore to fix and remove the agent.
本発明の硫化剤の除去方法によれば、ニッケル酸化鉱石の湿式製錬プロセスにて生じる硫化後液から硫化水素等の硫化剤を効果的に低減させることができ、硫化後液から硫化水素等の硫化剤を十分に除去することができる。 According to the method for removing a sulfiding agent of the present invention, a sulfiding agent such as hydrogen sulfide can be effectively reduced from a post-sulfurization solution generated in a hydrometallurgical process of nickel oxide ore, and a hydrogen sulfide or the like can be reduced from a post-sulfurization solution. The sulfurizing agent can be sufficiently removed.
このように本発明によれば、硫化後液中の硫化剤を効果的に低減することができるため、ニッケルを回収するための硫化剤を多量に添加することができる。したがって、本発明は、ニッケル酸化鉱の湿式製錬プロセスにおいて、ニッケルロスの低減及び硫化剤の除去不良発生の抑制による環境面や安全面の改善ができることから、その工業的価値はきわめて高い。 Thus, according to the present invention, since the sulfurizing agent in the solution after sulfiding can be effectively reduced, a large amount of the sulfurizing agent for recovering nickel can be added. Therefore, since the present invention can improve the environmental and safety aspects by reducing the nickel loss and suppressing the occurrence of defective removal of the sulfiding agent in the nickel oxide ore hydrometallurgical process, its industrial value is extremely high.
以下、本発明の具体的な実施形態（以下、「本実施の形態」という）について、図面を参照しながら詳細に説明する。なお、本発明は、以下の実施形態に限定されるものではなく、本発明の要旨を変更しない範囲で種々の変更が可能である。また、本明細書において、「Ｘ〜Ｙ」（Ｘ、Ｙは任意の数値）との表記は、「Ｘ以上Ｙ以下」の意味である。 Hereinafter, a specific embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment, A various change is possible in the range which does not change the summary of this invention. In this specification, the notation “X to Y” (X and Y are arbitrary numerical values) means “X or more and Y or less”.
≪１．概要≫
本実施の形態に係る硫化剤の除去方法は、ニッケル酸化鉱石を硫酸により高温高圧下で酸浸出して得られる浸出スラリーを固液分離してニッケルを含む浸出液と浸出残渣とを得て、浸出液に対し硫化剤により硫化処理を施してニッケルの硫化物と硫化後液とを生成させることで、ニッケル硫化物を得るニッケル酸化鉱石の湿式製錬プロセス（以下、単に「湿式製錬プロセス」ともいう）において生じる硫化後液から溶存する硫化水素等の硫化剤を除去する方法である。なお、本明細書において、除去対象である「硫化剤」には、硫化工程で用いた硫化水素、硫化ナトリウム、水素化硫化ナトリウム等の硫化剤自体の他、硫化剤から生じた硫化水素も含む。また、ニッケル硫化物とは、ニッケルを含む硫化物をいい、コバルト等の他の金属とニッケルとの混合硫化物をも含む。
<< 1. Overview >>
In the method for removing a sulfurizing agent according to the present embodiment, a leach slurry obtained by acid leaching nickel oxide ore with sulfuric acid under high temperature and high pressure is subjected to solid-liquid separation to obtain a leach liquid containing nickel and a leach residue, and the leach liquid The nickel oxide ore wet smelting process (hereinafter also simply referred to as “wet smelting process”) is obtained by subjecting to sulfiding treatment with a sulfiding agent to produce nickel sulfide and post-sulfurized liquid. In this method, the sulfurizing agent such as hydrogen sulfide is removed from the post-sulfurizing solution generated in (1). In the present specification, the “sulfurizing agent” to be removed includes hydrogen sulfide generated from the sulfurizing agent in addition to the sulfurizing agent itself such as hydrogen sulfide, sodium sulfide, sodium hydrogen sulfide, etc. used in the sulfurization step. . The nickel sulfide refers to a sulfide containing nickel, and also includes a mixed sulfide of nickel with another metal such as cobalt.
本実施の形態に係る硫化剤の除去方法は、具体的には、湿式製錬プロセスにおいて、酸浸出で得られる浸出スラリーのＦｅ３＋濃度を２．９ｇ／Ｌ以上にし、該浸出スラリーに中和処理を施して水酸化鉄（III）を生成させて水酸化鉄（III）を含む浸出スラリーを得て、該水酸化鉄（III）を含む浸出スラリーを固液分離処理して得られる水酸化鉄（III）を含む浸出残渣を３価の鉄イオン源として用いて、硫化後液に添加する。これにより、詳しくは後述するが、浸出残渣中に含まれる水酸化鉄（III）によって、硫化後液中に溶存する硫化水素等の硫化剤を固定して除去（回収）する。なお、ここでいう「固定」とは、化合物を安定な形態に変換することであり、本実施の形態に係る硫化剤の除去方法では、硫化後液中に溶存する硫化水素等の硫化剤が、水酸化鉄(III)との反応によって単体の硫黄（Ｓ０）として安定した形態に変換され、この単体の硫黄が沈殿生成して除去される。 Specifically, in the method of removing a sulfurizing agent according to the present embodiment, in the hydrometallurgical process, the leaching slurry obtained by acid leaching has an Fe 3+ concentration of 2.9 g / L or more and is neutralized to the leaching slurry. Treatment is performed to produce iron hydroxide (III) to obtain a leaching slurry containing iron (III) hydroxide, and the hydration obtained by subjecting the leaching slurry containing iron (III) hydroxide to solid-liquid separation treatment The leaching residue containing iron (III) is used as a trivalent iron ion source and added to the post-sulfurization solution. Thereby, as will be described in detail later, the sulfurizing agent such as hydrogen sulfide dissolved in the liquid after sulfidation is fixed and removed (recovered) by iron (III) hydroxide contained in the leaching residue. The term “fixed” as used herein refers to converting a compound into a stable form. In the method for removing a sulfiding agent according to the present embodiment, a sulfiding agent such as hydrogen sulfide dissolved in the solution after sulfiding is used. By the reaction with iron (III) hydroxide, it is converted to a stable form as single sulfur (S 0 ), and this single sulfur is precipitated and removed.
≪２．ニッケル酸化鉱石の湿式製錬プロセス≫
先ず、硫化剤の除去方法のより具体的な説明に先立ち、本実施の形態におけるニッケル酸化鉱石の湿式製錬方法の流れを示す工程図である図１を用いて、ニッケル酸化鉱石の湿式製錬プロセス全体について説明する。
≪2. Nickel oxide ore hydrometallurgical process »
First, prior to a more specific description of a method for removing a sulfiding agent, using FIG. 1 which is a process diagram showing a flow of a wet smelting method for nickel oxide ore in the present embodiment, wet smelting of nickel oxide ore is performed. The entire process will be described.
図１に示すようにこの湿式製錬プロセスは、原料のニッケル酸化鉱石に硫酸を用いて高温高圧下で酸浸出して浸出スラリーを得る浸出工程Ｓ１１と、浸出スラリーを必要に応じて多段洗浄しながらニッケルを含む浸出液と浸出残渣とを得る固液分離工程Ｓ１２と、浸出液に中和剤を添加して不純物を含む中和澱物スラリーとニッケルを含む中和終液とを得る中和工程Ｓ１３と、中和終液に対し硫化剤により硫化処理を施してニッケル硫化物と硫化後液とを得る硫化工程Ｓ１４とを有する。本実施の形態においては、さらに、硫化工程Ｓ１４で分離された硫化後液に対し中和処理を施して無害化する排水処理工程Ｓ２０を有する。 As shown in FIG. 1, this hydrometallurgical process includes a leaching step S11 for obtaining a leaching slurry by acid leaching under high temperature and high pressure using sulfuric acid as a raw material nickel oxide ore, and multi-stage cleaning of the leaching slurry as necessary. Solid-liquid separation step S12 for obtaining a leachate containing nickel and a leach residue while neutralizing step S13 for obtaining a neutralized starch slurry containing impurities by adding a neutralizing agent to the leachate and a neutralized final solution containing nickel And a sulfiding step S14 in which a sulfidizing agent is applied to the neutralized final solution to obtain nickel sulfide and a post-sulfurized solution. The present embodiment further includes a wastewater treatment step S20 that neutralizes the post-sulfurization solution separated in the sulfurization step S14 to render it harmless.
本実施の形態に係る硫化剤の除去方法は、このニッケル酸化鉱石の湿式製錬プロセスにより得られる硫化後液を処理対象とし、その硫化後液に溶存する硫化剤を除去する。 In the method for removing a sulfurizing agent according to the present embodiment, a post-sulfurization solution obtained by the hydrometallurgy process of nickel oxide ore is treated, and the sulfurizing agent dissolved in the post-sulfurization solution is removed.
（１）浸出工程
浸出工程Ｓ１１は、原料のニッケル酸化鉱石に硫酸を用いて高温高圧下で酸浸出して浸出スラリーを得る工程である。例えば高温加圧容器（オートクレーブ）等を用いて、ニッケル酸化鉱石のスラリーに硫酸を添加して２２０℃〜２８０℃の温度下で、加圧しながら撹拌処理を施し、ニッケルを含有する浸出液と浸出残渣とからなる浸出スラリーを生成させる。本実施の形態においては、詳しくは後述するが、浸出工程Ｓ１１において、酸浸出で得られる浸出スラリー中のＦｅ３＋濃度が２．９ｇ／Ｌ以上になるようにする。
(1) Leaching step The leaching step S11 is a step of obtaining a leaching slurry by acid leaching under high temperature and high pressure using sulfuric acid as a raw material nickel oxide ore. For example, using a high-temperature pressurized container (autoclave) or the like, sulfuric acid is added to a nickel oxide ore slurry and stirred at a temperature of 220 ° C. to 280 ° C. while being pressurized, and a leaching solution and a leaching residue containing nickel. A leaching slurry consisting of In this embodiment, as will be described in detail later, in the leaching step S11, the Fe 3+ concentration in the leaching slurry obtained by acid leaching is set to 2.9 g / L or more.
ここで、ニッケル酸化鉱石としては、主としてリモナイト鉱及びサプロライト鉱等のいわゆるラテライト鉱が挙げられる。ラテライト鉱のニッケル含有量は、通常、０．８〜２．５重量％であり、水酸化物又はケイ苦土（ケイ酸マグネシウム）鉱物として含有される。 Here, examples of the nickel oxide ore include so-called laterite ores such as limonite ore and saprolite ore. Laterite ore usually has a nickel content of 0.8 to 2.5% by weight, and is contained as a hydroxide or siliceous clay (magnesium silicate) mineral.
（２）固液分離工程
固液分離工程Ｓ１２は、浸出工程Ｓ１１で得られた浸出スラリーを、ニッケルやコバルト等の有価金属を含む浸出液と浸出残渣とに固液分離する工程である。本実施の形態においては、詳しくは後述するが、固液分離工程Ｓ１２は、浸出工程Ｓ１１で得られた浸出スラリーに中和処理を施して水酸化鉄（III）を生成させて水酸化鉄（III）を含む浸出スラリーを得る予備中和工程Ｓ１２１と、予備中和工程Ｓ１２１で得られた水酸化鉄（III）を含む浸出スラリーを固液分離処理して浸出液と水酸化鉄（III）を含む浸出残渣とを得る分離工程Ｓ１２２とを有する。
(2) Solid-liquid separation step The solid-liquid separation step S12 is a step for solid-liquid separation of the leaching slurry obtained in the leaching step S11 into a leaching solution containing valuable metals such as nickel and cobalt and a leaching residue. In the present embodiment, as will be described in detail later, in the solid-liquid separation step S12, the leaching slurry obtained in the leaching step S11 is neutralized to produce iron (III) hydroxide to produce iron hydroxide ( Pre-neutralization step S121 for obtaining a leaching slurry containing III), and the leaching slurry containing iron hydroxide (III) obtained in the pre-neutralization step S121 is subjected to solid-liquid separation treatment to obtain a leaching solution and iron (III) hydroxide. And a separation step S122 for obtaining a leaching residue.
予備中和工程Ｓ１２１では、浸出スラリーに中和剤を添加して、ｐＨを上昇させる（例えばｐＨ２．５〜３．２にする）中和処理を施す。これにより、浸出スラリーに含まれる余剰の硫酸（以下、「遊離硫酸」ともいう）が中和されるとともに、浸出スラリー中のＦｅ３＋の一部又は全部が水酸化鉄（III）になる。 In the preliminary neutralization step S121, a neutralizing agent is added to the leaching slurry to increase the pH (for example, to make the pH 2.5 to 3.2). Thereby, surplus sulfuric acid (hereinafter also referred to as “free sulfuric acid”) contained in the leaching slurry is neutralized, and part or all of Fe 3+ in the leaching slurry becomes iron (III) hydroxide.
予備中和工程Ｓ１２１の中和剤としては、従来公知のもの使用することができ、例えば、消石灰（水酸化カルシウム）、炭酸カルシウム、水酸化ナトリウム等の塩基性化合物が挙げられる。 A conventionally well-known thing can be used as a neutralizing agent of preliminary | backup neutralization process S121, For example, basic compounds, such as slaked lime (calcium hydroxide), calcium carbonate, sodium hydroxide, are mentioned.
分離工程Ｓ１２２では、例えば、予備中和工程Ｓ１２１後の浸出スラリーを洗浄液と混合した後、凝集剤供給設備等から供給される凝集剤を用いて、シックナー等の固液分離設備により固液分離処理を施す。具体的には、先ず、浸出スラリーが洗浄液により希釈され、次に、浸出スラリー中の浸出残渣がシックナーの沈降物として濃縮される。浸出スラリーを洗浄する洗浄液は、特に限定されないが、例えば、後段の硫化剤除去工程Ｓ３０後の硫化後液（処理後硫化後液）等を用いることができる。なお、固液分離工程Ｓ１２で得られる浸出残渣は、鉄化合物として、水酸化鉄（III）の他、酸化鉄(III)や硫酸鉄(III)を含む。 In the separation step S122, for example, the leaching slurry after the pre-neutralization step S121 is mixed with the cleaning liquid, and then the solid-liquid separation process is performed by a solid-liquid separation facility such as a thickener using the flocculant supplied from the flocculant supply facility. Apply. Specifically, the leaching slurry is first diluted with a cleaning liquid, and then the leaching residue in the leaching slurry is concentrated as a thickener sediment. The cleaning liquid for cleaning the leaching slurry is not particularly limited, and for example, a post-sulfurization liquid (post-treatment post-sulfurization liquid) after the subsequent sulfiding agent removal step S30 can be used. In addition, the leaching residue obtained in the solid-liquid separation step S12 includes iron (III) hydroxide and iron (III) sulfate in addition to iron (III) hydroxide as an iron compound.
分離工程Ｓ１２２で分離された浸出液は、中和工程Ｓ１３に移送され、一方で、浸出残渣は、シックナーの底部から回収される。浸出残渣には、ニッケルやコバルト等の有価金属が一部含まれる場合があるため、浸出残渣を洗浄して得られたニッケルやコバルト等の有価金属を含有する液も、中和工程Ｓ１３に移送するようにしてもよい。 The leachate separated in the separation step S122 is transferred to the neutralization step S13, while the leach residue is recovered from the bottom of the thickener. Since the leaching residue may contain some valuable metals such as nickel and cobalt, the liquid containing valuable metals such as nickel and cobalt obtained by washing the leaching residue is also transferred to the neutralization step S13. You may make it do.
（２）中和工程
中和工程Ｓ１３は、固液分離工程Ｓ１２により得られた浸出液に中和剤を添加して不純物を含む中和澱物スラリーとニッケルを含む中和終液とを得る工程である。固液分離工程Ｓ１２により得られた浸出液に、中和剤を添加してｐＨを調整し、不純物元素を含む中和澱物スラリーと中和終液とを得る。この中和工程Ｓ１３における中和処理により、ニッケルやコバルト等の有価金属は中和終液に含まれるようになり、鉄の大部分が中和澱物スラリーとなる。中和殿物スラリーの沈降速度を促進するために、凝結剤を添加してもよい。
(2) Neutralization step The neutralization step S13 is a step of adding a neutralizing agent to the leachate obtained in the solid-liquid separation step S12 to obtain a neutralized starch slurry containing impurities and a neutralized final solution containing nickel. It is. A neutralizing agent is added to the leachate obtained in the solid-liquid separation step S12 to adjust the pH, thereby obtaining a neutralized starch slurry containing an impurity element and a neutralized final solution. By the neutralization process in this neutralization process S13, valuable metals, such as nickel and cobalt, will be contained in the neutralization final liquid, and most iron will become neutralization starch slurry. A coagulant may be added to accelerate the sedimentation rate of the neutralized precipitate slurry.
中和剤としては、従来公知のもの使用することができ、例えば、消石灰（水酸化カルシウム）、炭酸カルシウム、水酸化ナトリウム等が挙げられる。 A conventionally well-known thing can be used as a neutralizer, For example, slaked lime (calcium hydroxide), calcium carbonate, sodium hydroxide etc. are mentioned.
中和工程Ｓ１３における中和処理では、浸出液の酸化を抑制しながら、ｐＨを１〜４の範囲に調整することが好ましく、２．５〜３．５の範囲に調整することがより好ましい。ｐＨが１未満であると、中和が不十分となり中和澱物スラリーと中和終液とに分離できない可能性があり、また、ｐＨが２．５未満であると、後段の硫化工程Ｓ１４の脱亜鉛工程やニッケル回収工程で硫化反応が進行しない可能性がある。一方で、ｐＨが４を超えると、アルミニウム等の不純物のみならず、ニッケルやコバルト等の有価金属も中和澱物スラリーに含まれる可能性がある。中和工程Ｓ１３で得られた中和殿物スラリーがニッケルやコバルト等の有価金属を含む場合は、中和殿物スラリーを固液分離工程Ｓ１２に供給するようにしてもよい。 In the neutralization process in neutralization process S13, it is preferable to adjust pH to the range of 1-4, suppressing the oxidation of leachate, and it is more preferable to adjust to the range of 2.5-3.5. If the pH is less than 1, neutralization may be insufficient and the neutralized starch slurry and the neutralized final solution may not be separated, and if the pH is less than 2.5, the subsequent sulfurization step S14. There is a possibility that the sulfidation reaction does not proceed in the dezincing step or nickel recovery step. On the other hand, when pH exceeds 4, not only impurities, such as aluminum, but valuable metals, such as nickel and cobalt, may be contained in neutralized starch slurry. When the neutralized precipitate slurry obtained in the neutralization step S13 contains valuable metals such as nickel and cobalt, the neutralized precipitate slurry may be supplied to the solid-liquid separation step S12.
（３）硫化工程
硫化工程Ｓ１４は、中和工程Ｓ１３により得られた中和終液に硫化剤により硫化処理を施してニッケル硫化物と硫化後液とを得る工程である。この硫化工程Ｓ１４における硫化処理により、ニッケル、コバルト、亜鉛等は硫化物となり、その他は硫化後液に含まれることになる。
(3) Sulfurization step Sulfurization step S14 is a step in which nickel sulfide and post-sulfurization solution are obtained by subjecting the neutralized final solution obtained in neutralization step S13 to sulfidation with a sulfiding agent. By the sulfiding treatment in the sulfiding step S14, nickel, cobalt, zinc and the like become sulfides, and the others are contained in the post-sulfurization solution.
具体的には、硫化工程Ｓ１４では、得られた中和終液に対して硫化剤を添加し、中和終液に含まれるニッケルやコバルトを硫化物の形態にする硫化反応を生じさせる。これにより、不純物成分の少ないニッケルの硫化物と、ニッケル濃度を低い水準で安定させた硫化後液とを生成させる。なお、中和終液中に亜鉛が含まれる場合には、硫化剤を添加してニッケル硫化物を生成するに先立って、硫化剤を用いて亜鉛を硫化物として選択的に分離することができる（脱亜鉛工程）。すなわち、中和工程Ｓ１３により得られた中和終液に硫化剤を添加することにより亜鉛硫化物を形成し該亜鉛硫化物を分離してニッケルを含むニッケル回収用母液を得る脱亜鉛工程と、ニッケル回収用母液に硫化剤を添加することによりニッケル硫化物を形成するニッケル回収工程とを有する、硫化工程Ｓ１４としてもよい。 Specifically, in the sulfidation step S14, a sulfiding agent is added to the obtained neutralized final solution to cause a sulfidation reaction in which nickel or cobalt contained in the neutralized final solution is converted to a sulfide form. As a result, a nickel sulfide having a small amount of impurity components and a post-sulfurization solution in which the nickel concentration is stabilized at a low level are generated. In addition, when zinc is contained in the neutralized final solution, zinc can be selectively separated as a sulfide using a sulfurizing agent prior to adding a sulfurizing agent to produce nickel sulfide. (Dezincing step). That is, a dezincification step of forming a zinc sulfide by adding a sulfiding agent to the neutralized final solution obtained in the neutralization step S13 to separate the zinc sulfide to obtain a nickel recovery mother liquor containing nickel; It is good also as sulfidation process S14 which has a nickel collection | recovery process which forms nickel sulfide by adding a sulfiding agent to the mother liquid for nickel collection | recovery.
硫化剤としては、例えば、硫化水素、硫化ナトリウム、水素化硫化ナトリウム等を用いることができるが、その中でも、硫化水素ガスを用いることが、取扱い容易さやコスト等の点で特に好ましい。 As the sulfiding agent, for example, hydrogen sulfide, sodium sulfide, sodium hydrogen sulfide, and the like can be used. Among them, it is particularly preferable to use hydrogen sulfide gas from the viewpoint of ease of handling and cost.
この硫化処理では、ニッケル硫化物のスラリーをシックナー等の沈降分離装置を用いて沈降分離処理して硫化物をシックナーの底部より分離回収する一方で、水溶液成分である硫化後液はオーバーフローさせて回収する。 In this sulfidation treatment, the nickel sulfide slurry is subjected to a sedimentation treatment using a sedimentation device such as thickener to separate and recover the sulfide from the bottom of the thickener, while the sulfidized solution as an aqueous solution overflows and is recovered. To do.
本実施の形態に係る硫化剤の除去方法においては、硫化工程Ｓ１４における硫化処理により得られた硫化後液、すなわち、硫化処理後のスラリーに対して固液分離処理を施して得られた硫化後液を処理対象とする。そして、本実施形態に係る硫化剤の除去方法は、実施例等に示すように硫化剤を効果的に低減できるため、前段の硫化工程Ｓ１４で添加する硫化剤量を多くすることができ、ニッケル硫化物を十分生成することができるため、ニッケルの回収ロスを低減することができる。 In the method for removing the sulfiding agent according to the present embodiment, the sulfidized liquid obtained by the sulfidation process in the sulfidation step S14, that is, the post-sulfurization obtained by subjecting the slurry after the sulfidation process to the solid-liquid separation process. The liquid is to be treated. And since the removal method of the sulfiding agent according to the present embodiment can effectively reduce the sulfiding agent as shown in the examples etc., the amount of the sulfiding agent added in the preceding sulfiding step S14 can be increased. Sulfide can be generated sufficiently, so that nickel recovery loss can be reduced.
（４）排水処理工程（中和処理工程）
排水処理工程Ｓ２０では、硫化工程Ｓ１４にて生成した硫化後液、すなわち、鉄、マグネシウム、マンガン等の不純物元素を含む硫化後液に対して、排出基準を満たす所定のｐＨ範囲に調整する中和処理を施して無害化する排水処理を行う。これにより、鉄、マグネシウム、マンガン等の成分が除去される。
(4) Wastewater treatment process (neutralization process)
In the wastewater treatment step S20, the post-sulfurization solution generated in the sulfurization step S14, that is, the post-sulfurization solution containing an impurity element such as iron, magnesium, manganese, etc., is neutralized to adjust to a predetermined pH range that satisfies the discharge standard. Wastewater treatment is performed to make it harmless. Thereby, components such as iron, magnesium and manganese are removed.
本実施の形態においては、詳しくは後述する硫化後液に対する硫化剤の除去処理である硫化剤除去工程Ｓ３０を経て、溶存する硫化水素等の硫化剤が除去された硫化後液に対して、排水処理工程Ｓ２０で排水処理を行う。 In the present embodiment, drainage is performed on the post-sulfurized liquid from which the sulfurizing agent such as dissolved hydrogen sulfide has been removed through a sulfurizing agent removal step S30 which is a sulfurizing agent removal process on the post-sulfurized liquid described later in detail. Waste water treatment is performed in the treatment step S20.
排水処理工程Ｓ２０における中和処理による無害化の方法、すなわちｐＨの調整方法としては、特に限定されないが、例えば炭酸カルシウム（石灰石）スラリーや水酸化カルシウム（消石灰）スラリー、水酸化ナトリウム等の中和剤を添加することによって所定の範囲に調整することができる。 Although it does not specifically limit as a detoxification method by the neutralization process in waste water treatment process S20, ie, the adjustment method of pH, For example, neutralization of calcium carbonate (limestone) slurry, calcium hydroxide (slaked lime) slurry, sodium hydroxide etc. It can be adjusted to a predetermined range by adding an agent.
また、排水処理工程Ｓ２０における中和処理では、石灰石を中和剤として用いた第１段階の中和処理（第１の工程）と、消石灰を中和剤として用いた第２段階の中和処理（第２の工程）とからなる段階的な処理を行うことができる。このように段階的な中和処理を行うことで、効率的にかつ効果的な中和処理を行うことができる。 Moreover, in the neutralization process in waste water treatment process S20, the neutralization process of the 1st step which used limestone as a neutralizing agent (1st process), and the 2nd step of neutralization process which used slaked lime as a neutralizing agent A stepwise process consisting of (second step) can be performed. By performing stepwise neutralization in this way, efficient and effective neutralization can be performed.
具体的に、第１の工程では、硫化剤除去工程Ｓ３０で回収した硫化後液を中和処理槽に装入し、石灰石スラリーを添加して撹拌処理を施す。この第１の工程では、石灰石スラリーを添加することによって、硫化後液のｐＨを５〜６に調整する。ｐＨが５以下であるとアルミニウムが完全に除去されず、中和に使用する消石灰の使用量が増加する。 Specifically, in the first step, the post-sulfurization solution recovered in the sulfidizing agent removal step S30 is charged into a neutralization treatment tank, and a limestone slurry is added to perform a stirring treatment. In this first step, the pH of the post-sulfurized solution is adjusted to 5-6 by adding limestone slurry. When the pH is 5 or less, aluminum is not completely removed, and the amount of slaked lime used for neutralization increases.
次に、第２の工程では、石灰石スラリーを添加して第１段階の中和処理を施した溶液に対して、消石灰スラリーを添加して撹拌処理を施す。この第２の工程では、消石灰スラリーを添加することによって、硫化後液のｐＨを８．５〜９．５に引き上げる。 Next, in a 2nd process, a slaked lime slurry is added and the stirring process is performed with respect to the solution which added the limestone slurry and performed the neutralization process of the 1st step. In this second step, the pH of the post-sulfurized solution is raised to 8.5 to 9.5 by adding slaked lime slurry.
排水処理工程Ｓ２０では、このような２段階の中和処理を施すことによって、中和処理残渣（排水処理澱物）が生成され、テーリングダムに貯留される（テーリング残渣）。一方、排水処理工程Ｓ２０後の溶液（排水処理終液）は、排出基準を満たすものとなり系外に排出される。 In the wastewater treatment step S20, by performing such a two-step neutralization treatment, a neutralization residue (drainage treatment starch) is generated and stored in the tailing dam (tailing residue). On the other hand, the solution after the wastewater treatment step S20 (drainage treatment final solution) satisfies the discharge standard and is discharged out of the system.
ここで、排水処理工程Ｓ２０における中和処理では、硫化後液中に残留している酸、硫化剤や、鉄イオン、マグネシウムイオンやマンガンイオン等の不純物元素イオンの量に応じて、消石灰や石灰石等の中和剤の量が決定される。したがって、硫化後液に残留する酸、硫化剤や、不純物の量が多ければ、中和剤の使用量も多くなる。 Here, in the neutralization treatment in the wastewater treatment step S20, slaked lime or limestone is selected depending on the amount of acid, sulfurizing agent, and impurity element ions such as iron ions, magnesium ions, and manganese ions remaining in the solution after sulfidation. The amount of neutralizing agent is determined. Therefore, if the amount of acid, sulfurizing agent and impurities remaining in the solution after sulfiding is large, the amount of neutralizing agent used is also increased.
この点、本実施の形態においては、排水処理工程Ｓ２０に先立ち、硫化剤除去工程Ｓ３０で、硫化工程Ｓ１４で得られた硫化後液に対して、その硫化後液に溶存する硫化水素等の硫化剤を除去するようにしている。そして、その硫化剤除去工程Ｓ３０では、詳しくは後述するが、酸浸出で得られる浸出スラリーのＦｅ３＋濃度を２．９ｇ／Ｌ以上にし、該浸出スラリーに中和処理を施して水酸化鉄（III）を生成させて水酸化鉄（III）を含む浸出スラリーを得て、該水酸化鉄（III）を含む浸出スラリーを固液分離処理して得られる水酸化鉄（III）を含む浸出残渣を、硫化水素等の硫化剤を酸化固定化するための３価の鉄イオン源として用いている。水酸化鉄(III)は酸化鉄(III)と同様に、硫化剤を除去する反応を生じさせるためには硫酸に溶解させる必要があるが、水酸化鉄(III)は酸化鉄(III)よりも溶解しやすい。そのため、水酸化鉄(III)を硫化剤の除去反応に用いると、酸化鉄(III)を硫化剤の除去反応に用いる場合よりも、硫化剤除去工程Ｓ３０での硫酸の添加量を少なくすることができる。このことから、排水処理工程Ｓ２０に対して、硫酸や硫化剤濃度が低い硫化後液を移送させることができる。また、硫化剤を除去するための３価の鉄イオン源として、浸出液が中和工程Ｓ１３、硫化工程Ｓ１４、排水処理工程Ｓ２０を経て得られる中和処理残渣（排水処理澱物）のみを用いた場合と比較して、マグネシウム、マンガン、アルミニウム等の不純物の濃度が低い硫化後液を移送させることができる。このことから、排水処理工程Ｓ２０に対しては、硫酸や硫化剤濃度が低く、また、鉄、マグネシウム、マンガン、アルミニウム等の不純物の濃度が低い硫化後液を移送させることができる。その結果として、排水処理工程Ｓ２０にて使用する中和剤の使用量を効果的に低減させることができ、ニッケル酸化鉱石処理全体としても効率的な操業を行うことができるという効果も奏する。 In this respect, in the present embodiment, prior to the waste water treatment step S20, in the sulfidizing agent removal step S30, sulfidation such as hydrogen sulfide dissolved in the sulfidized solution obtained in the sulfidation step S14. The agent is removed. In the sulfidizing agent removing step S30, as will be described in detail later, the Fe 3+ concentration of the leaching slurry obtained by acid leaching is set to 2.9 g / L or more, and the leaching slurry is neutralized to give iron hydroxide ( III) is obtained to obtain a leaching slurry containing iron (III) hydroxide, and a leaching residue containing iron (III) hydroxide obtained by subjecting the leaching slurry containing iron (III) to solid-liquid separation treatment Is used as a trivalent iron ion source for oxidatively fixing a sulfurizing agent such as hydrogen sulfide. Iron (III) hydroxide, like iron (III) oxide, needs to be dissolved in sulfuric acid in order to cause a reaction to remove the sulfurizing agent, but iron (III) hydroxide is more soluble than iron (III) oxide. Is easy to dissolve. Therefore, when iron (III) hydroxide is used for the removal reaction of the sulfiding agent, the amount of sulfuric acid added in the sulfidizing agent removal step S30 should be less than when iron (III) oxide is used for the removal reaction of the sulfiding agent. Can do. For this reason, the post-sulfurization solution having a low sulfuric acid or sulfiding agent concentration can be transferred to the wastewater treatment step S20. Further, as a trivalent iron ion source for removing the sulfurizing agent, only the neutralization residue (drainage treatment starch) obtained by the leachate through the neutralization step S13, the sulfurization step S14, and the wastewater treatment step S20 was used. Compared to the case, a post-sulfurized solution having a low concentration of impurities such as magnesium, manganese, and aluminum can be transferred. From this, for the wastewater treatment step S20, a post-sulfurization solution having a low concentration of sulfuric acid or a sulfiding agent and a low concentration of impurities such as iron, magnesium, manganese, and aluminum can be transferred. As a result, it is possible to effectively reduce the amount of the neutralizing agent used in the wastewater treatment step S20, and there is also an effect that efficient operation can be performed as the entire nickel oxide ore treatment.
≪３．硫化剤の除去方法の詳細説明≫
上述したニッケル酸化鉱石の湿式製錬プロセスにおいて、硫化工程Ｓ１４での硫化処理を経て生成した硫化後液には、硫化反応を生じさせるために添加した硫化水素等の硫化剤が溶存していることがある。加えて、硫化水素以外の硫化剤を使用した場合、溶液の状態によっては硫化水素ガスが発生し、反応後の液に未反応の硫化水素ガスが溶存することがある。
≪3. Detailed explanation of removal method of sulfurizing agent≫
In the above-described nickel smelting ore hydrometallurgy process, the sulfidation agent such as hydrogen sulfide added to cause the sulfidation reaction is dissolved in the post-sulfurization liquid produced through the sulfidation process in the sulfidation step S14. There is. In addition, when a sulfiding agent other than hydrogen sulfide is used, hydrogen sulfide gas may be generated depending on the state of the solution, and unreacted hydrogen sulfide gas may be dissolved in the liquid after the reaction.
このように硫化後液に硫化水素等の硫化剤が残存している場合、系外に放流することができない。また、その硫化後液を固液分離工程Ｓ１２や排水処理工程Ｓ２０へ払い出すと、設備周辺において硫化水素の臭気が発生して環境トラブルが生じる可能性がある等、環境面や安全面で問題となる。 In this way, when a sulfurizing agent such as hydrogen sulfide remains in the liquid after sulfiding, it cannot be discharged out of the system. Also, if the sulfidized liquid is dispensed to the solid-liquid separation step S12 or the wastewater treatment step S20, there is a possibility of environmental troubles due to the possibility of hydrogen sulfide odor generated around the equipment, causing problems in terms of environment and safety. It becomes.
そこで、本実施の形態においては、硫化後液に含まれる硫化剤を硫黄として固定化、すなわち、溶存する硫化水素等の硫化剤を固体の硫黄Ｓ０の形態として固定化し、その硫化後液から回収除去するようにしている（硫化剤除去工程Ｓ３０）。以下では、より詳細に、硫化工程Ｓ１４において硫化水素ガスを硫化剤として用いたときに、硫化剤除去工程Ｓ３０にて硫化後液に残存した硫化水素を除去する態様を一例として説明する。 Therefore, in the present embodiment, the sulfidizing agent contained in the sulfidized liquid is fixed as sulfur, that is, a sulfiding agent such as dissolved hydrogen sulfide is fixed as a form of solid sulfur S 0 , and Recovery and removal are performed (sulfurizing agent removal step S30). Hereinafter, in more detail, an example of removing hydrogen sulfide remaining in the liquid after sulfidation in the sulfidizing agent removing step S30 when hydrogen sulfide gas is used as a sulfiding agent in the sulfiding step S14 will be described as an example.
具体的に、硫化剤除去工程Ｓ３０では、Ｆｅ３＋濃度が特定範囲の浸出スラリーを予備中和工程Ｓ１２１及び分離工程Ｓ１２２を有する固液分離工程Ｓ１２に供して得られる水酸化鉄（III）を含む浸出残渣を、３価の鉄イオン源として用いる。硫化水素を含む硫化後液に対して、この水酸化鉄（III）を含む浸出残渣を添加することで、硫化後液に含まれる硫化水素を固体硫黄の形態に固定化し除去する。 Specifically, in the sulfidizing agent removal step S30, iron (III) hydroxide obtained by subjecting a leaching slurry having a Fe 3+ concentration in a specific range to a solid-liquid separation step S12 having a preliminary neutralization step S121 and a separation step S122 is included. The leaching residue is used as a trivalent iron ion source. By adding the leaching residue containing iron (III) hydroxide to the post-sulfurization liquid containing hydrogen sulfide, the hydrogen sulfide contained in the post-sulfurization liquid is fixed and removed in the form of solid sulfur.
硫化工程Ｓ１４にて得られる硫化後液は、例えば、ニッケルイオン濃度が０．０２ｇ／Ｌ〜０．１０ｇ／Ｌ程度であり、鉄、マンガン、マグネシウム、アルミニウム、クロム、鉛等の不純物を含む硫酸酸性溶液である。また、硫化後液のｐＨは、例えば１．５〜２．０程度である。そして、上述のように硫化後液には、硫化工程Ｓ１４での硫化処理にて用いた硫化水素が、例えば濃度２０ｍｇ／Ｌ〜４００ｍｇ／Ｌ程度の割合で溶存している。 The post-sulfurization solution obtained in the sulfiding step S14 has a nickel ion concentration of about 0.02 g / L to 0.10 g / L, for example, and sulfuric acid containing impurities such as iron, manganese, magnesium, aluminum, chromium and lead. It is an acidic solution. Moreover, the pH of the solution after sulfidation is, for example, about 1.5 to 2.0. As described above, the hydrogen sulfide used in the sulfiding treatment in the sulfiding step S14 is dissolved in the post-sulfurizing solution at a concentration of about 20 mg / L to 400 mg / L, for example.
本実施の形態においては、このような硫化後液に対して、浸出工程Ｓ１１の酸浸出で得られる浸出スラリーのＦｅ３＋濃度を２．９ｇ／Ｌ以上にし、予備中和工程Ｓ１２１にて該浸出スラリーに中和処理を施して水酸化鉄（III）を生成させて水酸化鉄（III）を含む浸出スラリーを得て、分離工程Ｓ１２２にて該水酸化鉄（III）を含む浸出スラリーを固液分離処理して得られる水酸化鉄（III）を含む浸出残渣を、添加する。浸出スラリーに含まれるＦｅ３＋から生成させ浸出残渣に含まれる水酸化鉄(III)を、３価の鉄イオン源として用いると、下記式（４）の反応が生じることによって、硫化後液に溶存する硫化水素が酸化されて固体の硫黄として固定化される。このように、３価の鉄イオン源として水酸化鉄(III)を含む浸出残渣を用いることで、硫化水素を効果的に分解して低減することができる。なお、浸出残渣に含まれる水酸化鉄(III)は、通常、固体として含まれる場合は、酸化水酸化鉄（ＦｅＯ（ＯＨ））として存在し、液体として含まれる場合は溶解した状態（Ｆｅ３＋、ＯＨ−）として存在する。下記式（４）に示すように、水酸化鉄(III)を硫化水素と反応させるためには水酸化鉄(III)を硫酸に溶解させる必要がある。そのため、処理対象の硫化後液に含まれる硫酸では水酸化鉄(III)の溶解が不十分な場合は、水酸化鉄(III)を含む浸出残渣を硫化後液に添加するとともに、硫酸も硫化後液に添加する。
Ｆｅ（ＯＨ）３＋１／２Ｈ２Ｓ＋Ｈ２ＳＯ４
→ＦｅＳＯ４＋１／２Ｓ０＋３Ｈ２Ｏ （４）
In the present embodiment, the leaching slurry obtained by acid leaching in the leaching step S11 is made to have a Fe 3+ concentration of 2.9 g / L or more with respect to the post-sulfurization solution, and the leaching is performed in the preliminary neutralization step S121. The slurry is neutralized to produce iron hydroxide (III) to obtain a leaching slurry containing iron (III) hydroxide, and the leaching slurry containing iron (III) hydroxide is solidified in a separation step S122. A leaching residue containing iron (III) hydroxide obtained by liquid separation treatment is added. When iron (III) hydroxide, which is generated from Fe 3+ contained in the leaching slurry and contained in the leaching residue, is used as a trivalent iron ion source, it dissolves in the post-sulfurization solution by the reaction of the following formula (4). Hydrogen sulfide is oxidized and fixed as solid sulfur. Thus, by using a leaching residue containing iron (III) hydroxide as a trivalent iron ion source, hydrogen sulfide can be effectively decomposed and reduced. The iron hydroxide (III) contained in the leaching residue is usually present as iron oxide hydroxide (FeO (OH)) when contained as a solid, and in a dissolved state (Fe 3+ ) when contained as a liquid. , OH − ). As shown in the following formula (4), in order to react iron (III) hydroxide with hydrogen sulfide, it is necessary to dissolve iron (III) hydroxide in sulfuric acid. For this reason, if the sulfuric acid contained in the post-sulfurization solution to be treated does not sufficiently dissolve iron (III) hydroxide, a leach residue containing iron (III) hydroxide is added to the post-sulfurization solution, and the sulfuric acid is also sulfided. Add to post-solution.
Fe (OH) 3 + 1 / 2H 2 S + H 2 SO 4
→ FeSO 4 + 1 / 2S 0 + 3H 2 O (4)
そして、本実施の形態においては、浸出工程Ｓ１１の酸浸出で得られる浸出スラリー中のＦｅ３＋濃度は２．９ｇ／Ｌ以上である。これにより、硫化水素を極めて効果的に低減できる。本発明者の検討により、後述する実施例にて説明する図３に示されるように、硫化剤除去工程Ｓ３０において、浸出スラリー中のＦｅ３＋濃度と、硫化剤除去効果とには、相関があることが見出された。このことは、Ｆｅ３＋濃度を２．９ｇ／Ｌ以上の範囲に調整した浸出スラリーから得られる浸出残渣を用いることで、式（４）で示される水酸化鉄(III)による硫化水素除去反応の反応性が顕著に向上し、硫化水素を極めて効果的に低減できることによると推測される。 And in this Embodiment, the Fe3 + density | concentration in the leaching slurry obtained by the acid leaching of leaching process S11 is 2.9 g / L or more. Thereby, hydrogen sulfide can be reduced very effectively. As shown in FIG. 3, which will be described in an example described later, by the inventors' investigation, there is a correlation between the Fe 3+ concentration in the leaching slurry and the sulfiding agent removal effect in the sulfiding agent removal step S30. It was found. This means that by using a leaching residue obtained from a leaching slurry whose Fe 3+ concentration is adjusted to a range of 2.9 g / L or more, hydrogen sulfide removal reaction by iron (III) hydroxide represented by the formula (4) is performed. It is presumed that the reactivity is remarkably improved and hydrogen sulfide can be reduced extremely effectively.
浸出スラリー中のＦｅ３＋濃度の調整は、浸出工程Ｓ１１における浸出処理での硫酸の添加量を制御して浸出スラリー中の遊離硫酸濃度を調整することによって行うことができる。なお、遊離硫酸とは、余剰の硫酸、すなわち、金属元素と結合可能な硫酸イオン以外の硫酸である。遊離硫酸濃度は、水酸化ナトリウム溶液で中和滴定することで求められる。 The Fe 3+ concentration in the leaching slurry can be adjusted by adjusting the free sulfuric acid concentration in the leaching slurry by controlling the amount of sulfuric acid added in the leaching process in the leaching step S11. The free sulfuric acid is surplus sulfuric acid, that is, sulfuric acid other than sulfate ions that can be combined with a metal element. The free sulfuric acid concentration can be determined by neutralization titration with a sodium hydroxide solution.
図２は、浸出スラリー中の遊離硫酸濃度と浸出スラリー中のＦｅ３＋濃度との関係を示すグラフ図である。この図２に示されるように、遊離硫酸濃度が増加するに従い、浸出スラリー中のＦｅ３＋濃度が増加することが分かる。浸出工程Ｓ１１における硫酸による浸出処理では、原料鉱石に含まれる鉄が浸出残渣として固定化されて浸出スラリー中に含まれることになるが、浸出処理に寄与しなかった未反応の硫酸（遊離硫酸）により、浸出残渣として固定化された鉄が再溶解してＦｅ３＋の形態で浸出スラリー中に存在するようになる。したがって、図２に示されるように、浸出スラリー中の遊離硫酸濃度とＦｅ３＋濃度とには、比例関係が成立する。そのため、浸出工程Ｓ１１における浸出処理での硫酸の添加量を制御して浸出スラリー中の遊離硫酸濃度を調整することによって、浸出スラリー中のＦｅ３＋濃度を調整することができる。 FIG. 2 is a graph showing the relationship between the free sulfuric acid concentration in the leaching slurry and the Fe 3+ concentration in the leaching slurry. As shown in FIG. 2, it can be seen that as the free sulfuric acid concentration increases, the Fe 3+ concentration in the leaching slurry increases. In the leaching treatment with sulfuric acid in the leaching step S11, iron contained in the raw ore is fixed as a leaching residue and contained in the leaching slurry, but unreacted sulfuric acid (free sulfuric acid) that did not contribute to the leaching treatment. As a result, iron fixed as a leaching residue is redissolved and is present in the leaching slurry in the form of Fe 3+ . Therefore, as shown in FIG. 2, a proportional relationship is established between the free sulfuric acid concentration and the Fe 3+ concentration in the leaching slurry. Therefore, the Fe 3+ concentration in the leaching slurry can be adjusted by controlling the amount of sulfuric acid added in the leaching process in the leaching step S11 to adjust the free sulfuric acid concentration in the leaching slurry.
また、浸出スラリー中のＦｅ３＋濃度は、３．６ｇ／Ｌ以下とすることが好ましい。浸出スラリー中のＦｅ３＋濃度を高くするためには、浸出工程Ｓ１１での硫酸添加量を増やす必要がある。硫酸添加量を増やすと、コストが増加する。また、硫酸添加量を増やすと、遊離硫酸濃度上昇により予備中和工程Ｓ１２１での中和剤添加量が増加するため、コストが増加する。また、硫酸添加量を増やすと、予備中和工程Ｓ１２１において微細な粒子が発生しやすくなり、分離工程Ｓ１２２において固液分離不良が発生する。そのため、浸出スラリー中のＦｅ３＋濃度は高すぎないほうがよく、３．６ｇ／Ｌ以下が好ましい。 The Fe 3+ concentration in the leaching slurry is preferably 3.6 g / L or less. In order to increase the Fe 3+ concentration in the leaching slurry, it is necessary to increase the amount of sulfuric acid added in the leaching step S11. Increasing the amount of sulfuric acid increases the cost. Further, when the amount of sulfuric acid added is increased, the amount of neutralizing agent added in the preliminary neutralization step S121 increases due to an increase in the free sulfuric acid concentration, which increases the cost. Further, when the amount of sulfuric acid added is increased, fine particles are likely to be generated in the preliminary neutralization step S121, and solid-liquid separation failure occurs in the separation step S122. Therefore, the Fe 3+ concentration in the leaching slurry should not be too high, and is preferably 3.6 g / L or less.
なお、本実施の形態においては、図１に示すように、固液分離工程Ｓ１２で得られた浸出残渣を、湿式製錬プロセスにおける排水処理工程Ｓ２０での処理に装入し、排水処理工程Ｓ２０にて中和処理を施すようにする。上述したように、排水処理工程Ｓ２０では、水酸化カルシウム、炭酸カルシウムや水酸化ナトリウム等の中和剤を添加して溶液のｐＨを８．５〜９．５程度に調整する中和処理が行われる。したがって、排水処理工程Ｓ２０における処理に浸出残渣を装入することで、その浸出残渣が含む酸化鉄(III)等の鉄化合物から水酸化鉄(III)を生成することができ、浸出残渣が含む水酸化鉄（III）量を多くすることができる。図１において、硫化後液に添加する水酸化鉄(III)を含む浸出残渣は、浸出残渣に対して排水処理（中和処理）を施すことで得られる排水処理残渣（中和処理残渣）及び溶液の両者でもよいし、該排水処理（中和処理）を施した後に固液分離して溶液から分離された排水処理残渣（中和処理残渣）のみでもよい。 In the present embodiment, as shown in FIG. 1, the leaching residue obtained in the solid-liquid separation step S12 is charged into the treatment in the wastewater treatment step S20 in the hydrometallurgical process, and the wastewater treatment step S20. The neutralization treatment is performed at As described above, in the wastewater treatment step S20, a neutralization treatment is performed in which a neutralizing agent such as calcium hydroxide, calcium carbonate, or sodium hydroxide is added to adjust the pH of the solution to about 8.5 to 9.5. Is called. Therefore, by introducing a leaching residue into the treatment in the waste water treatment step S20, iron (III) hydroxide can be generated from an iron compound such as iron (III) contained in the leaching residue, and the leaching residue is included. The amount of iron hydroxide (III) can be increased. In FIG. 1, the leaching residue containing iron (III) hydroxide added to the sulfidized solution is a wastewater treatment residue (neutralization treatment residue) obtained by subjecting the leaching residue to wastewater treatment (neutralization treatment). Both of the solutions may be used, or only the wastewater treatment residue (neutralization residue) separated from the solution by solid-liquid separation after the wastewater treatment (neutralization treatment) may be used.
ここで、湿式製錬プロセスにおいて、浸出スラリーを固液分離して得られた浸出残渣は、その浸出スラリーを固液分離して得られた浸出液が中和工程Ｓ１３、硫化工程Ｓ１４、排水処理工程Ｓ２０を経て得られる中和処理残渣（排水処理澱物）等よりも、マグネシウム、マンガンや、アルミニウム等の不純物が少ない。そのため、本実施の形態のように、硫化剤除去工程Ｓ３０において、浸出残渣を用いることにより、上記式（４）で示される水酸化鉄(III)による硫化水素除去反応がマグネシウム、マンガンや、アルミニウム等の元素によって阻害され難いため、硫化水素を効果的に除去することができる。 Here, in the hydrometallurgical process, the leaching residue obtained by solid-liquid separation of the leaching slurry is the leaching liquid obtained by solid-liquid separation of the leaching slurry is the neutralization step S13, the sulfidation step S14, the wastewater treatment step. There are few impurities, such as magnesium, manganese, and aluminum, than the neutralization processing residue (waste water processing starch) obtained through S20. Therefore, as in the present embodiment, in the sulfidizing agent removing step S30, by using the leaching residue, the hydrogen sulfide removing reaction by iron (III) hydroxide represented by the above formula (4) can be performed with magnesium, manganese, or aluminum. Therefore, hydrogen sulfide can be effectively removed.
また、浸出スラリーを固液分離して得られた浸出残渣は、浸出液が中和工程Ｓ１３、硫化工程Ｓ１４、排水処理工程Ｓ２０を経て得られる中和処理残渣（排水処理澱物）等に比べて、マグネシウム、マンガンや、アルミニウム等の不純物が少なく鉄の含有割合が高い。したがって、本実施の形態のように、硫化剤除去工程Ｓ３０において、浸出残渣を硫化後液に添加することにより、添加する量に対する硫化水素の除去量が多くなり、硫化水素を効果的に除去することができる。 In addition, the leach residue obtained by solid-liquid separation of the leach slurry is compared with the neutralization residue (drainage treatment starch) obtained by the leachate through the neutralization step S13, the sulfurization step S14, and the wastewater treatment step S20. There are few impurities, such as magnesium, manganese, and aluminum, and the content rate of iron is high. Therefore, as in the present embodiment, by adding the leaching residue to the sulfidized solution in the sulfidizing agent removing step S30, the amount of hydrogen sulfide removed with respect to the amount added is increased, and hydrogen sulfide is effectively removed. be able to.
なお、硫化水素を固定化する３価の鉄イオン源として、硫酸鉄(III)を用いることも考えられるが、設備投資や資材購入等のコスト面で不利である。 Although iron (III) sulfate may be used as a trivalent iron ion source for immobilizing hydrogen sulfide, it is disadvantageous in terms of costs such as capital investment and material purchase.
硫化剤除去工程Ｓ３０後の硫化後液（処理後硫化後液）は、例えばｐＨは１．５〜２．０である。また、硫化剤除去工程Ｓ３０に供給する硫化後液の流量や、排水処理工程Ｓ２０に払い出す硫化剤除去工程Ｓ３０後の硫化後液の流量は、例えば、５００〜７００ｍ３／Ｈｒである。また、硫化後液に添加する水酸化鉄(III)を含む浸出残渣の供給流量は４０〜５０ｍ３／Ｈｒである。 The pH of the post-sulfurization solution (the post-treatment post-sulfurization solution) after the sulfiding agent removal step S30 is, for example, 1.5 to 2.0. The flow rate of the post-sulfurization solution supplied to the sulfidation agent removal step S30 and the flow rate of the post-sulfurization solution after the sulfidation agent removal step S30 discharged to the wastewater treatment step S20 are, for example, 500 to 700 m 3 / Hr. Moreover, the supply flow rate of the leaching residue containing iron (III) hydroxide added to the solution after sulfidation is 40 to 50 m 3 / Hr.
また、硫化剤除去工程Ｓ３０における処理では、硫化後液に対して浸出残渣を添加するとともに、エアレーションを行うことが好ましい。すなわち、浸出残渣に含まれる水酸化鉄(III)と硫化水素との反応は、エアレーションを行う曝気槽で生じさせることが好ましい。例えば、特許文献２に記載されているように、縦型円筒形状の反応容器と、その反応容器内に設けられた撹拌羽根と、反応容器内の底部に設けられた多数の吹出口を有する円環状のエアレーション管とを備える曝気槽に硫化後液を供給し、浸出残渣を添加し、撹拌しながら、硫化後液のスラリー１ｍ３あたり１．８Ｎｍ３以上の割合でエアレーションする。このようなエアレーションにより、硫化後液中に溶存する硫化水素の酸化を促進させることができ、より効率的に硫化水素を除去することができる。 Further, in the treatment in the sulfidizing agent removing step S30, it is preferable to add a leaching residue to the sulfidized solution and perform aeration. That is, the reaction between iron (III) hydroxide and hydrogen sulfide contained in the leaching residue is preferably caused in an aeration tank that performs aeration. For example, as described in Patent Document 2, a circle having a vertical cylindrical reaction vessel, a stirring blade provided in the reaction vessel, and a number of outlets provided at the bottom of the reaction vessel A solution after sulfidation is supplied to an aeration tank equipped with an annular aeration tube, a leaching residue is added, and aeration is performed at a rate of 1.8 Nm 3 or more per 1 m 3 of slurry of the sulfidation solution while stirring. By such aeration, it is possible to promote the oxidation of hydrogen sulfide dissolved in the liquid after sulfiding, and it is possible to more efficiently remove hydrogen sulfide.
硫化剤除去工程Ｓ３０で硫化水素が除去された処理後硫化後液は、固液分離工程Ｓ１２の洗浄液として用いてもよい。 The post-treatment post-sulfurization solution from which hydrogen sulfide has been removed in the sulfiding agent removal step S30 may be used as a cleaning solution in the solid-liquid separation step S12.
以上のように、本実施の形態に係る硫化水素の除去方法によれば、３価の鉄イオン源として、Ｆｅ３＋濃度が２．９ｇ／Ｌ以上である浸出スラリーから生成させた水酸化鉄(III)を含む浸出残渣を硫化水素の酸化の反応主体にすることで、硫化水素を効果的に低減させることができるため、硫化水素を十分に除去することができる。 As described above, according to the method for removing hydrogen sulfide according to the present embodiment, as a trivalent iron ion source, iron hydroxide (Fe 3+ concentration generated from a leached slurry having a concentration of 2.9 g / L or more ( By making the leaching residue containing III) the reaction main component of the oxidation of hydrogen sulfide, the hydrogen sulfide can be effectively reduced, so that the hydrogen sulfide can be sufficiently removed.
このように本発明によれば、硫化後液中の硫化剤を効果的に低減することができるため、ニッケルを回収するための硫化剤を多量に添加することができる。したがって、本発明は、ニッケル酸化鉱の湿式製錬プロセスにおいて、ニッケルロスの低減及び硫化剤の除去不良発生の抑制による環境面や安全面の改善ができることから、その工業的価値はきわめて高い。 Thus, according to the present invention, since the sulfurizing agent in the solution after sulfiding can be effectively reduced, a large amount of the sulfurizing agent for recovering nickel can be added. Therefore, since the present invention can improve the environmental and safety aspects by reducing the nickel loss and suppressing the occurrence of defective removal of the sulfiding agent in the nickel oxide ore hydrometallurgical process, its industrial value is extremely high.
また、硫化水素を除去した後の処理後硫化後液は、排水処理工程Ｓ２０に移送されて排水処理（中和処理）が施されるが、硫化水素が除去されていることから、その処理後硫化後液に対する排水処理では中和剤の使用量も有効に低減させることができ、ニッケル酸化鉱石処理全体としても効率的な操業を行うことができる。 Further, the post-treatment liquid after removal of hydrogen sulfide is transferred to the waste water treatment step S20 and subjected to waste water treatment (neutralization treatment). In the wastewater treatment for the post-sulfurization solution, the amount of neutralizing agent used can be effectively reduced, and the nickel oxide ore treatment as a whole can be efficiently operated.
なお、硫化剤除去工程Ｓ３０や排水処理工程Ｓ２０等のその他の工程において、微量の硫化水素が残留した場合や、そのまま系外に排出することができない有害ガスが生じた場合には、除害塔等の有害ガスを除去する設備で有害ガスを除去した後に、大気中に排出すればよい。また、処理後硫化後液は、固液分離工程Ｓ１２における処理の洗浄液として用いてもよい。 In other steps such as the sulfidizing agent removal step S30 and the wastewater treatment step S20, when a small amount of hydrogen sulfide remains or harmful gas that cannot be discharged out of the system is generated, What is necessary is just to discharge | emit it in air | atmosphere, after removing harmful gas with the equipment which removes harmful gases. Further, the post-treatment sulfidized solution may be used as a cleaning solution for the treatment in the solid-liquid separation step S12.
以下に、本発明について実施例を示して具体的に説明するが、本発明は下記の実施例に何ら限定されるものではない。 EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.
（実施例１〜８及び比較例１〜４）
図１に示すニッケル酸化鉱石の湿式製錬プロセスで、硫化後液の硫化水素の除去操作を行った。具体的には、図１に示すように、先ず、浸出工程Ｓ１１において、ニッケル酸化鉱石のスラリーをオートクレーブに装入し、高温高圧下で硫酸を用いて浸出処理を施すことによって浸出液と浸出残渣とを含有する浸出スラリーを得て、固液分離工程Ｓ１２において、浸出工程Ｓ１１で得られた浸出スラリーに、中和剤として炭酸カルシウムを添加して中和処理を施して水酸化鉄（III）を生成させて水酸化鉄（III）を含む浸出スラリーを得て（予備中和工程Ｓ１２１）、得られた水酸化鉄（III）を含む浸出スラリーを固液分離処理して浸出液と水酸化鉄（III）を含む浸出残渣スラリーとを得た（分離工程Ｓ１２２）。
(Examples 1-8 and Comparative Examples 1-4)
In the nickel oxide ore hydrometallurgical process shown in FIG. 1, the operation of removing hydrogen sulfide from the sulfidized liquid was performed. Specifically, as shown in FIG. 1, first, in the leaching step S11, a slurry of nickel oxide ore is charged into an autoclave and subjected to a leaching process using sulfuric acid under high temperature and high pressure. In the solid-liquid separation step S12, a calcium carbonate is added as a neutralizing agent to the leaching slurry obtained in the leaching step S11 to neutralize the iron (III) hydroxide. A leaching slurry containing iron (III) hydroxide is obtained (preliminary neutralization step S121), and the leaching slurry containing iron (III) obtained is subjected to solid-liquid separation treatment to obtain a leaching solution and iron hydroxide ( A leach residue slurry containing III) was obtained (separation step S122).
次に、浸出液に対して不純物を中和除去した（中和工程Ｓ１３）。そして、硫化工程Ｓ１４で、中和工程Ｓ１３で得られた中和終液に硫化剤として硫化水素ガスを添加して生成した亜鉛硫化物を分離し（脱亜鉛工程）、脱亜鉛工程後に硫化剤として硫化水素ガスを添加して生成したニッケル硫化物を回収した（ニッケル回収工程）。この硫化工程Ｓ１４における硫化反応により、中和終液中のニッケル及びコバルトが硫化され、ニッケル・コバルト混合硫化物が生成した。生成した硫化物は、硫化処理後のスラリーをシックナーにより固液分離して回収した。 Next, the impurities were neutralized and removed from the leachate (neutralization step S13). Then, in the sulfurization step S14, zinc sulfide formed by adding hydrogen sulfide gas as a sulfurizing agent to the neutralized final solution obtained in the neutralization step S13 is separated (dezincing step), and after the dezincing step, the sulfurizing agent As a result, hydrogen sulfide gas was added to recover the generated nickel sulfide (nickel recovery step). By the sulfidation reaction in this sulfidation step S14, nickel and cobalt in the neutralized final solution were sulfided to produce a nickel / cobalt mixed sulfide. The produced sulfide was recovered by solid-liquid separation of the slurry after the sulfidation treatment using a thickener.
一方、硫化物を分離回収した後の硫化後液に溶存する硫化水素の濃度は２０〜４００質量ｐｐｍであった。そこで、その硫化後液に溶存する硫化水素を除去する処理を行った（硫化剤除去工程Ｓ３０）。 On the other hand, the concentration of hydrogen sulfide dissolved in the liquid after sulfidation after separating and recovering sulfide was 20 to 400 ppm by mass. Then, the process which removes the hydrogen sulfide which melt | dissolves in the liquid after the sulfidation was performed (sulfurizing agent removal process S30).
硫化水素の除去処理（硫化剤除去工程Ｓ３０）においては、ニッケル酸化鉱石の湿式製錬プロセスの固液分離工程Ｓ１２で得られた浸出残渣スラリーに対して中和剤（塩基性化合物）として炭酸カルシウムと水酸化カルシウムを添加してｐＨを８．５〜９．５にし（排水処理工程Ｓ２０）、得られた排水処理工程Ｓ２０後の浸出残渣スラリー、すなわち水酸化鉄(III)を含む浸出残渣を、硫化後液に供給した。なお、全ての実施例１〜８及び比較例１〜４において水酸化鉄(III)を含む浸出残渣を添加し硫酸を添加しなかった。浸出スラリー中の遊離硫酸の量を変更して、各実施例１〜８及び比較例１〜４の浸出スラリー中のＦｅ３＋濃度を変更した。 In the hydrogen sulfide removal treatment (sulfurization agent removal step S30), calcium carbonate is used as a neutralizing agent (basic compound) for the leach residue slurry obtained in the solid-liquid separation step S12 of the nickel oxide ore hydrometallurgical process. And calcium hydroxide are added to adjust the pH to 8.5 to 9.5 (drainage treatment step S20), and the obtained leaching residue slurry after the wastewater treatment step S20, that is, the leaching residue containing iron (III) hydroxide is removed. The solution was supplied to the liquid after sulfidation. In all of Examples 1 to 8 and Comparative Examples 1 to 4, a leaching residue containing iron (III) hydroxide was added and sulfuric acid was not added. The amount of free sulfuric acid in the leaching slurry was changed to change the Fe 3+ concentration in the leaching slurries of Examples 1-8 and Comparative Examples 1-4.
なお、硫化剤除去工程Ｓ３０は、水酸化鉄(III)を含む浸出残渣を添加した後の硫化後液を、撹拌するとともに空気を吹き込む曝気槽で行った。また、硫化剤除去工程Ｓ３０後の曝気槽中のガスを除害塔に移送し、除害塔で水酸化ナトリウムに接触させた後に、除害塔の排気ガス排出口から排ガスとして排出した。また、硫化剤除去工程Ｓ３０を経た硫化後液は、排水処理工程Ｓ２０へ払い出した。 The sulfiding agent removal step S30 was performed in an aeration tank in which the sulfidized liquid after addition of the leaching residue containing iron (III) hydroxide was stirred and air was blown. Moreover, after transferring the gas in the aeration tank after the sulfidizing agent removal step S30 to the detoxification tower and bringing it into contact with sodium hydroxide in the detoxification tower, the exhaust gas was discharged from the exhaust gas outlet of the detoxification tower. Moreover, the post-sulfurization solution that passed through the sulfiding agent removal step S30 was discharged to the waste water treatment step S20.
なお、硫化剤除去工程Ｓ３０に供給する硫化後液は、ニッケル濃度が０．０２〜０．１０ｇ／Ｌ、鉄濃度が０．６〜１．４ｇ／Ｌ、アルミニウム濃度が３．５〜８．０ｇ／Ｌ、マグネシウム濃度が３．５〜８．５ｇ／Ｌであった。 In addition, the post-sulfurization solution supplied to the sulfurizing agent removing step S30 has a nickel concentration of 0.02 to 0.10 g / L, an iron concentration of 0.6 to 1.4 g / L, and an aluminum concentration of 3.5 to 8. The concentration was 0 g / L and the magnesium concentration was 3.5 to 8.5 g / L.
また、硫化後液に添加した水酸化鉄(III)を含む浸出残渣は、中和処理残渣（排水処理殿物）及び溶液（排水処理終液）からなる。そして、該中和処理残渣（排水処理殿物）は、比重１．１５〜１．３５ｇ／ｃｍ３、固形分濃度２０〜３５質量％、鉄品位３５〜４５質量％であった。また、該溶液（排水処理終液）は、ニッケル濃度が０．１ｍｇ／Ｌ以下、コバルト濃度が０．０５ｍｇ／Ｌ以下、鉄濃度が０．１ｍｇ／Ｌ以下であった。 Further, the leaching residue containing iron (III) hydroxide added to the solution after sulfidation consists of a neutralization treatment residue (drainage treatment residue) and a solution (drainage treatment final solution). And this neutralization processing residue (waste water treatment thing) was specific gravity 1.15-1.35g / cm < 3 >, solid content concentration 20-35 mass%, and iron grade 35-45 mass%. Further, the solution (final waste water treatment liquid) had a nickel concentration of 0.1 mg / L or less, a cobalt concentration of 0.05 mg / L or less, and an iron concentration of 0.1 mg / L or less.
また、操業変動の影響を抑えるために、ニッケル回収工程に供給される始液流量は１２００〜１４００ｍ３／Ｈｒかつ始液温度は７３℃、硫化剤除去工程Ｓ３０に供給される硫化後液の流量は５００〜７００ｍ３／Ｈｒ、排水処理工程Ｓ２０に払い出される硫化剤除去工程Ｓ３０後の硫化後液の流量は５００〜７００ｍ３／Ｈｒ、硫化後液に添加する水酸化鉄(III)を含む浸出残渣の供給流量は４０〜５０ｍ３／Ｈｒ、曝気槽のエアレーション流量は２７００〜３１００Ｎｍ３／Ｈｒとした。 Moreover, in order to suppress the influence of operational fluctuations, the initial flow rate supplied to the nickel recovery process is 1200 to 1400 m 3 / Hr, the initial liquid temperature is 73 ° C., and the flow rate of the post-sulfurization liquid supplied to the sulfiding agent removal step S30. Is 500-700 m 3 / Hr, the flow rate of the sulfidized liquid after the sulfidizing agent removal step S30 discharged to the waste water treatment step S20 is 500-700 m 3 / Hr, and leaching containing iron (III) hydroxide added to the sulfidized liquid The supply flow rate of the residue was 40 to 50 m 3 / Hr, and the aeration flow rate of the aeration tank was 2700 to 3100 Nm 3 / Hr.
浸出スラリー中のＦｅ３＋濃度、及び、排気ガス排出口の排ガス中の硫化水素ガス濃度の測定結果を、表１及び図３に示す。なお、硫化剤除去工程Ｓ３０後の処理後硫化後液のｐＨは１．５〜２．０であった。 Table 1 and FIG. 3 show the measurement results of the Fe 3+ concentration in the leaching slurry and the hydrogen sulfide gas concentration in the exhaust gas at the exhaust gas outlet. In addition, the pH of the post-treatment sulfidation solution after the sulfiding agent removal step S30 was 1.5 to 2.0.
表１及び図３に示すように、硫化剤除去工程Ｓ３０において浸出残渣スラリー（水酸化鉄(III)を含む浸出残渣）を添加し、浸出スラリー中のＦｅ３＋濃度が２．９０ｇ／Ｌ以上であった実施例１〜８では、浸出スラリー中のＦｅ３＋濃度が２．９０ｇ／Ｌ未満の比較例１〜４に比べて、硫化水素ガス濃度が低く、硫化水素を大幅に低減させることができることが分かった。 As shown in Table 1 and FIG. 3, a leaching residue slurry (leaching residue containing iron (III) hydroxide) is added in the sulfidizing agent removal step S30, and the Fe 3+ concentration in the leaching slurry is 2.90 g / L or more. In Examples 1-8, the concentration of Fe 3+ in the leaching slurry is lower than that of Comparative Examples 1 to 4 in which the Fe 3+ concentration is less than 2.90 g / L, and hydrogen sulfide can be greatly reduced. I understood.
Claims (7)
前記酸浸出では、得られる浸出スラリー中のＦｅ３＋濃度を２．９ｇ／Ｌ以上にし、
前記固液分離では、前記浸出スラリーに中和処理を施して水酸化鉄（III）を生成させて水酸化鉄（III）を含む浸出スラリーを得た後、該水酸化鉄（III）を含む浸出スラリーを固液分離処理してニッケルを含む浸出液と水酸化鉄（III）を含む浸出残渣とを得、
前記硫化後液に対して、前記水酸化鉄（III）を含む浸出残渣を添加することにより、該硫化後液に含まれる硫化剤を固定化し除去する
硫化剤の除去方法。 The leaching slurry obtained by acid leaching of nickel oxide ore with sulfuric acid under high temperature and high pressure is subjected to solid-liquid separation to obtain a leaching solution containing nickel and a leaching residue. In a hydrometallurgical process for producing a sulfide and a post-sulfurization liquid, a method for removing a sulfurizing agent that removes a sulfurizing agent dissolved in the post-sulfurization liquid obtained by separating the sulfide of nickel,
In the acid leaching, the Fe 3+ concentration in the obtained leaching slurry is set to 2.9 g / L or more,
In the solid-liquid separation, the leaching slurry is neutralized to produce iron hydroxide (III) to obtain a leaching slurry containing iron hydroxide (III), and then the iron hydroxide (III) is contained. The leaching slurry is subjected to solid-liquid separation treatment to obtain a leaching solution containing nickel and a leaching residue containing iron (III) hydroxide,
A method for removing a sulfiding agent, wherein a leaching residue containing the iron (III) hydroxide is added to the sulfidized solution to fix and remove the sulfiding agent contained in the sulfidized solution.
前記硫化後液に対して、前記排水処理後の前記水酸化鉄（III）を含む浸出残渣を添加する
請求項１に記載の硫化剤の除去方法。 Wastewater treatment for detoxifying the leaching residue containing the iron (III) hydroxide obtained by solid-liquid separation of the leaching slurry by neutralizing the post-sulfurization solution in the hydrometallurgical process The method according to claim 1, wherein a leaching residue containing the iron (III) hydroxide after the wastewater treatment is added to the post-sulfurized solution.
請求項１又は２に記載の硫化剤の除去方法。 In the neutralization treatment for the leaching slurry, the pH of the leaching slurry is set to 2.5 to 3.2.
The method for removing a sulfurizing agent according to claim 1 or 2.
請求項１乃至３のいずれかに記載の硫化剤の除去方法。 The method for removing a sulfurizing agent according to any one of claims 1 to 3, wherein sulfuric acid is added to the post-sulfurized solution together with the leaching residue containing the iron (III) hydroxide.
請求項１乃至４のいずれかに記載の硫化剤の除去方法。 The post-sulfurization solution is a sulfuric acid acidic solution having a nickel ion concentration of 0.02 to 0.10 g / L and containing at least one selected from iron, manganese, magnesium, aluminum, and chromium. The removal method of the sulfurizing agent in any one.
請求項１乃至５のいずれかに記載の硫化剤の除去方法。 The method for removing a sulfurizing agent according to any one of claims 1 to 5, wherein a leaching residue containing the iron (III) hydroxide is added to the post-sulfurized solution and aeration is performed.
前記固液分離工程は、前記浸出工程で得られた前記浸出スラリーに中和処理を施して水酸化鉄（III）を生成させて水酸化鉄（III）を含む浸出スラリーを得る予備中和工程、及び、該予備中和工程で得られた前記水酸化鉄（III）を含む浸出スラリーを固液分離処理して浸出液と水酸化鉄（III）を含む浸出残渣とを得る分離工程を有し、
前記浸出工程では、前記浸出スラリー中のＦｅ３＋濃度を２．９ｇ／Ｌ以上にし、
前記硫化剤除去工程では、前記ニッケルの硫化物を分離して得られた前記硫化後液に対して、前記水酸化鉄（III）を含む浸出残渣を添加することにより、前記硫化後液に含まれる硫化剤を固定化し除去する
ニッケル酸化鉱石の湿式製錬方法。 Nickel oxide ore is leached with sulfuric acid under high temperature and high pressure to obtain a leaching slurry, and solid-liquid separation is performed to obtain a leaching solution containing nickel and a leaching residue by solid-liquid separation of the leaching slurry obtained in the leaching step. Obtained in a neutralization step, a neutralization step of adding a neutralizing agent to the leachate obtained in the solid-liquid separation step to obtain a neutralized final solution containing nickel and a neutralized starch containing impurity elements, and A sulfurization step of obtaining a nickel sulfide and a post-sulfurization solution by subjecting the neutralized final solution to a sulfurization treatment with a sulfurizing agent; and the post-sulfurization solution obtained by separating the nickel sulfide A method for hydrometallizing nickel oxide ore having a sulfiding agent removing step for fixing and removing the sulfiding agent,
The solid-liquid separation step is a pre-neutralization step in which the leaching slurry obtained in the leaching step is neutralized to produce iron (III) hydroxide to obtain a leaching slurry containing iron (III) hydroxide. And a separation step in which the leaching slurry containing the iron (III) hydroxide obtained in the preliminary neutralization step is subjected to solid-liquid separation treatment to obtain a leaching solution and a leaching residue containing iron (III) hydroxide. ,
In the leaching step, the Fe 3+ concentration in the leaching slurry is set to 2.9 g / L or more,
In the sulfidizing agent removing step, the sulfidation liquid containing iron hydroxide (III) is added to the post-sulfurization liquid obtained by separating the nickel sulfide, thereby adding to the post-sulfurization liquid. A method for hydrometallizing nickel oxide ore that fixes and removes the sulfurizing agent.
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| WO2017094308A1 (en) * | 2015-12-01 | 2017-06-08 | 住友金属鉱山株式会社 | Sulfurizing agent removal method |
| JP2017115231A (en) * | 2015-12-25 | 2017-06-29 | 住友金属鉱山株式会社 | Method for removing sulfurizing agent |
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