AU2002217171A1 - Method for the hydrolytic precipitation of iron - Google Patents
Method for the hydrolytic precipitation of ironInfo
- Publication number
- AU2002217171A1 AU2002217171A1 AU2002217171A AU2002217171A AU2002217171A1 AU 2002217171 A1 AU2002217171 A1 AU 2002217171A1 AU 2002217171 A AU2002217171 A AU 2002217171A AU 2002217171 A AU2002217171 A AU 2002217171A AU 2002217171 A1 AU2002217171 A1 AU 2002217171A1
- Authority
- AU
- Australia
- Prior art keywords
- iron
- zinc
- solution
- stage
- ferrous
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims description 144
- 229910052742 iron Inorganic materials 0.000 title claims description 69
- 238000000034 method Methods 0.000 title claims description 43
- 238000001556 precipitation Methods 0.000 title claims description 38
- 230000003301 hydrolyzing effect Effects 0.000 title claims description 5
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 39
- 229910052725 zinc Inorganic materials 0.000 claims description 39
- 239000011701 zinc Substances 0.000 claims description 39
- 229910052935 jarosite Inorganic materials 0.000 claims description 23
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical group [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 19
- 230000007935 neutral effect Effects 0.000 claims description 19
- 229910000859 α-Fe Inorganic materials 0.000 claims description 19
- 239000002253 acid Substances 0.000 claims description 17
- 239000002244 precipitate Substances 0.000 claims description 17
- 238000002386 leaching Methods 0.000 claims description 14
- 229910052751 metal Inorganic materials 0.000 claims description 14
- 239000002184 metal Substances 0.000 claims description 14
- 238000006386 neutralization reaction Methods 0.000 claims description 14
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 12
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 claims description 10
- 239000012141 concentrate Substances 0.000 claims description 10
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 claims description 10
- 239000011686 zinc sulphate Substances 0.000 claims description 10
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims description 8
- 235000009529 zinc sulphate Nutrition 0.000 claims description 8
- 238000005868 electrolysis reaction Methods 0.000 claims description 7
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 6
- -1 ferrous metals Chemical class 0.000 claims description 6
- 238000011084 recovery Methods 0.000 claims description 6
- 239000011734 sodium Substances 0.000 claims description 6
- 229910021653 sulphate ion Inorganic materials 0.000 claims description 6
- 229910052733 gallium Inorganic materials 0.000 claims description 5
- 239000007789 gas Substances 0.000 claims description 5
- 229910052738 indium Inorganic materials 0.000 claims description 5
- 229910052700 potassium Inorganic materials 0.000 claims description 5
- 229910052708 sodium Inorganic materials 0.000 claims description 5
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 claims description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 229910052732 germanium Inorganic materials 0.000 claims description 4
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 claims description 4
- 239000001301 oxygen Substances 0.000 claims description 4
- 229910052760 oxygen Inorganic materials 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 3
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 3
- 238000009835 boiling Methods 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 3
- 239000011591 potassium Substances 0.000 claims description 3
- 235000010269 sulphur dioxide Nutrition 0.000 claims description 3
- 239000004291 sulphur dioxide Substances 0.000 claims description 3
- 239000003513 alkali Substances 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims 1
- 239000000243 solution Substances 0.000 description 58
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical group [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 12
- 238000006722 reduction reaction Methods 0.000 description 12
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 11
- 150000002739 metals Chemical class 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 8
- 239000001117 sulphuric acid Substances 0.000 description 7
- 235000011149 sulphuric acid Nutrition 0.000 description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 6
- 230000003472 neutralizing effect Effects 0.000 description 6
- 239000011787 zinc oxide Substances 0.000 description 6
- 229910052595 hematite Inorganic materials 0.000 description 4
- 239000011019 hematite Substances 0.000 description 4
- 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 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910001308 Zinc ferrite Inorganic materials 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- 239000010931 gold Substances 0.000 description 3
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 3
- 239000011133 lead Substances 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- 239000004332 silver Substances 0.000 description 3
- WGEATSXPYVGFCC-UHFFFAOYSA-N zinc ferrite Chemical compound O=[Zn].O=[Fe]O[Fe]=O WGEATSXPYVGFCC-UHFFFAOYSA-N 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 2
- 229910003202 NH4 Inorganic materials 0.000 description 2
- 239000007832 Na2SO4 Substances 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 229910052598 goethite Inorganic materials 0.000 description 2
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 229910052938 sodium sulfate Inorganic materials 0.000 description 2
- 229910000368 zinc sulfate Inorganic materials 0.000 description 2
- 229910002588 FeOOH Inorganic materials 0.000 description 1
- JSKQRADCWGNYQD-UHFFFAOYSA-N N.O.[Na] Chemical compound N.O.[Na] JSKQRADCWGNYQD-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 235000014413 iron hydroxide Nutrition 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- UGZADUVQMDAIAO-UHFFFAOYSA-L zinc hydroxide Chemical compound [OH-].[OH-].[Zn+2] UGZADUVQMDAIAO-UHFFFAOYSA-L 0.000 description 1
- 229940007718 zinc hydroxide Drugs 0.000 description 1
- 229910021511 zinc hydroxide Inorganic materials 0.000 description 1
Description
METHOD FOR THE HYDROLYTIC PRECIPITATION OF IRON
The present invention relates to a method for the hydrolytic precipitation of iron from a sulphate solution as jarosite. A sulphate-containing solution, with iron present in the solution in divalent form, is routed to an iron precipitation stage, where the iron is oxidised to the trivalent form using oxygen- containing gas. Also present in the precipitation stage are Na, K or NH4 ions and jarosite nuclei.
Zinc calcine, obtained by roasting sulphidic zinc concentrates, is generally used as the starting material in the electrolytic preparation of zinc. The chief component of the calcine is zinc oxide, ZnO, but some of the zinc is also bound to iron in the form of zinc ferrite ZnOFe2O3. The amount of zinc ferrite is usually so considerable that zinc recovery from that is unavoidable. Zinc oxide is easily soluble even at high pH values (3-5) whereas ferrite has to be leached at higher acid content. Ferrite leaching is performed in a separate stage, where both zinc and iron are dissolved according to the following reaction: ZnOFe2O3 + 4H2SO4 ==> ZnSO4 + Fe2(SO4)3 + 4H2O (1 ) The iron has to be precipitated from the solution obtained before the solution can be returned to the neutral leach and from there to zinc sulphate solution purification and electrolysis. There are no clear guidelines as to how much iron may be in the solution to be returned to the neutral leach, but generally the level of 5 g/l Fe is considered acceptable. The above process is described in e.g. US patents 3,434,947 and 3,493,365.
In industrial processes zinc oxide leaching, neutral leach, is generally carried out in two stages at a pH of 2 - 5 and ferrite leaching can also be performed in two stages when the acid content is between 30 - 100 g/l. A precipitate is obtained from ferrite leaching, which contains the lead, silver and gold from the calcine. The recovery of these materials may be profitable in favourable conditions. The solution from ferrite leaching, which contains the dissolved
zinc and iron, is very acidic, and if often pre-neutralised, before the iron is precipitated from it. Three iron precipitation processes are in use and in them the iron is precipitated as either jarosite Na[Fe3(SO4)2(OH)6], goethite FeOOH or hematite Fe2O3.
When iron is precipitated as jarosite or goethite, a neutralising agent is to be used in precipitation to neutralise the sulphuric acid released in the reactions. Normally the neutralising agent is a calcine. When neutralisation is carried out with a calcine, the indium, gallium and most of the germanium contained in the solution remain in the jarosite precipitate in the same way as the zinc, copper and cadmium as well as the indium, gallium, silver, gold and lead contained in the ferrite of the calcine. In most cases these valuable metals are lost in the iron precipitate. In order to minimise the amount of calcine needed for neutralisation and therefore minimise losses as much as possible it is worth using pre-neutralisation.
When iron is precipitated as hematite, it occurs hydrolytically by oxidising from the solution without neutralisation, from which solution the iron is first reduced from trivalent to divalent form: 2FeS04 + O2(g) + 2 H2O ==> Fe2O3 + 2H2SO4 (2)
The loss of valuable metals mentioned above is avoided in hematite precipitation. The precipitation of iron must however be performed in an autoclave at temperatures of about 200 °C, which has essentially restricted the adoption of the method, even though hematite is in fact the most environmentally friendly form of iron precipitate.
The hydrolytic precipitation of iron without neutralisation in atmospheric conditions would give great benefits, and a certain method for the precipitation of iron as jarosite is described in US patent 4,305,915. The method is based on the fact that jarosite is stable in very acidic solutions and that the partial precipitation of iron is possible using the following balance reaction, when starting from a neutral ferri solution:
3Fe2(SO4)3 + Na2SO4 + 12H2O <=> 2Na[Fe3(SO4)2(OH)6] + 6 H2SO4 (3)
After ferrite leaching, the solution is cooled and the residual acid is neutralised for instance with a calcine. After neutralisation, the solution is heated and the iron may be precipitated from the solution in the presence of sodium, potassium or ammonium ions and recycled jarosite without the addition of a neutralising agent. The industrial realisation of this method has not however been successful, since the method is not economically profitable. In the first place, the solution containing trivalent iron from the ferrite leaching must be cooled before pre-neutralisation, so that the precipitation of iron does not take place at this stage. The second important factor is that iron cannot be precipitated out in the precipitation stage at sufficiently low contents, because the precipitation rate slows down due to the large amount of sulphuric acid generated in the reaction. In order for the precipitation to be successful, the solution has to be diluted to about half before precipitation. Precipitation of iron succeeds best from a hot solution, which means the solution has to be reheated almost to its boiling point. Cooling and heating as well as dilution of the solution make it uneconomic.
The method now developed will eliminate the disadvantages of the processes described above and make it possible to precipitate iron hydrolytically from a sulphate solution as a very pure jarosite. The sulphate solution, in which iron is dissolved in divalent ferrous form, is routed to the iron precipitation stage where the iron is oxidised into trivalent form using oxygen-containing gas. Present in the precipitation stage are alkali ions such as sodium, potassium or ammonium ions as well as jarosite nuclei, and the temperature of the solution is at most that of the boiling point of the solution. Precipitation is thus carried out in atmospheric conditions. The precipitation method is suitable for processes where iron is precipitated as jarosite. The essential features of the invention will be made apparent in the attached claims.
It is possible with this method to treat for instance all the zinc concentrates on the market cost-effectively. Using this method it is possible to recover all the valuable metals contained in zinc calcine in conditions that are technically easy to control. In the above-mentioned processes iron is always precipitated as jarosite from a trivalent solution. The method of this invention is based on the fact that iron is precipitated from a solution where the iron is in divalent ferrous form. When precipitation is performed from a ferrous iron solution considerably greater precipitation rates are achieved than that in the method described for example in US patent 4,305,914. Iron can be precipitated from a ferrous iron solution without a separate oxidation stage. The amount of zinc in the resulting jarosite is very small, only 0.1 - 0. 3 %.
The method of the invention is illustrated by flow chart 1.
In flow chart 1 the method of the invention is combined with an electrolytic zinc process, but please note that the method can be adapted for the precipitation of iron from other non-ferrous metal recovery processes, such as those of copper and nickel. In the method shown in flow chart 1 zinc calcine 1 is used as feed, which usually contains also other valuable metals. The zinc of the calcine is usually in the form of zinc oxide, but some of the zinc is also bound to the iron as zinc ferrite. The first treatment stage of the zinc calcine 1 is a neutral leach, which is preferable in two stages as is often the practice. In the neutral leach stages the calcine is leached with a dilute return acid solution of electrolysis so that the pH of the solution is maintained in the range of 2 - 5. From the first neutral leach stage 2 the zinc sulphate solution 3 obtained is taken to electrolysis via solution purification (not shown in detail in the diagram). The precipitate 4 from the first leach stage is taken to the second neutral leach stage 5, where the rest of the zinc oxide in the calcine dissolves.
The precipitate 6 from the second neutral leach stage 5 is routed to ferrite leaching i.e. a strong acid leach 7, which is carried out using return acid.
This stage may also be single or multi-stage. The H2SO4 content of the solution in the strong acid leach is of the order of 30 - 100 g/l. Precipitate 8 is obtained from ferrite leaching, containing mainly lead, silver, gold and other insoluble compounds such as silicates and gypsum. The precipitate may be routed to a valuable metals recovery process.
The calcine iron in the solution 9 generated in ferrite leaching is mainly trivalent as normal, but the solution is not now taken to the usual pre- neutralisation and iron precipitation, instead in accordance with the invention the iron is reduced to divalent form in a reduction stage 10. Reduction is carried out preferably using zinc concentrate or possibly for instance with sulphur dioxide. The following reactions occur in reduction, depending on the reductant: Fe2(SO4)3 + ZnS = 2FeSO4 + ZnSO4 + S° (4) Fe2(SO4)3 + SO2 + 2 H2O = 2FeSO4 + 2H2SO4 (5)
The precipitate 11 generated from reduction stage 10 contains sulphur formed in reduction and possibly the concentrate routed surplus, and it may be routed back to the roaster.
The reduction stage solution 12 is acidic, and has to be neutralised before the iron is precipitated. The solution now contains divalent iron and there is no danger of precipitation even at high temperatures, so that there is no need to cool the solution before pre-neutralisation. The solution can be neutralised as usual using zinc calcine, since ferrous iron hydroxide is more soluble than zinc hydroxide, so that iron remains in solution.
Pre-neutralisation can be performed in many different stages of the process, but the most beneficial is in the second stage 5 of the neutral leach, where the iron (ll)-bearing solution is neutralised at as high a pH value as possible. In general the pH is raised at this stage to about 3. When neutralising is performed in the second stage of the neutral leach, the neutraliser is the
precipitate from the first stage i.e. the undissolved zinc calcine, which is fed at this stage together with ferrite. The second neutral leach stage 5 solution 13 is routed to an iron precipitation stage 14. Iron is oxidised with oxygen- containing gas to trivalent in a solution that includes jarosite-forming ions (Na, K, NH4 etc). Iron is then precipitated as jarosite according to the following reaction: 6FeSO4 + Na2SO4 + 1.502 + 9 H2O = 2Na[Fe3(SO4)2(OH)6] + 3 H2SO4 (6)
Since iron is not precipitated in the pre-neutralisation stage 5, an internal circulation of iron in the strong acid leach and reduction stage is avoided, as only the ferrite precipitate that remains undissolved in the neutral leach is taken to the strong acid leach stage 7. The iron-containing solution 13 is routed after neutralisation directly to an iron precipitation 14. The iron precipitation stage yields a jarosite precipitate free of valuable metals and a zinc sulphate solution 15, that has such a low amount of iron that the solution can be taken to the first neutral leach stage.
It is known that the metals such as gallium, indium and germanium, which are in zinc concentrate in small amounts dissolve during ferrite leaching and are always precipitated with ferric iron. The separation of these metals is very difficult if the iron is kept in ferric form the whole time. As the iron in the solution going to pre-neutralisation is now divalent, the recovery of the above-mentioned metals is possible for example by neutralising some of the solution separately before it is taken to the actual neutralising stage 5. In this case the solution is neutralised preferably at least to a pH value of 4, whereby an iron-free precipitate containing Ga, In and Ge is achieved.
When using the method of this invention, it can be seen that the valuable materials contained in zinc concentrate can be recovered well at different stages and that the resulting jarosite is pure. When iron is precipitated from a ferrous iron solution, it is shown e.g. from reaction (6), that only half the
amount of sulphuric acid is generated compared with that generated in a ferric iron solution precipitation as in reaction (3). If zinc concentrate is used in the ferric iron reduction stage 10, the reduction reactions do not produce sulphuric acid, and thus only half as much sulphuric acid is generated as in conventional processes.
The flow chart shows a method where the solution coming from ferrite leaching is reduced in a separate reduction stage, but reduction can also take place in connection with the strong acid leach stage without a separate reduction stage.
The precipitation of divalent iron from a solution is described further by the following example.
Example 1
A solution was treated that contained zinc sulphate corresponding to 100 g/l Zn2+ and in addition 25 g/l ferrous iron, 2.5 g/l NH4 and 10 g/l of sulphuric acid plus an additional 200 g/l jarosite nuclei. The solution was heated to a temperature of 100 °C in a closed vessel. The slurry was mixed well and O2 gas was fed into it under the propeller, so that the partial pressure of the oxygen was held at 0.5 bar. The total iron and ferrous iron were monitored with samples, and the results are shown in the table below. The results also plainly show that in a few hours the iron can be made to precipitate to such a low level that it is possible to return the solution to the first neutral leach stage. Based on X-ray diffraction investigation the resulting precipitate was jarosite. The filtering properties of the jarosite precipitate were good. The amount of zinc left in the final precipitate was minimal.
This example indicates that sufficient iron is precipitated even though the solution is only neutralised up to the point where it still contains 10g/l sulphuric acid, which corresponds to a pH value of about 1. Professionals in the field know that the results will improve considerably if the solution is
neutralised further, for instance to a pH value of 2 - 4, which is completely realistic. In addition the ammonium content of the example was lower than is usually the case in zinc processes. The required ammonium, NH4, can also be fed as ammonia, NH3, to the precipitation stage, wherein a little less acid is generated:
6FeS04 + 2NH3 + 1.5O2 + 9 H2O => 2NH4[Fe3(SO4)2(OH)6] + 2 H2SO4 (7) Instead of ammonium sodium hydroxide NaOH may also be used. Since such unfavourable conditions also give such a good result, it is absolutely clear that with higher pH levels, the results will be even better.
Table 1
Claims (14)
1. A method for the precipitation of iron hydrolytically from a solution containing sulphates and non-ferrous metals, characterised in that iron is present in the sulphate solution in ferrous form, and the iron is oxidised into trivalent form using oxygen-containing gas in the iron precipitation stage, where sodium, potassium or ammonium ions and jarosite nuclei are present and that the temperature of the precipitation stage is at most that of the boiling point of the solution.
2. A method according to claim 1 , characterised in that the non-ferrous metal is zinc.
3. A method according to claim 1 , characterised in that the non-ferrous metal is nickel.
4. A method according to claim 1 , characterised in that the non-ferrous metal is copper.
5. A method according to claim 2, characterised in that the zinc sulphate- containing solution including ferrous iron is achieved by leaching the ferrite included in the zinc calcine with return acid of a zinc electrolysis, after which the ferric iron generated in the leach is reduced to ferrous form.
6. A method according to claim 5, characterised in that the ferric iron is reduced using zinc concentrate.
7. A method according to claim 5, characterised in that the ferric iron is reduced using sulphur dioxide.
8. A method according to claim 2, characterised in that the zinc sulphate- containing solution including ferrous iron is achieved by leaching the ferrite included in zinc calcine with return acid of a zinc electrolysis and that the reduction of the generated ferric iron is carried out using zinc concentrate, which is added to a ferrite leach stage.
9. A method according to claim 2, characterised in that the ferrous iron contained in the zinc sulphate containing solution is neutralised with zinc calcine.
10. A method according to claim 2, characterised in that the ferrous iron contained in the zinc sulphate containing solution is neutralised by routing the solution to the latter stage of a two-stage neutral leach of zinc calcine.
1 1. A method according to claim 2, characterised in that the ferrous iron contained in the zinc sulphate containing solution is neutralised at least to a pH level of 4 in order to precipitate gallium, indium and germanium.
12. A method for the hydrolytic precipitation of iron as jarosite from a sulphate-containing solution in connection with zinc recovery, whereby zinc calcine is leached in a two-stage neutral leach; the zinc sulphate solution formed is taken to electrolysis and the remaining undissolved ferrite is leached with return acid of the electrolysis in a strong acid leach stage, characterised in that the ferric iron dissolved in the strong acid leach is reduced to divalent form, after which the precipitate formed is routed to a zinc roaster and the solution to the second stage of the neutral leach, where the solution is neutralised using the residue from the first neutral leach stage; a residue from the second neutralisation stage is routed to the strong acid leach and the neutralised solution is routed to the iron precipitation stage, where the iron is precipitated as jarosite with oxygen in the presence of alkali or ammonium ions and jarosite nuclei.
13. A method according to claim 12, characterised in that the ferric iron is reduced using zinc concentrate.
14. A method according to claim 12, characterised in that the ferric iron is reduced using sulphur dioxide.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI20002699A FI20002699A0 (en) | 2000-12-08 | 2000-12-08 | Process for hydrolytic precipitation of iron |
| FI20002699 | 2000-12-08 | ||
| PCT/FI2001/001065 WO2002046481A1 (en) | 2000-12-08 | 2001-12-07 | Method for the hydrolytic precitpitation of iron |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2002217171A1 true AU2002217171A1 (en) | 2002-08-22 |
| AU2002217171B2 AU2002217171B2 (en) | 2006-03-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU1717102A Pending AU1717102A (en) | 2000-12-08 | 2001-12-07 | Method for the hydrolytic precitpitation of iron |
| AU2002217171A Expired AU2002217171B2 (en) | 2000-12-08 | 2001-12-07 | Method for the hydrolytic precipitation of iron |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU1717102A Pending AU1717102A (en) | 2000-12-08 | 2001-12-07 | Method for the hydrolytic precitpitation of iron |
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| EP (1) | EP1339883B1 (en) |
| JP (1) | JP4094949B2 (en) |
| KR (1) | KR100845169B1 (en) |
| CN (1) | CN1249257C (en) |
| AT (1) | ATE336595T1 (en) |
| AU (2) | AU1717102A (en) |
| BR (1) | BR0116028B1 (en) |
| CA (1) | CA2429889C (en) |
| DE (1) | DE60122370D1 (en) |
| EA (1) | EA005237B1 (en) |
| ES (1) | ES2269520T3 (en) |
| FI (1) | FI20002699A0 (en) |
| MX (1) | MXPA03005114A (en) |
| NO (1) | NO333462B1 (en) |
| PE (1) | PE20020807A1 (en) |
| WO (1) | WO2002046481A1 (en) |
| ZA (1) | ZA200304050B (en) |
Families Citing this family (32)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI116071B (en) * | 2003-02-26 | 2005-09-15 | Outokumpu Oy | Method for recovering zinc by countercurrent leaching |
| FI20030612A (en) * | 2003-04-23 | 2004-10-24 | Outokumpu Oy | Process for the treatment of waste materials arising in a metallurgical process |
| FI118226B (en) * | 2005-12-29 | 2007-08-31 | Outokumpu Technology Oyj | A method for recovering rare metals in a zinc leaching process |
| EP1971697B1 (en) * | 2006-01-10 | 2012-07-25 | Murrin Murrin Operations Pty Ltd | Hematite precipitation |
| JP4961603B2 (en) * | 2006-07-14 | 2012-06-27 | Ｄｏｗａメタルマイン株式会社 | Method for treating gallium-containing solution |
| WO2008128278A2 (en) * | 2007-04-19 | 2008-10-30 | Metallica Minerals Ltd | Treatment of nickel-containing solutions |
| BRPI0811938A2 (en) | 2007-05-21 | 2014-11-25 | Exploration Orbite Vspa Inc | PROCESSES FOR THE EXTRACTION OF ALUMINUM AND IRON FROM ALUMINUM ORE |
| FI122676B (en) * | 2010-10-12 | 2012-05-15 | Outotec Oyj | Method for treating a solution containing zinc sulphate |
| RU2588960C2 (en) | 2011-03-18 | 2016-07-10 | Орбит Элюминэ Инк. | Methods of extracting rare-earth elements from aluminium-containing materials |
| CA2813860A1 (en) * | 2011-04-15 | 2012-10-18 | Tam 5, S.L. | Hydrometallurgical method for recovery of zinc in sulphuric medium starting from sulphidic zinc concentrates |
| AU2012250460B2 (en) | 2011-05-04 | 2015-11-26 | Orbite Aluminae Inc. | Processes for recovering rare earth elements from various ores |
| CA2834356C (en) | 2011-06-03 | 2014-11-25 | Orbite Aluminae Inc. | Methods for preparing hematite |
| AU2012308068B2 (en) | 2011-09-16 | 2015-02-05 | Aem Technologies Inc. | Processes for preparing alumina and various other products |
| WO2013104059A1 (en) | 2012-01-10 | 2013-07-18 | Orbite Aluminae Inc. | Processes for treating red mud |
| EP2838848B1 (en) | 2012-03-29 | 2019-05-08 | Orbite Technologies Inc. | Processes for treating fly ashes |
| RU2597096C2 (en) | 2012-07-12 | 2016-09-10 | Орбит Алюминэ Инк. | Methods of producing titanium oxide and other products |
| MX349844B (en) | 2012-07-16 | 2017-08-16 | Tam 5 S L * | Hydrometallurgical method for recovering zinc in a sulphuric medium from zinc sulphide concentrates having a high iron content. |
| CN102766765B (en) * | 2012-08-07 | 2014-12-24 | 四川四环电锌有限公司 | Zinc oxide powder recycling method |
| US9353425B2 (en) | 2012-09-26 | 2016-05-31 | Orbite Technologies Inc. | Processes for preparing alumina and magnesium chloride by HCl leaching of various materials |
| CN102899502A (en) * | 2012-10-08 | 2013-01-30 | 来宾华锡冶炼有限公司 | Method for extracting indium-zinc and recovering tin from high tin high indium-zinc leaching residues |
| CN102899491B (en) * | 2012-10-12 | 2013-12-04 | 中南大学 | Method for floating and separating high-concentration iron ions from zinc sulfate leachate |
| EP2920114A4 (en) | 2012-11-14 | 2016-03-02 | Orbite Aluminae Inc | Methods for purifying aluminium ions |
| CN103922418B (en) * | 2013-03-20 | 2015-12-09 | 江苏理工学院 | Method for preparing jarosite |
| CN103290214A (en) * | 2013-05-28 | 2013-09-11 | 中国恩菲工程技术有限公司 | Method for depositing iron from ferruginous zinc sulfate solution |
| CN103695657A (en) * | 2013-12-24 | 2014-04-02 | 广西博士海意信息科技有限公司 | Method for enriching and recovering gallium and germanium from zinc hydrometallurgy waste residues |
| EP2902510A1 (en) * | 2014-01-29 | 2015-08-05 | Canbekte, Hüsnü Sinan | A new method for leaching of electric arc furnace dust (EAFD) with sulphuric acid |
| CN109970105B (en) * | 2019-04-24 | 2021-04-16 | 西南科技大学 | Method for cleanly recovering iron in zinc hydrometallurgy process |
| CN110079676B (en) * | 2019-05-05 | 2020-10-09 | 昆明理工大学 | Germanium-rich zinc oxide smoke dust gradient leaching process |
| CN110764545B (en) * | 2019-10-24 | 2020-11-27 | 中南大学 | Method for controlling pH value in neutral leaching process of zinc hydrometallurgy |
| CN112795795B (en) * | 2020-12-15 | 2023-10-03 | 深圳市中金岭南有色金属股份有限公司丹霞冶炼厂 | Method for separating gallium and germanium in sulfuric acid leaching solution through pressurized oxidation |
| CN113088710A (en) * | 2021-03-29 | 2021-07-09 | 云南驰宏资源综合利用有限公司 | Method for separating copper and germanium from copper and germanium replacement slag |
| CN114634257A (en) * | 2022-03-04 | 2022-06-17 | 太原碧蓝水利工程设计股份有限公司 | Method for treating acidic mine water and hydroxyl potassium ferric sulfate synthesized by acidic mine water |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE673023A (en) | 1965-04-30 | 1900-01-01 | ||
| IE32587B1 (en) | 1968-11-20 | 1973-09-19 | Mines Fond Zinc Vieille | Improvements in or relating to valorization |
| ES407811A2 (en) | 1972-10-20 | 1976-02-01 | Asturiana De Zinc Sa | Process for recovering zinc from ferrites |
| US4042474A (en) * | 1973-08-02 | 1977-08-16 | Pako Corporation | Separating nickel, cobalt and chromium from iron in metallurgical products |
| US4305914A (en) * | 1977-05-09 | 1981-12-15 | Electrolytic Zinc Company | Process for precipitating iron as jarosite with a low non-ferrous metal content |
| US4128617A (en) * | 1977-07-11 | 1978-12-05 | Newmont Exploration Limited | Treatment of zinc calcines for zinc recovery |
| CA1094326A (en) * | 1977-08-19 | 1981-01-27 | Verner B. Sefton | Process for the precipitation of iron as jarosite |
| DE3935362A1 (en) * | 1989-10-24 | 1991-04-25 | Ruhr Zink Gmbh | PROCESS FOR PREPARING JAROSITE-CONTAINING BACKPACKS |
| CA2104736A1 (en) | 1993-08-24 | 1995-02-25 | Lucy Rosato | Process for high extraction of zinc from zinc ferrites |
| FI98073C (en) * | 1995-08-14 | 1997-04-10 | Outokumpu Eng Oy | Process for the hydrometallurgical recovery of nickel from two different types of nickel stone |
| FI100806B (en) * | 1996-08-12 | 1998-02-27 | Outokumpu Base Metals Oy | Procedure for dissolving zinc-like under atmospheric conditions |
-
2000
- 2000-12-08 FI FI20002699A patent/FI20002699A0/en not_active IP Right Cessation
-
2001
- 2001-11-28 PE PE2001001194A patent/PE20020807A1/en active IP Right Grant
- 2001-12-07 DE DE60122370T patent/DE60122370D1/en not_active Expired - Lifetime
- 2001-12-07 ES ES01999677T patent/ES2269520T3/en not_active Expired - Lifetime
- 2001-12-07 EP EP01999677A patent/EP1339883B1/en not_active Expired - Lifetime
- 2001-12-07 AU AU1717102A patent/AU1717102A/en active Pending
- 2001-12-07 MX MXPA03005114A patent/MXPA03005114A/en active IP Right Grant
- 2001-12-07 CA CA2429889A patent/CA2429889C/en not_active Expired - Lifetime
- 2001-12-07 BR BRPI0116028-1A patent/BR0116028B1/en not_active IP Right Cessation
- 2001-12-07 KR KR1020037007661A patent/KR100845169B1/en active IP Right Grant
- 2001-12-07 AU AU2002217171A patent/AU2002217171B2/en not_active Expired
- 2001-12-07 CN CNB018201938A patent/CN1249257C/en not_active Expired - Lifetime
- 2001-12-07 WO PCT/FI2001/001065 patent/WO2002046481A1/en active IP Right Grant
- 2001-12-07 EA EA200300648A patent/EA005237B1/en not_active IP Right Cessation
- 2001-12-07 AT AT01999677T patent/ATE336595T1/en not_active IP Right Cessation
- 2001-12-07 US US10/450,921 patent/US7118719B2/en not_active Expired - Lifetime
- 2001-12-07 JP JP2002548197A patent/JP4094949B2/en not_active Expired - Lifetime
-
2003
- 2003-05-26 ZA ZA200304050A patent/ZA200304050B/en unknown
- 2003-06-03 NO NO20032509A patent/NO333462B1/en not_active IP Right Cessation
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