Hydromechanical recovery of metals from complex metal ores
Abstract
A continuous hydrometallurgical process for conversion of ore derived copper and zinc sulfides into recoverable water soluble sulfates is provided. The process comprises: i) contacting the ore derived copper and zinc sulfides with sulfuric acid and with nitric acid to form a reaction mixture in an acidic solution, ii) maintaining the reaction mixture at a temperature in the range of 110 DEG C. to 170 DEG C. while continuously mixing the reaction mixture, iii) adding sufficient sulfuric acid and nitric acid to the reaction mixture to form a light precipitate and a dark precipitate in the reaction mixture, the light precipitate comprising water soluble sulfate salts of copper sulfate, zinc sulfate and iron sulfate, and the dark precipitate being water insoluble and comprising mainly elemental sulfur and gangue, iv) introducing a source of oxygen to the reaction mixture to promote oxidation in the presence of the nitric acid, of the sulfides to sulfates and to oxidize gaseous NOx reaction products to regenerate nitric acid for the reaction mixture, v) removing the light and dark precipitates and any entrained acidic solution from the reaction mixture, vi) separating the light and dark precipitate from the acidic solution in preparation for treatment of the light precipitate for recovery of copper sulfate and zinc sulfate from the light precipitate, and vii) recycling the acidic solution to the reaction mixture.

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Expired 24 January 2014, 12.7 years ago.
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6 claims: 1 independent, 5 dependent
- 1Zastrzeżenia patentowe 1. Sposób hydrometalurgicznego ciągłego wytwarzania osadów zawierających miedź i/lub cynk do otrzymywania tych metali, w którym z rud wytwarza się siarczki miedzi i/lub cynku i miesza się je w obecności kwasu azotowego z kwasem siarkowym tworząc mieszaninę reakcyjną w kwaśnym roztworze, znamienny tym, że utrzymuje się mieszaninę reakcyjnąw temperaturze w zakresie od 110°C do 170°C jednocześnie ciągle ją mieszając, przy czym do mieszaniny reakcyjnej dodaje się kwas siarkowy i kwas azotowy w ilości wystarczającej do wytworzenia w mieszaninie reakcyjnej jasnego osadu zawierającego rozpuszczalne w wodzie sole siarczanowe siarczanu miedzi oraz ciemnego osadu nierozpuszczalnego w wodzie i zawierającego głównie wolną siarkę i skałę płonną, po czym wprowadza się źródło tlenu do mieszaniny reakcyjnej i utlenia się w obecności kwasu azotowego i kwasu siarkowego siarczki do siarczanów oraz utlenia się gazowe produkty reakcji NO X i regeneruje się kwas azotowy do zastosowania w mieszaninie reakcyjnej, a następnie usuwa się osady jasne i ciemne oraz związany z nimi roztwór kwasowy', z mieszaniny reakcyjnej, i oddziela się osady jasny i ciemny od roztworu kwasowego przygotowując jasny osad do obróbki, w której wytwarza się siarczan miedzi i/lub siarczan cynku z jasnego osadu, a roztwór kwasowy zawraca się do obiegu mieszaniny reakcyjnej.
- 2Sposób według zastrz. 1, znamienny tym, że w mieszaninie reakcyjnej miesza się z kwasem siarkowym i z kwasem azotowym rozdrobniony koncentrat rudy zawierającej siarczki miedzi i/lub cynku.
- 3Sposób według zastrz. 2, znamienny tym, że koncentrat rudy wytwarza się ze złoża chalkopirytu, sfalerytu lub innych minerałów siarczkowych.
- 4Sposób według zastrz. 1, znamienny tym, że do mieszaniny reakcyjnej dodaje się kwas siarkowy w ilości wystarczającej do utrzymania w tej mieszaninie stężenia objętościowego stężonego kwasu siarkowego do objętości mieszaniny reakcyjnej w zakresie od 35 do 65%.
- 5Sposób według zastrz. 4, znamienny tym, że do mieszaniny reakcyjnej dodaje się kwas azotowy w ilości wystarczającej do utrzymania w tej mieszaninie stężenia molowego kwasu azotowego wynoszącego co najmniej 0,5 mola kwasu azotowego na mol siarczku miedzi.
- 6Sposób według zastrz. 5, znamienny tym, że utrzymuje się stężenie molowe kwasu azotowego w zakresie od 0,5 moli do 3 moli na mol siarczku miedzi, a stężenie kwasu siarkowego utrzymuje się w zakresie od 40% do 65% objętości na objętość mieszaniny.
Independent claims6
104 paragraphs, as filed
The present invention relates to a hydrometallurgical process for the continuous production of copper and / or zinc containing sludges for the preparation of these metals.
In particular, the invention relates to a hydrometallurgical process for the continuous processing of copper and / or zinc sulfides found in various copper-containing ores, such as, for example, chalcopyrite, into deposits of their corresponding salts, from which metal is subsequently produced.
There is a clear desire to develop commercial forms of hydrometallurgical process for the production of various types of metals from ore deposits. A significant advantage of the hydrometallurgical process over the standard smelting process is a significant reduction in sulfur dioxide emissions. Although chemical methods may seem suitable for the production of, for example, copper and zinc from sulfide ores, all known commercial methods in this regard prove to be either useless or economically unjustified. It is known that many such hydrometallurgical processes leach copper, zinc and the like from concentrate
178 355 or rich ore requires the use of sulfuric acid and / or nitric acid as well as nitrate salts.
U.S. Patent 3,888,748 discloses a method for producing metal according to which copper can be obtained from sulfide ore concentrates containing minerals such as chalcopyrite (CuFeS<sub>2</sub>). Copper is produced by bringing the concentrate of such an ore into contact with a dilute aqueous solution of nitric acid and sulfuric acid to obtain a liquor solution containing copper salts and iron salts in the solution, and a residue. The lye liquid is subjected to a further process in which copper is obtained and the iron precipitates as jarosite. Jarozyt is worthless and complicates the process of making metal. Nitrate ions and their derivatives must be substantially removed from the liquor liquor to facilitate the electrolytic production of copper or zinc from this solution.
U.S. Patent 3,910, 636 discloses a method of field processing of minerals. Holes are drilled in the vein of the ore bed, which are filled with acid leaching solution containing nitrate ions in the pH range of 0.2 to about 2.0. However, this solution is diluted and hence the process is relatively slow in leaching copper from ore. In addition, this process cannot normally be used in limestone formations.
Another chemical field treatment process is disclosed in US Pat. No. 3,912,330, which relates especially to porphyry copper ores. Catalytic amounts of nitrate ion are added to the oxygenated leaching medium in the form of sulfuric acid to improve the rate of copper extraction from copper sulfide ores. Nitrate concentrations range from 0.05 to 0.50%, and the acid medium is oxygenated at oxygen pressures from 172.38 kPa to 1378.96 kPa. Jarosite precipitates but the process was considered unsuitable for surface-heap leaching.
U.S. Patent No. 4,647,307 states that complex copper ores can be treated with an acid oxidizing medium. Arsenic ore can be treated particularly well in this way.
The literature published in this area includes a doctoral dissertation (G. Van Weert, doctoral dissertation, De Technische Universiteit, Delft, Holland, 1989), which contains an attachment listing the treatment methods for mixed ores and concentrates containing chalcopyrite. Avramides et al. (Hydrometallurgy, vol. 5, pp. 325-336 (1980)) describe the process in which chalcopyrite leaching involves leaching of copper and cuprous ions with acetonitrile solutions. Kiknadze et al. (Izv. Akad. Sciences Rubble. SSR, Ser, Khim., Vol. 6 pages 363-366 (1980)) describe iron-ion leaching of chalcopyrite, where iron ion is regenerated with chlorine. Other iron-ion leaching, described by Tkacov and Balaz (Hydrometallurgy, vol. 21, pp. 103-112 (1988)), aims to increase the surface area of chalcopyrite, but it has also been mentioned that sulfur on the surface delays the dissolution of chalcopyrite. Pomianowski et al. Discovered (Electrocatal., Mater. Symp. Electrochem. Sect. Pol. Chem. Soc., 9th meeting 1987, pp. 241-247, publisher Paweł Nowak, Pol., Chem. Soc .: Warsaw, Poland) that the deposition of small amounts of silver on the surface of chalcopyrite catalyzes the rate of dissolution by electrochemical.
However, the above processes are inappropriate from at least one of the following points of view. The cost of the process in relation to the value of obtained metals is uneconomical on an industrial scale. The waste gases pollute the environment. The amount of valuable metal (valuable metals) obtained is inefficient. The waste gases cannot be treated for recovery and reuse in the process. Process conditions require the use of pressure reactors to obtain the conversion of copper and zinc sulfides into the corresponding sulfate salts.
According to the invention, the process of hydrometallurgical continuous production of copper and / or zinc containing sludges for the preparation of these metals consists in the fact that ores are used to produce copper and / or zinc sulfides and are mixed in the presence of nitric acid with sulfuric acid, forming a reaction mixture acid solution.
1718355
The process according to the invention is characterized in that the reaction mixture is kept at a temperature in the range from 110 ° C to 170 ° C while stirring continuously, with sufficient sulfuric acid and nitric acid added to the reaction mixture to produce a light reaction mixture sludge containing water-soluble copper sulphate sulphate salts and dark water-insoluble sludge and containing mainly sulfur and gangue. The source of oxygen is then introduced into the reaction mixture and oxidized in the presence of nitric acid and sulfuric acid sulfides to sulfates and the gaseous reaction products of NO are oxidized<sub>X</sub> and nitric acid is regenerated for reuse in the reaction mixture. Light and dark deposits and the associated acid solution are removed from the reaction mixture and the light and dark deposits are separated from the acid solution, preparing a light precipitate for treatment in which copper sulfate and / or zinc sulfate from the light precipitate is prepared, and the solution acidic is recycled to the reaction mixture.
In the reaction mixture, a ground ore concentrate containing copper and / or zinc sulfides is mixed with sulfuric acid and nitric acid. The ore concentrate is made from chalcopyrite, sphalerite or other sulphide minerals.
Sulfuric acid is added to the reaction mixture in an amount sufficient to maintain the volume concentration of concentrated sulfuric acid in this mixture to the volume of the reaction mixture in the range of 35 to 65%. Sufficient nitric acid is added to the reaction mixture to maintain a molar nitric acid concentration of at least 0.5 mole nitric acid per mole of copper sulfide in the mixture. The molar concentration of nitric acid is maintained in the range of 0.5 mole to 3 moles per mole of copper sulfide, and the concentration of sulfuric acid is in the range of 40% to 65% by volume.
According to the invention, copper sulfide present in the sulfide ore (CuFeS<sub>2</sub>) is transformed in this process into partially dehydrated white copper sulfate, which in an acid solution is precipitated and as a result forms part of a light precipitate.
The method according to the invention eliminates many known problems and does not require treatment at elevated pressure. Due to the use of high concentrations of sulfuric acid in the presence of oxidizing nitric acid and nitrogen gas, the desired metals are recovered as water-soluble salts, precipitated in the acid solution of the reaction mixture in the temperature range from 110 ° C to 170 ° C at which temperature and at high acidity water-soluble metal salts are less soluble. At the same time, nitrogen gas and gas N emissions are reduced<sub>2</sub>0.
The subject of the invention is shown in the drawing, which shows the flow chart of the process according to the invention.
The production method according to the invention is particularly adapted for the treatment of metal ores which contain copper sulphides and / or zinc sulphides. The ore can be either in the form of a fine fraction concentrate, fine fraction rich ore, or a combination of both. Examples of such movement containing minerals commonly include chalcopyrite, chaloxin, bornite, tetraherdite, sphalerite, galenite, molybdenite, pyrite, pyrotite and arsenopyrite. This process is mainly suitable for obtaining copper or zinc from these ores, depending on whether the ores contain copper or zinc. The ore is in particulate form or is preferably ground in such a way that 75% of the finest particles pass through the sieve number 27 5 MESZ. This ensures that a fine fraction material is obtained that participates in the reaction with the agents used in the process of the invention. Most source copper and / or zinc ores normally contain chalcopyrite, sphalerite, bornite, pyrite, galenite and mixtures thereof. Alternatively, the method of the invention is applied to processed ores that are enriched with copper or zinc. For example, ore containing copper and zinc is treated to advantageously remove some of the zinc and produce copper-enriched ore. Hence, the method of the invention is used to remove copper from the ore so treated.
In a preferred aspect, the process of the invention produces copper and / or zinc, first in the form of a water-soluble sludge containing zinc and / or copper in the form of sulfite, and then by further processing refining zinc or copper ions in solution to obtain copper and / or zinc in separate processes for the electrolytic production of metals.
It is also estimated that such ores may contain precious metals such as rhodium, palladium, platinum, silver and gold. Usually, these ingredients are found in trace amounts and may not guarantee proper process performance. It has been found that such precious metals do not pose a problem in terms of the process conditions of the invention. Similarly, commonly occurring small amounts of Pb, Cd, As and Sb were detected in these ores. It was also found that the presence of iron in the ore also does not create process problems, and in addition is desirable, iron can also be recovered from reaction products of this processing.
Although the chemical side in processing processes involving the use of very high concentrations of sulfuric acid and the amount of nitric acid needed is not completely understood, it is believed that such a reaction could be generally presented in the field of copper recovery from copper ore as follows:
CuFeS<sub>2</sub> + 22 HNO3 + 9 H<sub>2</sub>SO<sub>4</sub> => 6S + 6 CuSO<sub>4</sub> + 3 Fe<sub>2</sub>(SO<sub>4</sub>) 3 + 22 NO<sub>x</sub>t +2 0H<sub>2</sub>ABOUT
It was found that the conversion of NOx gases emitted into nitric acid can be accomplished by introducing oxygen-containing gas into the reaction system. In this case, it is assumed that the reaction scheme may look like this:
CuFeS2 + 11HNO3 + 5.5 O2 + 7.5 H2SO4 => 5 S = 5 CuSO4 + 2.5 Fe2 <SO4) 3 + 11 NO +13 H2O
Similarly, it is assumed that the reactions regarding zinc sulphide in the scope of zinc recovery from zinc zinc ore are as follows:
ZnS + 8 HNO3 + 4O2 => 5 ZnSO4 + 8 NO + 4 H2O
It is understood that these are general reaction patterns and that their stoichiometry may differ from the one described. However, the following examples show the formation of copper and iron sulphates, which are part of the orchard, and that NO and NO gases are produced<sub>2</sub>which are converted back to nitric acid and nitrous acid (HNO in the presence of oxygen)<sub>3</sub> and HNO<sub>2</sub>). There are minimal emissions of environmentally undesirable gases N<sub>2</sub>ABOUT.
The role nitric acid plays in the processing is not completely understood. It is believed that nitric acid can in some way catalyze the transformation of sulfur and iron in the form of particles with specific chemical properties to their higher valence states. It is noted that according to the invention, the amount of waste gases that can be re-converted or recycled to the process as nitric acid is quite large and normally exceeds 82% and even 92%. The residual nitrogen based on waste gas includes nitrogen and nitrous oxide, and can form the remaining 12 to 22%. From this mixture, nitric oxide has a lower concentration, usually in the range below 5% of the total amount of nitrogen gas contained. According to the requirements for environmental purposes, the exhaust gases containing nitrous oxide can be treated in an appropriate manner before being released into the atmosphere.
The amount of nitric acid used in the processing can be very different. Excessive amounts of nitric acid can be used with little or no effect on overall process efficiency. However, a minimum amount of nitric acid is required to ensure the conversion of zinc and copper sulphides into sulphates, which is manifested as clear deposits. According to a preferred embodiment of the invention, the nitric acid concentration should be at least 2.5 moles nitric acid per mole copper sulfide in the fed concentrate or ore. Based on research into preferred embodiments, it has been found that a concentration of nitric acid above 3 moles per mole of copper sulfide in no way increases the conversion of sulfides to sulfates. The preferred concentration of nitric acid is in the range from 2.5 to 1.5 moles of nitric acid per mole of copper sulfide. When nitric acid is added to the reaction mixture, preferably the acid is added over a period of time instead of immediate introduction. The rate of addition is determined based on the volume of the reaction mixture. The rate of nitric acid addition is preferably in the range of 2.3% to 1% by volume of nitric acid per minute, based on the volume of reaction mixture and the time required for this reaction.
178 355
Sulfuric acid is normally already present in the reaction mixture and is kept at a concentration of at least above 35% of the reaction mixture volume to 65% of the reaction mixture volume, as shown in Example 1 below. It was found that sulfuric acid concentration of less than 40% by volume per volume of the mixture does not create sufficient sulfide and sulfate processing to form a white precipitate and achieve separation of solid and liquid fractions. However, the use of sulfuric acid in excess of 65% tends to create hazardous vapors<sub>x</sub> in a white precipitate with redissolution. The molar concentration of the reaction mixture is preferably kept within the range of about 10. At this acidic concentration, the water-soluble copper, iron and zinc sulfates are predominantly insoluble to form a precipitate in this acidic mixture. In a continuous reactor, nitric acid and sulfuric acid are generally added continuously or once to maintain the desired sulfuric acid concentrations in the reaction mixture, as well as to maintain the molar relationship of nitric acid to moles of copper and / or zinc sulfides introduced. It is estimated that sulfuric acid concentrations can be expressed in other units, such as, for example, 9% H2SO4 per solution weight. For comparison purposes, 35% volume per volume mixture is equivalent to about 50% by weight. In the upper range of 65% by volume, the volume of the mixture is equivalent to 77% by weight. Other intermediate values include 40% volume by volume of the mixture = 55% by weight and 50% volume by volume of the mixture = 64.5% by weight.
It has been noticed that with increasing sulfuric acid concentrations, the amount of light and dark deposits increases, which also contains gangue in addition to sulfur. In addition, by increasing the concentration of sulfuric acid, more iron is precipitated in the light sediment, as well as the passage of more copper and zinc into the pellet than it remains in solution. There is also a slight increase in the amount of iron, copper and zinc that pass into the dark sludge at higher sulfuric acid concentrations. Thus, depending on the process parameters, the concentration of sulfuric acid can be set in the range of 40 to 65% by volume, in order to obtain an optimum achievement of at least copper and zinc in a light precipitate. It has proved extremely beneficial for this invention that the light precipitate is soluble in water, while the dark precipitate is soluble in organic solvents. This allows water extraction of the desired metal sulfates from the light sludge without extracting significant amounts of impurities from the dark sludge. In addition, the use of organic solvents to remove dark sludge before aqueous extraction of valuable metals from the light sludge is avoided. Although it is troublesome to predict at varying acid concentrations the structure of iron, copper and zinc material molecules in the sludge is presumed, at higher acid concentrations and / or higher temperatures, various salts tend to dehydrate. In their dehydrated form, iron, copper and zinc can occur with or without NO as:
[Fe<sub>2</sub>(SO<sub>4</sub>) H-3<sub>2</sub>SO<sub>4</sub> · 8 H<sub>2</sub>O] [CuSO<sub>4</sub>-3<sub>2</sub>O] [ZnSO<sub>4</sub> .H2O]
At higher acid concentrations and / or temperatures, the salts tend to dehydrate, giving:
[Fe<sub>2</sub>(SO4)<sub>2</sub> -H2SO4 · 2 H2O] [CuSO<sub>4</sub>-H<sub>2</sub>O] [ZnSO4]
Hence, in a continuous reactor, where the sulfuric acid concentration and temperature may vary, the salts of iron, copper and zinc are preferably released and / or partially or completely dehydrated during the process because they remain in a light precipitate. Either way, the dissolved forms of copper, zinc and iron in the acid solution are finally circulated again in the process, where equilibrium is finally obtained for the concentrations of these metals in the sulfate form in solution. In addition, it is converted back to nitric acid and nitrous acid during the generation of various nitrogen gases escaping from the reaction. Also the quantity
178 355 of the introduced nitric acid may be reduced, which results from the compensation of 10 to 20% of nitrogenous gases that cannot be recycled to nitric acid. It is preferred that the reaction proceeds at a temperature in the range of 110 ° C to the boiling point of the solution, which is about 175 ° C. The preferred reaction temperature is in the range of 110 ° C to 170 ° C, and most preferred in the range of 110 ° C to 150 ° C.
Preferably, the process of the invention is carried out in a batch reactor. However, for large volumes of ore or ore concentrate to be processed, it is preferred to use a continuous process. Various known systems are available in which a continuous reactor can be used to carry out the reaction according to the invention. The proposed process diagram for a single continuous reactor 8 is shown in the figure. The feed, usually consisting of a metal concentrate or a metal-rich ore, is fed through a feed line 10 to the bottom 11 of the tank 12 of the continuous reactor 8, which in this embodiment is in the form of a known reactor (Pachucha type). The oxidant, which is preferably pure oxygen, oxygen-enriched air, or air, is introduced through the oxygen line 14 to the inlet and led up through the bottom end 16 of the continuous reactor 8. The gases are passed up the suction pipe 18, causing the material in the tank 12 to circulate in the direction of the arrows 20. The sulfuric acid, nitric acid and reagents needed are fed through a side line 22 according to the process parameters as previously described. The gases are mixed with acids and reagents to introduce them into the circulating reaction mixture in the cylindrical part 24 of the tank 12, as well as in the bottom part 26 of the suction pipe 18 in the tank 12. Gases produced by the reaction that are not converted back to nitric acid and nitrous acid (HNO<sub>3</sub> and HNO<sub>2</sub>) is removed from the upper part 28 of the continuous reactor 8 and is discharged through the exhaust line 30 for treatment and recirculation. As described previously, the off-gases as desired are preferably treated to suit environmental requirements in other processes, or treated with water and oxygen to convert the remaining NO gases to nitric acid and nitrous acid (HNO)<sub>3</sub> and HNO<sub>3</sub>). Oxygen is introduced through inlet 15, and the necessary water is generated "on site" from the reaction mixture according to the previously given reaction scheme. Based on the mass flow rate through the feed line 10, the solution containing the reactants is removed below the liquid level in the upper part 31 of the tank 12 via vented overflow line 32 for further processing. The solution drained via the overflow line 32 contains a precipitate. The precipitate in the acid solution is transferred via line 32 to the separator 34 separating the solid and liquid fraction. The liquid separated from the light and dark sludge is drained via the return line 36 and recycled to the tank 12 normally through the side line 22. The solid fraction that contains most of the removed acid solution is transferred via a discharge line 38 to a centrifuge or to a filter press in which the remaining acid solution is removed from the solid precipitate. The remaining acid solution is removed from the centrifuge via a recycling line 42 and recycled to the tank 12 of the continuous reactor 8 by a side line
22. Wet solid fractions are removed from the centrifuge 40 via the discharge line 44, or discharged from the centrifuge 40, depending on the choice. It is understood that, if desired, a series of 8 continuous reactors can be cascaded to treat the feed concentrate in a size that meets the desired conversion of sulfides into insoluble copper and zinc sulfates.
In most cases, four reactors in series are used. The continuous reactor used has a height to diameter ratio of about 10: 1. Sludge in the form of wet solids contains both light and dark forms, and valuable metals intended for recovery from light sludge are preferably obtained by leaching. Solvent extraction is the proposed method for leaching metals from the residue, the procedure of which involves the use of solvent extraction reagents. Copper is preferably obtained from a solution with a pH of about 2.5 using a reagent commonly used for copper heap leaching. Because they are solutions with high acidity, they are partially neutralized with limestone and filtered to remove gypsum and iron (ghetto or jarosite) before solvent extraction. The extraction solvent is then stripped off and fractionated
178 355 with this electrolyte, which is strongly acidic (typically 200 g) H2SO4 and 35-40 g / l copper from electrolytic metal obtaining chambers, before being returned to these chambers for copper recovery. The solvent extraction raffinate contains residual copper, which is preferably cemented with zinc dust to remove it. The raffinate is furthermore preferably neutralized to pH 4-5, before adding zinc. Before extraction, the gypsum and iron oxide are again filtered. The zinc reagent used in solvent extraction is Di-2 ethyl hexyl phosphoric acid (D2EHPA), which transfers zinc from this solution through an organic reagent into a solution for the electrolytic preparation of zinc for the recovery of zinc.
In a preferred embodiment of the invention, illustrated with respect to the use of a continuous reactor, the reaction mixture is formed inside the tank 12 mainly in its lower part 24 and in the lower part 26 of the suction line 18. Acid and oxygen reagents and other process agents are added to the reactor as needed or continuously to ensure uninterrupted production of an optimum amount of light sludge and discharge through an overflow line 32. The solutions from which copper and zinc are subsequently obtained are further processed by electroplating metals to obtain copper and zinc of the desired quality. As a result of proper extraction of copper and zinc from the sludge, there is a minimum amount of iron in the respective solutions, so iron does not interfere with the electrolytic process of obtaining metals.
In addition, in this extraction, the nitric acid remaining in the sediment is present in a minimal amount and has little effect on the processes of electrolytic metal production. Copper in the electrolytic zinc stream is preferably cemented with Zn dust.
Preferred embodiments of the invention are shown in accordance with the following examples.
Example I.
Details of the experiment
The reactions were carried out at sulfuric acid concentrations of 45%, 50%, 65% and 75% (by volume). 10 g of concentrate, 65 ml of sulfuric acid solution and 12 ml of nitric acid (concentrated) were used in all reactions. Nitric acid was added over 20 minutes to the reaction mixture maintained at 120 ° C to 130 ° C for one hour. The reaction was continuously enriched with oxygen and gaseous products absorbed or captured above aqueous sodium hydroxide solution. After one hour, the reaction was further enriched for 30 minutes, and the cooled reaction products were weighed and vacuum filtered. The brightly colored white precipitate was dissolved in water. The remaining black to dark solid was extracted with carbon disulphide. The resulting dark gangue, white precipitate solution and primary filtrate were analyzed by atomic absorption spectroscopy. Titration of the sodium hydroxide solution was a method of recovering nitric acid as nitrate or nitrite.
Results
The sodium hydroxide solution indicates that under the above conditions, a large amount of nitric acid nitrate is not present in the gas stream. With 75% sulfuric acid filtrate, large amounts of brown gas are bubbled off when diluted with water. Nitric acid was added over extended periods. Longer reaction times at lower temperatures give more oxygen consumption, which means less nitric acid is needed.
The analytical results of both experiments are given in Table 2. The results for the solution, the white precipitate and the gangue are approximately 100%. These results indicate that a better extraction of copper to a white precipitate is obtained by reacting a 50% sulfuric acid solution than a 65% sulfuric acid solution. This is in line with the gangue weights given in Table 1, where the gangue weight increases with the increase in sulfuric acid concentration.
The effect of sulfuric acid concentration on the amount of sediment in its light and dark form is presented in Table 3, where sulfuric acid concentrations range up to 25% by volume on the volume of the mixture to 75% by volume on the volume of the mixture. At a concentration of about 35% by volume per volume of the mixture there is a noticeable increase in the weight of the sludge. This increase indicates that the lowest concentration of H2SO4 therefore the process is in the range of 35% volume per volume of mixture.
178 355
T ab e1 a 1
Weight of reagents and products
<td>H<sub>2</sub>SO4</td><td>substrates</td><td>products</td><td colspan="2">Filtrate</td><td>Settlements</td><td>The barren rock</td><td>Sulfur</td>
<td>(volume / volume)</td><td>(weight g)</td><td>(weight g)</td><td>(volume ml)</td><td>(weight g)</td><td>(weight g)</td><td>(weight g)</td><td>(weight g)</td>
<td> 45</td><td> 120,7</td><td> 114,8</td><td> 44,5</td><td> 64,5</td><td> 46,6</td><td> 0,707</td><td> 1,47</td>
<td> 50</td><td> 124,6</td><td> 117,1</td><td> 38</td><td> 57,7</td><td> 49,2</td><td> 0,798</td><td> 1,52</td>
<td> 65</td><td> 130,4</td><td> 125,6</td><td> 49</td><td> 75,9</td><td> 43,5</td><td> 1,151</td><td> 2,01</td>
<td> 75</td><td> 136,3</td><td> 131,9</td><td> 45</td><td> 72,9</td><td> 49,8</td><td> 1,78</td><td> 1,81</td>
Tebe 1 a 2 *
Analytical results
<td>A sample</td><td>Material</td><td>Iron%</td><td>Copper%</td><td>Zinc%</td>
<td>99-0 No. 1</td><td>Concentrate</td><td> 29,4</td><td> 26,8</td><td> 10,7</td>
<td>99-0 No. 2</td><td>Concentrate</td><td> 29,4</td><td> 26,4</td><td> 10,4</td>
<td>99-0 No. 3</td><td>Concentrate</td><td> 29,6</td><td> 26,5</td><td> 10,1</td>
<td>99-0 on average</td><td></td><td> 29,5</td><td> 26,5</td><td> 10,4</td>
<td> 99-1</td><td>50% solution</td><td> 7,79</td><td> 23,2</td><td> 37,8</td>
<td> 99-2</td><td>white precipitate</td><td> 80,3</td><td> 64,9</td><td> 46,3</td>
<td> 99-3</td><td>gangue</td><td> 5,62</td><td> 7,1</td><td> 0</td>
<td></td><td>Together</td><td> 93,8</td><td> 95,2</td><td> 84,1</td>
<td> 102-1</td><td>65% solution</td><td> 0,87</td><td> 10,72</td><td> 0,83</td>
<td> 102-2</td><td>white precipitate</td><td> 87,45</td><td> 71,32</td><td> 96,15</td>
<td> 102-3</td><td>gangue</td><td> 8,01</td><td> 11,02</td><td> 3,46</td>
<td></td><td>Together</td><td> 96,35</td><td> 93,1</td><td> 100,4</td>
*
Results for reaction products are calculated as a percentage of the total amount of metal expected in the concentrate sample
Table 3
Weights of reaction substrates and products
<td>H<sub>2</sub>SO4</td><td>substrates</td><td>products</td><td>Difference</td><td colspan="2">Filtrate</td><td>Density</td><td>Settlements</td><td>Scale vain</td><td>Sulfur</td>
<td>(volume / volume)</td><td>(weight g)</td><td>(weight g)</td><td>(weight g)</td><td>(volume ml)</td><td>(weight g)</td><td></td><td>(weight g)</td><td>(weight g)</td><td>(weight g)</td>
<td> 25</td><td> 107,67</td><td> 104,93</td><td> -2,74</td><td> 70</td><td> 97,2</td><td> 1,39</td><td> 5,67</td><td> 0,598</td><td> 1,68</td>
<td> 35</td><td> 113,79</td><td> 112,33</td><td> -1,46</td><td> 55</td><td> 77,92</td><td> 1,42</td><td> 31,55</td><td> 0,416</td><td> 1,49</td>
<td> 45</td><td> 120,7</td><td> 114,8</td><td> -5,9</td><td> 44,5</td><td> 64,5</td><td> 1,45</td><td> 46,6</td><td> 0,707</td><td> 1,47</td>
<td> 50</td><td> 124,6</td><td> 117,1</td><td> -7,5</td><td> 38</td><td> 57,7</td><td> 1,52</td><td> 49,2</td><td> 0,798</td><td> 1,52</td>
<td> 65</td><td> 130,4</td><td> 125,6</td><td> -4,8</td><td> 49</td><td> 75,9</td><td> 1,55</td><td> 43,5</td><td> 1,151</td><td> 2,01</td>
<td> 75</td><td> 136,3</td><td> 131,9</td><td> -4,4</td><td> 45</td><td> 72,9</td><td> 1,62</td><td> 49,8</td><td> 1,78</td><td> 1,81</td>
Example. The process of the invention was carried out with two different concentrations of sulfuric acid, with dilute nitric acid solutions based on the following results. It has been shown that the amount of nitric acid needed in the reaction mixture
178 355 may be reduced provided that oxygen is present in the reaction mixture. The reactions were carried out using 42% and 52% sulfuric acid, and 6 ml and 3 ml respectively 72% nitric acid. The third reaction was carried out with oxygen and 12 ml HNO3 as usual, but after 1 hour oxygen was replaced with argon and the reaction vessel was heated to a rise of about 172 ° C for 32 minutes. The fourth reaction was carried out all the time in argon. After 32 minutes, the temperature rose to a growing range from 175 to 182 ° C for 32 minutes. In this way, the effect of oxygen and nitric acid concentration were determined. The results of these studies are summarized in Table IV.
Table 4
Weight of substrates and products
<td>H<sub>2</sub>SO<sub>4</sub></td><td>substrates</td><td>products</td><td>Difference</td><td colspan="2">Filtrate</td><td>Density</td><td>Settlements</td><td>Scale* vain</td><td>Sulfur</td>
<td>(Obj./obj).</td><td>(weight g)</td><td>(weight g)</td><td>(weight g)</td><td>(volume ml)</td><td>(weight g)</td><td></td><td>(weight g)</td><td>(weight g)</td><td>(weight g)</td>
<td> 42</td><td> 127,3</td><td> 127,29</td><td> 2,26</td><td> 34</td><td> 49,4</td><td> 1,45</td><td>about 5Θ</td><td> 2,924</td><td> 1,651</td>
<td>4ϋ</td><td> 104,47</td><td> 126,59</td><td> 2,12</td><td> 41,5</td><td> 58,7</td><td> 1,41</td><td> 45,6</td><td> 1,862</td><td> 1,727</td>
<td> 42</td><td> 115,21</td><td> 114,8</td><td> -3,32</td><td> 64</td><td> 92,5</td><td> 1,44</td><td>around 25</td><td>ϋ, 342</td><td> 1,653</td>
<td> 52</td><td> 116,42</td><td> 117,1</td><td> -7,64</td><td>6Θ</td><td> 89,2</td><td> 1,48</td><td> 23,7</td><td>ok.3,6</td><td> 1,462</td>
* <sub>LT</sub>Moist cluster of filtered sediment, containing white sediment and some or all of the black sediment Black sediment extracted with carbon disulphide
From the results of the reaction with a reduced amount of nitric acid, it is evident that the processing of sulfides into sulfates is within an acceptable range to thus show the possibility of reducing the amount of nitric acid present in the reaction mixture while maintaining the presence of oxygen in the reaction mixture.
178 355
178 355
<img file="PL178355B1_D0001.tif" />
UP Department of Publications. Circulation of 70 copies Price PLN 4.00
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Priority claims8
| Document | Office | Kind | Date |
|---|---|---|---|
| 984493 | United States of America | A | |
| 984493 | United States of America | A | |
| 9400034 | Canada | W | |
| 9400034 | Canada | W | |
| 9844 | – | – | – |
| CA9400034 | – | – | – |
| US19930009844 | – | – | – |
| WO1994CA00034 | – | – | – |
Members27
| Document | Office | Kind | |
|---|---|---|---|
| CA2154560A1 | Canada | A1 | |
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| FI953562A0 | Finland | A0 | |
| FI953562A | Finland | A | |
| FI953562A7 | Finland | A7 | |
| EP0677118A1 | European Patent Office (EPO) | A1 | |
| PL310045A1 | Poland | A1 | |
| BR9406419A | Brazil | A | |
| US5484579A | United States of America | A | |
| CZ193795A3 | Czechia | A3 | |
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| CN1120355A | China | A | |
| JPH08505902A | Japan | A | |
| AU670670B2 | Australia | B2 | |
| EP0677118B1 | European Patent Office (EPO) | B1 | |
| AT144292T | Austria | T | |
| ATE144292T1 | Austria | T1 | |
| DE69400747D1 | Germany | D1 | |
| ES2096447T3 | Spain | T3 | |
| DE69400747T2 | Germany | T2 | |
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| PL178355B1This record | Poland | B1 | |
| CA2154560C | Canada | C |
Numbers
- Publication, DOCDB
- 178355
- Publication, EPODOC
- PL178355B
- Application
- 94310045
- Application, DOCDB
- 31004594
- Application, EPODOC
- PL19940310045
Titles2
- English
- HYDROMECHANICAL RECOVERY OF METALS FROM COMPLEX METAL ORES
- Polish
- Sposób hydrometalurgicznego ciągłego wytwarzania osadów zawierających miedź i/lub cynk do otrzymywania tych metali
Classification
- CPC, 7
- C22B3/10
- C22B3/44
- C22B3/065
- C22B11/04
- C22B15/0071
- C22B15/0073
- Y02P10/20
- IPC, 7
- C22B3 06
- C22B3 10
- C22B3 04
- C22B3 44
- C22B15 00
- C22B19 00
- C22B19 20