Manganese ore processing

Abstract

A method (10) for extracting manganese from a manganese-containing ore includes roasting (12.2) a feed mixture of particulate manganese-containing ore (26) containing Mn and Fe, and ammonium sulfate (24) at a first temperature T1 to result in a sulfonated mixture containing MnSO4(s) and FeSO4(s). The sulfonated mixture is roasted (12.3) at a second temperature T2, higher than the first temperature T1, to form a leachable mixture (30) containing MnSO4(s) and Fe2O3(s). The MnSO4(s) is leached (16) from the leachable mixture (30) preferentially over Fe2O3(s) to result in a leachate (34, 38) rich in dissolved MnSO4.

Description

[Technical field]

[0001] The present invention relates to the beneficiation of manganese-containing ores. In particular, the present invention relates to a method for extracting manganese from manganese-containing ores, and to manganese sulfates, hydroxides and oxides produced thereby. [Background technology]

[0002] MnSO 4 is a valuable salt. Besides the metal and alloy industry, MnSO in the electrochemical battery industry 4 The need for more is also increasing.

[0003] MnSO 4 Manganese can be produced from manganese-bearing ores. South Africa holds about 78% of the world's manganese reserves, most of which occur in the Northern Cape. Typical manganese-bearing ores contain between about 15% and about 50% Mn, with Mn occurring as mixed oxides of various valences.

[0004] Manganese-containing ores are roasted (typically in the presence of carbon at temperatures between about 900°C and about 1100°C) to reduce the manganese in the ore (Mn 3+ and Mn 4+ From Mn 2+ ), so that the reduced manganese can react with sulfuric acid (Mn 2+ is soluble in sulfuric acid, but Mn 3+ and Mn 4+Many conventional methods are known for removing manganese sulfate from manganese-containing ores (Fe is not soluble in sulfuric acid). After leaching with sulfuric acid, solid impurities such as Fe from the manganese-containing ore must be removed from the acidic manganese sulfate solution. Traditionally, this is done by alkaline precipitation using a precipitating agent such as calcium carbonate. However, when a calcium-containing precipitating agent is used, gypsum (calcium sulfate) is formed. Not only does the gypsum have to be dumped (i.e. refined and sold), but it is also difficult to wash the contaminated manganese sulfate from the gypsum. This typically results in an undesirable reduction in manganese yield, i.e. manganese loss. Summary of the Invention [Problem to be solved by the invention]

[0005] A method for extracting manganese from manganese-containing ores that does not suffer from at least some of the difficulties discussed above is desirable. [Means for solving the problem]

[0006] According to the present invention, there is provided a method for extracting manganese from a manganese-containing ore, comprising the steps of: A feed mixture of particulate manganese-containing ore containing Mn and Fe, and ammonium sulfate is heated to a first temperature T 1 Roasting with MnSO 4 (s) and FeSO 4 providing a sulfonation mixture comprising (s); The sulfonation mixture is heated to a first temperature T 1 A second temperature T 2 Roasting with MnSO 4 (s) and Fe 2 O 3 forming a leachable mixture comprising: Fe from leachable mixture 2 O 3 MnSO over (s) 4 (s) is leached to obtain dissolved MnSO 4 and producing a leachate rich in A method is provided, comprising: [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 illustrates an embodiment of the method of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The method may include preventing or at least inhibiting the ingress of oxygen, e.g. air, into the atmosphere in which the feed mixture is roasted. In one embodiment of the invention, the feed mixture is thus roasted in an atmosphere substantially free of oxygen.

[0009] "Substantially free of oxygen" means that, at steady state for the process of the present invention, the atmosphere in which the feed mixture is roasted does not contain free oxygen from the external environment of the apparatus in which the feed mixture is roasted, and the only free oxygen potentially present in the atmosphere in which the feed mixture is roasted is Fe 2 (SO 4 ) 3 (s) means the oxygen released or evolved as a result of the decomposition of

[0010] MnSO 4 (s) is typically leached from the leachable mixture using an aqueous leaching agent or solvent, such as water.

[0011] The manganese-containing ore may have a Mn concentration of at least about 5% by weight, preferably at least about 10% by weight, and most preferably at least about 20% by weight. Typically, the Mn concentration of the manganese-containing ore does not exceed about 55% by weight.

[0012] The manganese-containing ore may have an Fe concentration of about 20% by weight or less, or about 15% by weight or less, or about 10% by weight or less. Typically, the Fe concentration of the manganese-containing ore is at least about 1% by weight.

[0013] Advantageously, MnSO 4(s) is completely soluble in water (i.e., about 70 g per 100 ml at 70°C), while Fe 2 O 3 (s) is insoluble in water. Therefore, MnSO can be extracted from the leachable mixture using an aqueous leaching agent or solvent, e.g., water. 4 The step of leaching (s) leaves a leach residue or tailings in which the Mn:Fe mass ratio is much smaller than in the leachate, hence in other words the leachate is rich in Mn relative to Fe while the tailings is rich in Fe relative to Mn.

[0014] First temperature T 1 may range from about 300°C to about 550°C, preferably from about 350°C to about 500°C, and most preferably from about 375°C to about 475°C, for example about 450°C.

[0015] The second temperature T 2 may range from about 550°C to about 750°C, preferably from about 600°C to about 725°C, and most preferably from about 650°C to about 700°C, for example about 675°C.

[0016] In one embodiment of the invention, the feed mixture and the sulfonation mixture are roasted in a roasting step using a roaster, such as a rotary kiln, typically an externally or indirectly heated rotary kiln or calciner, the roaster typically having a range of roasting temperatures increasing from a roasting temperature at the feed inlet to a discharge temperature of the leachable mixture, and at least one zone of the roaster is heated to a first temperature T 1 and at least one zone of the roaster has a roasting temperature corresponding to a temperature range of a second temperature T 2 The roasting temperature corresponds to the temperature range of

[0017] Preferably, ingress of air into the roaster is prevented or at least suppressed.

[0018] The roasting furnace is heated to a first temperature T 1Roasting temperature T lower than the temperature range 初期 The at least one region may have the following structure:

[0019] The temperature T used 初期 The first temperature T 1 With the understanding that the roasting temperature T 初期 may range from about 225°C to about 375°C, preferably from about 250°C to about 350°C, and most preferably from about 275°C to about 325°C, for example about 300°C.

[0020] The feed mixture is heated to a roasting temperature T 初期 and may be baked for a time period between about 30 minutes and about 360 minutes, preferably between about 60 minutes and about 240 minutes, and most preferably between about 90 minutes and about 180 minutes, e.g., about 120 minutes.

[0021] The feed mixture is heated to a first temperature T 1 and may be baked for a time period between about 30 minutes and about 360 minutes, preferably between about 60 minutes and about 240 minutes, and most preferably between about 90 minutes and about 180 minutes, e.g., about 120 minutes.

[0022] The sulfonation mixture is heated to a second temperature T 2 and may be baked for a time period between about 30 minutes and about 360 minutes, preferably between about 60 minutes and about 240 minutes, and most preferably between about 90 minutes and about 180 minutes, e.g., about 120 minutes.

[0023] Without wishing to be bound by theory, the inventors have determined that the oxidizing agent is preferably heated to a first temperature T 1 or roasting temperature T 初期 Then, the mixture is roasted at a first temperature T 1 When roasted at 40°C, the following decomposition and reduction reactions are believed to occur. (NH 4 ) 2 SO 4 (s) → NH 3 (g)+NH 4 HSO4 (s) Formula [1] 3Mn x O y (s)+2NH 3 (g) → 3xMnO(s)+N 2 (g)+3H 2 O(g), y=x+1 formula [2] 3Fe x O y (s)+2NH 3 (g) → 3xFeO(s)+N 2 (g)+3H 2 O(g), y=x+1 formula [3]

[0024] NH 3 (g) is a strong reducing agent, and therefore the reduction reactions of Equations 2 and 3 occur at lower temperatures than the oxidation reactions used in the methods of the present invention.

[0025] Although the inventors do not wish to be bound by theory, it is preferred that the heating is performed in an atmosphere substantially free of oxygen at a first temperature T 1 It is further believed that when roasted at 40° C., the following decomposition and oxidation / sulfonation reactions occur: NH 4 HSO 4 (s) → NH 3 (g)+H 2 O(g)+SO 3 (g) Formula [4] MnO(s)+FeO(s)+2SO 3 (g) → MnSO 4 (s)+FeSO 4 (s) Formula [5] 2FeSO 4 (s)+2SO 3 (g) →Fe 2 (SO 4 ) 3 (s)+SO 2 Formula [6]

[0026] The second temperature T 2 While not wishing to be bound by theory, the inventors believe that the following decomposition reaction occurs: Fe 2 (SO 4) 3 (s) →Fe 2 O 3 (s)+3SO 2 (g) + 1.5O 2 (g) Formula [7]

[0027] Surprisingly, the SO produced in reaction 4 3 (g) is extremely oxidizing, but Mn, in contrast to Fe, has a high oxidation potential. 3 (g) is not oxidized by the reaction of (g), but instead is produced by the reaction of Eq. 5. 4 remains. Therefore, SO 3 (g) MnSO 4 FeSO in preference to (s) 4 It can be seen that (s) is selectively oxidized.

[0028] Advantageously, the second temperature T 2 So, Fe 2 (SO 4 ) 3 (s) decomposes, but MnSO 4 (s) does not decompose appreciably.

[0029] The method may include forming said feed mixture of particulate manganese-containing ore and ammonium sulfate.

[0030] Forming the feed mixture of particulate manganese-containing ore and ammonium sulfate may include mixing the particulate manganese-containing ore and particulate ammonium sulfate in a premixing step.

[0031] Alternatively, forming the feed mixture of particulate manganese-containing ore and ammonium sulfate can include feeding the particulate manganese-containing ore and particulate ammonium sulfate to a roasting step, such as roasting using a rotary kiln, and mixing the particulate manganese-containing ore and the particulate ammonium sulfate in the roasting step.

[0032] The particulate manganese-containing ore may have a D90 particle size ranging from about 25 μm to about 500 μm, preferably from about 45 μm to about 250 μm, and most preferably from about 75 μm to about 212 μm, for example a D90 particle size of about 106 μm.

[0033] The particulate ammonium sulfate can have a D90 particle size ranging from about 25 μm to about 500 μm, preferably from about 45 μm to about 250 μm, and most preferably from about 75 μm to about 212 μm, for example, a D90 particle size of about 106 μm.

[0034] The method may include withdrawing tail gases resulting from the roasting of the feed mixture and the roasting of the sulfonation mixture. The tail gases may include H 2 O(g), N 2 (g), SO 2 (g), and O 2 It may include (g).

[0035] The exhaust gas also contains SO 3 (g) and NH 3 It may also include (g).

[0036] The method involves extracting Mn(SO) from a leachable mixture. 4 )(s) before the step of leaching the second temperature T 2 cooling the leachable mixture resulting from the step of roasting the sulfonated mixture at 100° C.

[0037] The leachable mixture is allowed to leach at a temperature T ranging from about 15° C. to about 60° C., preferably from about 20° C. to about 50° C., and most preferably from about 25° C. to about 40° C. 3 , for example, at a temperature T of about 30°C 3 The mixture can be cooled to .

[0038] Typically the leachable mixture is cooled using water as a coolant, for example in a jacketed auger, with the cooling water passing through the jacket.

[0039] MnSO 4(s) may be leached from the leachable mixture using an aqueous leaching agent or solvent as set forth herein above at a temperature between about 50°C and about 90°C, preferably between about 60°C and about 80°C, for example at a temperature of about 70°C.

[0040] The particulate manganese-containing ore and ammonium sulfate may be present in the feed mixture in a mass ratio of ore:ammonium sulfate of between about 1:1 and about 1:4, typically between about 1:2 and about 1:3. However, as will be appreciated, the mass ratio of ore:ammonium sulfate required will depend, among other factors, on the concentrations of Mn, Ca, Mg, and Fe in the manganese-containing ore, and the excess amount of ammonium sulfate required to achieve the desired manganese yield.

[0041] The leachable mixture may be leached for a leach time of between about 15 and about 180 minutes, preferably between about 30 and about 120 minutes, and most preferably between about 45 and about 90 minutes, for example, a leach time of about 60 minutes. In other words, the residence time of the leachable mixture in the leach step may correspond to the leach time.

[0042] Typically the process includes the step of separating the leachate from the leach residue, which may be carried out in any suitable solid-liquid separation means, for example using filtration.

[0043] The method is to extract Mn(OH) from the leachate. 2 The method may further include precipitating Mn(OH). 2 NH 4 OH or NH 3 (g) was easily precipitated from the leachate using Mn(OH) 2 Precipitate and (NH 4 ) 2 SO 4 A solution of this precipitated MnO 2 can be reacted with sulfuric acid to produce manganese(II) sulfate monohydrate of exceptional purity, suitable for use in, for example, electrochemical cells.

[0044] The method includes, for example, separating (NH 4 ) 2 SO 4 From solution (NH 4 ) 2 SO 4 Crystal or (NH 4 ) 2 SO 4 The method may include forming a powder.

[0045] The method is (NH 4 ) 2 SO 4 Crystal or (NH 4 ) 2 SO 4 Powder, i.e. (NH 4 ) 2 SO 4 (NH 4 ) 2 SO 4 (s) may be recycled to form part of the feed mixture.

[0046] The process of the present invention may be carried out as a batch, semi-batch, or continuous process.

[0047] The present invention relates to MnSO produced by the production process described herein above, which includes a method for extracting manganese from manganese-containing ores. 4 or Mn(OH) 2 or MnO 2 This also applies.

[0048] The invention will now be described, purely by way of example, with reference to the following examples and with reference to one schematic diagram showing one embodiment of a continuous process according to the invention for extracting manganese from manganese-containing ores.

[0049] [Example] Manganese extraction tests were carried out using manganese-containing ores having the compositions shown in Table 1.

[0050] [Table 1]

[0051] 250 g of manganese-bearing ore from Table 1 was crushed to approximately 106 μm. 4 ) 2 SO 4 250 g was ground to about 106 μm. Both powders at about 106 μm were then blended to form a mixture, which was added to an open SiC crucible. The mixture was fired at 400° C. for 30 minutes, then at 450° C. for 1 hour, at 500° C. for 1 hour, and finally at 670° C. for 1 hour, immediately providing an atmosphere inside the crucible that was substantially free of oxygen as a result of the evolution of gases that displaced the air. 323.5 g of red powder was recovered.

[0052] 500 ml of water was added to the red powder to form a suspension, and the temperature of the suspension was raised to 60-70 °C. After stirring for 15 minutes, the suspension was filtered and washed with MnSO 4 600 ml of leachate was collected (see Table 1 for leachate composition). From the theoretical amount of Mn of 2.5 x 42.7 = 106.75 g, collected Mn units = 87100 mg / l x 0.6 l = 52.26 g. Thus, a Mn recovery of 49% was realized.

[0053] From Table 1, we can see that not only the Fe concentration decreases in the leachate, but also some other deleterious elements. The Mn / Mg mass ratio remains almost the same.

[0054] The experiment consisted of 1 part of crushed ore: crushed (NH 4 ) 2 SO 4 It was repeated using two portions and a Mn recovery of 76% was achieved. By modifying the experimental conditions, for example by further increasing the manganese-bearing ore:ammonium sulfate mass ratio, it was found that Mn recoveries of >95% could be obtained.

[0055] Referring to the drawings, reference numeral 10 generally indicates one embodiment of a continuous process according to the present invention for extracting manganese from manganese-containing ores. The process 10 generally includes a roasting stage comprising a slightly inclined, externally heated or indirectly heated rotary kiln 12 (often referred to as a rotary calciner), a leaching stage comprising a cooler 14, a leaching vessel 16, a first filter 18, a settler 20, and a second filter 22.

[0056] The rotary kiln 12 is provided with an ammonium sulfate feed line 24 and a particulate manganese-containing ore feed line 26. A flue gas withdrawal line 28 is provided adjacent the discharge end of the rotary kiln 12.

[0057] A leachable mixture transfer line 30 leads from the rotary kiln 12 to the cooler 14 and from the cooler 14 to the leach vessel 16. The leach vessel 16 is an agitated vessel equipped with a mechanical agitator and also includes a water supply line 32.

[0058] A slurry transfer line 34 leads from the leach vessel 16 to the first filter 18 which includes a tailings draw line 36 and a filtrate transfer line 38 .

[0059] The filtrate transfer line 38 leads into the precipitator 20, which contains NH 3 (g) A supply line 40 and a slurry transfer line 42 are also provided.

[0060] The slurry transfer line 42 leads to the second filter 22, which is a filter for separating Mn(OH) 2 A precipitate withdrawal line 44 and an ammonium sulfate solution withdrawal line 46 are provided.

[0061] To extract manganese from manganese-containing ores that also contain iron, powder of manganese-containing ore having a D90 particle size of about 106 μm is continuously fed into the rotary kiln 12 by a particulate manganese-containing ore feed line 26. At the same time, powder of ammonium sulfate having a D90 particle size of about 106 μm is continuously fed into the rotary kiln 12 by an ammonium sulfate feed line 24. The mass ratio of powdered manganese-containing ore to ammonium sulfate powder fed into the rotary kiln 12 depends on the composition of the manganese-containing ore. For the ores shown in Table 1, the mass ratio will be about 1:2.4.

[0062] The required mass ratios for the manganese-bearing ores of Table 1 can be determined as follows (based on 100 grams of manganese-bearing ore): 13.2% Fe = 0.236 moles x 1.5 = 0.354 moles Fe 2 (SO 3 ) 3 SO required to form 3 Ca5.3% = 0.133 mol × 1 = 0.133 mol CaSO 4 SO required to form 3 0.4% Mg = 0.017 moles × 1 = 0.017 moles MgSO 4 SO required to form 3 Mn42.7% = 0.776 moles × 1 = 0.776 moles MnSO 4 SO required to form 3 Ba1.36% = 0.010 mol × 1 = 0.01 mol BaSO 4 SO required to form 3 (Ba is not shown in Table 1) All SOs required 3 = 1.29 moles

[0063] A 100 g supply of manganese-bearing ore contains 1.29 moles of (NH 4 ) 2 SO4 × 132 g / mol = 170.28 g + 15% experimental excess = approximately 200 g (NH 4 ) 2 SO 4 , i.e., requiring a mass ratio of manganese-containing ore:ammonium sulfate of about 1:2.

[0064] Experimentally, efficiencies or Mn yields of about 80% have been achieved. 4 ) 2 SO 4 By using 1:2×1.2=1:2.4 manganese ore:ammonium sulfate, the sulfonation reaction is believed to proceed to near completion. This results in a required manganese-containing ore:ammonium sulfate mass ratio of about 1:2×1.2=1:2.4.

[0065] SO emitted inside rotary kiln 12 3 For each mole of (g), 2 moles of NH 3 (g) is released, so NH 3 (g) will always be present in excess (see Equation 1 + Equation 4).

[0066] The particulate manganese-containing ore and ammonium sulfate are fed from a hopper (not shown) through an inlet seal (not shown, typically used only if the hopper does not provide an adequate seal against air ingress) to inhibit the introduction of air into the rotary kiln 12.

[0067] In the rotary kiln 12, the particulate manganese-containing ore and the ammonium sulfate powder are mixed as a result of the rotating action of the rotary kiln 12, and the resulting mixture is roasted in an atmosphere substantially free of oxygen over most of the length of the rotary kiln 12 as the mixture moves through the rotary kiln 12 as a result of the rotation of the rotary kiln 12 and as a result of the slight tilt of the rotary kiln 12 relative to the horizontal.

[0068] In the inlet region 12.1 of the rotary kiln 12, the mixture is heated to a roasting temperature T, which typically ranges between about 300° C. and about 350° C. 初期 As the mixture progresses toward the discharge end of the rotary kiln 12, the mixture is heated to a first temperature T in the intermediate region 12.2, which is typically in the range of about 400° C. to about 500° C. 1 The mixture is then roasted at a temperature of about 180° C. for about 180 minutes. The mixture then enters an end region 12.3 of the rotary kiln 12 adjacent the discharge end of the rotary kiln 12. In the end region 12.3, the mixture is roasted at a second temperature T 2 for about 120 minutes. Thus, the total residence time of the material passing through the rotary kiln 12 is typically about 360 minutes.

[0069] In the inlet region 12.1, in an atmosphere substantially free of oxygen, ammonium sulfate decomposes to form ammonia gas in situ, presumably according to equation 1 previously described herein, and the gaseous ammonia then reacts with manganese oxide and iron oxide to reduce these oxides, presumably according to equations 2 and 3 previously described herein. Nitrogen gas and water vapor are generated, and these gases, along with any unreacted ammonia gas, are withdrawn through tail gas withdrawal line 28.

[0070] In the intermediate region 12.2, still in an atmosphere substantially free of oxygen, more gaseous ammonia and sulfur trioxide are produced, presumably according to equation 4 previously described herein, and MnO(s) and FeO(s) react with the sulfur trioxide to form MnSO, ​​presumably according to equation 5 previously described herein. 4 (s) and FeSO 4 (s) is thought to form FeSO 4 (s) further reacts with sulfur trioxide to produce Fe, presumably according to Equation 6 previously set forth herein. 2 (SO 4 ) 3 It is believed to form (s).

[0071] In the edge region 12.3, Fe 2 (SO 4 ) 3 (s) is presumably decomposed according to Equation 7 previously described herein to give Fe 2 O 3 (s), SO 2 (g), and gaseous oxygen. SO from regions 12.2 and 12.3 2 (g) Oxygen, water vapor, and any unreacted sulfur trioxide are also withdrawn via tail gas withdrawal line 28.

[0072] As will be appreciated, instead of using a single rotary kiln 12 with multiple temperature zones, separate rotary kilns or other roasters can be used to roast the feed mixture and the sulfonation mixture at different temperatures. As will be appreciated, one advantage of using separate rotary kilns or other roasters is that the atmosphere in which the feed mixture is roasted can be separated into separate zones, such as Fe 2 (SO 4 ) 3 (s) is decomposed, so Fe 2 (SO 4 ) 3 The advantage of this method is that it may be easier to exclude oxygen from the atmosphere in which the feed mixture is roasted, since it can be separated from the atmosphere which may contain oxygen released by the decomposition of (s).

[0073] The leachable mixture is withdrawn from the rotary kiln 12 through a discharge seal (not shown) and transferred by leachable mixture transfer line 30 to the cooler 14 where it is cooled using plant cooling water in an indirect heat transfer device to a temperature of about 30° C. before being transferred by leachable mixture transfer line 30 to the leach vessel 16. Alternatively, or in addition to using a separate cooler 14, the rotary kiln 12 can have an integral cooling zone.

[0074] Water is fed into leaching vessel 16 by water supply line 32 and mixed with the leachable mixture using a mechanical agitator in leaching vessel 16. Typically, the step of leaching the leachable mixture in leaching vessel 16 with water or a solvent as a leachant is carried out at a temperature of about 60° C. to 70° C., so if desired, leaching vessel 16 may be a heated vessel. Alternatively, the leachable mixture and water fed into leaching vessel 16 may be at a sufficiently high temperature to ensure that the leaching step occurs at the desired temperature.

[0075] In the leaching vessel 16, water is leached to remove MnSO from the leachable mixture. 4 The leachable mixture has a residence time of about 60 minutes in the leach vessel 16 and is then transferred as a slurry to the first filter 18 via the slurry transfer line 34.

[0076] In the first filter 18, the leach residue or tailings is separated from the slurry and withdrawn via a tailings withdrawal line 36. A leachate or filtrate rich in dissolved manganese sulfate is withdrawn from the first filter 18 and transferred to a settler 20. As will be appreciated, manganese sulfate is generally formed in the form of FeSO4, which is substantially insoluble in water. 3 In contrast to (s), the leach residue or tailings withdrawn by tailings withdrawal line 36 is depleted in manganese sulfate, since it is completely soluble in water, whereas the leachate or filtrate transferred to the settler 20 by filtrate transfer line 38 is rich in manganese sulfate, FeSO 3 The majority of (s) belongs to leach residues or tailings.

[0077] In the embodiment of the method of the invention illustrated in the drawings, Mn(OH) 2 is precipitated from the leachate fed to the precipitator 20. This is 3 (g) Gaseous ammonia is fed into the precipitator 20 via a feed line 40 to produce Mn(OH). 2 Although not shown, the precipitator 20 may be a stirred vessel.

[0078] Mn(OH) 2 The precipitate slurry is transferred by slurry transfer line 42 to the second filter 22 where Mn(OH) 2 The precipitate was separated from the ammonium sulfate solution and was dissolved in Mn(OH). 2 The precipitate is withdrawn through a withdrawal line 44. The ammonium sulfate solution is withdrawn through a withdrawal line 46.

[0079] The withdrawn ammonium sulfate solution can be processed, for example, by membrane separation and evaporation, to produce ammonium sulfate crystals or powder, which are then recycled to the rotary kiln 12 as part of the ammonium sulfate in ammonium sulfate supply line 24.

[0080] Mn(OH) 2 Mn(OH) extracted by the precipitate extraction line 44 2 By treating with Mn(OH) 2 From extremely pure MnO 2 The resulting MnO 2 can be reacted with sulfuric acid to produce manganese(II) sulfate monohydrate of exceptional purity, suitable for use, for example, in electrochemical cells.

[0081] As described, method 10 advantageously does not require digestion of roasted manganese-containing ore or concentration with sulfuric acid. As described, method 10 also advantageously does not require alkaline precipitation of soluble impurities such as Fe. Importantly, as described, method 10 also allows for recycling of the bulk reagent (ammonium sulfate).

[0082] Manganese-containing ores typically contain significant concentrations of Ca and Mg (see, for example, Table 1). In the process of the present invention, as explained, so-called dead gypsum or dead burnt plaster is advantageously formed. Therefore, in the process of the present invention, anhydrous CaSO 4is formed, but CaSO 4 If it is immersed in water, it will rehydrate and become CaSO 4 2H 2 Does not form O. CaSO 4 2H 2 O is undesirably a valuable MnSO 4 This facilitates aqueous leaching as the SiO 2 acts as a sponge that will capture the SiO 2 . Similar problems in conventional methods arise due to the formation of silica gel that is difficult to remove by filtration, but advantageously, as explained, the SiO 2 , which is easily removed by filtration in the method of the present invention. 2 is formed. [Explanation of symbols]

[0083] 10 ways 12 Rotary Kiln 12.1 Entrance area 12.2 Intermediate area 12.3 End area 14 Cooler 16 Leaching vessel 18 First Filter 20 Precipitator 22 Second Filter 24 Ammonium sulfate supply line 26 Particulate manganese ore supply line 28 Exhaust gas extraction line 30 Leachable mixture transfer line 32 Water Supply Line 34 Slurry transfer line 36 Tailings Extraction Line 38 Filtrate transfer line 40NH 3 (g) Supply Line 42 Slurry transfer line 44 Mn(OH) 2 Sediment Extraction Line 46 Ammonium sulfate solution withdrawal line

Claims

1. 1. A method for extracting manganese from a manganese-containing ore, comprising the steps of: A feed mixture of particulate manganese-containing ore containing Mn and Fe and ammonium sulfate is heated to a first temperature T １ Roasting with MnSO ４ (s) and FeSO ４ providing a sulfonation mixture comprising (s); The sulfonation mixture is heated to a first temperature T １ A second temperature T ２ Roasting with MnSO ４ (s) and Fe ２ O ３ forming a leachable mixture comprising: Fe from the leachable mixture ２ O ３ MnSO is preferred over (s) ４ (s) is leached to obtain dissolved MnSO ４ and producing a leachate enriched in A method comprising:

2. 10. The method of claim 1, comprising preventing or at least inhibiting the ingress of oxygen into the atmosphere in which the feed mixture is roasted.

3. The MnSO ４ 3. The method of claim 1 or 2, wherein (s) is leached from the leachable mixture using an aqueous leaching agent or solvent.

4. The first temperature T １ 4. The method according to claim 1, wherein the heating temperature is in the range between 300° C. and 550° C.

5. The first temperature T １ 5. The method of claim 4, wherein the heating temperature is between 350°C and 500°C, or between 375°C and 475°C.

6. The second temperature T ２ 6. The method according to claim 1 , wherein the heating temperature is in the range between 550° C. and 750° C.

7. The second temperature T ２ The method of claim 6, wherein the heating temperature is between 600°C and 725°C, or between 650°C and 700°C.

8. The feed mixture and the sulfonation mixture are roasted in a roasting step using a roaster, the roaster having a series of roasting temperatures increasing from a roasting temperature at a feed inlet to a discharge temperature of the leachable mixture, and at least one zone of the roaster is heated to the first temperature T １ and at least one zone of the roaster has a roasting temperature corresponding to the second temperature T ２ 8. The method according to claim 1 , wherein the roasting temperature corresponds to a temperature range of:

9. The roasting furnace is heated to the first temperature T １ A roasting temperature T lower than the temperature range 初期 and the roasting temperature T 初期 The method of claim 8, wherein the temperature is in the range between 225°C and 375°C.

10. The roasting temperature T 初期 The method of claim 9, wherein the heating temperature is between 250° C. and 350° C.

11. The temperature T used 初期 is the first temperature T １ With the understanding that the roasting temperature T 初期 10. The method of claim 9, wherein the heating temperature is between 275°C and 325°C.

12. 12. The method of any one of claims 1 to 11, wherein the particulate manganese-containing ore and the ammonium sulfate are present in the feed mixture in a mass ratio of ore:ammonium sulfate of between 1:1 and 1:

4.

13. 13. The method of claim 12, wherein the particulate manganese-containing ore and the ammonium sulfate are present in the feed mixture in a mass ratio of ore:ammonium sulfate of between 1:2 and 1:

3.

14. N.H. ４ OH or NH ３ (g) extracting Mn(OH) from the leachate using ２ is precipitated to give Mn(OH) ２ Precipitate and (NH ４ ) ２ SO ４ 14. The method of any one of claims 1 to 13, comprising the step of forming a solution.

15. (NH ４ ) ２ SO ４ From the solution (NH ４ ) ２ SO ４ Crystal or (NH ４ ) ２ SO ４ forming a powder; and ４ ) ２ SO ４ Crystal or (NH ４ ) ２ SO ４ Powder, i.e., (NH ４ ) ２ SO ４ (NH ４ ) ２ SO ４ and (s) recycling said feed mixture to form a portion of said feed mixture.

16. MnSO produced by a manufacturing method comprising the method according to any one of claims 1 to 15. ４ Or Mn(OH) ２ Or MnO ２ .

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