A method for processing metallurgical grade manganese concentrate from refractory manganese oxide ore

Abstract

The invention discloses a method for processing metallurgical grade manganese concentrate from a refractory manganese oxide ore, wherein a certain amount of anthracite powder is mixed with the manganese oxide ore for magnetization reduction roasting, and the roasted sand after magnetization reduction roasting is cooled by water quenching, and the roasted sand after cooling is crushed to 2-0 mm and then subjected to a weak magnetic selection for a roughing and a concentrating, respectively obtaining a weak magnetic concentrate, a weak magnetic roughing tailing, and a weak magnetic concentrating tailing; the obtained weak magnetic concentrating ore is ground and then subjected to a weak magnetic selection, and the magnetic material produced is a manganese-containing iron concentrate, and the non-magnetic minerals produced are combined with weak magnetic roughing tailings and weak magnetic concentrating tailings to form a final manganese concentrate. The present invention has the advantages of simple process flow, high grade and recovery rate of the obtained manganese concentrate, and high manganese-iron ratio, and is particularly suitable for the production of metallurgical grade manganese concentrate from a refractory manganese oxide ore with a manganese content of 31.0-40.0% in the ore, harmful impurity iron mainly hematite and limonite, and an iron content of 12.0-18.0%.

Description

Technical Field

[0001] The invention belongs to the technical field of manganese ore dressing, and in particular relates to a separation method for manganese oxide ore, which is particularly suitable for producing metallurgical-grade manganese concentrate from a difficult-to-select manganese oxide ore in which the manganese content in the ore is 31.0-40.0%, harmful impurity iron is mainly hematite and limonite, and the iron content is 12.0-18.0%. Background Art

[0002] Manganese is widely used in the metallurgical industry and the battery industry. Its sources are mainly manganese oxide ore and manganese carbonate ore. With the development of the manganese industry, the demand for manganese ore resources has increased dramatically. Domestic high-quality manganese carbonate resources are scarce, low in grade and high in mining and processing costs. It is of great significance to accelerate the development and utilization of manganese oxide ore resources. Since industrial applications have certain requirements for manganese or ferromanganese grade, ferromanganese ratio, phosphorus manganese ratio, silicon dioxide content and other indicators in manganese ore, manganese oxide ore resources are generally processed by beneficiation.

[0003] At present, the main beneficiation method of manganese oxide ore is gravity separation. Weathered manganese oxide ore often contains a large amount of ore mud and powder ore, and the washing-gravity separation method is used in production. The original ore is washed to remove the ore mud. Some of the clean ore after mud washing can be used as finished ore, and some need to be re-selected by jigging and shaking table. Ore washing overflow sometimes also needs to be further recovered by gravity separation or strong magnetic separation. Some sedimentary primary manganese oxide ores are mined and depleted, so heavy media and jigging gravity separation are used in production to remove gangue and obtain block concentrates. In iron-containing manganese oxide ores, the iron minerals are mainly limonite, and iron and manganese are difficult to separate by gravity separation, flotation or strong magnetic separation.

[0004] In the article "Experimental Study on Ore Dressing of a Certain Oxidized Manganese Ore in Gansu" published in the 1st issue of Yunnan Metallurgy in 2018, the Mn content in the raw ore of a certain oxidized manganese ore in Gansu was 21.48%. Through the raw ore grinding-gravity separation process, a manganese concentrate with a manganese grade of 25.50% and a recovery rate of 58.73% can be obtained; through the raw ore grinding-wet strong magnetic separation process, under the conditions of grinding particle size -0.074mm accounting for 68.45% and magnetic field intensity 1650mT, the manganese concentrate contains 28.75% manganese and a recovery rate of 55.59%. The recovery rates of manganese concentrate obtained by the two processes are relatively low. In the article "Experimental Study on Ore Dressing of a Certain Low-grade Refractory Manganese Ore in Guangxi" published in the 10th issue of Mining Machinery in 2015, a certain low-grade manganese ore in Guangxi was seriously muddied, with manganese mainly in hard manganese ore and iron mainly in limonite. Due to the similar density and specific magnetic susceptibility of the two, it is difficult to separate manganese and iron. For a foreign manganese oxide ore with a manganese grade of 39.62% and an iron content of 16.68%, the inventors did not obtain ideal indicators by using the ore washing-strong magnetic separation process and the ore grinding-strong magnetic separation-reverse flotation process. When the ore grinding-gravity separation-reverse flotation process was adopted, the separation indicators of manganese concentrate grade of 50.09% and manganese recovery rate of 51.86% could be obtained, wherein Mn / Fe was 5.30 and P / Mn was 0.0047, which met the quality requirements of metallurgical secondary manganese concentrate, but the recovery rate of manganese concentrate was still low. Therefore, how to improve the manganese recovery rate while obtaining qualified manganese concentrate is an urgent problem to be solved in the current manganese oxide ore dressing. Summary of the invention

[0005] The purpose of the present invention is to provide a method for processing metallurgical grade manganese concentrate from difficult-to-select manganese oxide ore in view of the technical difficulties existing in the existing manganese oxide ore dressing process, such as complex process flow, low grade of manganese concentrate, low recovery rate, difficulty in separating ferromanganese, and difficulty in removing phosphorus from manganese ore.

[0006] To achieve the above-mentioned object of the present invention, a method for processing metallurgical grade manganese concentrate from refractory manganese oxide ore is implemented according to the following process and steps:

[0007] 1) Coarse crushing - magnetic reduction roasting operation: First, the manganese oxide ore is crushed to 12-0 mm, and then a certain amount of anthracite powder is added and mixed for magnetic reduction roasting. The reducing atmosphere and temperature are controlled to reduce the hematite in the ore to magnetite, and the limonite in the ore is burned and reduced to magnetite. The roasted sand after magnetic reduction roasting is cooled by water quenching.

[0008] In this step, the amount of anthracite added in the magnetization reduction roasting is preferably 5-8% of the mass of the manganese oxide ore raw material, the roasting temperature is preferably in the range of 800-850° C., and the roasting time is preferably between 1.5-2.0 h.

[0009] 2) Fine crushing - weak magnetic separation: The roasted sand cooled in step 1) is crushed to 2-0 mm, and then subjected to a weak magnetic separation for a roughing separation and a fine separation to obtain a weak magnetic concentrate, a weak magnetic roughing tailings, and a weak magnetic fine tailings, respectively.

[0010] The weak magnetic separation adopts a permanent magnetic drum magnetic separator, the roughing magnetic field strength is 143-175 kA / m, preferably 151-167 kA / m, and the fine magnetic field strength is 79-127 kA / m, preferably 87-111 kA / m.

[0011] 3) Weak magnetic concentrate grinding - weak magnetic separation operation: Grind the weak magnetic concentrate obtained in step 2) to -0.076mm≥60%, and then undergo a weak magnetic separation. The magnetic material produced is manganese-containing iron concentrate, and the non-magnetic minerals (weak magnetic tailings) produced are combined with the weak magnetic rougher tailings and weak magnetic concentrate tailings in step 2) to form the final manganese concentrate.

[0012] In step 3), the weak magnetic separation adopts a permanent magnetic drum magnetic separator, and the magnetic field strength of the weak magnetic separation is 79-127 kA / m, preferably in the range of 87-111 kA / m.

[0013] Compared with the prior art, the method for processing metallurgical grade manganese concentrate from refractory manganese oxide ore of the present invention has the following innovativeness and beneficial effects:

[0014] (1) Refractory manganese oxide ore contains more limonite (Fe2O 3n H2O) and other types of hydrated oxides of iron, which are roasted at high temperature to release water; after magnetic roasting, the grade of roasted sand can be increased by 5 percentage points compared with the original ore, and 2-0mm roasted sand can be obtained in advance through weak magnetic separation, one roughing and one concentrating, with a yield of about 47%, and a manganese concentrate (weak magnetic roughing tailings, weak magnetic concentrating tailings) with a manganese grade greater than 56%. This process does not require fine grinding, which is beneficial to improving the system processing capacity and reducing the subsequent grinding and concentrating amount.

[0015] (2) The grinding-weak magnetic separation process is simple. Under the condition of coarse grinding particle size, a weak magnetic separation can further recover some low-iron and manganese concentrate minerals (non-magnetic minerals, i.e., weak magnetic separation tailings), with a manganese grade of about 60%, thus achieving selective grinding and simultaneous recovery of useful minerals.

[0016] (3) The process flow of this method is simple, and the manganese concentrate finally obtained has a coarse particle size, which is conducive to smelting and agglomeration, and the grade can reach more than 56%, the recovery rate is as high as more than 83%, Mn / Fe≥5, P / Mn≤0.005, which meets the requirements of metallurgical grade manganese concentrate.

[0017] (4) For the refractory manganese oxide ore with a manganese content of 31.0-40.0%, harmful impurities of iron mainly in the form of hematite and limonite and an iron content of 12.0-18.0%, the magnetic material - manganese-containing iron concentrate produced by the step 3) grinding-weak magnetic separation operation has an iron grade of about 45.0% and a manganese grade of about 22%. Moreover, it is a strongly magnetic mineral recovered by weak magnetic separation and can be sold as a heavy medium product for coal preparation, thereby achieving 100% resource utilization of the refractory manganese oxide ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a process flow chart of the principle of a method for processing metallurgical grade manganese concentrate from a difficult-to-select manganese oxide ore.

[0019] Figure 2 The present invention is a numerical and qualitative flow chart of a method for processing metallurgical-grade manganese concentrate from refractory manganese oxide ore. DETAILED DESCRIPTION

[0020] To further describe the present invention, a method for processing metallurgical grade manganese concentrate from a refractory manganese oxide ore of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0021] The ore in the embodiment is manganese ore from a certain African country, and the average content of manganese in the ore is 36.73%, iron 14.88%, SiO2 6.78%, and phosphorus 0.31%. The ore minerals are mainly pyrolusite, psilomelane, manganese silicate minerals, hematite, and limonite, with the manganese mineral content reaching 80% and the limonite content being 15%; the gangue minerals are mainly quartz, with a small amount of flaky clay minerals, and the content of quartz and clay minerals is about 5%.

[0022] The ore is mainly earthy-colloidal in structure, with particle sizes less than 0.1mm, accounting for 80%, and very few particles exceeding 1.0mm. Manganese minerals are in various forms, mainly xenomorphic to semi-automorphic. Quartz is xenomorphic, with particle sizes less than 0.2mm, and there are a small amount of phosphorus sheet clay minerals, accounting for 15%.

[0023] The ore structure is massive. Its characteristics are that the iron and manganese mineral monomers and aggregates are irregularly embedded with quartz monomers and aggregates. The ore is often found with irregular loss holes.

[0024] Three process tests were conducted, including the ore grinding, gravity separation, reverse flotation roughing-scavenging process (secondary manganese concentrate product), the ore grinding, gravity separation, desliming, reverse flotation roughing-concentrating process (tertiary manganese concentrate product), and the ore magnetic roasting-crushing-weak magnetic separation-grinding (-0.076㎜60%)-weak magnetic separation process. The main process test results are shown in Table 1.

[0025] From the test results, although the raw ore grinding, gravity separation, reverse flotation roughing - scavenging process (process I) obtained a higher manganese ore grade (secondary manganese concentrate), the Mn recovery rate of the manganese concentrate was only 51.86%, and the Mn / Fe ratio was only 5.30; the manganese concentrate grade obtained by the raw ore grinding, gravity separation, desliming, reverse flotation roughing - concentrating process was only 45.71%, the manganese-iron ratio was only 3.73, and the manganese recovery rate was not high; while the magnetic roasting - crushing - weak magnetic separation - grinding (-0.076㎜60%) - weak magnetic separation process obtained a metallurgical grade manganese concentrate with a manganese grade of 56.50%, and the recovery rate was as high as 83.92%, and the manganese-iron ratio was as high as 9.74, with significant results.

[0026] Table 1 Final results of main process tests

[0027]

[0028] Depend on Figure 1 The principle process flow chart of the invention of a method for processing metallurgical grade manganese concentrate from refractory manganese oxide ore is shown in combination with Figure 2 It can be seen that the method for processing metallurgical grade manganese concentrate from refractory manganese oxide ore of the present invention adopts the following steps:

[0029] 1) Coarse crushing - magnetization reduction roasting: First, the manganese oxide ore is crushed to 12-0 mm, and then anthracite powder accounting for 6wt% of the manganese oxide ore is added and mixed evenly, and magnetization roasting is performed under the conditions of roasting temperature of 850℃ and roasting time of 2.0 hours to reduce the hematite in the ore to magnetite, and the limonite in the ore is burned and reduced to magnetite. The roasted sand after magnetization reduction roasting is cooled by water quenching;

[0030] 2) Fine crushing - weak magnetic separation: crush the roasted sand cooled in step 1) to 2-0 mm, and then undergo a weak magnetic separation for a roughing separation and a fine separation to obtain a weak magnetic concentrate, a weak magnetic roughing tailings, and a weak magnetic fine tailings respectively; the roughing magnetic field strength is 155 kA / m, and the fine separation magnetic field strength is 94 kA / m.

[0031] 3) Weak magnetic concentrate grinding - weak magnetic separation operation: the weak magnetic concentrate obtained in step 2) is ground to -0.076mm with a mass content of 60%, and then subjected to one weak magnetic separation with a magnetic field strength of 94kA / m. The magnetic material produced is manganese-containing iron concentrate, and the produced non-magnetic minerals are combined with the weak magnetic rougher tailings and weak magnetic concentrate tailings in step 2) to form the final manganese concentrate. The final manganese concentrate has a grade of 56.50%, a recovery rate of 83.92%, Mn / Fe=9.74, P / Mn=0.004, and meets the quality requirements of metallurgical first-level manganese concentrate.

[0032] The magnetic manganese-containing iron concentrate produced has an iron grade of 45.00% and a manganese grade of 21.88%. The "manganese + iron" content is as high as 66.88%. It is a strongly magnetic mineral recovered through weak magnetic separation. Its density is equivalent to that of magnetite concentrate with an iron grade of 66%. It can be sold as a heavy medium product for coal preparation, setting a precedent for 100% resource utilization of difficult-to-select manganese oxide ore.

Claims

1. A method for processing a metallurgical-grade manganese concentrate from a refractory manganese oxide ore, which is used to produce a metallurgical-grade manganese concentrate from a refractory manganese oxide ore having a manganese content of 31.0-40.0%, harmful impurities of iron being mainly hematite and limonite, and an iron content of 12.0-18.0%, characterized in that This is done using the following steps: 1) Coarse crushing - magnetic reduction roasting: First, crush the manganese oxide ore to 12-0 mm, then add a certain amount of anthracite powder and mix well for magnetic reduction roasting, control the reducing atmosphere and temperature, reduce the hematite in the ore to magnetite, and burn the limonite in the ore and reduce it to magnetite, and use water quenching to cool the roasted sand after magnetic reduction roasting; the amount of anthracite added in magnetic reduction roasting is 5-8% of the mass of the manganese oxide ore raw material, the roasting temperature is 800-850℃, and the roasting time is 1.5-2.0h; 2) Fine crushing - weak magnetic separation: crush the roasted sand cooled in step 1) to 2-0 mm, and then undergo a weak magnetic separation for a roughing separation and a fine separation to obtain a weak magnetic separation concentrate, a weak magnetic roughing separation tailings, and a weak magnetic fine separation tailings respectively; the roughing magnetic field strength is 143-175 kA / m, and the fine separation magnetic field strength is 87-111 kA / m; 3) Weak magnetic concentrate grinding - weak magnetic separation operation: the weak magnetic concentrate obtained in step 2) is ground to -0.076mm with a mass content of 58-70%, and then subjected to one weak magnetic separation. The magnetic material produced is manganese-containing iron concentrate. The magnetic field strength of the weak magnetic separation is 87-111 kA / m. The produced non-magnetic minerals are combined with the weak magnetic rougher tailings and weak magnetic concentrate tailings in step 2) to form the final manganese concentrate; the manganese-containing iron concentrate obtained is sold as a heavy medium product for coal preparation. The manganese grade of the final manganese concentrate obtained is more than 56%, the recovery rate is more than 83%, Mn / Fe≥5, P / Mn≤0.

005.

2. The method for processing metallurgical grade manganese concentrate from refractory manganese oxide ore according to claim 1, characterized in that: The weak magnetic separation adopts a permanent magnetic drum magnetic separator.

3. The method for processing metallurgical grade manganese concentrate from refractory manganese oxide ore according to claim 2, characterized in that: In step 2), the roughing magnetic field strength is 151-167 kA / m.

4. The method for processing metallurgical grade manganese concentrate from refractory manganese oxide ore according to claim 3, characterized in that: Step 3) The particle size of the weak magnetic separation concentrate grinding is controlled at -0.076mm and the mass content is between 60~65%.

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