Method for removing arsenic from high-arsenic nickel ore

Abstract

The present invention provides a method for dearsenicizing a high-arsenic nickel ore, which comprises the following steps: obtaining a high-arsenic nickel ore, and an additive containing FeS2, and controlling the mass of FeS2 to be 1.22-1.48 times the mass of NiAs, and then outputting a mixed material; obtaining a mixed material and oxygen, and controlling the mass of oxygen to be 1.14-1.38 times the mass of NiAs, and then performing an exothermic aerobic pyrolysis on the mixed material, and outputting pyrolysis gas containing arsenic and sulfur, and pyrolysis materials containing nickel and iron, respectively. The method for dearsenicating a high-arsenic nickel ore of the present invention, through FeS2 and NiAs undergoing pyrolysis reaction in an aerobic atmosphere, can make the arsenic in NiAs become gaseous As2O3, and the nickel in NiAs become solid NiO, so that they can be output separately and separated, and the pyrolysis temperature is low, which not only saves energy, but also does not cause the problem of material melting and wall sticking.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste treatment, and in particular to a method for removing arsenic from high-arsenic nickel ore. Background Art

[0002] Nickel arsenide (NiAs) is contained in nickel ore. The presence of arsenic in nickel ore causes more harm to the nickel smelting process. If the nickel ore can be de-arsenicized before smelting, the harm of arsenic will be greatly reduced. The de-arsenication method of high-arsenic nickel ore in the prior art is to heat and dissociate the nickel arsenide at high temperature in a neutral atmosphere to convert the arsenic in the nickel arsenide into gaseous elemental arsenic, thereby removing the arsenic in the nickel arsenide. The heating and dissociation temperature is above 1300°C, which not only consumes a lot of energy, but also when the temperature is too high, it may cause the material to melt and cause the problem of sticking to the wall.

[0003] Therefore, it is necessary to provide a method for removing arsenic from high-arsenic nickel ore to solve the above technical problems. Summary of the invention

[0004] The present invention provides a method for removing arsenic from high-arsenic nickel ore, which can remove arsenic in nickel arsenide through a sulfidation oxidation reaction at low temperature with low energy consumption; and effectively solves the technical problems of high operating energy consumption and material melting in the existing high-arsenic nickel ore dearsenicization.

[0005] The pyrolysis temperature of the pyrolysis process does not need to be too high, which not only saves energy but also does not cause problems of material melting and wall sticking.

[0006] The technical solution of the present invention is:

[0007] A method for removing arsenic from a high-arsenic nickel ore is used for removing arsenic from a high-arsenic nickel ore, wherein the high-arsenic nickel ore contains NiAs. The method for removing arsenic from a high-arsenic nickel ore comprises the following steps:

[0008] S11, obtaining the high-arsenic nickel ore and an additive containing FeS2, and controlling the mass of FeS2 to be 1.22-1.48 times the mass of NiAs, and then mixing the high-arsenic nickel ore and the additive, and outputting the mixed material; and,

[0009] S12, obtaining the mixed material and oxygen, and controlling the mass of oxygen to be 1.14-1.38 times the mass of NiAs, and then performing external heating aerobic pyrolysis on the mixed material at a set temperature and for a set time, and outputting pyrolysis gas containing arsenic and sulfur, and pyrolysis material containing nickel and iron, respectively.

[0010] In the method for dearsenicizing high-arsenic nickel ore described in the present invention, in step S12, the set temperature is set to 600° C.-800° C., and the set time is set to 60 min-120 min.

[0011] In the method for dearsenicizing high-arsenic nickel ore described in the present invention, in step S12, in step S11, the mass of FeS2 is 1.35 times the mass of NiAs; in step S12, the mass of oxygen is 1.26 times the mass of NiAs.

[0012] In the method for removing arsenic from high-arsenic nickel ore described in the present invention, the step S12 further includes: stirring the mixed material.

[0013] In the method for removing arsenic from high-arsenic nickel ore described in the present invention, step S12 also includes: aerobic pyrolysis of the mixed material under a slight negative pressure.

[0014] In the method for dearsenicizing high-arsenic nickel ore described in the present invention, the method for dearsenicizing high-arsenic nickel ore also includes step S13, obtaining the pyrolysis material, magnetically separating the pyrolysis material, and outputting nickel-containing pig iron.

[0015] In the method for dearsenicating high-arsenic nickel ore described in the present invention, the method for dearsenicating high-arsenic nickel ore includes step S14, obtaining the pyrolysis gas, condensing the pyrolysis gas to collect arsenic, and outputting refined white arsenic and sulfur-containing gas respectively.

[0016] In the method for dearsenicizing high-arsenic nickel ore described in the present invention, the step S14 also includes a step S15, obtaining the pyrolysis gas, performing high-temperature gas-solid separation on the pyrolysis gas, and outputting dust and arsenic-containing separation gas respectively; the step S14 is to obtain the separation gas, condense the separation gas to collect arsenic.

[0017] In the method for dearsenicizing high-arsenic nickel ore described in the present invention, step S14 further includes step S16, obtaining the sulfur-containing gas, desulfurizing the sulfur-containing gas, and outputting the waste gas.

[0018] In the method for removing arsenic from high-arsenic nickel ore of the present invention, step S11 further includes: conveying the mixed material by a closed conveyor.

[0019] Compared with the prior art, the present invention has the following beneficial effects: the method for arsenic removal from high-arsenic nickel ore of the present invention can convert arsenic in NiAs into gaseous As2O3 and nickel in NiAs into solid NiO by pyrolysis reaction of FeS2 and NiAs in an oxygen atmosphere, so that the arsenic in NiAs can be output separately for separation, and the pyrolysis temperature does not need to be too high, which not only saves energy but also does not cause the problem of material melting and wall sticking. At the same time, the mass of FeS2 is controlled to be 1.22-1.48 times the mass of NiAs, and the mass of oxygen is controlled to be 1.14-1.38 times the mass of NiAs, so that NiAs can be completely reacted, FeS2 is not wasted, and As2O5 is not generated, so that the best arsenic removal effect is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. The drawings described below are only drawings corresponding to some embodiments of the present invention.

[0021] Figure 1 A schematic flow chart of a method for removing arsenic from high-arsenic nickel ore provided in a preferred embodiment of the present invention.

[0022] Figure 2 A structural block diagram of the arsenic removal equipment used in the method for removing arsenic from high-arsenic nickel ore provided in a preferred embodiment of the present invention.

[0023] in, Figure 2 The labels are as follows:

[0024] 11. Mixing device,

[0025] 12. Closed conveyor,

[0026] 13. Oxygen controlled pyrolysis furnace,

[0027] 14. High temperature gas-solid separator,

[0028] 15. Condensation arsenic collection device,

[0029] 16. Gas purification device,

[0030] 17. Magnetic separation device.

[0031] In the figures, structurally similar elements are denoted by the same reference numerals. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0033] The directional terms mentioned in the present invention, such as "up", "down", "front", "back", "left", "right", "inside", "outside", "side", "top" and "bottom", are only for reference to the orientation of the drawings. The directional terms used are used to illustrate and understand the present invention, but not to limit the present invention.

[0034] The terms "first", "second", etc. in the present invention are used for descriptive purposes only and should not be understood as indicating or implying relative importance, and should not be used as a limitation on the order of precedence.

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The existing method for removing arsenic from high-arsenic nickel ore is to heat nickel arsenide at high temperature in a neutral atmosphere to dissociate the arsenic in the nickel arsenide, so as to convert the arsenic in the nickel arsenide into gaseous elemental arsenic, thereby removing the arsenic in the nickel arsenide. The heating condition is above 1300°C, which not only wastes energy, but also causes the material to melt due to the high temperature, resulting in the problem of sticking to the wall.

[0037] The following is a preferred embodiment of a method for dearsenicizing high-arsenic nickel ore provided by the present invention that can solve the above technical problems.

[0038] Please refer to Figure 1 and Figure 2 , a preferred embodiment of the present invention provides a method for dearsenicating high-arsenic nickel ore, which is used for dearsenicating high-arsenic nickel ore, wherein the high-arsenic nickel ore contains NiAs, and the method for dearsenicating high-arsenic nickel ore includes step S11 and step S12. Step S11 is to obtain high-arsenic nickel ore and an additive containing FeS2, and control the mass of FeS2 to be 1.22-1.48 times the mass of NiAs, then mix the high-arsenic nickel ore and the additive, and output the mixed material. Step S11 can be performed in the mixing device 11. Step S12 is to obtain the mixed material and oxygen, and control the mass of oxygen to be 1.14-1.38 times the mass of NiAs, and then perform external heating aerobic pyrolysis on the mixed material at a set temperature and keep warm for a set time, and output pyrolysis gas containing arsenic and sulfur, and pyrolysis material containing nickel and iron, respectively. Step S12 can be performed in the oxygen-controlled pyrolysis furnace 13.

[0039] During the pyrolysis process, the chemical reaction formula of NiAs, FeS2 and oxygen is:

[0040] 2NiAs+3FeS2+10.5O2=As2O3+2NiO+6SO2+Fe3O4

[0041] If FeS2 is too little, the arsenic removal will be incomplete; if FeS2 is too much, FeS2 will react with excess oxygen, or if there is insufficient oxygen, FeS2 will not react, both of which will result in FeS2 waste. If oxygen is too little, the arsenic removal will be incomplete; if oxygen is too much, excess oxygen will react with As2O3 to generate As2O5, which is solid and mixed in the pyrolysis material, resulting in arsenic in the pyrolysis material.

[0042] The method for removing arsenic from high-arsenic nickel ore of the present invention can make arsenic in NiAs become gaseous As2O3 and nickel in NiAs become solid NiO by pyrolysis reaction of FeS2 and NiAs in oxygen atmosphere, so that they can be output separately for separation, and the pyrolysis temperature does not need to be too high, which not only saves energy but also does not cause the problems of material melting and wall sticking. At the same time, the mass of FeS2 is controlled to be 1.22-1.48 times the mass of NiAs, and the mass of oxygen is controlled to be 1.14-1.38 times the mass of NiAs, so that NiAs can be completely reacted, FeS2 is not wasted, and As2O5 is not generated, so that the best effect of arsenic removal is achieved.

[0043] Moreover, the dearsenication method of high-arsenic nickel ore in the prior art requires many types of materials to be prepared, which is relatively troublesome. In the dearsenication method of high-arsenic nickel ore of the present invention, only one additive FeS2 needs to be added, and the preparation is simple.

[0044] In step S12, the set temperature is set to 600°C-800°C. In the prior art method for removing arsenic from high-arsenic nickel ore, the roasting temperature required is relatively high, requiring more than 1300°C, which not only wastes energy, but also causes the material to melt and stick to the wall due to the high temperature. In the method for removing arsenic from high-arsenic nickel ore of the present invention, the pyrolysis temperature is 600°C-800°C, which not only saves energy, but also does not cause the material to melt and stick to the wall.

[0045] In step S12, the time length is set to 60 min-120 min. This method can make the pyrolysis more complete.

[0046] The arsenic removal effect is best when the mass of FeS2 is 1.35 times that of NiAs and the mass of oxygen is 1.26 times that of NiAs.

[0047] Step S12 also includes: stirring the mixed material. By adopting this method, the mixed material can be heated more evenly and pyrolyzed more fully.

[0048] Step S12 also includes: aerobic pyrolysis of the mixed material under a slight negative pressure, which is specifically set to about 0-200 Pa. This method can avoid As2O3 overflow.

[0049] The method for removing arsenic from high-arsenic nickel ore further includes step S13, obtaining pyrolysis material, magnetically separating the pyrolysis material, and outputting nickel-containing pig iron. Step S13 can be performed in the magnetic separation device 17. By adopting this method, nickel-containing pig iron with higher added value can be obtained.

[0050] The method for removing arsenic from high-arsenic nickel ore includes step S14, obtaining pyrolysis gas, condensing the pyrolysis gas to collect arsenic, and outputting refined white arsenic and sulfur-containing gas respectively. Step S14 can be performed in the condensation arsenic collection device 15. The above method can recover arsenic and effectively utilize resources.

[0051] Before step S14, step S15 is also included, obtaining pyrolysis gas, performing high-temperature gas-solid separation on the pyrolysis gas, and outputting dust and arsenic-containing separation gas respectively; step S14 is to obtain separation gas, condense the separation gas to collect arsenic. Step S15 can be performed in the high-temperature gas-solid separator 14. By adopting the above method, dust in the pyrolysis gas can be filtered out, and the purity of the refined white arsenic output in step S14 can be improved.

[0052] After step S14, step S16 is also included, obtaining sulfur-containing gas, desulfurizing the sulfur-containing gas, and outputting waste gas. Step S16 can be performed in a gas purification device. The above method can remove sulfur from the sulfur-containing gas so that the output waste gas meets the emission standard.

[0053] Step S11 also includes: conveying the mixed material by a closed conveyor. This step can be performed by the closed conveyor 12. By adopting this method, arsenic-containing dust can be prevented from spreading into the working environment.

[0054] Example:

[0055] The main components of high-arsenic nickel ore are NiAs and SiO2, in which the arsenic content is as high as 25%. Pyrite is used as an additive. After the raw materials and additives are mixed, they are placed in a preheated externally heated oxygen-controlled pyrolysis furnace 13 through a closed conveyor 12, heated to 600-800°C, kept warm for 60-120 minutes, and slightly negative pressure. At the same time, a proper amount of oxygen is introduced into the oxygen-controlled pyrolysis furnace 13. The arsenic in the high-arsenic nickel ore is de-volatilized from the furnace in the form of gaseous oxides, thereby obtaining a de-arsenicized pyrolysis material, the arsenic content of which can be as low as 1%; at the same time, the pyrolysis material can obtain more than 20% nickel-containing pig iron through simple magnetic separation.

[0056] The method for removing arsenic from high-arsenic nickel ore of the present invention can make arsenic in NiAs become gaseous As2O3 and nickel in NiAs become solid NiO by pyrolysis reaction of FeS2 and NiAs in oxygen atmosphere, so that they can be output separately for separation, and the pyrolysis temperature does not need to be too high, which not only saves energy but also does not cause the problems of material melting and wall sticking. At the same time, the mass of FeS2 is controlled to be 1.22-1.48 times the mass of NiAs, and the mass of oxygen is controlled to be 1.14-1.38 times the mass of NiAs, so that NiAs can be completely reacted, FeS2 is not wasted, and As2O5 is not generated, so that the best effect of arsenic removal is achieved.

[0057] To sum up, although the present invention has been disclosed as above in the form of preferred embodiments, the protection scope of the present invention is not limited thereto, and any technician familiar with the technical field can make equivalent substitutions or changes according to the concept of the technical solution of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for removing arsenic from high-arsenic nickel ore, characterized in that: Used for dearsenifying high-arsenic nickel ore, wherein the high-arsenic nickel ore contains NiAs, the method for dearsenifying high-arsenic nickel ore comprises the steps of: S11, obtaining the high-arsenic nickel ore and an additive containing FeS2, and controlling the mass of FeS2 to be 1.22-1.48 times the mass of NiAs, and then mixing the high-arsenic nickel ore and the additive, and outputting the mixed material; S12, obtaining the mixed material and oxygen, and controlling the mass of oxygen to be 1.14-1.38 times the mass of NiAs, and then performing external heating aerobic pyrolysis on the mixed material at a set temperature and for a set time, and outputting pyrolysis gas containing arsenic and sulfur, and pyrolysis material containing nickel and iron, respectively; and, S14, obtaining the pyrolysis gas, condensing the pyrolysis gas to collect arsenic, and outputting refined white arsenic and sulfur-containing gas respectively; Wherein, in step S12, the set temperature is set to 600°C-800°C, and the set time is set to 60min-120min.

2. The method for removing arsenic from high-arsenic nickel ore according to claim 1, characterized in that: In the step S11, the mass of FeS2 is 1.35 times the mass of NiAs; in the step S12, the mass of oxygen is 1.26 times the mass of NiAs.

3. The method for removing arsenic from high-arsenic nickel ore according to claim 1, characterized in that: The step S12 also includes: stirring the mixed material.

4. The method for removing arsenic from high-arsenic nickel ore according to claim 1, characterized in that: Step S12 also includes: aerobic pyrolysis of the mixed material under a slight negative pressure.

5. The method for removing arsenic from high-arsenic nickel ore according to claim 1, characterized in that: The method for removing arsenic from high-arsenic nickel ore also includes step S13, obtaining the pyrolysis material, performing magnetic separation on the pyrolysis material, and outputting nickel-containing pig iron.

6. The method for removing arsenic from high-arsenic nickel ore according to claim 1, characterized in that: Before step S14, the method further includes step S15, obtaining the pyrolysis gas, performing high-temperature gas-solid separation on the pyrolysis gas, and outputting dust and arsenic-containing separation gas respectively; step S14 is to obtain the separation gas, condense the separation gas to collect arsenic.

7. The method for removing arsenic from high-arsenic nickel ore according to claim 1, characterized in that: The step S14 also includes a step S16 of obtaining the sulfur-containing gas, performing desulfurization treatment on the sulfur-containing gas, and outputting waste gas.

8. The method for removing arsenic from high-arsenic nickel ore according to claim 1, characterized in that: Step S11 also includes: conveying the mixed material by a closed conveyor.

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