Processing technology for sufficient combustion of sulfur ore in fluidized bed furnace

Abstract

The invention relates to the technical field of mineral separation and metallurgy, in particular to a processing technology for sufficient combustion of sulfur ore in a fluidized bed roaster, which comprises the following steps: crushing pyrite, screening, compounding, and carrying out flotation by using an efficient inhibitor to obtain pretreated pyrite powder; the pretreated pyrite powder is added into a fluidized bed furnace, and sufficient combustion treatment is carried out after the pretreated pyrite powder is spread flatly, so that furnace gas and furnace slag are obtained; the efficient inhibitor is obtained by mixing sodium hydrosulfite, sodium thioglycollate, sodium humate and a buffering agent; wherein the furnace temperature during sufficient combustion treatment is 910-930 DEG C, the combustion time is 4-5 h, and the oxygen concentration of an outlet of the fluidized bed furnace is 2.5%-3.0%. The specific particle size and high quality of the pretreated pyrite powder are combined with a roasting process, so that compared with the prior art, the method has the advantages that the firing rate is higher, the iron grade of slag is higher, the service life of a circulating pump is longer, and the application prospect is wider.

Description

Technical Field

[0001] The invention relates to the technical field of ore dressing and metallurgy, and in particular to a processing technology for fully burning sulfur ore in a boiling furnace. Background Art

[0002] Pyrite is a general term for three sulfur-containing minerals: pyrite, marcasite and pyrrhotite. It is often golden yellow, brass-colored, sometimes yellow-green, with a bright metallic luster, and streaks of green-black or brown-black. It is mostly in block, granular or crystalline form, and its crystal structure is mostly cubic. The main component of pyrite is ferrous disulfide, with a hardness of 6.0-6.5. It can burn in the air, producing a blue flame and emitting a pungent odor. Pyrite is first roasted to produce sulfur dioxide, and then sulfuric acid can be prepared through catalytic oxidation and hydration reactions. At the same time, the tail gas produced during roasting can also be used to produce sulfur, and the high-grade slag after roasting can also be directly used for iron and steel making. The low-grade slag can be processed for iron making or used as cement ingredients. This shows that the roasting process is particularly important in the treatment of pyrite.

[0003] If pyrite cannot burn in a fluidized bed furnace, it will not only reduce the burn-out rate, but also reduce the grade of the slag and increase the yield of the original acid mist and gaseous sulfur in the furnace gas. However, the existing technical methods still lack attention to this. For example, the patent technical document CN102586618A discloses a pyrite smelting process, which first uses an oxidation smelting method to smelt pyrite, and after smelting, generates a matte enriched with precious metals and high-iron molten slag and high-temperature flue gas containing sulfur dioxide. The matte settles on the bottom of the furnace and is discharged. After the matte is separated from the high-iron molten slag, the high-iron molten slag is reduced and smelted in a reduction smelting pool smelting furnace to generate pig iron. The discharged matte is used to recover precious metals, and the discharged high-temperature flue gas is used for waste heat recovery and acid production. The invention focuses on achieving energy-saving effects through the oxidation reaction heat of the pyrite itself and the sensible heat of the molten slag. However, problems such as the burn-out rate and the slag grade are ignored.

[0004] Therefore, according to the above-mentioned related technologies, it is urgent to develop a processing technology for fully burning sulfur ore in a boiling furnace. Summary of the invention

[0005] In view of this, the purpose of the present invention is to propose a processing technology for fully burning sulfur ore in a boiling furnace to solve the problems of low burnout rate of pyrite and low iron grade in slag in the prior art.

[0006] Based on the above purpose, the present invention provides a processing technology for fully burning sulfur ore in a boiling furnace.

[0007] A process for fully burning sulfur ore in a fluidized bed furnace comprises the following steps:

[0008] Step S1: crushing and screening the pyrite, and compounding to obtain compound pyrite powder;

[0009] Step S2: flotation the compound pyrite powder with a high-efficiency inhibitor to obtain pretreated pyrite powder;

[0010] Step S3: adding the treated pyrite powder into the fluidized bed furnace, flattening it and performing sufficient combustion treatment to obtain furnace gas and slag;

[0011] The high-efficiency inhibitor in step S2 is obtained by mixing sodium dithionite, sodium thioglycolate, sodium humate and a buffer;

[0012] The furnace temperature during the sufficient combustion treatment in step S3 is 910-930°C, the combustion time during the sufficient combustion treatment is 4-5h, the outlet oxygen concentration of the boiling furnace during the sufficient combustion treatment is 2.5%-3.0%, the outlet negative pressure of the boiling furnace during the sufficient combustion treatment is -0.6kPa--0.4kPa, and the bottom pressure of the boiling furnace during the sufficient combustion treatment is 16.0kPa-17.0kPa.

[0013] Preferably, the boiling furnace in step S3 is a modified boiling furnace, and the modification method is to first increase the boiling furnace cavity by 4000-4390mm, then change the flue opening from L-shaped to oblique square flue opening, and finally add two Φ240mm supplementary air holes on the oblique square flue opening. The bottom area of ​​the modified boiling furnace is 54m 2 , furnace bottom air volume is 21000Nm 3 / h, the flue gas residence time is 21-23s, and the roasting intensity is 12t·m -2 ·d -1 .

[0014] Preferably, the screening process in step S1 is as follows:

[0015] First, sieve with a sieve with an aperture size of 150 μm, then sieve with a sieve with an aperture size of 48 μm, and then sieve with a sieve with an aperture size of 38 μm to obtain pyrite powder with a particle size of 48-150 μm, pyrite powder with a particle size of 38-48 μm, and pyrite powder with a particle size of 0-38 μm.

[0016] Preferably, the composite pyrite powder is obtained by mixing pyrite powder with a particle size of 48-150 μm, pyrite powder with a particle size of 38-48 μm and pyrite powder with a particle size of 0-38 μm in a mass ratio of 1-2:14-18:80.

[0017] Preferably, the flotation process in step S2 is as follows:

[0018] Step A1: Add compound pyrite powder to water, stir evenly, add high-efficiency inhibitor and maintain the pH value of the pulp at 9-10, then add collector and frother in sequence to carry out flotation for 3-6 minutes to obtain foam product 1 and tailings 1;

[0019] Step A2: adding a high-efficiency inhibitor to the tailings 1 and maintaining the pH value of the pulp at 9-10, and then sequentially adding a collector and a frother for 1-3 minutes of scavenging to obtain a foam product 2 and tailings 2; the scavenging operation further weakens the non-selective adsorption and mass transfer of the collector on the surface of the arsenopyrite by precisely controlling the dosage of the reagent and reducing the flotation time, thereby improving the recovery rate and quality of the foam product;

[0020] Step A3: Mix the foam product 1 and the foam product 2, then add a high-efficiency inhibitor, and concentrate for 1-3 minutes to obtain the foam product 3 and tailings 3;

[0021] Step A4: Tailings 2 and 3 are mixed and dried to obtain pretreated pyrite powder.

[0022] Preferably, the mass ratio of the sodium dithionite, sodium thioglycolate, sodium humate and buffer is 2-3:1:1:1-2.

[0023] Preferably, the buffer is any one or more of sodium phosphate, sodium carbonate, and sodium borate;

[0024] The collector is any one or more of sodium ethyl xanthate, sodium butyl xanthate, and sodium dibutyl dithiophosphate;

[0025] The foaming agent is any one or more of pine oil, methyl isobutyl carbinol and camphor oil.

[0026] Preferably, the mass ratio of water to compound pyrite powder in step A1 is 100:15-25;

[0027] The dosage of the high-efficiency inhibitor in step A1 is 900-1100 g / t;

[0028] The amount of the collector in step A1 is 100-200 g / t;

[0029] The amount of the foaming agent used in step A1 is 30-60 g / t.

[0030] Preferably, the dosage of the high-efficiency inhibitor in step A2 is 300-600 g / t;

[0031] The amount of the collector in step A2 is 20-60 g / t;

[0032] The amount of the foaming agent used in step A2 is 6-20 g / t.

[0033] Preferably, the dosage of the high-efficiency inhibitor in step A3 is 300-900 g / t.

[0034] Preferably, the thickness of the pretreated pyrite powder in the boiling furnace after being leveled in step S3 is 550-600 mm.

[0035] Beneficial effects of the present invention:

[0036] The present invention provides a processing technology for fully burning sulfur ore in a boiling furnace. The present invention not only improves the residence time of pyrite burning in the furnace by transforming the boiling furnace, but also prolongs the residence time of furnace gas. The present invention performs a specific roasting process in the transformed boiling furnace to fully burn pyrite powder, which not only improves the burn-out rate of pyrite and the iron grade of the roasted slag, and reduces the total sulfur content of the roasted slag, but also reduces the generation of original acid mist and gaseous sulfur in the furnace gas, and reduces the generation of sublimated sulfur in the power wave packing tower of the purification section, thereby prolonging the resistance rising period, promoting the stability of system resistance, prolonging the service life of the circulating pump of the power wave and the packing tower, preventing the occurrence of pump leakage, and improving the acid production of the device.

[0037] The present invention performs screening treatment before flotation and compounding according to a specific ratio, thereby improving the flotation efficiency and controlling the volume expansion during the roasting process, thereby controlling the slag volume within the tolerable range of the slag discharge drum.

[0038] The special high-efficiency inhibitor added in the flotation process of the present invention selectively and maximally inhibits the adsorption and mass transfer of groups on the mineral surface, while weakening the oxidation and mass transfer on the mineral surface, so that there are still active areas and sites on the mineral surface where the collector can be adsorbed, thereby making the pyrite that emerges more accurate.

[0039] The flotation of the present invention improves the feed quality of the boiling furnace, thereby further increasing the acid production and the total iron content in the slag. Therefore, compared with the prior art, the pyrite processing technology of the present invention not only has a high burn-out rate and a high iron grade in the slag, but also has a wider application prospect. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0041] Example 1: A process for fully burning sulfur ore in a fluidized bed furnace is as follows:

[0042] The method of fluidized bed furnace transformation is to first increase the height of the fluidized bed furnace cavity by 4000mm, then change the flue opening from L-shaped to oblique flue shape, and finally add two Φ240mm supplementary air holes on the oblique flue opening. The bottom area of ​​the fluidized bed furnace after the transformation is 54m 2 , furnace bottom air volume is 21000Nm 3 / h, the flue gas residence time is 21s, and the roasting intensity is 12t·m-2 ·d -1 .

[0043] Example 2: A process for fully burning sulfur ore in a fluidized bed furnace is as follows:

[0044] The method of fluidized bed furnace transformation is to first increase the height of the fluidized bed furnace cavity by 4390mm, then change the flue opening from L-shaped to oblique flue shape, and finally add two Φ240mm supplementary air holes on the oblique flue opening. The bottom area of ​​the fluidized bed furnace after the transformation is 54m 2 , furnace bottom air volume is 21000Nm 3 / h, the flue gas residence time is 23s, and the roasting intensity is 12t·m -2 ·d -1 .

[0045] Example 3: A process for fully burning sulfur ore in a fluidized bed furnace is as follows:

[0046] S1: After 100t of pyrite is crushed, it is first sieved with a sieve with an aperture size of 150μm, then sieved with a sieve with an aperture size of 48μm, and then sieved with a sieve with an aperture size of 38μm to obtain pyrite powder with a particle size of 48-150μm, pyrite powder with a particle size of 38-48μm, and pyrite powder with a particle size of 0-38μm.

[0047] S2: 1 t of pyrite powder with a particle size of 48-150 μm, 14 t of pyrite powder with a particle size of 38-48 μm and 80 t of pyrite powder with a particle size of 0-38 μm are mixed to obtain a composite pyrite powder;

[0048] S3: 36 kg of sodium dithionite, 18 kg of sodium thioglycolate, 18 kg of sodium humate, and 18 kg of sodium phosphate were mixed to obtain a highly effective inhibitor.

[0049] S4: Add compound pyrite powder into water at a mass ratio of 100:15, stir evenly, add high-efficiency inhibitor and maintain the pH value of the slurry at 9-10, then add sodium ethyl xanthate and pine oil in sequence for 3 minutes of flotation to obtain foam product 1 and tailings 1; wherein, the dosage of high-efficiency inhibitor is 900 g / t; the dosage of sodium ethyl xanthate is 100 g / t; the dosage of pine oil is 30 g / t.

[0050] S5: Add a high-efficiency inhibitor to the tailings 1 and maintain the pH value of the slurry at 9-10, then add sodium ethyl xanthate and pine oil in sequence for 1 minute of scavenging to obtain foam product 2 and tailings 2; wherein the dosage of the high-efficiency inhibitor is 300 g / t; the dosage of sodium ethyl xanthate is 20 g / t; and the dosage of pine oil is 6 g / t.

[0051] S6: Foam product 1 and foam product 2 are mixed, and then a high-efficiency inhibitor is added, and after concentrating for 1 minute, foam product 3 and tailings 3 are obtained; the dosage of the high-efficiency inhibitor is 300 g / t.

[0052] S7: Mix the tailings 2 and the tailings 3 and dry them to obtain pretreated pyrite powder.

[0053] S8: Add the treated pyrite powder into the fluidized bed furnace, flatten it and then carry out full combustion treatment to obtain furnace gas and slag; wherein, the thickness of the pretreated pyrite powder in the fluidized bed furnace after flattening is 550mm; the furnace temperature during full combustion treatment is 910℃, the combustion time is 4h, the outlet oxygen concentration of the fluidized bed furnace is 2.5%, the outlet negative pressure of the fluidized bed furnace is -0.4kPa, and the bottom pressure of the fluidized bed furnace is 16.0kPa.

[0054] Example 4: A process for fully burning sulfur ore in a fluidized bed furnace is as follows:

[0055] S1: After the pyrite is crushed, it is first sieved with a sieve with a pore size of 150 μm, then sieved with a sieve with a pore size of 48 μm, and then sieved with a sieve with a pore size of 38 μm to obtain pyrite powder with a particle size of 48-150 μm, pyrite powder with a particle size of 38-48 μm, and pyrite powder with a particle size of 0-38 μm.

[0056] S2: 1.5 t of pyrite powder with a particle size of 48-150 μm, 15 t of pyrite powder with a particle size of 38-48 μm and 80 t of pyrite powder with a particle size of 0-38 μm are mixed to obtain composite pyrite powder.

[0057] S3: 39.65 kg of sodium dithionite, 17.25 kg of sodium thioglycolate, 17.25 kg of sodium humate, and 25.86 kg of sodium carbonate were mixed to obtain a high-efficiency inhibitor.

[0058] S4: Add compound pyrite powder into water at a mass ratio of 100:18, stir evenly, add high-efficiency inhibitor and maintain the pH value of the pulp at 9-10, then add dibutyl sodium dithiophosphate and camphor oil in sequence for 4 minutes of flotation to obtain foam product 1 and tailings 1; wherein the amount of high-efficiency inhibitor is 1000 g / t; the amount of dibutyl sodium dithiophosphate is 130 g / t; the amount of camphor oil is 40 g / t.

[0059] S5: Add a high-efficiency inhibitor to the tailings 1 and maintain the pH value of the slurry at 9-10, then add sodium butyl xanthate and methyl isobutyl carbinol in sequence for 2 minutes of scavenging to obtain a foam product 2 and tailings 2; the dosage of the high-efficiency inhibitor is 400 g / t; the dosage of the sodium butyl xanthate is 30 g / t; the dosage of the methyl isobutyl carbinol is 10 g / t.

[0060] S6: Foam product 1 and foam product 2 are mixed, and then a high-efficiency inhibitor is added, and after concentrating for 2 minutes, foam product 3 and tailings 3 are obtained; the dosage of the high-efficiency inhibitor is 400 g / t.

[0061] S7: Mix the tailings 2 and the tailings 3 and dry them to obtain pretreated pyrite powder.

[0062] S8: Add the treated pyrite powder into the boiling furnace, flatten it and then carry out full combustion treatment to obtain furnace gas and slag; wherein, the thickness of the pretreated pyrite powder in the boiling furnace after flattening is 560mm; the furnace temperature during full combustion treatment is 915℃, the combustion time is 4.4h, the oxygen concentration at the outlet of the boiling furnace is 2.7%, the negative pressure at the outlet of the boiling furnace is -0.5kPa, and the bottom pressure of the boiling furnace is 16.3kPa.

[0063] Example 5: A process for fully burning sulfur ore in a fluidized bed furnace is as follows:

[0064] S1: After the pyrite is crushed, it is first sieved with a sieve with a pore size of 150 μm, then sieved with a sieve with a pore size of 48 μm, and then sieved with a sieve with a pore size of 38 μm to obtain pyrite powder with a particle size of 48-150 μm, pyrite powder with a particle size of 38-48 μm, and pyrite powder with a particle size of 0-38 μm.

[0065] S2: 1.7t of pyrite powder with a particle size of 48-150μm, 16t of pyrite powder with a particle size of 38-48μm and 80t of pyrite powder with a particle size of 0-38μm are mixed to obtain composite pyrite powder.

[0066] S3: 44.3 kg of sodium dithionite, 16.4 kg of sodium thioglycolate, 16.4 kg of sodium humate, 16.4 kg of sodium carbonate, and 11.5 kg of sodium borate were mixed to obtain a high-efficiency inhibitor.

[0067] S4: Add compound pyrite powder to water in a mass ratio of 100:22, stir evenly, add high-efficiency inhibitor and maintain the pH value of the slurry at 9-10, then add sodium ethyl xanthate, sodium butyl xanthate, pine oil and methyl isobutyl carbinol in sequence for 5 minutes of flotation to obtain foam product 1 and tailings 1; wherein, the dosage of high-efficiency inhibitor is 1050 g / t; the dosage of sodium ethyl xanthate is 100 g / t; the dosage of sodium butyl xanthate is 70 g / t; the dosage of pine oil is 30 g / t; the dosage of methyl isobutyl carbinol is 20 g / t.

[0068] S5: Add a high-efficiency inhibitor to the tailings 1 and maintain the pH value of the slurry at 9-10, then add sodium butyl xanthate, sodium dibutyl dithiophosphate, methyl isobutyl carbinol and camphor oil in sequence for 2 minutes of scavenging to obtain foam product 2 and tailings 2; wherein, the amount of the high-efficiency inhibitor is 500 g / t; the amount of sodium butyl xanthate is 30 g / t; the amount of sodium dibutyl dithiophosphate is 20 g / t; the amount of methyl isobutyl carbinol is 9 g / t, and the amount of camphor oil is 9 g / t.

[0069] S6: Foam product 1 and foam product 2 are mixed, and then a high-efficiency inhibitor is added, and after concentrating for 2 minutes, foam product 3 and tailings 3 are obtained; the dosage of the high-efficiency inhibitor is 800 g / t.

[0070] S7: Mix the tailings 2 and the tailings 3 and dry them to obtain pretreated pyrite powder.

[0071] S8: Add the treated pyrite powder into the fluidized bed furnace, flatten it and then carry out full combustion treatment to obtain furnace gas and slag; wherein, the thickness of the pretreated pyrite powder in the fluidized bed furnace after flattening is 580 mm; the furnace temperature during full combustion treatment is 925°C, the combustion time is 4.8 h, the outlet oxygen concentration of the fluidized bed furnace is 2.8%, the outlet negative pressure of the fluidized bed furnace is -0.55 kPa, and the bottom pressure of the fluidized bed furnace is 16.8 kPa.

[0072] Example 6: A process for fully burning sulfur ore in a fluidized bed furnace is as follows:

[0073] S1: After the pyrite is crushed, it is first sieved with a sieve with a pore size of 150 μm, then sieved with a sieve with a pore size of 48 μm, and then sieved with a sieve with a pore size of 38 μm to obtain pyrite powder with a particle size of 48-150 μm, pyrite powder with a particle size of 38-48 μm, and pyrite powder with a particle size of 0-38 μm.

[0074] S2: 2 t of pyrite powder with a particle size of 48-150 μm, 18 t of pyrite powder with a particle size of 38-48 μm and 80 t of pyrite powder with a particle size of 0-38 μm are mixed to obtain composite pyrite powder.

[0075] S3: 47.15 kg of sodium dithionite, 15.71 kg of sodium thioglycolate, 15.71 kg of sodium humate, 15.71 kg of sodium phosphate, and 15.71 kg of sodium borate were mixed to obtain a high-efficiency inhibitor.

[0076] S4: Add compound pyrite powder to water in a mass ratio of 100:25, stir evenly, add high-efficiency inhibitor and maintain the pH value of the slurry at 9-10, then add sodium ethyl xanthate, sodium butyl xanthate, sodium dibutyl dithiophosphate and pine oil, methyl isobutyl methanol and camphor oil in sequence for 6 minutes of flotation to obtain foam product 1 and tailings 1; the dosage of the high-efficiency inhibitor is 1100 g / t; the dosage of the sodium ethyl xanthate is 100 g / t; the dosage of the sodium butyl xanthate is 50 g / t; the dosage of the sodium dibutyl dithiophosphate is 50 g / t; the dosage of the pine oil is 20 g / t; the dosage of the methyl isobutyl methanol is 20 g / t; the dosage of the camphor oil is 20 g / t.

[0077] S5: Add a high-efficiency inhibitor to the tailings 1 and maintain the pH value of the slurry at 9-10, then add sodium ethyl xanthate, sodium butyl xanthate, sodium dibutyl dithiophosphate and pine oil, methyl isobutyl carbinol and camphor oil in turn for 3 minutes of scavenging to obtain foam product 2 and tailings 2; wherein, the amount of the high-efficiency inhibitor is 600 g / t; the amount of sodium ethyl xanthate is 20 g / t; the amount of sodium butyl xanthate is 20 g / t; the amount of sodium dibutyl dithiophosphate is 20 g / t; the amount of pine oil is 10 g / t; the amount of methyl isobutyl carbinol is 5 g / t; the amount of camphor oil is 5 g / t.

[0078] S6: Foam product 1 and foam product 2 are mixed, and then a high-efficiency inhibitor is added, and after beneficiation for 3 minutes, foam product 3 and tailings 3 are obtained; the dosage of the high-efficiency inhibitor is 900 g / t.

[0079] S7: Mix the tailings 2 and the tailings 3 and dry them to obtain pretreated pyrite powder.

[0080] S8: Add the treated pyrite powder into the boiling furnace, flatten it and carry out sufficient combustion treatment to obtain furnace gas and slag; wherein, the thickness of the pretreated pyrite powder in the boiling furnace after flattening is 600mm; the furnace temperature during the sufficient combustion treatment is 930℃, the combustion time is 5h, the outlet oxygen concentration of the boiling furnace is 3.0%, the outlet negative pressure of the boiling furnace is -0.6kPa, and the bottom pressure of the boiling furnace is 17.0kPa.

[0081] Comparative Example 1:

[0082] Compared with Example 3, the boiling furnace was not modified in this comparative example, and the remaining steps and parameters were the same, which will not be repeated in this comparative example. Finally, slag was obtained; wherein the bottom area of ​​the modified boiling furnace was 54m 2 , furnace bottom air volume is 20000Nm 3 / h, the flue gas residence time is 18s, and the roasting intensity is 11.1t·m -2 ·d -1 .

[0083] Comparative Example 2:

[0084] Compared with Example 3, this comparative example only replaces the step of "mixing pyrite powder with a particle size of 48-150 μm, pyrite powder with a particle size of 38-48 μm and pyrite powder with a mass ratio of 1.5:15:80" with "mixing pyrite powder with a particle size of 38-150 μm and pyrite powder with a mass ratio of 0-38 μm in a mass ratio of 5:91.5" in the preparation process of the composite pyrite powder. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, slag is obtained.

[0085] Comparative Example 3:

[0086] Compared with Example 1, this comparative example only replaces "sodium dithionite and sodium thioglycolate" with "sodium humate", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and slag is finally obtained.

[0087] Comparative Example 4:

[0088] Compared with Example 1, this comparative example only replaces "sodium humate" with "sodium dithionite, sodium thioglycolate", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and slag is finally obtained.

[0089] Comparative Example 5:

[0090] Compared with Example 1, this comparative example only replaces the "tailings 2 and tailings 3" dried in the preparation process of the pretreated pyrite powder with "tailings 1", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and slag is finally obtained.

[0091] Comparative Example 6:

[0092] Compared with Example 1, this comparative example only replaces the thickness of the pretreated pyrite powder in the boiling furnace after leveling from "550mm" to "700mm", and the remaining steps and parameters are the same and will not be repeated in this comparative example, and slag is finally obtained.

[0093] Performance Test:

[0094] Determination of effective sulfur content of slag:

[0095] Mix 0.12% methyl red alcohol solution and 0.08% methylene blue alcohol solution in a volume ratio of 1:1 to obtain a mixed indicator. Weigh 2g of slag and spread it evenly in a petri dish. Dry it at 105℃ for 1h and grind it to 100 mesh. Dry it at 105℃ for half an hour and then spread it evenly in a porcelain boat. Turn on the electric furnace and keep the temperature rising. In the case of exhaust, inject 20mL of 3% hydrogen peroxide solution with a separatory funnel, then add 3-4 drops of mixed indicator and 80ml of distilled water, and close the stopcock at the same time. Then add 0.1% sodium hydroxide solution with a burette to neutralize the absorption liquid, and then add the sodium hydroxide solution to the zero scale of the burette. When the temperature of the electric furnace rises to 860℃, take out the porcelain boat containing the sample placed in the drying oven and send it to the center of the combustion tube under continuous exhaust. At the same time, plug the leather plug at the end of the tube and burn at a constant temperature for 15min. While burning, titrate with 0.1% sodium hydroxide solution until the color of the absorption liquid completely changes from purple-red to brown-green, which is the titration endpoint. Then continue to absorb for 5 minutes until the absorption liquid no longer changes color, indicating that the combustion and absorption have been completed. After the combustion is completed, flush with the flushing branch pipe for more than three times, each time using about 5mL, and then continue to titrate with 0.1% sodium hydroxide solution, while the solution in the absorption liquid is discarded, and repeat the washing for 3 times; record the total amount of sodium hydroxide solution, and calculate the effective sulfur content in the slag according to formula 1. According to this method, the effective sulfur content (%) of the slag fired in Examples 3 to 6 of the present invention and Comparative Examples 1 to 6 is determined.

[0096] Formula 1:

[0097] In formula 1, V is the amount of 0.1% sodium hydroxide solution, mL.

[0098] Burn-out rate:

[0099] Mix 0.12% methyl red alcohol solution and 0.08% methylene blue alcohol solution in a volume ratio of 1:1 to obtain a mixed indicator. Weigh 2g of pyrite and spread it evenly in a petri dish. Dry it at 105℃ for 1h and grind it to 100 mesh. Dry it at 105℃ for half an hour and then spread it evenly in a porcelain boat. Turn on the electric furnace to keep the temperature rising. Under the condition of exhaust, inject 20mL of 3% hydrogen peroxide solution with a separatory funnel, then add 3-4 drops of mixed indicator and 80ml of distilled water, and close the stopcock at the same time. Then add 0.1% sodium hydroxide solution with a burette to neutralize the absorption liquid, and then add the sodium hydroxide solution to the zero scale of the burette. When the temperature of the electric furnace rises to 860℃, take out the porcelain boat containing the sample placed in the drying oven and send it to the center of the combustion tube under continuous exhaust. At the same time, plug the leather plug at the end of the tube and burn at a constant temperature for 15min. While burning, titrate with 0.1% sodium hydroxide solution until the color of the absorption liquid completely changes from purple-red to brown-green, which is the titration endpoint. Then continue to absorb for 5 minutes until the absorption liquid no longer changes color, indicating that the combustion absorption has been completed. After the combustion is completed, flush with the flushing branch pipe for more than three times, each time using about 5mL, and then continue to titrate with 0.1% sodium hydroxide solution, while the solution in the absorption liquid is discarded, and repeat the washing 3 times; record the total amount of sodium hydroxide solution, and calculate the effective sulfur content of the pyrite according to formula 1. Then calculate the burn-out rate (%) of Example 3-Example 6 and Comparative Example 1-Comparative Example 6 according to formula 2:

[0100] Formula 2:

[0101] Determination of total iron content of slag:

[0102] Weigh 0.50g of slag in a 250mL conical flask, add 0.5g of sodium fluoride and 50mL of concentrated hydrochloric acid, heat and dissolve on a discharge furnace plate until about 10mL is dissolved, and reduce with 7% stannous chloride until the solution turns light yellow, then slowly add until the solution turns colorless, and add 2-3 drops in excess, add 50ml of water, cool and add 5mL of saturated mercuric chloride solution, let stand for 2-3min, add 20mL of sulfur-phosphorus mixed acid, add 5-6 drops of 1% sodium diphenylamine sulfonate, immediately add 1% potassium dichromate standard solution until the solution turns stable blue-purple, record it as the end point, and calculate the total iron content according to formula 3; according to this method, the total iron content (%) in the slag prepared in Examples 3 to 6 of the present invention and Comparative Examples 1 to 6 is determined; the determination results are shown in Table 1.

[0103] Formula 3: Total iron content (%) = V × T × 100%

[0104] In formula 3, V is the number of milliliters of 1% potassium dichromate standard solution consumed by 2 g of slag; T is the total iron content of 2 g of standard sample / the number of milliliters of 1% potassium dichromate standard solution consumed by 2 g of standard sample.

[0105] Table 1 Statistics of effective sulfur content, burn-out rate and total iron content of slag

[0106] project Effective sulfur content of slag / % Burn-out rate / % Total iron content of slag / % Example 3 0.29 99.31 62.0 Example 4 0.27 99.36 61.9 Example 5 0.27 99.36 62.2 Example 6 0.25 99.40 62.2 Comparative Example 1 0.63 98.50 59.2 Comparative Example 2 0.39 99.07 61.1 Comparative Example 3 0.36 99.14 61.4 Comparative Example 4 0.40 99.05 60.9 Comparative Example 5 0.60 98.57 59.7 Comparative Example 6 0.48 98.86 60.3

[0107] Data Analysis:

[0108] As can be seen from Table 1, the processing technology of the present invention has a higher burn-out rate and slag total iron content;

[0109] This may be because the present invention not only improves the residence time of pyrite burning in the furnace by transforming the boiling furnace, but also prolongs the residence time of the furnace gas; the present invention performs a specific process of roasting in the transformed boiling furnace, so that the pyrite powder is fully burned, which not only improves the burn-out rate of pyrite and the iron grade of the slag after roasting, reduces the total sulfur content of the slag after roasting, but also reduces the generation of original acid mist and gaseous sulfur in the furnace gas, reduces the generation of sublimated sulfur in the power wave packing tower of the purification section, and thus prolongs the resistance increase cycle, promotes the stability of system resistance, prolongs the service life of the circulating pump of the power wave packing tower, prevents the occurrence of pump leakage, and increases the acid production of the device. The present invention performs pyrite powder particle size screening before flotation and compounding according to a specific ratio, which improves the flotation efficiency, and also controls the volume expansion during the roasting process, thereby controlling the slag volume within the tolerable range of the slag discharge drum. The special high-efficiency inhibitor obtained by mixing sodium dithionite, sodium thioglycolate, sodium humate and sodium carbonate added in the flotation process of the present invention selectively and maximally inhibits the adsorption and mass transfer of groups on the mineral surface, while weakening the oxidation and mass transfer on the mineral surface, so that there are still active areas and sites on the mineral surface where the collector can be adsorbed, thereby making the pyrite that emerges more accurate. The flotation of the present invention improves the feed quality of the boiling furnace, thereby further increasing the acid production and the total iron content in the slag. Therefore, compared with the prior art, the pyrite processing technology of the present invention not only has a high burnout rate, but also has a high iron grade in the slag.

[0110] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0111] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A process for fully burning sulfur ore in a fluidized bed furnace, characterized in that: The following steps are involved: Step S1: crushing and screening the pyrite, and compounding to obtain compound pyrite powder; Step S2: flotation the compound pyrite powder with a high-efficiency inhibitor to obtain pretreated pyrite powder; Step S3: adding the pretreated pyrite powder into the fluidized bed furnace, flattening it and performing sufficient combustion treatment to obtain furnace gas and slag; The high-efficiency inhibitor in step S2 is obtained by mixing sodium dithionite, sodium thioglycolate, sodium humate and a buffer; The furnace temperature during the sufficient combustion treatment in step S3 is 910-930°C, the combustion time during the sufficient combustion treatment is 4-5h, the outlet oxygen concentration of the boiling furnace during the sufficient combustion treatment is 2.5%-3.0%, the outlet negative pressure of the boiling furnace during the sufficient combustion treatment is -0.6kPa--0.4kPa, and the bottom pressure of the boiling furnace during the sufficient combustion treatment is 16.0kPa-17.0kPa.

2. The process for fully burning sulfur ore in a fluidized bed furnace according to claim 1, characterized in that: The screening process in step S1 is as follows: First, sieve with a sieve with an aperture size of 150 μm, then sieve with a sieve with an aperture size of 48 μm, and then sieve with a sieve with an aperture size of 38 μm to obtain pyrite powder with a particle size of 48-150 μm, pyrite powder with a particle size of 38-48 μm, and pyrite powder with a particle size of 0-38 μm.

3. The process for fully burning sulfur ore in a fluidized bed furnace according to claim 2, characterized in that: The composite pyrite powder is obtained by mixing pyrite powder with a particle size of 48-150 μm, pyrite powder with a particle size of 38-48 μm and pyrite powder with a particle size of 0-38 μm in a mass ratio of 1-2:14-18:

80.

4. The process for fully burning sulfur ore in a fluidized bed furnace according to claim 1, characterized in that: The mass ratio of the sodium dithionite, sodium thioglycolate, sodium humate and buffer is 2-3:1:1:1-2.

5. The process for fully burning sulfur ore in a fluidized bed furnace according to claim 1, characterized in that: The flotation process in step S2 is as follows: Step A1: Add compound pyrite powder to water, stir evenly, add high-efficiency inhibitor and maintain the pH value of the pulp at 9-10, then add collector and frother in sequence to carry out flotation for 3-6 minutes to obtain foam product 1 and tailings 1; Step A2: adding a high-efficiency inhibitor to the tailings 1 and maintaining the pH value of the slurry at 9-10, and then sequentially adding a collector and a frother to perform scavenging for 1-3 minutes to obtain a foam product 2 and tailings 2; Step A3: Mix the foam product 1 and the foam product 2, then add a high-efficiency inhibitor, and concentrate for 1-3 minutes to obtain the foam product 3 and tailings 3; Step A4: Tailings 2 and 3 are mixed and dried to obtain pretreated pyrite powder.

6. The process for fully burning sulfur ore in a fluidized bed furnace according to claim 5, characterized in that: The buffer is any one or more of sodium phosphate, sodium carbonate, and sodium borate; The collector is any one or more of sodium ethyl xanthate, sodium butyl xanthate, and sodium dibutyl dithiophosphate; The foaming agent is any one or more of pine oil, methyl isobutyl carbinol and camphor oil.

7. The process for fully burning sulfur ore in a fluidized bed furnace according to claim 5, characterized in that: The mass ratio of water to compound pyrite powder in step A1 is 100:15-25; The dosage of the high-efficiency inhibitor in step A1 is 900-1100 g / t; The amount of the collector in step A1 is 100-200 g / t; The amount of the foaming agent used in step A1 is 30-60 g / t.

8. The process for fully burning sulfur ore in a fluidized bed furnace according to claim 5, characterized in that: The dosage of the high-efficiency inhibitor in step A2 is 300-600 g / t; The amount of the collector in step A2 is 20-60 g / t; The amount of the foaming agent used in step A2 is 6-20 g / t.

9. The process for fully burning sulfur ore in a fluidized bed furnace according to claim 5, characterized in that: The dosage of the high-efficiency inhibitor in step A3 is 300-900 g / t.

10. The process for fully burning sulfur ore in a fluidized bed furnace according to claim 1, characterized in that: The thickness of the pretreated pyrite powder in the boiling furnace after being leveled in step S4 is 550-600 mm.