PREPARATION METHOD OF MERCURY REMOVAL MATERIAL

Abstract

A modified natural sulfide ore material, a preparation method, and a use thereof are disclosed. A natural sulfide ore and a copper salt are used as raw materials. The natural sulfide ore is modified through mechanical grinding for activation, drying, and the like to synthesize a sulfide ore composite. The copper salt is subjected to a reaction to increase metal sites, produce fine microcrystalline particles, and change the crystal structure, such that active sites can be fully exposed. When contacting mercury in a gas phase and/or a liquid phase, the modified natural sulfide ore material can convert the mercury into a stable compound to realize the immobilization and removal of the mercury, which has advantages such as large mercury adsorption capacity, high adsorption rate, wide application temperature range, low cost, abundant raw material reserves, simple operation, and environmentally-friendly mercury removal products without secondary pollution and shows promising industrial application prospects.

Claims

1. A method of preparing a mercury removal material, wherein a main body of the mercury removal material is a modified natural sulfide ore material, and the modified natural sulfide ore material is prepared by mixing a natural sulfide ore and a copper salt and subjecting a resulting mixture to a mechanical ball-milling for an activation and a drying.

2. The method according to claim 1, wherein in the natural sulfide ore, a mass fraction of a sulfur is higher than or equal to 10%.

3. The method according to claim 1, wherein the natural sulfide ore is at least one selected from the group consisting of a chalcopyrite, a chalcocite, a bornite, a tetrahedrite, a galena, a sphalerite, a marmatite, a pyrite, a pyrhotite, a molybdenite, and a stibnite.

4. The method according to claim 1, wherein the copper salt is at least one selected from the group consisting of cuprous chloride, cupric chloride, a hydrate of the cuprous chloride, and a hydrate of the cupric chloride.

5. The method according to claim 1, wherein a mass ratio of the copper salt to the natural sulfide ore is 1:20 to 2:1.

6. The method according to claim 1, wherein before the copper salt and the natural sulfide ore are mixed, the natural sulfide ore is subjected to a ball-milling treatment.

7. The method according to claim 6, wherein before the natural sulfide ore is subjected to the ball-milling treatment, the natural sulfide ore is washed with a dilute acid for an impurity removal.

8. The method according to claim 1, wherein the modified natural sulfide ore material is prepared through the following specific steps: (1) washing a surface of the natural sulfide ore with a dilute acid to remove an oxide film and impurities, and washing the natural sulfide ore with water; drying or calcining and crushing the natural sulfide ore to obtain a crushed natural sulfide ore; and placing the crushed natural sulfide ore in a ball mill to subject to a thorough ball-milling; (2) adding the copper salt to the ball mill, conducting a mechanical grinding for the activation to obtain a ground material, and then drying or lyophilizing the ground material, wherein a mass ratio of the copper salt to the natural sulfide ore is 1:20 to 2:1; and (3) further grinding and sieving the ground material.

9. The method according to claim 8, wherein In step (1), the dilute acid has a concentration of 1 wt % to 5 wt % and is one selected from the group consisting of a sulfuric acid, a hydrochloric acid, a nitric acid, and an acetic acid, the washing is conducted by soaking the natural sulfide ore in the dilute acid for 5 min to 20 min, the drying is conducted at 100° C. to 200° C., the calcining is conducted at 400° C. to 700° C., and the thorough ball-milling is conducted for 5 min to 30 min; in step (2), the mechanical grinding is conducted at 25° C. to 75° C. for 5 min to 60 min, the drying is a vacuum-drying conducted at 60° C. to 150° C., and the lyophilizing is conducted at −20° C. to −40° C.; and in step (3), the further grinding is conducted for 5 min to 20 min, and the sieving is conducted until a particle size is 74 μm or less.

10. The method according to claim 2, wherein a mass ratio of the copper salt to the natural sulfide ore is 1:20 to 2:1.

11. The method according to claim 3, wherein a mass ratio of the copper salt to the natural sulfide ore is 1:20 to 2:1.

12. The method according to claim 4, wherein a mass ratio of the copper salt to the natural sulfide ore is 1:20 to 2:1.

13. The method according to claim 2, wherein the modified natural sulfide ore material is prepared through the following specific steps: (1) washing a surface of the natural sulfide ore with a dilute acid to remove an oxide film and impurities, and washing the natural sulfide ore with water; drying or calcining and crushing the natural sulfide ore to obtain a crushed natural sulfide ore; and placing the crushed natural sulfide ore in a ball mill to subject to a thorough ball-milling; (2) adding the copper salt to the ball mill, conducting a mechanical grinding for the activation to obtain a ground material, and then drying or lyophilizing the ground material, wherein a mass ratio of the copper salt to the natural sulfide ore is 1:20 to 2:1; and (3) further grinding and sieving the ground material.

14. The method according to claim 13, wherein In step (1), the dilute acid has a concentration of 1 wt % to 5 wt % and is one selected from the group consisting of a sulfuric acid, a hydrochloric acid, a nitric acid, and an acetic acid, the washing is conducted by soaking the natural sulfide ore in the dilute acid for 5 min to 20 min, the drying is conducted at 100° C. to 200° C., the calcining is conducted at 400° C. to 700° C., and the thorough ball-milling is conducted for 5 min to 30 min; in step (2), the mechanical grinding is conducted at 25° C. to 75° C. for 5 min to 60 min, the drying is a vacuum-drying conducted at 60° C. to 150° C., and the lyophilizing is conducted at −20° C. to −40° C.; and in step (3), the further grinding is conducted for 5 min to 20 min, and the sieving is conducted until a particle size is 74 μm or less.

15. The method according to claim 3, wherein the modified natural sulfide ore material is prepared through the following specific steps: (1) washing a surface of the natural sulfide ore with a dilute acid to remove an oxide film and impurities, and washing the natural sulfide ore with water; drying or calcining and crushing the natural sulfide ore to obtain a crushed natural sulfide ore; and placing the crushed natural sulfide ore in a ball mill to subject to a thorough ball-milling; (2) adding the copper salt to the ball mill, conducting a mechanical grinding for the activation to obtain a ground material, and then drying or lyophilizing the ground material, wherein a mass ratio of the copper salt to the natural sulfide ore is 1:20 to 2:1; and (3) further grinding and sieving the ground material.

16. The method according to claim 15, wherein In step (1), the dilute acid has a concentration of 1 wt % to 5 wt % and is one selected from the group consisting of a sulfuric acid, a hydrochloric acid, a nitric acid, and an acetic acid, the washing is conducted by soaking the natural sulfide ore in the dilute acid for 5 min to 20 min, the drying is conducted at 100° C. to 200° C., the calcining is conducted at 400° C. to 700° C., and the thorough ball-milling is conducted for 5 min to 30 min; in step (2), the mechanical grinding is conducted at 25° C. to 75° C. for 5 min to 60 min, the drying is a vacuum-drying conducted at 60° C. to 150° C., and the lyophilizing is conducted at −20° C. to −40° C.; and in step (3), the further grinding is conducted for 5 min to 20 min, and the sieving is conducted until a particle size is 74 μm or less.

17. The method according to claim 4, wherein the modified natural sulfide ore material is prepared through the following specific steps: (1) washing a surface of the natural sulfide ore with a dilute acid to remove an oxide film and impurities, and washing the natural sulfide ore with water; drying or calcining and crushing the natural sulfide ore to obtain a crushed natural sulfide ore; and placing the crushed natural sulfide ore in a ball mill to subject to a thorough ball-milling; (2) adding the copper salt to the ball mill, conducting a mechanical grinding for the activation to obtain a ground material, and then drying or lyophilizing the ground material, wherein a mass ratio of the copper salt to the natural sulfide ore is 1:20 to 2:1; and (3) further grinding and sieving the ground material.

18. The method according to claim 17, wherein In step (1), the dilute acid has a concentration of 1 wt % to 5 wt % and is one selected from the group consisting of a sulfuric acid, a hydrochloric acid, a nitric acid, and an acetic acid, the washing is conducted by soaking the natural sulfide ore in the dilute acid for 5 min to 20 min, the drying is conducted at 100° C. to 200° C., the calcining is conducted at 400° C. to 700° C., and the thorough ball-milling is conducted for 5 min to 30 min; in step (2), the mechanical grinding is conducted at 25° C. to 75° C. for 5 min to 60 min, the drying is a vacuum-drying conducted at 60° C. to 150° C., and the lyophilizing is conducted at −20° C. to −40° C.; and in step (3), the further grinding is conducted for 5 min to 20 min, and the sieving is conducted until a particle size is 74 μm or less.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIGS. 1A and 1B show a natural ore without modification and a mechanochemically-modified ore.

[0035] FIG. 2 shows the comparison of mercury removal performance of the natural pyrite and natural chalcopyrite with the mechanochemically-modified pyrite and mechanochemically-modified chalcopyrite in Application Example 8.

[0036] FIG. 3 shows the influence of mechanochemical modification, simple mixing of a natural sulfide and CuCl.sub.2, and impregnation on the mercury removal performance of the natural ore material in Application example 9.

[0037] FIG. 4 shows the influence of different superficial velocities on the mercury removal performance of mechanically-modified molybdenite in Application Example 10.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] To make the objective, technical solutions, and advantages of the present disclosure more comprehensible, the present disclosure will be further described below in detail below with reference to the examples. It should be understood that the specific examples described herein are merely intended to explain the present disclosure, rather than to limit the present disclosure.

[0039] Further, the technical features involved in the various embodiments of the present disclosure described below may be combined as long as they do not constitute a conflict with each other.

Example 1

[0040] Chalcopyrite (S: 30 wB %) was soaked in 4 wt % dilute hydrochloric acid for 10 min, dried at 150° C. for 3 h, crushed with a crushing machine, and ball-milled in a ball mill for 5 min. Cuprous chloride and milled chalcopyrite were mixed in a mass ratio of 3:2, mechanically ground at 50° C. for 20 min in a ball mill to allow activation, and vacuum-dried at 100° C. for 8 h. The dried material was further ground for 10 min and sieved until the particle size was 74 μm or less to obtain a modified ore material.

[0041] 300 mg of the modified ore material was weighed and placed in a simulated flue gas scrubbing device, where a simulated scrubbing solution had a temperature of 25° C., a pH of 4, and a volume of 200 mL. A mercury permeation tube was used to produce elemental mercury. A VM-3000 mercury analyzer was used to determine a mercury concentration in real-time. A mass flow meter was used to accurately control the gas flow rate of each component to simulate a composition of flue gas. A total gas flow rate was 0.5 L/min, an initial Hg.sup.0 concentration was 200 f 2 μg/m.sup.3, and in a pure N.sub.2 atmosphere, an Hg.sup.0 removal rate of the modified natural sulfide ore material within 1 h was 94.8%.

Example 2

[0042] Molybdenite (S: 55 wB %) was soaked in 2 wt % dilute sulfuric acid for 20 min, dried at 120° C. for 6 h, crushed with a crushing machine, and ball-milled in a ball mill for 20 min. Cupric chloride and milled molybdenite were mixed in a mass ratio of 1:2, mechanically ground at 75° C. for 30 min in a ball mill to allow activation, and vacuum-dried at 120° C. for 12 h. The dried material was further ground for 20 min and sieved until the particle size was 74 μm or less to obtain a modified ore material.

[0043] 75 mg of the modified ore material was weighed and injected into a pilot-scale jet tower with a volume of 1 m.sup.3. A mercury generator was used to produce elemental mercury. A VM-3000 mercury analyzer was used to determine a mercury concentration in real-time. A flue gas flow valve was used to control a gas flow rate. An initial Hg.sup.0 concentration was 100 μg/m.sup.3, a flue gas flow rate was 1 m.sup.3/min, a temperature was 125° C., and in a pure N.sub.2 atmosphere, an Hg.sup.0 removal rate within 1 h was 97.2%.

Example 3

[0044] Chalcocite (S: 15 wB %) was soaked in 3 wt % dilute sulfuric acid for 10 min, dried at 100° C. for 8 h, crushed with a crushing machine, and ball-milled in a ball mill for 10 min. Cupric chloride and milled chalcocite were mixed in a mass ratio of 3:4, mechanically ground at 40° C. for 25 min in a ball mill to allow activation, and lyophilized at −35° C. for 6 h. The dried material was further ground for 15 min and sieved until the particle size was 74 μm or less to obtain a modified ore material. Clay was added to the modified ore material, and the resulting mixture was extruded into 2 mm to 3 mm pellets.

[0045] 80 mg of the pellets were weighed and placed in a simulated fixed-bed reactor. A mercury permeation tube was used to produce elemental mercury. A VM-3000 mercury analyzer was used to determine a mercury concentration in real-time, and a mass flow meter was used to accurately control the gas flow rate of each component to simulate a composition of flue gas.

[0046] The total gas flow rate was 1 L/min, the initial Hg.sup.0 concentration was 65±1 μg/m.sup.3, and the reaction temperature was 100° C. In a pure N.sub.2 atmosphere, an Hg.sup.0 removal rate was 98.2%. In a N.sub.2+500 ppm SO.sub.2 atmosphere, an Hg.sup.0 removal rate was 96.5%. In a N.sub.2+8% H.sub.2O+500 ppm SO.sub.2 atmosphere, an Hg.sup.0 removal rate within 2 h was 94.1%.

Example 4

[0047] Chalcopyrite (S: 30 wB %) was soaked in 2 wt % dilute sulfuric acid for 15 min, dried at 100° C. for 8 h, crushed with a crushing machine, and ball-milled in a ball mill for 15 min. Cupric chloride and milled chalcopyrite were mixed in a mass ratio of ratio 2:3, mechanically ground at 50° C. for 30 min in a ball mill to allow activation, and vacuum-dried at 120° C. for 6 h. The dried material was further ground for 15 min and sieved until the particle size was 74 μm or less to obtain a modified ore material.

[0048] 25 mg of the modified ore material was weighed and placed in a simulated fixed-bed reactor. A mercury permeation tube was used to produce elemental mercury. A VM-3000 mercury analyzer was used to determine a mercury concentration in real-time. A mass flow meter was used to accurately control the gas flow rate of each component to simulate the composition of flue gas. The total gas flow rate was 1 L/min, the initial Hg.sup.0 concentration was 500 f 2 μg/m.sup.3, and the reaction temperature was 100° C. In a pure N.sub.2 atmosphere, an Hg.sup.0 removal rate was 95.2%. In a N.sub.2+200 ppm SO.sub.2 atmosphere, an Hg.sup.0 removal rate within 4 h was 92.5%. In a pure N.sub.2 atmosphere, a saturated mercury removal capacity was 83.5 mg/g.

Example 5

[0049] Pyrite (S: 51 wB %) was soaked in 2 wt % dilute sulfuric acid for 20 min, calcined at 500° C. for 1 h, crushed with a crushing machine, and ball-milled in a ball mill for 30 min. Cupric chloride and milled pyrite were mixed in a mass ratio of 1:1, mechanically ground at 50° C. for 30 min in a ball mill to allow activation, and vacuum-dried at 105° C. for 10 h. The dried material was further ground for 15 min and sieved until the particle size was 74 μm or less to obtain a modified ore material.

[0050] 50 mg of the modified ore material was weighed and placed in a simulated fixed-bed reactor. A mercury permeation tube was used to produce elemental mercury. A VM-3000 mercury analyzer was used to determine a mercury concentration in real-time. A mass flow meter was used to accurately control the gas flow rate of each component to simulate a composition of flue gas. A total gas flow rate was 1 L/min, an initial Hg.sup.0 concentration was 1,000 f 2 μg/m.sup.3, and a reaction temperature was 75° C. In a pure N.sub.2 atmosphere, an Hg.sup.0 removal rate after 4 h was 100%; in a pure N.sub.2 atmosphere, a saturated mercury removal capacity was 357 mg/g.

Example 6

[0051] Molybdenite (S: 55 wB %) was soaked in 2 wt % dilute sulfuric acid for 20 min, calcined at 550° C. for 30 min, crushed with a crushing machine, and ball-milled in a ball mill for 20 min. Cupric chloride and milled molybdenite were mixed in a mass ratio of 1:1, mechanically ground at 75° C. for 30 min in a ball mill to allow activation, and vacuum-dried at 100° C. for 12 h. The dried material was further ground for 20 min and sieved until the particle size was 74 μm or less to obtain a modified ore material.

[0052] 20 mg of the modified ore material was weighed and placed in a simulated fixed-bed reactor. A mercury permeation tube was used to produce elemental mercury, a VM-3000 mercury analyzer was used to determine a mercury concentration in real-time, and a mass flow meter was used to accurately control the gas flow rate of each component to simulate a composition of flue gas. A total gas flow rate was 1 L/min, an initial Hg.sup.0 concentration was 2000±5 μg/m.sup.3, and a reaction temperature was 75° C. In a pure N.sub.2 atmosphere, an Hg.sup.0 removal rate after 1 h was 100%.

Example 7

[0053] A pilot-scale experiment was conducted in a power plant with a flue gas flow rate of 6,000 m.sup.3/min and a mercury concentration of 0.31 mg/m.sup.3 to 0.36 mg/m.sup.3. The modified natural ore material obtained in Example 4 was injected upstream of a wet desulfurization device (temperature: about 100° C.) at an injection amount of 120 mg/m.sup.3 and a removal rate of mercury from flue gas was 95% or higher.

Comparative Example 1

[0054] 300 mg of the unmodified chalcopyrite in Example 1 was weighed and placed in a simulated flue gas scrubbing device, where a simulated scrubbing solution had a temperature of 25° C., pH of 4, and volume of 200 mL. A mercury permeation tube was used to produce elemental mercury, a VM-3000 mercury analyzer was used to determine a mercury concentration in real-time, and a mass flow meter was used to accurately control the gas flow rate of each component to simulate a composition of flue gas. A total gas flow rate was 0.5 L/min, an initial Hg.sup.0 concentration was 200±2 μg/m.sup.3, and in a pure N.sub.2 atmosphere, an Hg.sup.0 removal rate of the modified natural sulfide ore material within 1 h was 3.2%.

Comparative Example 2

[0055] The molybdenite in Example 2 was soaked in 2 wt % dilute sulfuric acid for 20 min, dried at 120° C. for 6 h, crushed with a crushing machine, and ball-milled in a ball mill for 20 min.

[0056] 75 mg of the milled molybdenite was weighed and injected into a pilot-scale jet tower with a volume of 1 m.sup.3. A mercury generator was used to produce elemental mercury, a VM-3000 mercury analyzer was used to determine a mercury concentration in real-time, and a flue gas flow valve was used to control a gas flow rate. An initial Hg.sup.0 concentration was 100 μg/m.sup.3, a flue gas flow rate was 1 m.sup.3/min, a temperature was 125° C., and in a pure N.sub.2 atmosphere, an Hg.sup.0 removal rate within 1 h was 5.6%.

Comparative Example 3

[0057] The molybdenite in Example 2 was soaked in 2 wt % dilute sulfuric acid for 20 min, dried at 120° C. for 6 h, crushed with a crushing machine, and ball-milled in a ball mill for 20 min. Cupric chloride and molybdenite were simply mixed in a mass ratio of 1:2 to obtain a mixture.

[0058] 75 mg of the mixture was weighed and injected into a pilot-scale jet tower with a volume of 1 mi. A mercury generator was used to produce elemental mercury, a VM-3000 mercury analyzer was used to determine a mercury concentration in real-time, and a flue gas flow valve was used to control a gas flow rate. An initial Hg.sup.0 concentration was 100 μg/m.sup.3, a flue gas flow rate was 1 m.sup.3/min, a temperature was 125° C., and in a pure N.sub.2 atmosphere, an Hg.sup.0 removal rate within 1 h was 7.4%.

Application Example 8

[0059] 25 mg of each of natural pyrite, natural chalcopyrite, the mechanochemically-modified pyrite prepared in Example 5, and the mechanochemically-modified pyrite prepared in Example 1 were weighed and placed in a simulated fixed-bed reactor. A mercury permeation tube was used to produce elemental mercury, a VM-3000 mercury analyzer was used to determine a mercury concentration in real-time, and a mass flow meter was used to accurately control the gas flow rate of each component to simulate a composition of flue gas. A total gas flow rate was 1 L/min, pure nitrogen was adopted as a reaction atmosphere, an initial Hg.sup.0 concentration was 800±2 μg/m.sup.3, and a reaction temperature was 90° C. Mercury removal effects were shown in FIG. 2.

[0060] After the mechanochemical modification, the mercury removal abilities of the pyrite and chalcopyrite were increased by hundreds or even thousands of times.

Application Example 9

[0061] Pyrite (S: 51 wB %) was soaked in 2 wt % dilute sulfuric acid for 20 min, dried at 100° C. for 8 h, crushed with a crushing machine, and ball-milled in a ball mill for 30 min. Cupric chloride and milled pyrite were mixed in a mass ratio of 3:2, mechanically ground at 50° C. for 30 min in a ball mill to allow activation, and vacuum-dried at 105° C. for 10 h. The dried material was further ground for 15 min and sieved until the particle size was 74 μm or less to obtain a mechanochemically-modified ore material.

[0062] Pyrite (S: 51 wB %) was soaked in 2 wt % dilute sulfuric acid for 20 min and then dried at 100° C. for 8 h: and cupric chloride and the pyrite were simply mixed in a mass ratio of 2:3, then vacuum-dried at 105° C. for 10 h, and sieved until a particle size was 74 μm or less to obtain a simple-mixing-modified ore material.

[0063] Pyrite (S: 51 wB %) was soaked in 2 wt % dilute sulfuric acid for 20 min and then dried at 100° C. for 8 h. Cupric chloride was weighed according to a cupric chloride-to-pyrite mass ratio of 2:3 and prepared into a cupric chloride impregnation solution. The pyrite was added to the cupric chloride impregnation solution, and the resulting mixture was stirred for 24 h and then centrifuged. The resulting solid was vacuum-dried at 105° C. for 10 h and sieved until the particle size was 74 μm or less to obtain an impregnation-modified ore material.

[0064] 25 mg of each of the mechanochemically-modified ore material, the simple-mixing-modified ore material, and the impregnation-modified ore material prepared in this example were weighed and placed in a simulated fixed-bed reactor. A mercury permeation tube was used to produce elemental mercury, a VM-3000 mercury analyzer was used to determine a mercury concentration in real-time, and a mass flow meter was used to accurately control the gas flow rate of each component to simulate a composition of flue gas. The total gas flow rate was 1 L/min, pure nitrogen was adopted as the reaction atmosphere, the initial Hg.sup.0 concentration was 800 f 2 μg/m.sup.3, and the reaction temperature was 110° C. Mercury removal effects were shown in FIG. 3. The mercury removal performance of the mechanochemically-modified ore material was much higher than that of the simple-mixing-modified ore material and the impregnation-modified ore material.

Application Example 10

[0065] Chalcocite (S: 18 wB %) was soaked in 2 wt % dilute sulfuric acid for 20 min, dried at 100° C. for 8 h, crushed with a crushing machine, and ball-milled in a ball mill for 30 min. Cupric chloride and milled pyrite were mixed in a mass ratio of 3:4, mechanically ground at 50° C. for 20 min in a ball mill to allow activation, and vacuum-dried at 105° C. for 6 h. The dried material was further ground for 15 min and sieved until the particle size was 74 μm or less to obtain a mechanochemically-modified ore material.

[0066] The mechanochemically-modified chalcocite obtained was placed in a simulated fixed-bed reactor. A mercury permeation tube was used to produce elemental mercury, a VM-3000 mercury analyzer was used to determine a mercury concentration in real-time, and a mass flow meter was used to accurately control the gas flow rate of each component to simulate a composition of flue gas. Pure nitrogen was adopted as the reaction atmosphere, the initial Hg.sup.0 concentration was 800±2 μg/m.sup.3, and the reaction temperature was 60° C. Mercury removal effects at different superficial velocities (gaseous hourly space velocity (GHSV)) were shown in FIG. 4. The superficial velocity in the experiment was thousands of times higher than the actual superficial velocity in industrial application, indicating that the mechanochemically-modified ore material still has an excellent mercury removal effect under extremely-harsh conditions.