Method for improving grinding, grading and capacity of ores by reducing fineness content ratio in settled ores

Abstract

A method of improving grinding, grading and capacity of ores by reducing a fineness content ratio ?.sub.0 in settled ores includes providing a two-stage ore grinding and grading system including a first fully closed circuit including a grinder and a hydrocyclone, or a two-stage ore grinding and grading system including a first-stage open circuit, and controlling parameters for ore grinding and grading as follows: controlling a dc an value of a point B on a separation cone of a second-stage ?500 mm hydrocyclone; controlling a fineness content ratio ?.sub.0 in settled ores; controlling a second-stage ore grinding and grading load Q.sub.2; and acquiring a first-stage grinding, grading and capacity Q of ores.

Claims

1. A method of improving grinding, grading and capacity of ores, the method comprising: providing a two-stage ore grinding and grading system comprising a first fully closed circuit comprising a grinder and a hydrocyclone, wherein: the hydrocyclone comprises a feeding pipe, a cylinder, a cone body, a release nozzle, and an overflow pipe; the cone body comprises a grading section and a separation section; the feeding pipe is connected to the cylinder; the feeding pipe is adapted to introduce feeding ores into the cylinder for rotation; the grading section of the cone body is connected to the cylinder, and the separation section of the cone body is connected to the release nozzle; the overflow pipe is disposed within the cylinder; the hydrocyclone is adapted to rotate the feeding ores to create an overflow and underflow ores; the release nozzle is adapted to discharge the underflow ores out of the hydrocyclone to the grinder; and the overflow pipe is adapted to discharge the overflow out of the hydrocyclone; and controlling parameters for ore grinding and grading as follows: controlling a centrifugal force strength dcan value of a point B; in the separation section; controlling a fineness content ratio ?.sub.0 in the underflow ores; controlling a second-stage ore grinding and grading load Q.sub.2; and acquiring a first-stage grinding, grading and capacity Q of ores.

2. The method of claim 1, wherein in the grading section, a centrifugal force strength dnan at a point A is 12-13 gravitational accelerations; in the separation section, a centrifugal force strength dcan at a at the point B is 72.6-84.45 gravitational accelerations; and the centrifugal force strength dcan at the point B of the separation section is 6.05-6.50 times of an an at the point A of the grading section.

3. The method of claim 1, wherein the fineness content ratio ?.sub.0 in the underflow ores in the hydrocyclone is 23.74-16.52%.

4. The method of claim 2, wherein the fineness content ratio ?.sub.0 in the underflow ores in the hydrocyclone is 23.74-16.52%.

5. The method of claim 1, wherein reducing the fineness content ratio ?.sub.0 in the underflow ores in the hydrocyclone decreases tons of ?200 mesh grade ores in the underflow ores, and one ton of new capacity is increased, with a convertible ratio as follows: 1) A convertible ratio of medium-low grade collophanite is 1.512:1, which means, every 1.512 tons of ?200 mesh grade ores in the underflow ores of the medium-low grade collophanite is reduced, and one ton of new capacity of the medium-low grade collophanite is increased; 2) A convertible ratio of copper oxide ores is 2.64:1, which means, every 2.64 tons of ?200 mesh grade ores in the underflow ores of the copper oxide ores is reduced, and one ton of new capacity of the copper oxide ores is increased; and 3) A convertible ratio of bauxite is 2.45:1, which means, every 2.45 tons of ?200 mesh grade ores in the underflow ores of the bauxite is reduced, and one ton of new capacity of the bauxite is increased.

6. The method of claim 1, wherein the centrifugal force strength dcan at the point B of the separation section of the hydrocyclone is calculated as follows: the centrifugal force strength dcan at the point B=5875.69 K.sub.D.sup.2?K.sub.a.sup.2?P?dn.sup.2/dc.sup.3; K.sub.D is a diameter correction coefficient of the hydrocyclone; K.sub.a is a core angle correction coefficient of the hydrocyclone; dn is an equivalent diameter of the feeding pipe, cm; dc is a diameter of the overflow pipe, cm; P is an ore feeding pressure, MPa; and 5875.69 is a constant value.

7. The method of claim 1, wherein a concentration and a fineness of the overflow in the hydrocyclone are increased respectively, as follows: 1) 3.01% and 2.3% for medium-low grade collophanite; 2) 1% and 3.5% for copper oxide ores; and 3) 0.61% and 6.71% for bauxite.

8. The method of claim 1, wherein a cylindrical diameter D of the hydrocyclone is ?466-?500 mm.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1A is an ore grinding and grading process in the related art.

(2) FIG. 1B is a parameter diagram of the process in FIG. 1A.

(3) FIG. 2A is an ore grinding and grading process of Kunyang mine (conventional method).

(4) FIG. 2B is a parameter diagram of the process in FIG. 2A.

(5) FIG. 3A is an ore grinding and grading process of Kunyang mine (First generation in the research and development center).

(6) FIG. 3B is a parameter diagram of the process in FIG. 3A.

(7) FIG. 4A is an ore grinding and grading process of Kunyang mine (Second generation in the research and development center).

(8) FIG. 4B is a parameter diagram of the process in FIG. 4A.

(9) FIG. 5A is an ore grinding and grading process of Kunyang mine (Third generation in the research and development center, the disclosure).

(10) FIG. 5B is a parameter diagram of the process in FIG. 5A.

(11) FIG. 6A is a conventional copper ore grinding and grading process in Dahongshan mine (Example 2).

(12) FIG. 6B is a parameter diagram of the process in FIG. 6A.

(13) FIG. 7A is a third generation copper ore grinding and grading process in Dahongshan mine (Example 2).

(14) FIG. 7B is a parameter diagram of the process in FIG. 7A.

(15) FIG. 8A is a conventional two-stage one-closed-circuit ore grinding and grading process flow of Guangxi Pingguo bauxite plant (Example 3).

(16) FIG. 8B is a parameter diagram of the process in FIG. 8A.

(17) FIG. 9A is a fourth generation two-stage one-closed-circuit ore grinding and grading process flow of Guangxi Pingguo bauxite plant (Example 3).

(18) FIG. 9B is a parameter diagram of the process in FIG. 9A.

(19) FIG. 10 is a schematic diagram of a cyclone of the disclosure.

(20) In the drawings, the following reference numbers are used: 1. Outer overflow pipe; 2. Inner overflow pipe; 3. Pulp inflow body; 4. Cylinder; 5. Overflow column; 6. Air column; 7. Cone body; 8. Ore release nozzle; h.sub.1. Generation and grading cone for settled ores and overflow; h.sub.2. Separation cone for settled ores and overflow.

DETAILED DESCRIPTION

(21) To further illustrate the disclosure, embodiments detailing a method of improving the grinding, grading and capacity of ores by reducing the fineness content ratio ?.sub.0 in the settled ores are described below. It should be noted that the following embodiments are intended to describe and not to limit the disclosure.

(22) In addition, in the description below, the working schematic drawing of the cyclone is provided, while known structural parameters and descriptions are omitted.

Example 1 Medium-Low Grade Collophanite

(23) 1. The Dcan at the Point B is Gravitational Acceleration, as Shown in Table 3.

(24) The dcan values of the conventional Kunming Jiyuan Company-first generation-second generation-third generation (the disclosure, similarly hereinafter) are respectively 38.43-50.19-61.88-72.60 gravitational accelerations. The disclosure is 1.9 times of the conventional one, namely, 1.9=72.6/38.43. Under the action of the powerful separating centrifugal force strength on the separation cone, the settled ores and the overflow products are fully separated, and the fineness content ratio ?.sub.0 in the settled ores is reduced greatly.

(25) 2. Fineness Content Ratio ?.sub.0 Refers to Table 3.

(26) The fineness content ratio ?.sub.0 of the conventional Kunming Jiyuan Company-first generation-second generation-third generation are respectively 47.57-34.54-26.86-23.74%. Compared with the conventional value, the fineness content ratio 0.sub.0 of the disclosure is decreased, namely, 2.0=47.57/23.74. The smaller the ?.sub.0 is, the smaller the ?200 mesh grade ores in the settled ores is.

(27) 3. Q.sub.-200-mesh Ore Quantity t/h in the Settled Ores as Shown in FIG. 2A-FIG. 5B.

(28) The ore quantities of the conventional Kunming Jiyuan Company-first generation-second generation-third generation are respectively 139.92-87.27-66.32-63.24% t/h. Compared with the conventional value, the Q-200.sub.-mesh ore quantity of the disclosure is decreased by 2.21 times, namely, 2.21=139.92/63.24. 76.68 tons of ?200 mesh grade ores are decreased every hour, so that the load of the grinder is alleviated greatly, thereby providing a certain space for a newly added capacity.

(29) 4. Capacity Q, t/h, Refer to FIG. 2A to FIG. 5B.

(30) The capacities of the conventional Kunming Jiyuan Company-first generation-second generation-third generation are respectively 179.30-185.39-203.67-230. Compared with the conventional capacity, the capacity of the disclosure is increased by 50.70 t/h.

(31) 5. Convertible Ratio

(32) The convertible ratio is: (139.92?63.24)/(230.00?179.30)=1.512, namely, 1.512:1.1.512 tons of ?200 mesh grade ores are reduced in the settled product, so that one ton of new capacity of the grinder is produced.

(33) 6. Concentration and Fineness of the Overflow Product, C %, ?%, Refer to FIG. 2A to FIG. 5B.

(34) The concentration and the fineness of the conventional Kunming Jiyuan Company-first generation-second generation-third generation are respectively 25.89, 86.00-25.05, 89.22-28.82, 88.66-28.90, 88.30. The overflow concentration C % is improved by 3.01% compared with the conventional one, namely, 3.01=28.90-25.89. The overflow fineness ?% is improved by 2.3% compared with the conventional one, namely, 2.3=88.30?86.00. Increase of C % and ?% verifies that the conventional technical design and research direction leaves much to be desired.

(35) 7. The Overflow Yield ?% in the Ore Grinding and Grading Circuit is Shown in Table 3.

(36) The overflow yields of the conventional Kunming Jiyuan Company-first generation-second generation-third generation are respectively 30.07-34.04-37.29-38.32. The overflow yield is improved by 8.25% compared with the conventional one, namely, 8.25=38.32-30.07. Increase of they value and decrease of the fineness content ratio 0.sub.0 are completely same in effect to play a role of preventing a lot of ?200 mesh grade ores from returning to the grinder to be ground again, so that the load of the grinder is alleviated and the capacity is improved.

(37) 8. Grading Efficiency E %, Refer to FIG. 2A to FIG. 5B.

(38) The grading efficiencies E % of the conventional Kunming Jiyuan Company-first generation-second generation-third generation are respectively 44.12-58.62-65.42-68.20. The grading efficiency E % is improved by 24.08% compared with the conventional one, namely, 24.08=68.20?44.12.

(39) The grading efficiency E % is defined as a ratio of the quantity T of ?200 mesh grade ores in the overflow to the quantity T.sub.0 of ?200 mesh grade ores in the feeding ores, namely, T/T.sub.0=E %.

(40) $T=\left(?-?\right)100\left(?-?\right)=\left(44.37-17.08\right)100\left(88.30-44.37\right)=119884.97$$T_0=?\left(?-?\right)\left(100-?\right)=44.37\left(88.30-17.08\right)\left(100-44.37\right)=175792.55$$E=\frac{T}{T_0}=\frac{119884.97}{175792.55}=68.20\%.$

(41) The ? value and the T value in the formula (???) are in reverse proportion, and the value T increases while the ? value decreases.

(42) The ? value in the formula (???) may inhibit proper increase of the T.sub.0 value to prevent the T.sub.0 value from being too great.

(43) The grading efficiency formula supports the nonobviousness of the disclosure theoretically.

(44) 9. Economic Benefit

(45) The floating plant, Jinning beneficiation branch company, Yunnan Phosphate Group Co., Ltd. is designed by China Bluestar Lehigh Engineering Corporation according to a conventional method. The designed capacity of two series of Kunyang mines is 2?150=3000 thousand tons/year (raw ores), and the capacity of a single series is 208.33 t/h; for the Jinning mines, the capacity of one series is 1500 thousand tons/year (raw ores), and the capacity of a single series is 208.33 t/h, totally, 4500 thousand tons/year (raw ores).

(46) The Kunyang mine series: after implemented in 2012 with the conventional method, the processing capacity per hour for the two series was 179.30 tons according to production data reports from 2014-2016, which was decreased by 29.03 t/h compared with the designed capacity 208.33 t/h, the total capacity was decreased to 2581.9 thousand tons/year (raw ores), and the decreasing extent was 418.1 thousand tons/year (raw ores). The electric consumption of the grinder was 27.28 kW.Math.h/t (raw ores).

(47) After implemented by technical transformation in the company since January 2017, the processing quantities per hour for the two series were both 230 tons, which was increased by 50.70 t/h compared with 179.30 t/h after the conventional method was implemented. The capacity was increased by 730.1 thousand tons/year, namely, 50.70?2?24?300=730.1 thousand tons/year. Based on a concentration yield 65%, 474.6 thousand tons/year was increased, and based on net margin per ton of 34.16 yuan, newly added profit was 16210700 yuan/year. The electric consumption of the grinder was decreased from 27.28 kW.Math.h/t (raw ores) in the conventional method to 18.42 kW.Math.h/t (raw ores), and the electric consumption was decreased by 8.86 kW.Math.h/t (raw ores). Based on 0.45 yuan per kilowatt-hour, the electric charge per ton of raw ores was decreased by 3.987 yuan. The total capacity of the disclosure was increased to 1656.0 thousand tons/year, the electric charge was saved by 1656000?3.987=6602400 yuan, 18156800 yuan for 33 months. The total economic benefit of the Kunyang ore series was 16210700+6602400=22813100 yuan/year, 62736000 yuan for 33 months.

(48) The Kunyang mine series: after implemented in 2012 in the conventional method, the processing capacity per hour for the single series was 189.00 tons according to production data reports from 2014-2016, which was decreased by 19.33 t/h compared with the designed capacity 208.33 t/h. The designed total capacity was decreased from 1500 thousand tons/year (raw ores) to 1360.8 thousand tons/year (raw ores), which was decreased by 139.2 thousand tons/year (raw ores). The electric consumption of the grinder was 25.25 kW.Math.h/t (raw ores).

(49) After implemented by technical transformation in the company since January, 2017, the processing capacity per hour for the single series was both 245 tons, which was increased by 56.00 t/h compared with 189.00 t/h after the conventional method was implemented. The total capacity was increased by 403.2 thousand tons/year, namely, 56.00?24?300=403.2 thousand tons/year. Based on a concentration yield 65%, 262.1 thousand tons/year of concentration was increased, and based on net margin per ton of concentration 34.16 yuan, newly added profit was 8952700 yuan/year. The electric consumption of the grinder was decreased from 25.25 kW.Math.h/t (raw ores) in the conventional method to 17.74 kW.Math.h/t (raw ores), and the electric consumption was decreased by 7.51 kW.Math.h/t (raw ores). Based on 0.45 yuan per kilowatt-hour, the electric charge per ton of raw ores was decreased by 3.3795 yuan. The total capacity of the disclosure was increased to 1764.0 thousand tons/year, the electric charge was saved by 1764000?3.3795=5961400 yuan, 16394000 yuan for 33 months. The total economic benefit of the Kunyang ore series was 8952700+5961400=14914100 yuan/year, 41013800 yuan for 33 months.

(50) Compared with the related art, the economic benefits of the totally three series: Kunyang mines, Jinning mines in Jinning beneficiation branch company are increased after the method of the disclosure is implemented: 1. Concentrate benefit is increased by 16210700+8952700=25163300 yuan/year; 2. Electricity is saved by 6602400+5961400=12563800 yuan/year; 3. The total annular benefit is 25163300+12563800=37727100 yuan/year; 4. The total economic benefit for 21 months is 69200000+34550500=103750500 yuan.

Example 2 Copper Ores

(51) The grinding and grading process of copper ore of Yunnan Dahongshan mine is as same as that in Example 1.

(52) 1. The Dcan Value at the Point B is Gravitational Acceleration, as Shown in Table 4:

(53) TABLE-US-00004 TABLE 4 Centrifugal force field of generation and separation of settled ores and overflow of hydrocyclone Bauxite Copper ore ?466 mm ?500 mm Fourth Third ?500 mm generation ?500 mm generation Conventional of R & D Conventional of R & D Name Symbol Unit hydrocyclone Center hydrocyclone Center Centrifugal force field of generation of settled ores and overflow at point A Ore feeding pressure P MPa 0.10 0.20 0.13 0.20 Volume flow dnV m.sup.3/h 280.01 137.87 239.83 133.83 Tangential speed dnu m/s 3.87 5.32 4.65 5.35 Rotation speed dnn rpm 1411.06 2083.67 1697.64 1952.72 Centrifugal force dnan g 6.10 12.40 8.83 11.69 strength Centrifugal force field of separation of settled ores and overflow at point B Separation speed dcu m/s 4.89 6.69 4.99 6.26 Rotation speed dcn rpm 4955.17 11295.02 5510.01 10377.01 Centrifugal force dcan Gravitational 27.09 84.45 30.70 72.60 strength acceleration Separation d.sub.97 ?m 86.07 56.29 72.24 57.44 granularity Primary parameters Effective volume V.sub.1 m.sup.3 0.252 0.205 0.252 0.208 Working time t s 3.24 5.36 3.78 5.60 Equivalent diameter dn? ?mm 160 95.70 135 94 of slurry feeding pipe Overflow pipe dc? ?mm 180 108 165 110 diameter Diameter of ore d.sub.H? ?mm 80 69 78 70 release nozzle Processing capacity Q t/h 85.93 115.00 186.00 210.00 Fineness content ?.sub.0 % 58.70 16.52 44.76 23.74 ratio Overflow rate of grinding % 12.40 29.74 31.16 41.49 circuit

(54) The dc values of the conventional Haiwang Company and the disclosure (third generation, similarly hereinafter) are respectively 30.7 and 72.6 gravitational acceleration. The method of the disclosure is 2.36 times of the conventional one. Under the action of the powerful separating centrifugal force strength on the separation cone, the settled ores and the overflow products are fully separated, and the fineness content ratio ?.sub.0 in the settled ores is reduced greatly.

(55) 2. Fineness Content Ratio ?.sub.0, as Shown in Table 4.

(56) The fineness content ratios 0.sub.0 of the conventional Haiwang Company and the disclosure are respectively 44.76% and 23.74%. Compared with the conventional value, the fineness content ratio 0.sub.0 of the disclosure is decreased by 1.89 times. The smaller the ?.sub.0 is, the smaller the ore quantity of ?200 mesh in the settled ores is.

(57) 3. Q-200.sub.-mesh Ore Quantity t/h in the Settled Ores, as Shown in FIG. 6A-FIG. 7B.

(58) The Q-200.sub.-mesh ore quantities of the conventional Haiwang Company and the disclosure are respectively 113.01 and 49.59 t/h. Compared with the conventional ore quantity, the ore quantity of the disclosure is decreased by 2.28 times. 63.42 tons of ?200 mesh grade ores are decreased every hour, so that the load of the grinder is alleviated greatly, thereby providing a certain space for a newly added capacity.

(59) 4. Capacity Q, t/h, as Shown in FIG. 2A to FIG. 5B.

(60) The capacities of the conventional Haiwang Company and the disclosure are respectively 186 and 210. Compared with the conventional capacity, the capacity of the disclosure is increased by 24 t/h.

(61) 5. Convertible Ratio

(62) The convertible ratio is: (113.01?49.59)/(210?186)=2.64, namely, 2.64:1.2.64 tons of the ?200 mesh grade ores are reduced in the settled product, and one ton of capacity of the grinder is obtained.

(63) 6. Concentration and Fineness of the Overflow Product, C %, ?%, as Shown in FIG. 6A-FIG. 7B.

(64) The concentrations of the conventional Haiwang Company and the disclosure are respectively 40.0 and 41. The fineness of the conventional Haiwang Company and the fineness of the disclosure are respectively 75 and 78.5. The overflow concentration C % is improved by 1% compared with the conventional one. The overflow fineness ?% is improved by 3.5% compared with the conventional one.

(65) 7. The Overflow Yield ?% in the Ore Grinding and Grading Circuit, as Shown in Table 4.

(66) The overflow yields of the conventional Haiwang Company and the disclosure are respectively 31.16 and 41.49. The overflow yield is improved by 10.33% compared with the conventional one, namely, 10.33=41.49-31.16. Increase of they value and decrease of the fineness content ratio 0.sub.0 are completely same in effect to play a role of preventing a lot of ?200 mesh grade ores from returning to the grinder to be ground again, so that the load of the grinder is alleviated and the capacity is improved.

(67) 8. Efficiency E %, Refer to FIG. 6A to FIG. 7B.

(68) The efficiencies E % of the conventional Haiwang Company and the disclosure are respectively 41.74 and 61.44. The efficiency E % is improved by 19.7% compared with the conventional one. This owes to the increase of 3.5% of the overflow fineness and decrease of 21.02% of the fineness content ratio ?.sub.0 in the settled ores, which leads to a final result that the ore quantity of ?200 mesh grade ores in the overflow product is increased greatly.

Example 3 Bauxite

(69) The aluminum oxide plant of Guangxi branch company of Aluminum Corporation of China Limited employs a two-stage ore grinding process with a first-stage open circuit.

(70) 1. The Dcan Value at the Point B is Gravitational Acceleration, as Shown in Table 4.

(71) The dc values of the conventional Weidongshan Company and the disclosure (third generation, similarly hereinafter) are respectively 27.09 and 84.45 gravitational accelerations. The disclosure is 3.13 times of the conventional one. Under the action of the powerful separating centrifugal force strength on the separation cone, the settled ores and the overflow products are fully separated, and the fineness content ratio ?.sub.0 in the settled ores is reduced greatly.

(72) 2. Fineness Content Ratio 0.sub.0, Refer to Table 4.

(73) The fineness content ratios 0.sub.0 of the conventional Weidongshan Company and the disclosure are respectively 58.70% and 16.52%. Compared with the conventional value, the fineness content ratio 0.sub.0 of the disclosure is decreased by 3.55 times. The smaller the ?.sub.0 is, the smaller the ?200 mesh grade ores in the settled ores is.

(74) 3. Q-200.sub.-mesh Ore Quantity t/h in the Settled Ores, as Shown in FIG. 8A-FIG. 9B.

(75) The Q-200.sub.-mesh ore quantities of the conventional Haiwang Company and the disclosure are respectively 89.53 and 18.20 t/h. Compared with the conventional value, the ore quantity of the disclosure is decreased by 4.92 times. 71.33 tons of ?200 mesh grade ores are decreased every hour, so that the load of the grinder is alleviated greatly, thereby providing a certain space for increasing the capacity.

(76) 4. Capacity Q, t/h, as Shown in FIG. 8A and FIG. 9B.

(77) The fineness content ratios 0.sub.0 of the conventional Weidongshan Company and the disclosure are respectively 85.93 and 115. Compared with the conventional capacity, the capacity of the disclosure is increased by 29.07 t/h.

(78) 5. Convertible Ratio

(79) The convertible ratio is: (89.53?18.20)/(115?85.93)=2.45, namely, 2.45:1.2.45 tons of ?200 mesh grade ores are reduced in the settled ores, so that one ton of capacity of the grinder is produced.

(80) 6. Concentration and Fineness of the Overflow Product, C %, ?%, as Shown in FIG. 8A and FIG. 9B.

(81) The concentrations of the conventional Weidongshan Company and the disclosure are respectively 20.98 and 21.59. The fineness of the conventional Weidongshan Company and the fineness of the disclosure are respectively 73.29 and 80. The overflow concentration C % is improved by 0.61% compared with the conventional one. The overflow fineness ?% is improved by 6.71% compared with the conventional one.

(82) 7. The Overflow Yield ?% in the Ore Grinding and Grading Circuit Refers to Table 4.

(83) The overflow yields of the conventional Weidongshan Company and the disclosure are respectively 12.40 and 29.74. The overflow yield is improved by 2.4% compared with the conventional one. Increase of they value and decrease of the fineness content ratio 0.sub.0 are completely same in effect to play a role of preventing a lot of ?200 mesh grade ores from returning to the grinder to be ground again, so that the load of the grinder is alleviated and the capacity is improved.

(84) 8. Efficiency E %, Refers to FIG. 8A and FIG. 9B.

(85) The efficiencies E % of the conventional Weidongshan Company and the disclosure are respectively 37.05 and 75.16. The Efficiency E % is improved by 2.03% compared with the conventional one. This owes to increase of 6.71% of the overflow fineness and decrease of 42.18% of the fineness content ratio ?.sub.0 in the settled ores, which leads to a final result that the ore quantity of ?200 mesh grade ores in the overflow product is increased greatly.