Low-grade specularite whole-size-fraction dry-type pre-concentration combined process

Abstract

The invention discloses a low-grade specularite whole-fraction dry-type pre-selection combined process which is characterized in that powder low-grade weakly-magnetic iron ore is pre-selected through a multi-roller series pre-selection means, the grade of pre-selected concentrate of 3-0mm fine ore is improved, and a part of metal is effectively recovered; the model selection of pre-selection equipment is carried out according to the characteristics of minerals with different particle fractions, the pre-selection concentrate grade of lump ores with small particle fractions of 30-3mm is improved by utilizing the most economical and effective mode, and meanwhile, the metal recovery rate is guaranteed; and thirdly, advanced intelligent separation equipment is introduced for efficient and intelligent pre-separation of lump ore with the particle size of 30-100 mm, and the grade and the recovery rate of comprehensive pre-separation concentrate are integrally improved while the raw ore treatment capacity is guaranteed. Compared with an existing ball milling-strong magnetic separation process, the ore grinding amount is reduced by 25%-30%, the grade of iron entering the mill is improved to 27% or above, and the comprehensive concentrate grade after preselection is improved to 27%-28% from 22%-23% and is improved by 5%-6%; and the comprehensive metal recovery rate reaches 88% or above, so that the beneficiation cost is reduced, and benefits are remarkable.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing, and in particular relates to a low-grade specularite full-grained dry pre-selection combined process. Background Art

[0002] my country's iron ore resources are mostly poor ores and few magnetic ores. Weakly magnetic iron ore that is difficult to select accounts for more than 70% of the total reserves. The selection of weakly magnetic iron ore has always been a major problem for mining companies. The Jingtieshan Huashugou Mine of Jiugang Company produces about 4.5 million tons of 0-100mm weakly magnetic Jingtieshan iron ore annually, of which 1.1 million tons are V ore body iron ore in the Jingtieshan Huashugou Mine. The V ore body iron ore in the Jingtieshan Huashugou Mine is quite special, with a low iron grade of only about 22-23%, and a SiO2 content of between 35 and 48%. The gangue and iron minerals are interwoven, impregnated, interlayered, and intergrown, and are typical high-silicon refractory ores. Direct application without pre-selection has a great impact on the selection indicators of the concentrator. The concentrator limits the proportion of ore used, and the annual output of iron ore from the V ore body drops from 1.15 million tons to about 500,000 tons, resulting in an imbalance in the mining ratio between the V ore body and other ore bodies, affecting the implementation of the mining plan of the entire Huashugou mining area.

[0003] The 0-100mm weak magnetic ore mined in Huashugou mining area is a weak magnetic and difficult-to-select iron ore with coexistence of specularite, hematite and limonite. The surrounding rock is easily muddied iron-bearing phyllite. After entering the grinding and selection system, this type of iron-bearing phyllite surrounding rock is easy to make the slurry muddied. The ball mill is used for fine grinding to produce polarization of coarse and fine particles. The fine particle size has the problem of over-crushing, and the coarse particle size has the problem of some iron particles not being dissociated, which seriously affects the strong magnetic separation index; the gangue is jasper and quartz with higher hardness than specularite. Jasper and quartz enter the grinding and selection system. Because the gangue has a high iron grade and fine embedded particle size, most of the iron ions are interdependent and not dissociated. It is easy to select this part of iron ions during strong magnetic separation by high gradient magnetic separator, which affects the quality of strong magnetic separation iron concentrate and leads to a high content of impurities such as SiO2. Therefore, direct grinding of weakly magnetic iron ore without pre-selection of phyllite surrounding rock, jadeite and quartz will result in low iron concentrate grade and high SiO2 content, making the utilization rate of such weakly magnetic iron ore low or unusable.

[0004] In summary, it is necessary to develop a high-efficiency pre-selection technology for all particle sizes of weakly magnetic, low-grade, difficult-to-select iron ore, so as to remove impurities such as phyllite and gangue in advance and improve the grade and efficiency of the grinding process. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of achieving full-size preselection of low-grade difficult-to-select ores. In the existing process, in order to improve the grade of the next process entering the mill, preselection is usually not performed, and the 0-3mm powder ore with an iron content of less than 20% is discarded and discharged into the waste rock dump, thereby losing part of the metal content, and large and small size block ores with an iron content of about 22-23% and above 3mm enter the grinding process at the same time, and the mixing of surrounding rocks and gangue causes low grinding efficiency. In order to solve the above problems, the present invention provides a low-grade mirror iron ore full-size dry preselection combined process.

[0006] The present invention provides a combined process for dry preselection of low-grade mirror iron ore of all particle sizes. First, preselection of powdered low-grade weakly magnetic iron ore is performed by means of multi-roller series preselection, the grade of 3-0mm powder ore preselection concentrate is improved, and a portion of the metal content is effectively recovered; second, the preselection equipment is selected according to the characteristics of minerals of different particle sizes, and the preselection concentrate grade of 30-3mm small particle size block ore is improved in the most economical and effective way, while ensuring the metal recovery rate; third, advanced intelligent sorting equipment is introduced to perform efficient intelligent preselection of 30-100mm particle size block ore, while ensuring the original ore processing capacity, the overall grade and recovery rate of the comprehensive preselection concentrate are improved. The process includes the following steps: A. For the ore output from the mine that is crushed to less than 100mm and has an original iron grade of 22-23%, it is classified into three particle size ranges: 3-0mm powder ore, 30-3mm lump ore, and 100-30mm lump ore; the original ore output from the mine has a particle size range of 100-0mm, an iron grade of 22-33%, and a SiO2 content of 35-48%. The gangue and iron minerals are interwoven, impregnated, interlayered, and intergrown with each other, which is a typical high-silicon difficult ore dressing; direct application without pre-selection has a greater impact on the selection index of the dressing plant, and its separation difficulty is also greater.

[0007] B. The iron grade of fine ore powder in the classification range of 3-0mm is 17-18%, accounting for 12-15%. The pre-selection operation is carried out using a five-roller series dry pre-selector. The pre-selection magnetic field intensity is 1.1-1.3T. The iron grade of the obtained strong magnetic pre-selection pre-extraction concentrate is 24-25%. The iron grade of the discarded tailings is controlled below 10% and is discharged as qualified tailings; C. The grading range is 30-3mm small-size lump ore, which is then screened into two size ranges of 15-3mm and 30-15mm, and pre-selected using a strong magnetic dry magnetic separator: the ore grade of the 15-3mm small-size lump ore is 22-23%, accounting for 14-16%, the magnetic field strength of the strong magnetic pre-selection is 1200-1400mT, the belt speed setting range is 25-35Hz, the tailings iron grade is controlled below 8%, the iron grade of the pre-selected concentrate is increased by 5-6 percentage points to more than 28%, the scrap rate is controlled at 26-30%, and the metal recovery rate is more than 90%; The ore grade of 30-15mm particle size block ore is 23-24%, accounting for 37-38%. The magnetic field strength of strong magnetic pre-selection is 1200-1400mT, the belt speed setting range is 25-30Hz, the tailings iron grade is controlled below 10%, the pre-selected concentrate grade is increased by more than 4.5 percentage points to more than 28%, the scrap rate is controlled at 24-26%, and the metal recovery rate reaches more than 88%.

[0008] D. The grading range is 100-30mm particle size lump ore, which is pre-selected by X-ray intelligent sorting machine. The ore grade of 100-30mm particle size lump ore is 23-24%, accounting for 34-35%, with a processing capacity of 60-70t / h, and an average tailings grade of 10.6-10.8%, which is discharged as qualified tailings; the grade of pre-selected concentrate is increased by more than 4 percentage points to more than 27%, the waste rate is controlled at 20-25%, and the metal recovery rate is more than 88%.

[0009] E. The comprehensive concentrate is obtained by combining 3-0mm powder ore pre-selected concentrate, 30-3mm lump ore pre-selected concentrate and 100-30mm lump ore pre-selected concentrate. The comprehensive fine product grade reaches more than 27.5%, and the comprehensive metal recovery rate reaches more than 85%.

[0010] The present invention aims at low-grade ores with different particle sizes and ore properties, and implements pre-selection through different and novel iron ore pre-selection equipment, so as to discard surrounding rocks and waste rocks in advance, improve the selected grade, and obtain qualified iron concentrate with a comprehensive grade of more than 27.5%. At the same time, it reduces the ore selection amount of the back-end separation process, and releases the production capacity of the back-end process.

[0011] The five-roller series dry pre-selector used for 3-0mm powder ore pre-selection is a new type of dry selection equipment. Through a large number of tests, it has been determined that the five-roller series dry pre-selector is a composite force dry magnetic separator, which belongs to the magnetic swing operation type magnetic separator. It increases the number of magnetic tumbling times of the material and can carry out iron enrichment treatment on low-grade weak magnetic minerals below 3mm. An intelligent sorting machine is used to carry out 100-30mm block ore pre-selection, and a combination of mechanical and photoelectric separation is used for mineral separation. Under X-ray transmission, the differences in the composition and properties of different minerals are utilized, and the ultra-high-speed X-ray detector acquisition system is used to perform transmission identification on each piece of material. After rapid calculation in the background, it is determined whether it belongs to ore or waste rock, and an instruction is issued to start the action of the injection actuator, accurately injecting the set waste rock or ore to achieve ore and waste separation. At present, this magnetic separation equipment has achieved fruitful application in iron ore sorting.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a low-grade mirror iron ore full-size dry pre-selection combined process, which can process 100-0mm weakly magnetic refractory iron ore. Compared with the existing ball mill-strong magnetic separation process, the amount of ore entering the mill is reduced by 25-30%, the iron grade entering the mill is increased to more than 27%, and the comprehensive concentrate grade after pre-selection is increased from 22-23% to 27-28%, which is increased by 5-6 percentage points; the comprehensive metal recovery rate reaches more than 88%, thereby reducing the ore dressing cost and achieving remarkable benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0014] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0015] Jiugang Specular Iron Ore is a typical weakly magnetic and difficult-to-select iron ore with symbiotic specular iron ore, limonite and siderite. The surrounding rock is easily argillized iron-bearing phyllite, and the gangue is iron-bearing jadeite, quartz and dolomite, which are harder than specular iron ore. The iron grade of the pre-selected concentrate and the metal recovery rate index are improved by the process of the present invention. The ore used in the present invention comes from the V ore body in the Huashugou mining area of ​​Jingtie Mountain, Jiugang. The sampled ore grade is 22-23%, the mixing ratio of surrounding rock and gangue is 25-30%, and the iron grade of surrounding rock and gangue is less than 11%.

[0016] Example 1 The 0-100mm full-size ore with an iron grade of 22.79% output from Jiugang Jingtieshan Mine was processed.

[0017] A. The ore crushed to less than 100mm and with an original iron grade of 22.64% is classified into three particle size ranges: 3-0mm powder ore, 30-3mm lump ore, and 100-30mm lump ore; B. The iron grade of fine-grained powder ore in the classification range of 3-0mm is 17.56%, accounting for 13.11%. The pre-selection operation is carried out using a five-roller series dry pre-selector with a pre-selection magnetic field intensity of 1.2T. The iron grade of the obtained strong magnetic pre-selection pre-extraction concentrate is 24.33%, and the iron grade of the discarded tailings is 9.23%, which is discharged as qualified tailings; C. The 30-3mm small-size lump ore is screened again into two size ranges of 15-3-mm and 30-15mm, and pre-selected using a strong magnetic dry magnetic separator: the grade of 15-3mm small-size lump ore is 22.23%, accounting for 15.02%, the magnetic field strength of the strong magnetic pre-selection is 1300mT, the belt speed setting range is 30Hz, the tailings iron grade is 7.6%, the pre-selected concentrate iron grade is 28.12%, the waste ratio is 28.7%, and the metal recovery rate is 90.18%; The grade of 30-15mm lump ore is 23.48%, accounting for 37.25%, the magnetic field strength of strong magnetic pre-selection is 1300mT, the belt speed setting range is 28Hz, the tailings grade is 9.72%, the pre-selected concentrate grade is 28.03%, the waste ratio is 24.85%, and the metal recovery rate reaches 89.72%; D. The grading range is 100-30mm particle size lump ore, which is pre-selected by X-ray intelligent sorting machine. The grade of 100-30mm particle size lump ore is 23.85%, accounting for 34.62%, with a processing capacity of 65t / h, and an average tailings grade of 10.62%, which is discharged as qualified tailings; the grade of pre-selected concentrate is 27.68%, the waste ratio is 22%, and the metal recovery rate reaches 90.53%; E. The comprehensive concentrate is obtained by combining 3-0mm powder ore pre-selected concentrate, 30-3mm lump ore pre-selected concentrate, and 100-30mm lump ore pre-selected concentrate. The comprehensive fine product grade can reach 27.55%, and the comprehensive metal recovery rate can reach 88.14%. The comprehensive tailings grade is 9.74%.

[0018] Example 2 The 0-100mm full-size ore with an iron grade of 22.59% output from Jiugang Jingtieshan Mine was processed.

[0019] A. The ore crushed to less than 100mm and with an original iron grade of 22.64% is classified into three particle size ranges: 3-0mm powder ore, 30-3mm lump ore, and 100-30mm lump ore; B. The iron grade of fine ore powder in the classification range of 3-0mm is 17.33%, accounting for 13.07%. The pre-selection operation is carried out using a five-roller series dry pre-selector with a pre-selection magnetic field intensity of 1.2T. The iron grade of the obtained strong magnetic pre-selection pre-extraction concentrate is 24.26%, and the iron grade of the discarded tailings is 9.16%, which is discharged as qualified tailings; C. The 30-3mm small-size lump ore is screened again into two size ranges of 15-3-mm and 30-15mm, and pre-selected using a strong magnetic dry magnetic separator: the grade of the 15-3mm small-size lump ore is 22.53%, accounting for 15.11%, the magnetic field intensity of the strong magnetic pre-selection is 1300mT, the iron grade of the tailings is 7.45%, the iron grade of the pre-selected concentrate is 28.66%, the waste ratio is 28.90%, and the metal recovery rate is 90.44%; The grade of 30-15mm lump ore is 23.52%, accounting for 37.60%, the magnetic field strength of strong magnetic pre-selection is 1300mT, the grade of tailings iron is 9.54%, the grade of pre-selected concentrate is 28.15%, the proportion of waste is 24.88%, and the metal recovery rate reaches 89.91%; D. The grading range is 100-30mm particle size lump ore, which is pre-selected by X-ray intelligent sorting machine. The grade of 100-30mm particle size lump ore is 23.61%, accounting for 34.22%, with a processing capacity of 65t / h, and an average tailings grade of 10.56%, which is discharged as qualified tailings; the grade of pre-selected concentrate is 27.42%, the waste ratio is 23.60%, and the metal recovery rate reaches 89.89%; E. The comprehensive concentrate is obtained by combining 3-0mm powder ore pre-selected concentrate, 30-3mm lump ore pre-selected concentrate and 100-30mm lump ore pre-selected concentrate. The comprehensive fine ore grade can reach 27.58%, and the comprehensive metal recovery rate can reach 88.13%.

[0020] The comprehensive tailings grade is 9.64%.

[0021] By using this process for pre-selection, the grade of the pre-selected concentrate is improved, the amount of ore entering the mill is reduced, and the grade of the ore entering the mill is improved, thereby reducing the cost of ore selection and achieving significant benefits.

Claims

1. A low-grade specular iron ore full-size dry pre-selection combined process, characterized in that The process includes the following steps: A. For the ore crushed to less than 100mm and with an original iron grade of 22-23%, it is classified into three particle size ranges: 3-0mm powder ore, 30-3mm lump ore, and 100-30mm lump ore; B. The iron grade of fine ore powder in the classification range of 3-0mm is 17-18%, accounting for 12-15%. The pre-selection operation is carried out using a five-roller series dry pre-selector. The pre-selection magnetic field intensity is 1.1-1.3T. The iron grade of the obtained strong magnetic pre-selection pre-extraction concentrate is 24-25%. The iron grade of the discarded tailings is controlled below 10% and is discharged as qualified tailings; C. The grading range is 30-3mm small-size lump ore, which is then screened into two size ranges of 15-3mm and 30-15mm, and pre-selected using a strong magnetic dry magnetic separator: the ore grade of the 15-3mm small-size lump ore is 22-23%, accounting for 14-16%, the magnetic field strength of the strong magnetic pre-selection is 1200-1400mT, the belt speed setting range is 25-35Hz, the tailings iron grade is controlled below 8%, the iron grade of the pre-selected concentrate is increased by 5-6 percentage points to more than 28%, the scrap rate is controlled at 26-30%, and the metal recovery rate is more than 90%; The ore grade of 30-15mm lump ore is 23-24%, accounting for 37-38%. The magnetic field strength of strong magnetic pre-selection is 1200-1400mT, the belt speed setting range is 25-30Hz, the tailings iron grade is controlled below 10%, the pre-selected concentrate grade is increased by more than 4.5 percentage points to more than 28%, the waste rate is controlled at 24-26%, and the metal recovery rate is more than 88%; D. The grading range is 100-30mm particle size lump ore, which is pre-selected by X-ray intelligent sorting machine. The ore grade of 100-30mm particle size lump ore is 23-24%, accounting for 34-35%, with a processing capacity of 60-70t / h, an average tailing grade of 10.6-10.8%, and is discharged as qualified tailings; the grade of pre-selected concentrate is increased by more than 4 percentage points to more than 27%, the waste rate is controlled at 20-25%, and the metal recovery rate is more than 88%; E. The comprehensive concentrate is obtained by combining 3-0mm powder ore pre-selected concentrate, 30-3mm lump ore pre-selected concentrate and 100-30mm lump ore pre-selected concentrate. The comprehensive fine product grade reaches more than 27.5%, and the comprehensive metal recovery rate reaches more than 85%.

2. A low-grade specularite full-size dry pre-selection combined process as claimed in claim 1, characterized in that: The raw ore output from the mine in step A has a particle size range of 100-0 mm, an iron content of 22-33%, and a SiO2 content of 35-48%.

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