System and method for underground mining of low-grade phosphorite based on photoelectric beneficiation pre-separation

Abstract

The invention relates to the technical field of mineral separation, and discloses a system and a method for underground mining of low-grade phosphorite based on photoelectric beneficiation pre-separation, which mainly utilize a '3 + 2 'scheme of a photoelectric beneficiation technology to carry out pre-separation work on the mined low-grade phosphorite so as to obtain various phosphorite meeting the application requirements of different downstream phosphorus chemical products. The mined low-grade phosphorite with the size of 10-40 mm is sequentially separated to obtain qualified phosphorite meeting the utilization requirements of downstream feed-grade calcium phosphate, ammonium phosphate and tailings, compared with raw ore, the grade of P2O5 in the low-grade phosphorite and the ammonium phosphate is improved, the contents of Fe2O3, Al2O3, MgO and SiO2 in the low-grade phosphorite and the ammonium phosphate are reduced, the grade of remaining tailings is reduced, the content of oxide is increased, and the comprehensive tailing discarding rate is smaller than 12%; according to the method, graded utilization of phosphorus resources is achieved, the use ways of the phosphorus resources are increased, the difficulty of subsequent mineral separation and phosphorus chemical production is relieved or even reduced, and the production cost is effectively saved.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral separation, and in particular to a system and method for underground mining of low-grade phosphate ore based on photoelectric separation pre-separation. Background Art

[0002] The utilization of phosphorus resources involves agriculture, chemical industry, pharmaceuticals, food, electronic semiconductor materials, environmental protection and other fields. Various forms of phosphorus resources mainly come from the processing of phosphate ore. Phosphate ore is a non-renewable resource. Although the known reserves of phosphate ore in China are relatively high, most of them are low-grade and medium-grade poor ores. With the long-term mining of surface phosphate ore, as a non-renewable resource, it has been difficult to meet the demand for different phosphorus or phosphorus chemical products in many aspects. At the same time, the accompanying grade reduction problem also has a great impact on the downstream phosphorus chemical product segment. Although the source and amount of phosphate ore have been phased out from the underground mining stage from surface mining, most underground mines are complex low-grade phosphate ores, and the content of major oxides such as Fe2O3, Al2O3, MgO and SiO2 that have a great impact on the phosphorus chemical reaction process is also high. Overall, it is difficult to meet the basic quality and quantity requirements of a variety of phosphorus chemical products, which has a great impact on the quality and process production of phosphorus compound raw materials for phosphate ore flotation and its downstream phosphorus chemical products, and is accompanied by the challenge of low comprehensive utilization of phosphorus resources. As the primary link in the process of utilizing other phosphorus resources, the processing and utilization of phosphate ore is also facing great pressure due to the decline in the grade of phosphate ore and the complexity of its components. The existing single or combined beneficiation methods such as chemical flotation, gravity separation, magnetic separation, and biological separation will also face the problems of insufficient adaptability to different low-grade and complex phosphate ores, limited single impurity removal methods, complex processes, high costs and non-greenness. Using low-grade, complex and difficult-to-select phosphate ores mined underground to meet the raw material needs of various existing phosphorus chemical products has become a problem that must be faced and solved.

[0003] With the development and progress of technology, photoelectric beneficiation, as a new beneficiation method, has been fruitful in mineral processing. Coupled with the boost of machine learning and intelligent algorithms, the equipment has developed some new beneficiation processes in coal mines and metal mines. Its efficient and accurate identification and sorting principles and excellent processing capabilities have good applicability for complex phosphate ores of different grades, providing a better path for solving the above problems. After the photoelectric beneficiator was used to sort low-grade complex phosphate ores mined underground, it was found that whether it was surface ore or underground mining, or various types of phosphate ores with different component distributions, the original ore could be sorted into concentrate and tailings, or concentrate, middlings and tailings according to the sorting scheme set after deep learning of the machine. Combined with the different grades and oxide contents of the selected original ore, the diversified and adjustable sorting schemes, the obtained concentrate, middlings and tailings can meet the raw material ore requirements of different downstream phosphorus chemical products to a certain extent, realizing the multi-directional utilization of low-grade poor phosphate ores mined underground. This technology does not require the addition of any reagents or increase unnecessary costs. It is intelligent and efficient, has a wide range of applications, and has broad industrial application prospects.

[0004] In order to solve the above problems, a system and method for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-separation is needed. Summary of the invention

[0005] The object of the present invention is to provide a system and method for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-separation.

[0006] The scheme of the present invention is:

[0007] The low-grade phosphate ore is sorted by using a photoelectric concentrator. The raw phosphate ore is screened by a double-layer vibrating screen of 10 mm and 40 mm in a closed circuit and a vibrating cloth screen of the photoelectric concentrator to obtain ore particles of 10-40 mm. After being transmitted by X-rays on a conveyor belt, an electrical signal containing mineral information is obtained. The electric signal is identified by the mineral classification learning model algorithm of the photoelectric concentrator, and the central processor directs the injection system to operate, so that the low-grade phosphate ore is sorted into raw ore and tailings containing feed-grade calcium phosphate and ammonium phosphate with different P2O5 grades and oxide contents, and the tailings throwing rate is less than 12%. The photoelectric concentrator performs three-product scheme sorting, and the medium ore selected from the three-product scheme is again sorted by the photoelectric concentrator to perform two-product scheme sorting.

[0008] As a preferred technical solution, the three-product solution is set and sorted by the sorting threshold range in the photoelectric concentrator, the concentrate sorting threshold range of the three-product solution is ≥45, 45>the middling sorting threshold range of the three-product solution>19, and the tailings sorting threshold range of the three-product solution is ≤19.

[0009] As a preferred technical solution, the two-product solution is set and sorted by the sorting threshold range in the photoelectric sorting machine. The concentrate sorting threshold range of the two-product solution is ≥36, and the tailings reverse selection threshold range of the two-product solution is ≤35.

[0010] As a preferred technical solution, the three-product solution of the photoelectric concentrator is used to sort the mined low-grade phosphate ore to obtain concentrate, middlings and tailings with different P2O5 grades in turn. Among the concentrates, the concentrates with P2O5 grade > 26%, MgO content < 2%, Fe2O3 content < 0.85%, and Al2O3 content < 0.90% are used as raw materials for feed-grade calcium phosphate, the middlings are used for further sorting by the subsequent two-product solution of the photoelectric concentrator, and the tailings with P2O5 grade of 3% to 6% and MgO content of 10% to 12% are used as aggregate for backfilling in underground mining goafs.

[0011] As a preferred technical solution, the middling ore with a P2O5 grade of 15% to 20% obtained by sorting the three-product solution is used as the new raw ore, and the concentrate and tailings are sorted by the two-product solution. The concentrate with a P2O5 grade of 20% to 22% and a MgO content of 5% to 7% selected by the two-product solution is used as the raw material ore of ammonium phosphate; the P2O5 grade of 4% to 8% and the MgO content of 8% to 11% selected by the two-product solution are used as backfill aggregate in underground mining goafs.

[0012] As a preferred technical solution, the parameters of the raw ore selection of the photoelectric concentrator are 10-40mm particle size and less dust on the surface; the parameters of the vibrating cloth screen of the photoelectric concentrator are working frequency 42-50HZ, current 6.0-6.5A, amplitude 7-15mm, and mesh aperture 10mm; the transmission belt parameters of the photoelectric concentrator are working frequency 45HZ, moving speed 0.4m / s, and width 2m; the X-ray source parameters of the photoelectric concentrator are X The wavelength of the ray is 0.2-0.5nm, the power is 10-50kv, the source temperature is 8-40℃, and the X-ray incident angle is 30-60°; the injection valve parameters of the photoelectric ore concentrator are: 192 large valves, 2mm aperture, 0.4-0.65Mpa injection pressure, 382 small valves, 1mm aperture, 0.2-0.55Mpa injection pressure, 42-96° injection angle between large and small valves, and 0.65-0.85Mpa for the air intake pipe.

[0013] As a preferred technical solution, a system for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-sorting includes a vibrating distribution screen, a transmission belt, an X-ray source, a blowing system and a central processing unit, wherein the central processing unit includes a data analysis and processing system, an operation and an online operation system, the discharge port of the vibrating distribution screen is located above the upstream of the transmission belt, an X-ray source is provided on the transmission belt, the blowing system is provided at the downstream tail end of the transmission belt, and the sensor of the X-ray source is connected to the central processing unit.

[0014] Advantages of the present invention:

[0015] The present invention efficiently sorts low-grade phosphate ore with complex components to obtain phosphate ore of different grades and different oxide contents, and uses these different types of sorted ores to meet the needs of feed-grade calcium phosphate and ammonium phosphate production with different downstream utilization requirements. At the same time, part of the tailings are discarded in advance, thereby expanding the multi-channel utilization of the original mined phosphate ore and improving the comprehensive utilization rate of phosphate ore resources.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. Wide range of mineral applications. The photoelectric separator is equipped with a variety of separation options for different minerals, grades and oxides. The phosphate separation scheme that can be changed and set to adapt to different process mineralogical characteristics can be set according to production needs.

[0018] 2. Intelligent and efficient, with large processing capacity. The photoelectric concentrator process has the advantages of machine learning, artificial intelligence and big data algorithm models, enabling it to quickly and accurately separate different grades of phosphate ores within 0.4ms at a processing capacity of 50-55t / h.

[0019] 3. Realize the multi-channel utilization of phosphorus resources. The photoelectric concentrator can use different sorting schemes set by machine learning to separate single raw ore into feed-grade calcium phosphate, ammonium phosphate and tailings raw materials that meet the different utilization needs of downstream, thus realizing the comprehensive utilization of phosphorus resources.

[0020] 4. Green and low-cost. As a dry-process mineral processing equipment, the photoelectric concentrator does not need to add any chemical reagents or media to participate in the sorting process. During the operation, it only needs electricity as energy to carry out the sorting work normally.

[0021] 5. Adjustable multi-thread processing of high-content oxides. Unlike the existing phosphate ore sorting process, the photoelectric concentrator can simultaneously sort sesquioxides and other main oxides with high content in the mineral, and can also freely change different oxide sorting indicators and parameters according to different mineral categories. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a process flow chart of the present invention;

[0023] Figure 2 It is a structural schematic diagram of the photoelectric ore concentrator in the present invention;

[0024] Figure 3 It is a framework diagram of the K value selection principle and calculation process of the photoelectric concentrator in the present invention;

[0025] Among them, 1-vibrating distributor; 2-transmission belt; 3-X-ray source; 4-X-ray detection sensor; 5-injection system; 6-data analysis and processing system; 7-operation and online monitoring system; 8-mined low-grade phosphate ore. DETAILED DESCRIPTION

[0026] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0027] Figure 2 The present invention shows a system for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-sorting, which includes a vibrating distribution screen, a transmission belt, an X-ray source, a blowing system and a central processing unit. The central processing unit includes a data analysis and processing system, an operation and an online operation system. The discharge port of the vibrating distribution screen is located above the upstream of the transmission belt. The transmission belt is provided with an X-ray source. The blowing system is provided at the downstream tail end of the transmission belt. The sensor of the X-ray source is connected to the central processing unit.

[0028] Working principle:

[0029] Representative concentrates, middlings and tailings that meet the requirements of feed-grade calcium phosphate and ammonium phosphate raw materials are selected in advance from the underground low-grade phosphate ore to be sorted. Then, according to the sorting requirements, photoelectric concentrators are used to carry out machine learning on representative samples of each phosphate ore. The corresponding big data algorithm model and optimized process parameters are tested and optimized to develop, and then mature process solutions for the sorting of underground low-grade phosphate ore are obtained in turn. After the above work is completed, the low-grade ore mined underground is put into the mobile crushing station and passed through the two-stage one-closed-circuit crushing and screening system to obtain ore particles with a particle size of 10-40mm that meet the requirements of entering the photoelectric ore concentrator. The ore particles then pass through the vibrating cloth screen 1 to form a layer of non-stacked ore layers and enter the conveyor belt 2. The ore particles on the conveyor belt 2 are transmitted by the X-ray source 4 and the collected mineral information and spectrum data are transmitted to the data analysis and processing system 6. After the efficient calculation of the big data model, all the transmitted phosphate ores are labeled with digital virtual labels of fine, medium and tailings. When the phosphate ores on the conveyor belt 2 are thrown out of the belt, they are accurately sprayed by the spraying system 5 to different mining areas to achieve the sorting of the ore. Among them, in the big data model, the ore with P2O5 grade>20% and MgO content<5% is defined as concentrate; the ore with P2O5 grade<6% and MgO content greater than 8% is defined as tailings; and the ore between the two is medium ore.

[0030] In the algorithm model, the content values ​​of the main spectral information of the ore P2O5, MgO, Fe2O3, Al2O3, SiO2, and CaCO3 extracted from the X-ray source are normalized to obtain the standard value. This value and the weight value of each compound component obtained by machine learning are substituted into the K value calculation formula to calculate the K value of each piece of phosphate rock. This K value is then compared with the pre-set selection threshold Ki_{\text{threshold}} range of each of the two or three products. The corresponding product is selected according to the K value within the threshold range.

[0031] like Figure 1 As shown, an optoelectronic concentrator is used to perform X-ray scanning on bulk raw materials and tailings that meet the production needs of feed-grade calcium phosphate and ammonium phosphate in underground low-grade raw ores, and the corresponding characteristic parameters of different minerals are obtained. According to the user's different requirements for the P2O5 grade, Fe2O3, Al2O3, MgO, SiO2 and other major oxides in the raw ore, an algorithm model is established, including two- or three-product sorting parameter settings and pre-production debugging, and then continuous optimization is performed to achieve the most suitable sorting process parameters. Finally, two-product and three-product solutions are obtained for sorting different raw ores and then obtaining the ore requirements of phosphorus chemical products with different utilization methods.

[0032] After the plan is determined, the mined ore is screened, crushed, screened, and distributed by the mobile crushing station at the front end to obtain a layer of non-stacked and non-agglomerated ore particles that meet the 10-40mm particle size requirements for photoelectric sorting. The ore layer is transported to the bottom of the X-ray source of the equipment by the conveyor belt and transmitted. The ore sample sorting information and spectral data obtained by transmission are entered into the data processing and analysis system together. After processing and analysis by the efficient artificial intelligence algorithm model, the system digitally identifies the ore in the ore that meets the requirements of concentrate, middlings, and tailings. The digitally identified mineral information is transmitted to the injection system and then accurately sprayed and sorted into different products. The concentrate obtained after the three-product plan sorts the ore is used as feed-grade calcium phosphate raw material ore, and the middling ore is used as the ore for the next stage of the two-product plan sorting. The tailings are recovered for backfilling the underground goaf. The middling ore from the first sorting is used as the raw material for the second sorting and enters the photoelectric concentrator again. The concentrate from the second sorting meets the requirements of ammonium phosphate raw material ore for the production of phosphate fertilizer, and the tailings are recovered for backfilling the underground goaf.

[0033] like Figure 3As shown in the figure, before the photoelectric beneficiation two-product and three-product separation scheme is applied to the original ore spraying, the main spectral information must be extracted according to the X-ray transmission of the source through the ore, and the contents of P2O5, MgO, Fe2O3, Al2O3 and SiO2 are calculated. Then, the content value of each compound is calculated according to the normalization formula to obtain the standard content value of each main compound. Subsequently, these standardized values ​​and the weight values ​​of each compound obtained by machine learning are substituted into the K value calculation formula. The calculated K value is the real-time value of a single piece of ore. Finally, the K value is compared with the threshold Ki_{\text{threshold}} of each product pre-set in the judgment condition. The ore greater than the threshold 1 is selected as the concentrate, the ore less than the threshold 2 is selected as the tailings, and the ore between the two thresholds is selected as the medium ore; or the ore greater than the threshold 3 is selected as the concentrate, and the ore less than the threshold 4 is selected as the tailings. According to the actual grade of underground phosphate ore, machine learning results and sorting objectives, the threshold values ​​of each product in each sorting scheme are as follows: the sorting threshold K is set as follows in the three-product scheme: concentrate K≥K_{\text{threshold}}=45, middlings K_{\text{threshold}}=45>K>K_{\text{threshold}}=19, tailings K≤K_{\text{threshold}}=19; the sorting threshold K is set as follows in the two-product scheme: concentrate K≥K_{\text{threshold}}=36, tailings K≤K_{\text{threshold}}=35.

[0034] The process parameters of the three-product and two-product separation scheme of the photoelectric concentrator are mainly divided into five aspects: a. Raw ore selection parameters. 10-40mm particle size, less mud and dust on the surface. b. Vibrating cloth screen parameters. Working frequency 42-50HZ, current 6.0-6.5A, amplitude 7-15mm, screen aperture 10mm. c. Belt distributor parameters. Working frequency 45HZ, moving speed 0.4m / s, width 2m. d. Source parameters. X-ray wavelength 0.2-0.5nm, power 10-50kv, source temperature 8-40℃, X-ray incident angle 30-60°. e. Blowing valve parameters. Large valves: quantity 192, aperture 2mm, injection pressure 0.4-0.65Mpa, small valves: quantity 382, ​​aperture 1mm, injection pressure 0.2-0.55Mpa, injection angles of large and small valves 42-96°, air intake pipe 0.65-0.85Mpa.

[0035] Example 1

[0036] The underground low-grade phosphate ore with a P2O5 grade of 18.71% and a MgO content of 5.74% is sorted through a three-product scheme to obtain a concentrate with a P2O5 grade of 26.55%, tailings with a grade of 5.21%, and a middling with a grade of 17.08% and used as the raw ore in the subsequent two-product sorting scheme. The contents of major oxides such as Fe2O3, Al2O3, MgO and SiO2 in the concentrate are lower than those of the raw ore. The concentrate with a P2O5 grade of >26% and a MgO content of <2% is used as the raw material ore of feed-grade calcium phosphate. The middling is used for re-sorting in the two-product scheme, and the tailings are recycled and reused.

[0037]

[0038] Example 2

[0039] The intermediate ore in Example 1 is used as the raw ore, and after sorting using the two-product solution of the photoelectric concentrator, a concentrate with a P2O5 grade of 20.95% and a tailings with a P2O5 content of 5.25% are obtained in turn. The contents of major oxides such as Fe2O3, Al2O3, MgO and SiO2 in the concentrate are lower than those of the raw ore. The concentrate with a P2O5 grade of 20%-22% and a MgO content of 5%-7% is used as a raw material ore for ammonium phosphate, and the tailings are also recycled and reused.

[0040]

[0041] Example 3

[0042] The underground medium-grade phosphate ore with a P2O5 grade of 21.90% and a MgO content of 4.62% is directly sorted through a three-product plan to obtain a concentrate with a P2O5 grade of 28.72%, a middling ore of 12.03%, and a tailings of 4.89%. The content of major oxides such as Fe2O3, Al2O3, MgO and SiO2 in the concentrate is lower than that of the original ore. The concentrate meets the requirements of raw material ore for feed-grade calcium phosphate, and the middling ore and tailings are comprehensively recycled.

[0043]

[0044] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-separation, characterized in that: The low-grade phosphate ore is sorted by using a photoelectric concentrator. The raw phosphate ore is screened by a double-layer vibrating screen of 10 mm and 40 mm in a closed circuit and a vibrating cloth screen of the photoelectric concentrator to obtain ore particles of 10-40 mm. After being transmitted by X-rays on a conveyor belt, an electrical signal containing mineral information is obtained. Through the mineral classification and identification of the photoelectric concentrator, the central processor directs the injection system to operate, and the low-grade phosphate ore is sorted into raw ore and tailings containing feed-grade calcium phosphate and ammonium phosphate with different P2O5 grades and oxide contents, and the tailings throwing rate is less than 12%. The photoelectric concentrator performs three-product scheme sorting, and the middlings sorted out by the three-product scheme are sorted again by the photoelectric concentrator according to the two-product scheme.

2. A method for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-separation as claimed in claim 1, characterized in that: The three-product solution is set and sorted by the sorting threshold range in the photoelectric concentrator. The concentrate sorting threshold range of the three-product solution is ≥45, 45>the middling sorting threshold range of the three-product solution is>19, and the tailings sorting threshold range of the three-product solution is ≤19.

3. A method for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-separation as claimed in claim 1, characterized in that: The two-product scheme is set and sorted by the sorting threshold range in the photoelectric sorting machine. The concentrate sorting threshold range of the two-product scheme is ≥36, and the tailings reverse selection threshold range of the two-product scheme is ≤35.

4. A method for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-separation as claimed in claim 1 or 2, characterized in that: The three-product solution of the photoelectric concentrator is used to sort the mined low-grade phosphate ore, and concentrate, middlings and tailings with different P2O5 grades are obtained in turn. Among the concentrates, the concentrates with P2O5 grade > 26%, MgO content < 2%, Fe2O3 content < 0.85%, and Al2O3 content < 0.90% are used as raw materials for feed-grade calcium phosphate, and the middlings are used for further sorting by the subsequent two-product solution of the photoelectric concentrator. The tailings with a P2O5 grade of 3% to 6% and a MgO content of 10% to 12% are used as aggregate backfill in underground mining goafs.

5. A method for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-separation as claimed in claim 1 or 3, characterized in that: The middlings with a P2O5 grade of 15% to 20% obtained from the three-product plan are used as new raw ore, and the concentrates and tailings are obtained by the two-product plan. The concentrates with a P2O5 grade of 20% to 22% and a MgO content of 5% to 7% selected from the two-product plan are used as raw material ore for ammonium phosphate; the P2O5 grade of 4% to 8% and the MgO content of 8% to 11% selected from the two-product plan are used as backfill aggregates in underground mining goafs.

6. A method for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-separation as claimed in claim 1, characterized in that: The parameters of the raw ore selection of the photoelectric concentrator are 10-40mm particle size and less dust on the surface; the parameters of the vibrating cloth screen of the photoelectric concentrator are working frequency 42-50HZ, current 6.0-6.5A, amplitude 7-15mm, and mesh aperture 10mm; the transmission belt parameters of the photoelectric concentrator are working frequency 45HZ, moving speed 0.4m / s, and width 2m; the X-ray source parameters of the photoelectric concentrator are X-ray wavelength 0 .2~0.5nm, power 10~50kv, source temperature 8~40℃, X-ray incident angle 30~60°; the injection valve parameters of the photoelectric ore concentrator are: large valve number 192, aperture 2mm, injection pressure 0.4~0.65Mpa, small valve number 382, ​​aperture 1mm, injection pressure 0.2~0.55Mpa, large valve and small valve injection angle 42~96°, air intake pipe 0.65~0.85Mpa.

7. A method for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-separation as claimed in claim 1, characterized in that: The method uses a system for underground mining of low-grade phosphate ore based on photoelectric beneficiation pre-sorting, which includes a vibrating distribution screen, a transmission belt, an X-ray source, a blowing system and a central processing unit. The central processing unit includes a data analysis and processing system, an operation and an online operation system. The discharge port of the vibrating distribution screen is located above the upstream of the transmission belt. The transmission belt is provided with an X-ray source, and the blowing system is provided at the downstream tail end of the transmission belt. The sensor of the X-ray source is connected to the central processing unit.

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