Processing method of phosphate rock in cooperation with waste mill scale

Abstract

The application discloses a processing method of phosphorite and waste ore powder, and full-quality utilization of phosphorite and waste ore powder containing phosphorus is realized through process optimization, and artificial phosphate rock used for yellow phosphorus production is obtained, which can be directly used for yellow phosphorus production. On the one hand, the utilization efficiency of phosphorus resources is improved, and a new way is provided for guaranteeing the production demand of yellow phosphorus. On the other hand, the storage and discharge of solid waste are reduced, and the pollution to the environment is avoided. The process method can realize full-quality utilization of large, medium and small full-particle-size minerals in the process of mining and processing of phosphorite, significantly improve the utilization efficiency of phosphorus resources, and significantly improve the social and economic benefits.

Description

Technical Field

[0001] This invention relates to methods for producing and processing phosphate rock, specifically to a method for processing raw phosphate ore in conjunction with waste mineral powder, belonging to the field of phosphate rock production and processing technology. Background Technology

[0002] Phosphate mining can be conducted through two methods: open-pit mining and underground mining. Open-pit mining, which targets shallow deposits, is currently the most common method. Due to the successful use of large mining machinery, the costs of both stripping overburden and extracting phosphate layers are relatively low. For some solid ore bodies, blasting can be used to loosen them before excavation. The extracted ore is then transported (by machinery or pipelines) to a nearby concentrator for processing. Underground mining, which targets deeper deposits with significant overburden stripping, often employs the room-and-pillar method.

[0003] Phosphate rock is a non-renewable resource. Due to its wide range of uses and relatively low output, and the lack of corresponding substitutes, it is considered a scarce resource. Currently, phosphate rock resources can be sustainably mined for about 50 years, and the producing areas are mainly concentrated in a few countries. The scarcity and irreplaceability of phosphate rock resources determine that its valuation should be higher than that of other resources.

[0004] With the increasing depletion of high-quality phosphate rock, the availability of high-quality phosphate rock suitable for yellow phosphorus production is also decreasing, leading to a growing shortage of natural phosphate rock resources and rising market prices. Solving the problem of ore sourcing for yellow phosphorus production is urgent and has become crucial for ensuring the normal operation of yellow phosphorus enterprises. The main process for preparing yellow phosphorus from phosphate rock is the electric furnace method: natural phosphate rock lumps are heated together with a reducing agent in an electric furnace. The reducing agent's reducing properties at high temperatures cause elemental phosphorus to escape as yellow phosphorus vapor, which is then cooled and collected to obtain yellow phosphorus. However, this process has high requirements for phosphate rock raw materials, generally requiring: uniform particle size, low moisture and carbonate content, P2O5 content above 20%, and a certain thermal strength. To meet production needs, Chinese yellow phosphorus producers mainly use natural lump phosphate rock as raw material.

[0005] With increasing mining difficulty and continuous mining, the mining volume and cost of high-grade phosphate rock have increased dramatically, leading to a sharp decrease in the production of natural lump phosphate rock for yellow phosphorus production and an inevitable price increase. In addition, the stock of waste high-quality powder ore generated during phosphate mining and processing will also increase dramatically and will not be rationally utilized. Summary of the Invention

[0006] In response to the problems in existing technologies, such as the declining production of high-grade natural phosphate ore leading to a future shortage and increased costs of natural phosphate ore for yellow phosphorus production, and the inefficient utilization of large quantities of high-quality phosphate powder during phosphate mining and processing, this invention provides a processing method for phosphate ore and phosphorus-containing waste ore powder. Through process optimization, the method fully utilizes phosphate ore and phosphorus-containing waste ore powder to produce artificial phosphate ore that can be directly used for yellow phosphorus production. On the one hand, this improves the utilization efficiency of phosphorus resources and provides a new way to ensure the production demand of yellow phosphorus; on the other hand, it reduces the accumulation and discharge of solid waste, avoiding environmental pollution.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for processing phosphate ore and waste mineral powder together, the processing method comprising the following steps:

[0009] S1) The raw phosphate ore from open-pit mines and raw phosphate ore from deep-buried mines are mixed and then refined to obtain a raw ore mixture.

[0010] S2) The raw ore mixture is washed, dried and screened in sequence to obtain raw ore lump ore, raw ore large particle ore and raw ore fine particle ore.

[0011] S3) Grind and classify the large particles of raw ore to obtain coarse ore powder, fine ore powder and micro ore powder.

[0012] S4) The fine ore powder of the raw ore is subjected to flotation, magnetic separation, photoelectric separation and calcination in sequence, and then mixed with the fine ore particles, coarse ore powder, micro ore powder and waste phosphate rock powder to obtain phosphate rock powder.

[0013] S5) The phosphate rock powder is mixed with the dust from yellow phosphorus production, biomass straw pellets and calcium hydroxide solution to obtain a mixture.

[0014] S6) After the mixture is pressed into blocks, the original ore blocks are used as the base material for sintering to obtain phosphate ore blocks.

[0015] In this invention, open-pit phosphate ore generally has low impurity content and hard texture, and is often mined by blasting; deep-buried phosphate ore generally has high impurity content and soft texture, and is often mined by drilling and electric scraper; the mixing ratio of the two can be any ratio, such as 1:1, 2:1, or 3:2, etc.

[0016] Preferably, the particle size of the raw ore mixture is no greater than 30 mm, more preferably no greater than 25 mm, and even more preferably no greater than 22 mm.

[0017] Preferably, the washing process involves multiple water washes of the raw ore mixture. The liquid-to-solid mass ratio during a single wash is 1-6:1.

[0018] Preferably, the drying is performed at a temperature of 110–300°C (preferably 120–250°C, more preferably 150–200°C) until the moisture content of the raw ore mixture is less than 10 wt% (preferably 6–10 wt%, more preferably 7–9 wt%).

[0019] Preferably, the particle size of the raw ore lump is ≥20mm and ≤30mm. The particle size of the raw ore large particles is >5mm and <20mm. The particle size of the raw ore fine particles is ≤5mm.

[0020] Preferably, the grinding process involves grinding the raw ore into large particles with a particle size ≤1mm, with a proportion of not less than 95% (preferably not less than 97%, more preferably not less than 99%).

[0021] Preferably, the particle size of the coarse ore powder is >1 mm and ≤5 mm. The particle size of the fine ore powder is ≥0.5 mm and ≤1 mm. The particle size of the micro-ore powder is <0.5 mm.

[0022] Preferably, the waste phosphate rock powder includes phosphate rock powder generated during the mining of open-pit phosphate mine ore and deep-buried phosphate mine ore, as well as phosphate rock powder generated during the reprocessing of open-pit phosphate mine ore and deep-buried phosphate mine ore (including screening, drying and dust removal processes).

[0023] Preferably, the calcination temperature is 400–600°C (preferably 450–550°C, more preferably 500–550°C).

[0024] Preferably, the P2O5 content in the phosphate rock powder is not less than 10%, and more preferably 10-15%.

[0025] In this invention, the main components of the phosphate rock powder are generally as follows: P2O5 content is 10-15%, SiO2 content is 10-20%, CaO content is 40-50%, Fe2O3 content is 0.5-1%, Al2O3 content is 3-5%, MgO content is 1-2%, F content is 0.1-0.3%, and S content is 0.5-0.8%.

[0026] Preferably, the mixing mass ratio of the phosphate rock powder, yellow phosphorus production dust, and biomass straw pellets is 70-85:5-10:8-20, and more preferably 75-82:7-8:10-18.

[0027] As a preferred option, the phosphate rock powder may be washed and dried again before mixing, or not (for example, by using rapid high-temperature hot airflow or microwave rapid drying, which can significantly shorten the drying time and save time; at the same time, it can also prevent some minerals in the phosphate powder from crystallizing and affecting the subsequent crushing).

[0028] Preferably, the concentration of the calcium hydroxide solution is 0.01–0.1 mol / L, more preferably 0.02–0.05 mol / L. The amount of calcium hydroxide solution added accounts for 0.8–4% of the total mass of the mixture, preferably 1–3%.

[0029] Preferably, the biomass straw pellets have a particle size ≤3mm (preferably ≤2mm). More preferably, the biomass straw pellets are modified biomass straw pellets that have been soaked and dried in a calcium hydroxide solution.

[0030] Preferably, the dust from yellow phosphorus production is modified dust from yellow phosphorus production after being mixed and ground with aluminosilicates. Preferably, the aluminosilicate is one or more of potassium feldspar, sodium feldspar, calcium feldspar, montmorillonite, and zeolite. The mixing mass ratio of the yellow phosphorus production dust to the aluminosilicate is 100:1 to 6 (preferably 100:1.5 to 5.5, more preferably 100:2 to 5).

[0031] In this invention, the main components of the dust produced from modified yellow phosphorus are generally as follows: P2O5 content 20-30%, SiO2 content 30-35%, CaO content 20-25%, Fe2O3 content 1-3%, Al2O3 content 7-9%, MgO content 2-4%, F content 0.5-1%, S content 0.1-0.3%, and moisture content 0.1-1%.

[0032] Preferably, the process of pressing the mixture into blocks is carried out using a method of 3-8 t / cm³. 2 The pressure compresses the mixture into regular oval, pillow-shaped, or flat material blocks, preferably into flat material blocks of (30-35) mm × (20-25) × (10-15) mm.

[0033] Preferably, the sintering process includes:

[0034] Drying: The material to be sintered is first dried at 180-300℃ (preferably 200-260℃) for 15-60 min (preferably 20-45 min). Then it is dried at 320-400℃ (preferably 340-380℃) for 10-40 min (preferably 15-30 min). Finally, it is dried at 400-480℃ (preferably 420-450℃) for 8-30 min (preferably 10-25 min). The first drying is intermittent microwave drying, and the second and third drying are hot air drying.

[0035] Preheating: The dried material is first preheated at 500-650℃ (preferably 550-600℃) for 2-20 minutes (preferably 5-15 minutes). Then it is preheated at 700-900℃ (preferably 750-850℃) for 15-60 minutes (preferably 20-40 minutes).

[0036] Calcination: The preheated material is calcined at a temperature of 1000-1350℃ (preferably 1050-1200℃) for 0.1-5 hours, preferably 0.5-4 hours.

[0037] Cooling: First, cool the roasted material to 600-800℃ (preferably 620-750℃). Then further cool it to 120-300℃ (preferably 150-250℃). The cooling medium used for both cooling processes is room temperature air.

[0038] Preferably, the hot air generated during the first cooling is circulated as hot air for the first preheating and / or the second preheating.

[0039] Preferably, the hot air generated during the second cooling is circulated as the hot air for the second drying.

[0040] Preferably, the hot air generated during roasting and the second preheating is treated with dust removal and then used as the hot air for the third drying.

[0041] The hot air generated from the second and third drying processes, as well as the first preheating process, is discharged after dust removal, desulfurization, and denitrification treatment.

[0042] Preferably, the P2O5 content in the raw ore block is not less than 18%. The thickness of the base material is 60-95 mm, preferably 70-90 mm. The thickness of the mixed material block layer is 150-250 mm, preferably 180-220 mm.

[0043] Preferably, the sintered clinker is screened, and the clinker with a diameter <5mm is returned to step S5) to participate in the mixing, while the clinker with a diameter ≥5mm is used as the finished phosphate rock for yellow phosphorus production.

[0044] In this invention, the method for obtaining open-pit phosphate ore is generally as follows: the open-pit phosphate mine is first blasted, and then mined to obtain the open-pit phosphate ore. The method for obtaining deep-buried phosphate ore is generally as follows: the deep-buried phosphate mine is first drilled, and then the ore is extracted using an electric scraper to obtain the deep-buried phosphate ore. In this process, it is necessary to collect and store the phosphate ore powder (one type of waste phosphate ore powder) generated during the blasting and mining of the open-pit phosphate mine, as well as the phosphate ore powder (one type of waste phosphate ore powder) generated during the drilling and electric scraper extraction of the deep-buried phosphate mine.

[0045] In this invention, the mixing of open-pit phosphate ore and deep-buried phosphate ore has a wider range of applications and can expand the scope of resource utilization. By washing the refined ore mixture with water, the wet mud adhering to the phosphate ore can be removed, as well as soluble substances (such as sodium chloride and free lime), which helps to improve the grade of the phosphate ore and reduce the difficulty of subsequent processing.

[0046] In this invention, the washed and dried raw ore mixture is graded and screened to separate it into three grades: mixed raw phosphate ore with a particle size of 20mm to 30mm is classified as irregular raw ore lump (which can be used as a base material for subsequent sintering); mixed raw phosphate ore with a particle size between 5mm and 20mm is classified as raw ore large particle ore; and ore powder with a particle size ≤5mm is classified as raw ore fine particle ore (which can be used to obtain phosphate ore powder for subsequent sintering batching and briquetting). The purpose of grading and screening is to refine and classify the raw ore mixture so that it can be fully utilized in subsequent processes, thereby improving the utilization efficiency of phosphorus resources and avoiding the production of solid waste.

[0047] In this invention, the large particles of raw ore with a particle size between 5 mm and 20 mm are further ground (the proportion of particles with a particle size ≤ 1 mm is not less than 95%), thereby obtaining raw ore coarse powder with a particle size of 1 mm to 5 mm, raw ore fine powder with a particle size of 0.5 mm to 1 mm, and raw ore micro powder with a particle size < 0.5 mm. The fine ore powder with a particle size of 0.5mm to 1mm undergoes impurity removal treatment (including flotation, magnetic separation, photoelectric separation, and calcination). Specifically, the process begins with the use of flotation agents (for phosphate rock flotation, the agents used include collectors, depressants, and synergists. Collectors can be long-chain fatty acids and their soaps. In flotation, long-chain fatty acids and their soaps are used to float phosphate and carbonate minerals, exhibiting strong collecting ability and sensitivity to the pulp and certain ions. Depressants can be carboxymethyl cellulose, citric acid, etc. Phosphate ore often contains carbonate minerals such as dolomite and calcite; depressants can remove these impurities. Synergists can be surfactants). As an alkanolamide, in phosphate rock flotation, the flotation performance can be improved by adding a small amount of activator to a long-chain fatty acid collector, causing the phosphate minerals to float while gangue and other impurities sink, thus obtaining initially enriched phosphate rock. Then, the initially enriched phosphate rock undergoes magnetic separation to remove the magnetic minerals, followed by photoelectric separation. Utilizing the different colors of the phosphate rock and impurity minerals, photoelectric elements are used for identification, and compressed air jets are controlled to separate the phosphate rock from the impurity minerals, resulting in enriched phosphate rock. Finally, the enriched phosphate rock is calcined by burning a mixture of combustible gas and air to obtain the final enriched phosphate rock powder. Generally, the calorific value of the combustible gas is ≥1000 kcal / Nm³. 3 The calcination temperature is 400-600℃. Through calcination, organic matter, carbon dioxide and some fluorine in the enriched phosphate rock are removed. The hot gas after calcination can be returned to the raw ore drying step to dry the mixed raw phosphate rock, thereby improving the grade of this part of the phosphate rock powder. This not only improves the utilization value of this part of the phosphate rock powder, but also helps to improve the grade of the final artificial finished product, phosphate lump ore.

[0048] In this invention, the sintering mixture includes phosphate rock powder, yellow phosphorus production dust, and biomass straw pellets; then, it is mixed and briquetted by spraying calcium hydroxide solution to obtain raw material blocks for sintering. During the briquetting process, the briquetting pressure is generally 3-8 t / cm². 2 In order to obtain regular oval, pillow-shaped or flat material blocks, it should be noted that the material blocks obtained by briquetting generally need to be screened to screen out material blocks that meet the particle size requirements of sintering heat treatment (e.g., flat material blocks with a size of (30~35)mm×(20~25)×(10~15)mm).

[0049] In this invention, the dust collected during the production of yellow phosphorus in an electric furnace has a fine particle size and weak adhesion, which is not conducive to subsequent briquetting and is difficult to recycle. Therefore, before utilizing it, the yellow phosphorus dust is modified with aluminosilicate. On the one hand, this increases the adhesion of the yellow phosphorus dust and improves the strength of the briquetting material without the need for additional binders or other auxiliary materials. On the other hand, the improved adhesion of the yellow phosphorus dust allows it to be used in large quantities as a briquetting raw material. Moreover, the dust contains a high content of P2O5, and adding a large amount of the modified dust to the phosphate rock powder can further improve the grade of the briquetting material without loss during roasting. Experiments have shown that the use of yellow phosphorus dust can increase the P2O5 content of the finished phosphate ore by at least 1%.

[0050] In this invention, the raw material blocks, after being pressed into briquettes, require transfer and heat treatment during sintering to obtain finished phosphate ore briquettes. The roasting temperature reaches over 1000℃, necessitating sufficient strength in the raw material blocks to prevent breakage during transfer and cracking during heat treatment. Therefore, this invention incorporates biomass straw pellets into the raw material blocks. These pellets distribute throughout the blocks, providing diffusion channels for internal moisture evaporation during drying, significantly increasing the rate of water vapor escape. They also effectively prevent cracking caused by rapid evaporation of water molecules at high temperatures. Furthermore, the fibers of the biomass straw enhance the adhesion between phosphate ore particles, improving the strength of the biomass blocks. Additionally, the biomass straw provides heat during subsequent roasting, aiding in high-temperature consolidation and further enhancing physical strength and chemical properties.

[0051] In this invention, the finished phosphate ore obtained after sintering heat treatment also needs to be screened to select finished phosphate ore that meets the requirements for yellow phosphorus production (generally, the particle size is required to be not less than 5 mm, preferably not less than 8 mm). The bulk materials generated in the above screening steps are recycled and returned for batching and briquetting, thereby saving resources and minimizing solid waste discharge.

[0052] In this invention, when compressing the mixture into briquettes, the addition of calcium hydroxide solution not only improves the strength of the briquettes but also adjusts their acidity, enhancing their physicochemical and metallurgical properties. This invention uses an aqueous solution of calcium hydroxide as the briquetting raw material, mixing it with the raw materials. During mixing, the calcium hydroxide solution adsorbs onto the surface of the raw material particles, existing as molecular water. This results in a uniform distribution of a large number of calcium ions on the surface of the raw material particles, avoiding the situation in conventional raw materials where the calcium component is mainly in the calcium hydroxide particles, with virtually no calcium ions in the molecular water on the particle surface. The molecular water does not flow on the particle surface. During the briquetting process, water adsorbs on the surface of the raw material particles and migrates between them. When the calcium ions in the molecular water uniformly dispersed on the surface of the raw material particles come into contact with carbonate ions in the water, a carbonation reaction occurs, generating calcium carbonate. The precipitation of the newly formed calcium carbonate binds the contacting raw material particles together, increasing the carbonation and consolidation rate of the raw material briquettes and improving their strength.

[0053] In this invention, to further improve the strength of the raw material blocks, the biomass straw pellets are pretreated before mixing. Specifically, the biomass straw pellets are soaked in a calcium hydroxide solution of a certain concentration (e.g., 0.01-0.5 mol / L) for 0.1-5 hours. After soaking, the biomass straw pellets are filtered and dried before being added to the batch. Because the biomass straw adsorbs calcium hydroxide, it can improve its bonding performance with other materials during the batching process, increasing the strength of the raw material blocks and significantly reducing the breakage rate during handling. Simultaneously, during subsequent heat treatment, the biomass straw decomposes upon heating, releasing carbon dioxide and water. The released carbon dioxide, under the action of water vapor, reacts with the internal calcium hydroxide to form a compound that acts as a binder (the adsorbed calcium hydroxide solidifies internally as calcium carbonate), further improving the bonding strength between the biomass straw and other raw materials. This helps prevent high-temperature cracking while greatly ensuring and improving the strength of the finished phosphate ore and reducing the powder rate. It should be noted that the amount of biomass straw added should not be too much or too little. Too much straw will reduce the proportion of phosphate rock powder and dust, thus reducing the yield. At the same time, too much straw particles will create more large pores inside the finished phosphate ore after heat treatment, which will easily lead to the collapse and pulverization of the finished phosphate ore, which is not conducive to improving the strength of the finished phosphate ore. On the other hand, if the amount added is too little, it will not be conducive to improving the internal bonding strength of the raw material blocks, and the raw material blocks will easily break into pieces before heat treatment.

[0054] In this invention, the drying process of raw material blocks includes intermittent microwave drying (primary drying) and two-stage hot air drying (secondary and tertiary drying). Microwave heating is used first, allowing for simultaneous heating of the raw material blocks both internally and externally. This causes the internal and external moisture to vaporize and diffuse outwards simultaneously, preventing cracking due to uneven drying. Furthermore, the three-stage drying process of this invention is a variable-temperature drying method. The drying stages are divided into multiple sections arranged in a sequence from low to high temperature and from long to short time. Compared to conventional drying, this increases the drying speed, shortens the drying time, avoids cracking of the material blocks during drying, and improves the strength of the material blocks.

[0055] In this invention, during the sintering heat treatment process, the dust after the hot air is purged is collected. This dust is first humidified and then returned to the sintering mixing step to participate in the briquetting process.

[0056] In this invention, natural phosphate rock ore blocks (with a P2O5 content of approximately 18% to 20%) of a grade higher than that of low-grade phosphate rock powder are used as a base material. This mixing method can improve the average grade of the finished product blocks. At the same time, the metallurgical properties of the natural phosphate rock ore blocks are further improved after heat treatment. Using natural phosphate rock ore blocks as a base material increases permeability and protects the roasting equipment. By selecting an appropriate base material thickness, production capacity is also increased.

[0057] In this invention, to reduce heat emissions and save energy, the hot air emitted from each node of the system is selectively recycled based on the characteristics of each operating condition within the system. Specifically, the hot air generated during cooling is recycled to provide heat for processes such as drying and preheating. Furthermore, waste heat is fully recovered through cascaded utilization, significantly reducing additional heating energy consumption. In addition, this invention also recycles and utilizes various bulk materials and dust generated during the process. The cascaded utilization of waste heat further significantly reduces additional heating energy consumption, achieving the recycling of valuable resources and contributing to environmental protection.

[0058] In this invention, the final artificial phosphate rock product has a large quantity with a particle size of 16-35mm, a concentrated and stable particle size distribution, good air permeability, and a low pulverization rate under the high-temperature reducing atmosphere of subsequent yellow phosphorus preparation, which can greatly reduce the amount of dust in phosphorus production; in addition, it also has the advantages of high grade, good chemical composition, high strength, convenient subsequent transportation, and strong transportability.

[0059] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0060] 1. This invention reuses phosphate rock powder from phosphate mining and processing, solving the problem of resource waste caused by the inability to reuse phosphate rock powder in existing phosphate mining and processing. It also realizes the full utilization of phosphate rock, greatly alleviating the pressure on the production and use of phosphate resources, and solving the problem of land resource waste caused by the large-scale stockpiling of phosphate rock powder in existing phosphate mining and processing.

[0061] 2: This invention significantly improves the lumpy properties of yellow phosphorus production dust by modifying it. At the same time, it further enhances the strength of the raw material lumps through the bridging of biomass straw, effectively ensuring the quality of the finished lumpy mineral products. It can also accommodate more dust and improve the utilization efficiency of the dust.

[0062] 3. The finished phosphate ore product obtained by this invention has a concentrated and stable particle size distribution, good permeability, and low pulverization rate under the high-temperature reducing atmosphere of subsequent yellow phosphorus production, which can greatly reduce the amount of dust in phosphorus production. Furthermore, the ore has high grade, good chemical composition, and high strength, facilitating subsequent transportation and exhibiting strong transportability. Its low moisture content and low carbonate content can effectively reduce the power consumption of subsequent lump ore phosphorus production and improve the purity of the yellow phosphorus product.

[0063] 4: This invention effectively mixes natural irregular raw ore blocks with artificial regular ore blocks and performs sintering heat treatment, which not only greatly improves the grade of the finished phosphate rock blocks, but also helps to improve the physical, chemical and metallurgical properties of phosphate rock, thus realizing the effective deep processing of phosphate rock. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the process flow of the processing method described in this invention (I).

[0065] Figure 2 This is a schematic diagram (II) of the process flow of the processing method described in this invention. Detailed Implementation

[0066] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0067] Example 1

[0068] Open-pit phosphate mines are first blasted and then mined to obtain open-pit phosphate ore. Deep-buried phosphate mines are first drilled and then extracted using electric scrapers to obtain deep-buried phosphate ore. The open-pit and deep-buried phosphate ores are mixed at a mass ratio of 1:1 and then finely crushed to a particle size ≤30mm to obtain a raw ore mixture. This mixture is then washed three times with water at a liquid-to-solid mass ratio of 4:1. After drying at 200℃ until the moisture content is below 10wt%, it is screened to obtain raw ore lumps with a particle size ≥20mm and ≤30mm (collected for later use), large raw ore particles with a particle size >5mm and <20mm, and fine raw ore particles with a particle size ≤5mm (collected for later use). Further, the large particles of raw ore with a particle size of >5mm and <20mm are ground until the proportion of particles with a particle size of ≤1mm is greater than 95%, and then screened again to obtain raw ore coarse powder with a particle size of >1mm and ≤5mm (collected for later use), raw ore fine powder with a particle size of ≥0.5mm and ≤1mm, and raw ore micro powder with a particle size of <0.5mm (collected for later use).

[0069] First, the fine ore powder with a particle size ≥0.5mm and ≤1mm is subjected to mineral processing. A flotation agent is used to float the phosphate minerals while gangue and other impurities sink, resulting in pre-enriched phosphate ore powder. Then, the pre-enriched phosphate ore is subjected to magnetic separation to remove the magnetic minerals. Finally, the different colors of the phosphate ore and impurity minerals are used to identify them with photoelectric elements, and compressed air jets are controlled to separate the phosphate ore and impurity minerals, resulting in the final enriched phosphate ore powder.

[0070] The final enriched phosphate rock powder is calcined at 500℃ to remove organic matter, carbon dioxide and some fluorine from the final enriched phosphate rock. Then, the calcined phosphate rock powder is mixed with fine particles of raw ore, coarse powder of raw ore, micro powder of raw ore and waste phosphate rock powder to obtain phosphate rock powder with a P2O5 content of about 14.55%.

[0071] Dust collected during the yellow phosphorus production process (P2O5 content approximately 26.51%) was mixed and ground with potassium feldspar (added at 2% of the mass of the yellow phosphorus production dust) to obtain modified dust for later use. Corn stalks were crushed to a particle size of less than 2 mm to obtain straw pellets. Then, phosphate rock powder, yellow phosphorus production dust, and straw pellets were mixed at a mass ratio of 82:6:12 to obtain a mixture. Next, 1.9% (based on the total mass of the mixture), 0.02 mol / L calcium hydroxide solution was added to the mixture and stirred until homogeneous. Finally, a 6t / cm³ flow rate was used for further processing. 2 The raw material is compressed under pressure to obtain flat raw material blocks with dimensions of approximately 32×24×16mm.

[0072] The raw ore lump (P2O5 content approximately 19.61%) was laid as the base material for the sintering trolley, with a thickness of 85 mm. Then, a 200 mm thick layer of raw meal blocks was laid on top of the base material. After laying, the sintering layer was first dried using microwave at 220℃ for 40 min, then dried a second time with hot air at 350℃ for 20 min, and finally dried a third time with hot air at 450℃ for 10 min. After drying, the sintering layer was preheated with hot air at 550℃ for 8 min, and then preheated again with hot air at 850℃ for 25 min. After preheating, natural gas (9000 kcal / Nm³) was used... 3 After combustion with air, the sintered material layer is roasted at 1150℃ for 45 minutes. After roasting, the roasted clinker is cooled to about 700℃ with room temperature air, and then cooled a second time to about 200℃ with room temperature hot air. After cooling, the clinker is screened, and clinker blocks ≥5mm are collected as finished phosphate ore (P2O5 content is about 40.54%).

[0073] Example 2

[0074] Open-pit phosphate mines are first blasted and then mined to obtain open-pit phosphate ore. Deep-buried phosphate mines are first drilled and then extracted using electric scrapers to obtain deep-buried phosphate ore. The open-pit and deep-buried phosphate ores are mixed at a mass ratio of 2:1 and then finely crushed to a particle size ≤30mm to obtain a raw ore mixture. This mixture is then washed three times with water at a liquid-to-solid mass ratio of 4:1, and dried at 200℃ until the moisture content is below 8wt%. After drying, it is screened to obtain raw ore lumps with a particle size ≥20mm and ≤30mm (collected for later use), large raw ore particles with a particle size >5mm and <20mm, and fine raw ore particles with a particle size ≤5mm (collected for later use). Further, the large particles of raw ore with a particle size of >5mm and <20mm are ground until the proportion of particles with a particle size of ≤1mm is greater than 97%, and then screened again to obtain raw ore coarse powder with a particle size of >1mm and ≤5mm (collected for later use), raw ore fine powder with a particle size of ≥0.5mm and ≤1mm, and raw ore micro powder with a particle size of <0.5mm (collected for later use).

[0075] First, the fine ore powder with a particle size ≥0.5mm and ≤1mm is subjected to mineral processing. A flotation agent is used to float the phosphate minerals while gangue and other impurities sink, resulting in pre-enriched phosphate ore powder. Then, the pre-enriched phosphate ore is subjected to magnetic separation to remove the magnetic minerals. Finally, the different colors of the phosphate ore and impurity minerals are used to identify them with photoelectric elements, and compressed air jets are controlled to separate the phosphate ore and impurity minerals, resulting in the final enriched phosphate ore powder.

[0076] The final enriched phosphate rock powder is calcined at 550℃ to remove organic matter, carbon dioxide and some fluorine from the final enriched phosphate rock. Then, the calcined phosphate rock powder is mixed with fine particles of raw ore, coarse powder of raw ore, micro powder of raw ore and waste phosphate rock powder to obtain phosphate rock powder with a P2O5 content of about 14.87%.

[0077] Dust collected during the yellow phosphorus production process (P2O5 content approximately 26.51%) was mixed and ground with potassium feldspar (added at 3% of the mass of the yellow phosphorus production dust) to obtain modified dust for later use. Corn stalks were crushed to a particle size of less than 2 mm to obtain straw pellets. Then, phosphate rock powder, yellow phosphorus production dust, and straw pellets were mixed at a mass ratio of 80:7:13 to obtain a mixture. Next, 2.1% (based on the total mass of the mixture), 0.02 mol / L calcium hydroxide solution was added to the mixture and stirred until homogeneous. Finally, a 6t / cm³ flow rate was used for further processing. 2 The raw material is compressed under pressure to obtain flat raw material blocks with dimensions of approximately 30×25×15mm.

[0078] The raw ore lump (P2O5 content approximately 19.61%) was laid as the base material for the sintering trolley, with a thickness of 85 mm. Then, a 200 mm thick layer of raw meal blocks was laid on top of the base material. After laying, the sintering layer was first dried using microwave at 220℃ for 40 min, then dried a second time with hot air at 350℃ for 20 min, and finally dried a third time with hot air at 450℃ for 10 min. After drying, the sintering layer was preheated with hot air at 550℃ for 8 min, and then preheated again with hot air at 850℃ for 25 min. After preheating, natural gas (9000 kcal / Nm³) was used... 3 After combustion with air, the sintered material layer is roasted at 1200℃ for 45 minutes. After roasting, the roasted clinker is cooled to about 700℃ with room temperature air, and then cooled a second time to about 200℃ with room temperature hot air. After cooling, the clinker is screened, and clinker blocks ≥5mm are collected as finished phosphate ore (P2O5 content is about 41.63%).

[0079] Example 3

[0080] Open-pit phosphate mines are first blasted and then mined to obtain open-pit phosphate ore. Deep-buried phosphate mines are first drilled and then extracted using electric scrapers to obtain deep-buried phosphate ore. The open-pit and deep-buried phosphate ores are mixed at a mass ratio of 2:1 and then finely crushed to a particle size ≤30mm to obtain a raw ore mixture. This mixture is then washed three times with water at a liquid-to-solid mass ratio of 4:1, and dried at 200℃ until the moisture content is below 6wt%. After drying, it is screened to obtain raw ore lumps with a particle size ≥20mm and ≤30mm (collected for later use), large raw ore particles with a particle size >5mm and <20mm, and fine raw ore particles with a particle size ≤5mm (collected for later use). Further, the large particles of raw ore with a particle size of >5mm and <20mm are ground until the proportion of particles with a particle size of ≤1mm is greater than 99%, and then screened again to obtain raw ore coarse powder with a particle size of >1mm and ≤5mm (collected for later use), raw ore fine powder with a particle size of ≥0.5mm and ≤1mm, and raw ore micro powder with a particle size of <0.5mm (collected for later use).

[0081] First, the fine ore powder with a particle size ≥0.5mm and ≤1mm is subjected to mineral processing. A flotation agent is used to float the phosphate minerals while gangue and other impurities sink, resulting in pre-enriched phosphate ore powder. Then, the pre-enriched phosphate ore is subjected to magnetic separation to remove the magnetic minerals. Finally, the different colors of the phosphate ore and impurity minerals are used to identify them with photoelectric elements, and compressed air jets are controlled to separate the phosphate ore and impurity minerals, resulting in the final enriched phosphate ore powder.

[0082] The final enriched phosphate rock powder is calcined at 580℃ to remove organic matter, carbon dioxide and some fluorine from the final enriched phosphate rock. Then, the calcined phosphate rock powder is mixed with fine particles of raw ore, coarse powder of raw ore, micro powder of raw ore and waste phosphate rock powder to obtain phosphate rock powder with a P2O5 content of about 14.93%.

[0083] Dust collected during the yellow phosphorus production process (P2O5 content approximately 26.51%) was mixed and ground with potassium feldspar (3% of the dust collected during yellow phosphorus production) to obtain modified dust for later use. Corn stalks were crushed to a particle size of less than 2 mm to obtain straw particles, which were then soaked in a 0.02 mol / L calcium hydroxide solution for 1 hour and filtered dry to obtain modified straw particles. Phosphate rock powder, yellow phosphorus production dust, and straw particles were then mixed at a mass ratio of 80:7.5:12.5 to obtain a mixture. 2.1% (based on the total mass of the mixture), 0.02 mol / L calcium hydroxide solution was then added to the mixture and stirred until homogeneous. Finally, a 6t / cm³ flow rate was used for further processing. 2 The raw material is compressed under pressure to obtain flat raw material blocks with dimensions of approximately 30×25×15mm.

[0084] The raw ore lump (P2O5 content approximately 19.61%) was laid as the base material for the sintering trolley, with a thickness of 85 mm. Then, a 200 mm thick layer of raw meal blocks was laid on top of the base material. After laying, the sintering layer was first dried using microwave at 220℃ for 40 min, then dried a second time with hot air at 350℃ for 20 min, and finally dried a third time with hot air at 450℃ for 10 min. After drying, the sintering layer was preheated with hot air at 550℃ for 8 min, and then preheated again with hot air at 850℃ for 25 min. After preheating, natural gas (9000 kcal / Nm³) was used... 3 After combustion with air, the sintered material layer is roasted at 1200℃ for 45 minutes. After roasting, the roasted clinker is cooled to about 700℃ with room temperature air, and then cooled a second time to about 200℃ with room temperature hot air. After cooling, the clinker is screened, and clinker blocks ≥5mm are collected as finished phosphate ore (P2O5 content is about 42.10%).

[0085] Example 4

[0086] Open-pit phosphate mines are first blasted and then mined to obtain open-pit phosphate ore. Deep-buried phosphate mines are first drilled and then extracted using electric scrapers to obtain deep-buried phosphate ore. The open-pit and deep-buried phosphate ores are mixed at a mass ratio of 2:1 and then finely crushed to a particle size ≤30mm to obtain a raw ore mixture. This mixture is then washed three times with water at a liquid-to-solid mass ratio of 4:1, and dried at 200℃ until the moisture content is below 8wt%. After drying, it is screened to obtain raw ore lumps with a particle size ≥20mm and ≤30mm (collected for later use), large raw ore particles with a particle size >5mm and <20mm, and fine raw ore particles with a particle size ≤5mm (collected for later use). Further, the large particles of raw ore with a particle size of >5mm and <20mm are ground until the proportion of particles with a particle size of ≤1mm is greater than 97%, and then screened again to obtain raw ore coarse powder with a particle size of >1mm and ≤5mm (collected for later use), raw ore fine powder with a particle size of ≥0.5mm and ≤1mm, and raw ore micro powder with a particle size of <0.5mm (collected for later use).

[0087] First, the fine ore powder with a particle size ≥0.5mm and ≤1mm is subjected to mineral processing. A flotation agent is used to float the phosphate minerals while gangue and other impurities sink, resulting in pre-enriched phosphate ore powder. Then, the pre-enriched phosphate ore is subjected to magnetic separation to remove the magnetic minerals. Finally, the different colors of the phosphate ore and impurity minerals are used to identify them with photoelectric elements, and compressed air jets are controlled to separate the phosphate ore and impurity minerals, resulting in the final enriched phosphate ore powder.

[0088] The final enriched phosphate rock powder is calcined at 550℃ to remove organic matter, carbon dioxide and some fluorine from the final enriched phosphate rock. Then, the calcined phosphate rock powder is mixed with fine particles of raw ore, coarse powder of raw ore, micro powder of raw ore and waste phosphate rock powder to obtain phosphate rock powder with a P2O5 content of about 14.87%.

[0089] Dust collected during the yellow phosphorus production process (P2O5 content approximately 26.51%) was mixed and ground with potassium feldspar (added at 3% of the mass of the yellow phosphorus production dust) to obtain modified dust for later use. Corn stalks were crushed to a particle size of less than 2 mm to obtain straw pellets. Then, phosphate rock powder, yellow phosphorus production dust, and straw pellets were mixed at a mass ratio of 88.3:7.7:3 to obtain a mixture. Next, 2.1% (based on the total mass of the mixture), 0.02 mol / L calcium hydroxide solution was added to the mixture and stirred until homogeneous. Finally, a 6t / cm³ flow rate was used for further processing. 2 The raw material is compressed under pressure to obtain flat raw material blocks with dimensions of approximately 30×25×15mm.

[0090] The raw ore lump (P2O5 content approximately 19.61%) was laid as the base material for the sintering trolley, with a thickness of 85 mm. Then, a 200 mm thick layer of raw meal blocks was laid on top of the base material. After laying, the sintering layer was first dried using microwave at 220℃ for 40 min, then dried a second time with hot air at 350℃ for 20 min, and finally dried a third time with hot air at 450℃ for 10 min. After drying, the sintering layer was preheated with hot air at 550℃ for 8 min, and then preheated again with hot air at 850℃ for 25 min. After preheating, natural gas (9000 kcal / Nm³) was used... 3 After combustion with air, the sintered material layer is roasted at 1200℃ for 45 minutes. After roasting, the roasted clinker is cooled to about 700℃ with room temperature air, and then cooled a second time to about 200℃ with room temperature hot air. After cooling, the clinker is screened, and clinker blocks ≥5mm are collected as finished phosphate ore (P2O5 content is about 30.42%).

[0091] Example 5

[0092] Open-pit phosphate mines are first blasted and then mined to obtain open-pit phosphate ore. Deep-buried phosphate mines are first drilled and then extracted using electric scrapers to obtain deep-buried phosphate ore. The open-pit and deep-buried phosphate ores are mixed at a mass ratio of 2:1 and then finely crushed to a particle size ≤30mm to obtain a raw ore mixture. This mixture is then washed three times with water at a liquid-to-solid mass ratio of 4:1, and dried at 200℃ until the moisture content is below 8wt%. After drying, it is screened to obtain raw ore lumps with a particle size ≥20mm and ≤30mm (collected for later use), large raw ore particles with a particle size >5mm and <20mm, and fine raw ore particles with a particle size ≤5mm (collected for later use). Further, the large particles of raw ore with a particle size of >5mm and <20mm are ground until the proportion of particles with a particle size of ≤1mm is greater than 97%, and then screened again to obtain raw ore coarse powder with a particle size of >1mm and ≤5mm (collected for later use), raw ore fine powder with a particle size of ≥0.5mm and ≤1mm, and raw ore micro powder with a particle size of <0.5mm (collected for later use).

[0093] First, the fine ore powder with a particle size ≥0.5mm and ≤1mm is subjected to mineral processing. A flotation agent is used to float the phosphate minerals while gangue and other impurities sink, resulting in pre-enriched phosphate ore powder. Then, the pre-enriched phosphate ore is subjected to magnetic separation to remove the magnetic minerals. Finally, the different colors of the phosphate ore and impurity minerals are used to identify them with photoelectric elements, and compressed air jets are controlled to separate the phosphate ore and impurity minerals, resulting in the final enriched phosphate ore powder.

[0094] The final enriched phosphate rock powder is calcined at 550℃ to remove organic matter, carbon dioxide and some fluorine from the final enriched phosphate rock. Then, the calcined phosphate rock powder is mixed with fine particles of raw ore, coarse powder of raw ore, micro powder of raw ore and waste phosphate rock powder to obtain phosphate rock powder with a P2O5 content of about 14.87%.

[0095] Dust collected during the yellow phosphorus production process (P2O5 content approximately 26.51%) was mixed and ground with potassium feldspar (added at 3% of the mass of the yellow phosphorus production dust) to obtain modified dust for later use. Corn stalks were crushed to a particle size of less than 2 mm to obtain straw pellets. Then, phosphate rock powder, yellow phosphorus production dust, and straw pellets were mixed at a mass ratio of 71.8:6.2:22 to obtain a mixture. Next, 2.1% (based on the total mass of the mixture), 0.02 mol / L calcium hydroxide solution was added to the mixture and stirred until homogeneous. Finally, a 6t / cm³ flow rate was used for further processing. 2 The raw material is compressed under pressure to obtain flat raw material blocks with dimensions of approximately 30×25×15mm.

[0096] The raw ore lump (P2O5 content approximately 19.61%) was laid as the base material for the sintering trolley, with a thickness of 85 mm. Then, a 200 mm thick layer of raw meal blocks was laid on top of the base material. After laying, the sintering layer was first dried using microwave at 220℃ for 40 min, then dried a second time with hot air at 350℃ for 20 min, and finally dried a third time with hot air at 450℃ for 10 min. After drying, the sintering layer was preheated with hot air at 550℃ for 8 min, and then preheated again with hot air at 850℃ for 25 min. After preheating, natural gas (9000 kcal / Nm³) was used... 3 After combustion with air, the sintered material layer is roasted at 1200℃ for 45 minutes. After roasting, the roasted clinker is cooled to about 700℃ with room temperature air, and then cooled a second time to about 200℃ with room temperature hot air. After cooling, the clinker is screened, and clinker blocks ≥5mm are collected as finished phosphate ore (P2O5 content is about 22.04%).

[0097] Example 6

[0098] Open-pit phosphate mines are first blasted and then mined to obtain open-pit phosphate ore. Deep-buried phosphate mines are first drilled and then extracted using electric scrapers to obtain deep-buried phosphate ore. The open-pit and deep-buried phosphate ores are mixed at a mass ratio of 2:1 and then finely crushed to a particle size ≤30mm to obtain a raw ore mixture. This mixture is then washed three times with water at a liquid-to-solid mass ratio of 4:1, and dried at 200℃ until the moisture content is below 8wt%. After drying, it is screened to obtain raw ore lumps with a particle size ≥20mm and ≤30mm (collected for later use), large raw ore particles with a particle size >5mm and <20mm, and fine raw ore particles with a particle size ≤5mm (collected for later use). Further, the large particles of raw ore with a particle size of >5mm and <20mm are ground until the proportion of particles with a particle size of ≤1mm is greater than 97%, and then screened again to obtain raw ore coarse powder with a particle size of >1mm and ≤5mm (collected for later use), raw ore fine powder with a particle size of ≥0.5mm and ≤1mm, and raw ore micro powder with a particle size of <0.5mm (collected for later use).

[0099] First, the fine ore powder with a particle size ≥0.5mm and ≤1mm is subjected to mineral processing. A flotation agent is used to float the phosphate minerals while gangue and other impurities sink, resulting in pre-enriched phosphate ore powder. Then, the pre-enriched phosphate ore is subjected to magnetic separation to remove the magnetic minerals. Finally, the different colors of the phosphate ore and impurity minerals are used to identify them with photoelectric elements, and compressed air jets are controlled to separate the phosphate ore and impurity minerals, resulting in the final enriched phosphate ore powder.

[0100] The final enriched phosphate rock powder is calcined at 550℃ to remove organic matter, carbon dioxide and some fluorine from the final enriched phosphate rock. Then, the calcined phosphate rock powder is mixed with fine particles of raw ore, coarse powder of raw ore, micro powder of raw ore and waste phosphate rock powder to obtain phosphate rock powder with a P2O5 content of about 14.87%.

[0101] The dust collected during the yellow phosphorus production process (P2O5 content approximately 26.51%) is collected for later use. Corn stalks are crushed to a particle size of less than 2mm to obtain straw pellets. Then, phosphate rock powder, yellow phosphorus production dust, and straw pellets are mixed at a mass ratio of 80:7:13 to obtain a mixture. Next, 2.1% (based on the total mass of the mixture), 0.02mol / L calcium hydroxide solution is added to the mixture and stirred until homogeneous. Finally, a 6t / cm³ flow rate is used. 2 The raw material is compressed under pressure to obtain flat raw material blocks with dimensions of approximately 30×25×15mm.

[0102] The raw ore lump (P2O5 content approximately 19.61%) was laid as the base material for the sintering trolley, with a thickness of 85 mm. Then, a 200 mm thick layer of raw meal blocks was laid on top of the base material. After laying, the sintering layer was first dried using microwave at 220℃ for 40 min, then dried a second time with hot air at 350℃ for 20 min, and finally dried a third time with hot air at 450℃ for 10 min. After drying, the sintering layer was preheated with hot air at 550℃ for 8 min, and then preheated again with hot air at 850℃ for 25 min. After preheating, natural gas (9000 kcal / Nm³) was used... 3 After combustion with air, the sintered material layer is roasted at 1200℃ for 45 minutes. After roasting, the roasted clinker is cooled to about 700℃ with room temperature air, and then cooled a second time to about 200℃ with room temperature hot air. After cooling, the clinker is screened, and clinker blocks ≥5mm are collected as finished phosphate ore (P2O5 content is about 35.70%).

[0103] Comparative Example 1

[0104] Open-pit phosphate mines are first blasted and then mined to obtain open-pit phosphate ore. Deep-buried phosphate mines are first drilled and then extracted using electric scrapers to obtain deep-buried phosphate ore. The open-pit and deep-buried phosphate ores are mixed at a mass ratio of 2:1 and then finely crushed to a particle size ≤30mm to obtain a raw ore mixture. This mixture is then washed three times with water at a liquid-to-solid mass ratio of 4:1, and dried at 200℃ until the moisture content is below 8wt%. After drying, it is screened to obtain raw ore lumps with a particle size ≥20mm and ≤30mm (collected for later use), large raw ore particles with a particle size >5mm and <20mm, and fine raw ore particles with a particle size ≤5mm (collected for later use). Further, the large particles of raw ore with a particle size of >5mm and <20mm are ground until the proportion of particles with a particle size of ≤1mm is greater than 97%, and then screened again to obtain raw ore coarse powder with a particle size of >1mm and ≤5mm (collected for later use), raw ore fine powder with a particle size of ≥0.5mm and ≤1mm, and raw ore micro powder with a particle size of <0.5mm (collected for later use).

[0105] First, the fine ore powder with a particle size ≥0.5mm and ≤1mm is subjected to mineral processing. A flotation agent is used to float the phosphate minerals while gangue and other impurities sink, resulting in pre-enriched phosphate ore powder. Then, the pre-enriched phosphate ore is subjected to magnetic separation to remove the magnetic minerals. Finally, the different colors of the phosphate ore and impurity minerals are used to identify them with photoelectric elements, and compressed air jets are controlled to separate the phosphate ore and impurity minerals, resulting in the final enriched phosphate ore powder.

[0106] The final enriched phosphate rock powder is calcined at 550℃ to remove organic matter, carbon dioxide and some fluorine from the final enriched phosphate rock. Then, the calcined phosphate rock powder is mixed with fine particles of raw ore, coarse powder of raw ore, micro powder of raw ore and waste phosphate rock powder to obtain phosphate rock powder with a P2O5 content of about 14.87%.

[0107] Corn stalks are crushed to a particle size of less than 2 mm to obtain stalk pellets. Then, phosphate rock powder and stalk pellets are mixed at a mass ratio of 86:14 to obtain a mixture. Next, 2.1% (based on the total mass of the mixture) of a 0.02 mol / L calcium hydroxide solution is added to the mixture and stirred until homogeneous. Finally, a 6t / cm³ flow rate is used. 2 The raw material is compressed under pressure to obtain flat raw material blocks with dimensions of approximately 30×25×15mm.

[0108] The raw ore lump (P2O5 content approximately 19.61%) was laid as the base material for the sintering trolley, with a thickness of 85 mm. Then, a 200 mm thick layer of raw meal blocks was laid on top of the base material. After laying, the sintering layer was first dried using microwave at 220℃ for 40 min, then dried a second time with hot air at 350℃ for 20 min, and finally dried a third time with hot air at 450℃ for 10 min. After drying, the sintering layer was preheated with hot air at 550℃ for 8 min, and then preheated again with hot air at 850℃ for 25 min. After preheating, natural gas (9000 kcal / Nm³) was used... 3 After combustion with air, the sintered material layer is roasted at 1200℃ for 45 minutes. After roasting, the roasted clinker is cooled to about 700℃ with room temperature air, and then cooled a second time to about 200℃ with room temperature hot air. After cooling, the clinker is screened, and clinker blocks ≥5mm are collected as finished phosphate ore (P2O5 content is about 24.27%).

[0109] Comparative Example 2

[0110] Open-pit phosphate mines are first blasted and then mined to obtain open-pit phosphate ore. Deep-buried phosphate mines are first drilled and then extracted using electric scrapers to obtain deep-buried phosphate ore. The open-pit and deep-buried phosphate ores are mixed at a mass ratio of 2:1 and then finely crushed to a particle size ≤30mm to obtain a raw ore mixture. This mixture is then washed three times with water at a liquid-to-solid mass ratio of 4:1, and dried at 200℃ until the moisture content is below 8wt%. After drying, it is screened to obtain raw ore lumps with a particle size ≥20mm and ≤30mm (collected for later use), large raw ore particles with a particle size >5mm and <20mm, and fine raw ore particles with a particle size ≤5mm (collected for later use). Further, the large particles of raw ore with a particle size of >5mm and <20mm are ground until the proportion of particles with a particle size of ≤1mm is greater than 97%, and then screened again to obtain raw ore coarse powder with a particle size of >1mm and ≤5mm (collected for later use), raw ore fine powder with a particle size of ≥0.5mm and ≤1mm, and raw ore micro powder with a particle size of <0.5mm (collected for later use).

[0111] First, the fine ore powder with a particle size ≥0.5mm and ≤1mm is subjected to mineral processing. A flotation agent is used to float the phosphate minerals while gangue and other impurities sink, resulting in pre-enriched phosphate ore powder. Then, the pre-enriched phosphate ore is subjected to magnetic separation to remove the magnetic minerals. Finally, the different colors of the phosphate ore and impurity minerals are used to identify them with photoelectric elements, and compressed air jets are controlled to separate the phosphate ore and impurity minerals, resulting in the final enriched phosphate ore powder.

[0112] The final enriched phosphate rock powder is calcined at 550℃ to remove organic matter, carbon dioxide and some fluorine from the final enriched phosphate rock. Then, the calcined phosphate rock powder is mixed with fine particles of raw ore, coarse powder of raw ore, micro powder of raw ore and waste phosphate rock powder to obtain phosphate rock powder with a P2O5 content of about 14.87%.

[0113] Dust collected during the yellow phosphorus production process (P2O5 content approximately 26.51%) was mixed and ground with potassium feldspar (3% of the dust collected during yellow phosphorus production) to obtain modified dust for later use. Then, phosphate rock powder and modified dust were mixed at a mass ratio of 92:8 to obtain a mixture. Next, 2.1% (based on the total mass of the mixture), 0.02 mol / L calcium hydroxide solution was added to the mixture and stirred until homogeneous. Finally, a 6t / cm³ flow rate was used for further processing. 2 The raw material is compressed under pressure to obtain flat raw material blocks with dimensions of approximately 30×25×15mm.

[0114] The raw ore lump (P2O5 content approximately 19.61%) was laid as the base material for the sintering trolley, with a thickness of 85 mm. Then, a 200 mm thick layer of raw meal blocks was laid on top of the base material. After laying, the sintering layer was first dried using microwave at 220℃ for 40 min, then dried a second time with hot air at 350℃ for 20 min, and finally dried a third time with hot air at 450℃ for 10 min. After drying, the sintering layer was preheated with hot air at 550℃ for 8 min, and then preheated again with hot air at 850℃ for 25 min. After preheating, natural gas (9000 kcal / Nm³) was used... 3 After combustion with air, the sintered material layer is roasted at 1200℃ for 45 minutes. After roasting, the roasted clinker is cooled to about 700℃ with room temperature air, and then cooled a second time to about 200℃ with room temperature hot air. After cooling, the clinker is screened, and clinker blocks ≥5mm are collected as finished phosphate ore (P2O5 content is about 26.33%).

[0115] Result detection

[0116] The finished phosphate ore obtained from each of the above embodiments and comparative examples was subjected to various quality tests, and the test results are shown in the table below:

[0117]

[0118]

Claims

1. A method for processing of rock phosphate in association with waste rock fines, characterized by: The processing method includes the following steps: S1) The raw phosphate ore from open-pit mines and raw phosphate ore from deep-buried mines are mixed and then refined to obtain a raw ore mixture. S2) The raw ore mixture is washed, dried and screened in sequence to obtain raw ore lumps, raw ore large particles and raw ore fine particles; the particle size of the raw ore lumps is ≥20mm and ≤30mm; the particle size of the raw ore large particles is >5mm and <20mm; the particle size of the raw ore fine particles is ≤5mm. S3) The large particles of raw ore are ground and classified to obtain coarse ore powder, fine ore powder, and micro ore powder; the grinding process involves grinding the large particles of raw ore to a particle size ≤1mm, with at least 95% of the particles being coarse ore powder with a particle size >1mm and ≤5mm; the fine ore powder with a particle size ≥0.5mm and ≤1mm; and the micro ore powder with a particle size <0.5mm. S4) The fine ore powder of the raw ore is subjected to flotation, magnetic separation, photoelectric separation and calcination in sequence, and then mixed with the fine ore particles, coarse ore powder, micro ore powder and waste phosphate rock powder to obtain phosphate rock powder. S5) Phosphate rock powder is mixed with yellow phosphorus production dust, biomass straw pellets, and calcium hydroxide solution to obtain a mixture; the yellow phosphorus production dust is modified yellow phosphorus production dust after being treated with aluminosilicate grinding; the mass ratio of phosphate rock powder, yellow phosphorus production dust, and biomass straw pellets is 70~85:5~10:8~20; the concentration of the calcium hydroxide solution is 0.01~0.1mol / L; the amount of calcium hydroxide solution added accounts for 0.8~4% of the total mass of the mixture; S6) After the mixture is pressed into blocks, the original ore blocks are used as the base material for sintering to obtain phosphate ore blocks.

2. The method of claim 1, wherein: The particle size of the raw ore mixture is no greater than 30 mm; and / or The washing process involves multiple water washes of the raw ore mixture; the liquid-to-solid mass ratio during a single wash is 1-6:1; and / or The drying process involves drying the raw ore mixture at a temperature of 110~300℃ until the moisture content is less than 10wt%.

3. The method of claim 1 wherein: The waste phosphate rock powder includes phosphate rock powder generated during the mining of open-pit and buried phosphate mine ore, as well as phosphate rock powder generated during the reprocessing of open-pit and buried phosphate mine ore; and / or The calcination treatment temperature is 400~600℃; and / or The phosphate rock powder contains no less than 10% P2O5.

4. The method of claim 3, wherein: The P2O5 content in the phosphate rock powder is 10-15%.

5. The method of claim 1 wherein: The mass ratio of the phosphate rock powder, yellow phosphorus production dust, and biomass straw pellets is 75~82:7~8:10~18; the concentration of the calcium hydroxide solution is 0.02~0.05mol / L; and the amount of calcium hydroxide solution added accounts for 1~3% of the total mass of the mixture.

6. The method of claim 1 wherein: The particle size of the biomass straw pellets is ≤3mm; and / or The aluminosilicate is one or more of potassium feldspar, sodium feldspar, calcium feldspar, montmorillonite, and zeolite; the mass ratio of the yellow phosphorus production dust to the aluminosilicate is 100:1~6.

7. The method of claim 6, wherein: The biomass straw pellets are modified biomass straw pellets that have been soaked and filtered dry in a calcium hydroxide solution.

8. The method of claim 1 wherein: The mixture is pressed into blocks using a pressure of 3 to 8 t / cm 2 The mixture is pressed into regular oval or pillow or flat blocks.

9. The method of processing according to any one of claims 1-8, wherein: The sintering process includes: Drying: The material to be sintered is first dried at 180-300℃ for 15-60 minutes; then dried at 320-400℃ for 10-40 minutes; and finally dried at 400-480℃ for 8-30 minutes. The first drying is done by microwave intermittent drying, and the second and third drying are done by hot air drying. Preheating: Preheat the dried material at 500-650℃ for 2-20 minutes; then preheat it at 700-900℃ for 15-60 minutes. Calcination: The preheated material is calcined at 1000-1350℃ for 0.1-5 hours; Cooling: First, cool the roasted material to 600-800℃; then further cool it to 120-300℃; the cooling medium used for both cooling processes is room temperature air.

10. The method of processing according to any one of claims 1-8, wherein: The sintering process includes: Drying: The material to be sintered is first dried at 200-260℃ for 20-45 minutes; then dried at 340-380℃ for 15-30 minutes; and finally dried at 420-450℃ for 10-25 minutes. The first drying is done by microwave intermittent drying, and the second and third drying are done by hot air drying. Preheating: Preheat the dried material at 550-600℃ for 5-15 minutes; then preheat it at 750-850℃ for 20-40 minutes. Calcination: The preheated material is calcined at 1050-1200℃ for 0.5-4 hours; Cooling: First, cool the roasted material to 620-750℃; then further cool it to 150-250℃; the cooling medium used for both cooling processes is room temperature air.

11. The method of claim 9, wherein: The hot air generated during the first cooling is circulated as hot air for the first and / or second preheating; and / or The hot air generated during the second cooling is circulated as hot air for the second drying; and / or The hot air generated during roasting and the second preheating is treated with dust removal and then used as the hot air for the third drying; and / or The hot air generated from the second and third drying processes, as well as the first preheating process, is discharged after dust removal, desulfurization, and denitrification treatment.

12. The method of claim 10, wherein: The hot air generated during the first cooling is circulated as hot air for the first and / or second preheating; and / or The hot air generated during the second cooling is circulated as hot air for the second drying; and / or The hot air generated during roasting and the second preheating is treated with dust removal and then used as the hot air for the third drying; and / or The hot air generated from the second and third drying processes, as well as the first preheating process, is discharged after dust removal, desulfurization, and denitrification treatment.

13. The method of processing according to any one of claims 1-8, wherein: The P2O5 content in the raw ore block is not less than 18%; the thickness of the base material is 60-95mm; the thickness of the mixed material block layer is 150-250mm; and / or The sintered clinker is screened, and the clinker with a diameter <5mm is returned to step S5) to participate in the mixing, while the clinker with a diameter ≥5mm is used as the finished phosphate rock for yellow phosphorus production.

14. The method of claim 13, wherein: The thickness of the underlayer is 70-90 mm; the layer thickness of the mixed material block is 180-220 mm.

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