Phosphate rock pellets from phosphate rock gravity separation tailings and a method for making same

Abstract

The application discloses a kind of phosphorus ore heavy separation tailings phosphorus ore pellets and its preparation method, phosphorus ore heavy separation tailings is mixed with inorganic binder, then it is added by spraying to organic binder while carrying out disc granulation, then it is prepared by drying, baking to obtain phosphorus ore pellet, the falling strength of the phosphorus ore green pellet prepared is 7-12 times per ball, the compressive strength is 40-80N per ball, the compressive strength of phosphorus ore dry pellet is 160-260N per ball, meet the strength requirement for subsequent used in yellow phosphorus production.The phosphorus ore pellet prepared by only using inorganic binder and sodium carboxymethyl cellulose aqueous solution with phosphorus ore heavy separation tailings, chemical composition is simple, high grade of phosphorus product, realizes the resource utilization of phosphorus ore heavy separation tailings, reduces the pressure of stockpiling and pollution to environment, while preparation method is simple and easy to popularize, with wide application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of phosphorus tailing resource utilization, and particularly relates to a phosphorus ore pellet of phosphorus-containing ore heavy separation tailings and a preparation method thereof. BACKGROUND

[0002] Heavy separation refers to a method for separation by using the difference in specific gravity of minerals and the different settling speeds thereof in a medium. The method can separate high-grade ore from low-grade ore, thereby improving the grade of the ore. However, the heavy separation tailings after heavy separation contain not only useful components such as reselectable metal ore and non-metal ore, but also a large amount of final tailings which are not reselectable. Therefore, directly discarding the tailings will cause serious waste of a large amount of mineral resources. In addition, the discarded tailings need to occupy a large amount of land, and are easy to cause environmental pollution, water and soil loss, and vegetation damage. Moreover, the large amount of stored tailings are easy to flow and collapse, and are prone to collapse and landslide in the rainy season, thereby causing serious safety hazards. Therefore, resource utilization of the tailings is one of the common means at present. The P2O5 content of the phosphorus ore heavy separation tailings produced after flotation and spiral chute heavy separation of the phosphorus ore is only about 22%, which belongs to medium-low grade phosphorus ore. In addition, the proportion of the phosphorus ore with a particle size of less than 74 μm is as high as 89%. Therefore, the conventional beneficiation method cannot effectively recover the phosphorus ore resources in the tailings, and a large amount of phosphorus resources will still be wasted.

[0003] In order to improve the utilization rate and economic benefits of the phosphorus ore resources, the phosphorus ore powder is generally prepared into phosphorus ore pellets for producing yellow phosphorus at present. For example, CN102602900A discloses a method for digesting and carbonizing phosphorus ore powder into pellets. The phosphorus ore powder and lime powder are uniformly mixed, water is added for digestion reaction, and then coke powder is added for mixing, pressing and carbonization to obtain pellets with high cold and hot strength and good mine pressure strength, which can be used as raw material for electric furnace method for producing phosphorus, and has good economic and environmental benefits. CN104925773A discloses a method for producing yellow phosphorus by using mud phosphorus slag and phosphorus ore powder. The mud phosphorus slag, phosphorus ore powder and binder are pressed, dried and solidified to be directly sent into a yellow phosphorus electric furnace for producing yellow phosphorus, thereby realizing comprehensive utilization of the mud phosphorus slag and the phosphorus ore powder. CN116216669A discloses a method for enriching and compounding phosphorus tailing powder into pellets. The low-grade phosphorus tailings separated by heavy separation cyclone are mixed with silica powder, coal powder or coke powder, and the by-product leaching residue in the production of wet-process phosphoric acid is added as a binding agent. After the concentration is adjusted by water, the mixture is pressed and dried to obtain phosphorus ore pellets. The prepared pellets have a furnace entry grade of 1-8% and high strength, no cracking at high temperature, and a small amount of CO2, which can reduce the energy consumption of yellow phosphorus production and realize comprehensive utilization of phosphorus resources.

[0004] However, the above-mentioned technology adds a plurality of other substances and binders in the process of preparing the phosphate ore pellets, resulting in that the prepared phosphate ore pellets have complex chemical composition and low phosphorus grade, and the preparation process is relatively complex and cumbersome, so there are many uncertain factors in subsequent processing and application, which has a negative impact on production and utilization. SUMMARY

[0005] In view of the above technical problems, the present application provides a phosphate ore pellet containing phosphate ore heavy concentrate tailings and a preparation method thereof, in which inorganic binders and organic binders are introduced into the phosphate ore heavy concentrate tailings, and the phosphate ore pellets are prepared through disc granulation, drying and calcination, wherein the organic binder is sodium carboxymethyl cellulose, which needs to be prepared into an aqueous solution and then added into the phosphate ore pellets by spraying when disc granulation is performed. The falling strength of the green pellets in the preparation process can reach 7-12 times per ball, and the compressive strength can reach 60-80 N per ball, and the compressive strength of the dried dry pellets can reach 160-260 N per ball, which meets the requirements of yellow phosphorus production, and realizes the resource utilization of the phosphate ore heavy concentrate tailings, avoids the waste of mineral resources, and reduces the pollution to the environment.

[0006] In order to achieve the above-mentioned purpose, the present application provides a phosphate ore pellet containing phosphate ore heavy concentrate tailings, which is composed of phosphate ore heavy concentrate tailings, pellet binder and organic solution, wherein the mass ratio of the phosphate ore heavy concentrate tailings and the pellet binder is 100:1-4, and the amount of the organic solution is 10-15% of the weight of the raw material.

[0007] Preferably, the pellet binder is an inorganic binder, specifically one or more of calcium oxide, sodium silicate and bentonite.

[0008] Preferably, the organic solution is a sodium carboxymethyl cellulose solution with a mass fraction of 0.5-1%.

[0009] Preferably, the phosphate ore heavy concentrate tailings are the heavy concentrate tailings produced after flotation and spiral chute of phosphate ore, and the mass percentage of the fineness of <0.074 mm is 80-90%, and the phosphorus grade is 20%-25%.

[0010] The present application also provides a preparation method of a phosphate ore pellet containing phosphate ore heavy concentrate tailings, which specifically comprises the following steps:

[0011] (1) The phosphate ore is subjected to flotation and heavy concentrate separation by a spiral chute to obtain heavy concentrate tailings;

[0012] (2) Preparing a pellet binder: dissolving sodium carboxymethyl cellulose in water to obtain a sodium carboxymethyl cellulose aqueous solution;

[0013] (3) Mixing the heavy concentrate tailings obtained in step (1) with inorganic binders in proportion to obtain a mixture;

[0014] (4) the mixture is subjected to disc granulation, and the sodium carboxymethyl cellulose aqueous solution prepared in step (2) is sprayed to roll into green pellets;

[0015] (5) the green pellets are dried at 100-120 DEG C for 1-4h to obtain dry pellets;

[0016] (6) the dry pellets are calcined at 600-800 DEG C for 2-3h to obtain phosphorite pellets after cooling.

[0017] Preferably, the sodium carboxymethyl cellulose in step (2) is dissolved into sodium carboxymethyl cellulose aqueous solution by stirring at 50-60 DEG C for 0.5-1h, wherein the mass fraction of sodium carboxymethyl cellulose is 0.5%-1%; the amount of sodium carboxymethyl cellulose aqueous solution is 10-15% of the mass of the mixture.

[0018] Preferably, the rotating speed of disc granulation in step (4) is 30-40 rpm / min, and the inclination angle is 45-50 DEG ; the particle size of the green pellets is 10-30mm.

[0019] The present application has the advantages that: the present application uses the gravity separation tailings of phosphorite and a binder to mix, and the phosphorite pellets are prepared by granulation, drying and calcination, wherein the falling strength of the green pellets directly obtained after granulation is more than 7 times per ball, and the highest can reach 12 times per ball, and the compressive strength can be up to 80 N per ball; the compressive strength of the dry pellets obtained by drying can be up to 260 N per ball, and the strength of the prepared phosphorite pellets can meet the requirements for subsequent production of yellow phosphorus.

[0020] The present application only adds inorganic binder and organic binder sodium carboxymethyl cellulose in the gravity separation tailings of phosphorite, and the amount is relatively small, which has little effect on the phosphorus grade of the gravity separation tailings, reduces the introduction of other chemical components, and reduces the difficulty in subsequent utilization and treatment of the waste produced by the phosphorite pellets and calcination, and is easy to master.

[0021] The preparation method of the phosphorite pellets in the present application is simple, the raw materials are simple and easy to obtain, and the prepared phosphorite pellets can meet the strength requirements for production of yellow phosphorus, and can be widely applied. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The process flow chart for preparing phosphorite pellets from gravity separation tailings of phosphorite. DETAILED DESCRIPTION

[0023] The technical solutions of the present application are further explained and described below in combination with the drawings and specific embodiments. It should be noted that the following embodiments are only preferred embodiments of the present application and should not be construed as limiting the present application. The protection scope of the present application should be subject to the content recited in the claims. Modifications and replacements of the technical solutions of the present application made by those skilled in the art without creative labor fall within the protection scope of the present application.

[0024] Phosphate rock gravity separation tailings: gravity separation tailings produced after the phosphate rock is subjected to demagnesium reverse flotation and then spiral chute, fineness <0.074mm mass percentage 89%, P2O5 content 22%.

[0025] Example 1

[0026] (1) 1.2 kg of gravity separation tailings separated after flotation and spiral chute was weighed;

[0027] (2) Sodium carboxymethyl cellulose was placed in water and stirred at 50°C for 1 h to dissolve it, and a sodium carboxymethyl cellulose aqueous solution was prepared, wherein the mass fraction of sodium carboxymethyl cellulose was 0.5%-1%;

[0028] (3) 48 g of bentonite was weighed according to 4% of the weight of the gravity separation tailings, and was mixed with the gravity separation tailings in step (1) in a mixer to obtain a mixture;

[0029] (4) The mixture obtained in step (3) was sent to a disc granulator, the rotation speed was adjusted to 30 rpm / min, the inclination angle was 45°, and rolling granulation was performed, and sodium carboxymethyl cellulose aqueous solution was sprayed thereinto during the granulation to obtain green pellets with a particle size of 10-30 mm, and the amount of sodium carboxymethyl cellulose aqueous solution was 10% of the mixture;

[0030] (5) The green pellets prepared in step (4) were placed in a drying box and dried at 120°C for 2 h to obtain dry pellets;

[0031] (6) The dry pellets were placed in a muffle furnace and calcined at 600°C for 3 h, and then naturally cooled to obtain phosphate rock pellets.

[0032] Example 2

[0033] (1) 1.2 kg of gravity separation tailings separated after flotation and spiral chute was weighed;

[0034] (2) Sodium carboxymethyl cellulose was placed in water and stirred at 55°C for 0.5 h to fully dissolve it, and a sodium carboxymethyl cellulose aqueous solution was prepared, wherein the mass fraction of sodium carboxymethyl cellulose was 0.5%-1%;

[0035] (3) Take 48g sodium silicate nonahydrate according to 4% of the weight of the gravity separation tailings, and mix it with the gravity separation tailings in the mixing machine to obtain a mixture;

[0036] (4) Put the mixture obtained in step (3) into a disc granulator, adjust the rotating speed to 35 rpm / min and the inclination angle to 47°, and conduct rolling granulation, while spraying sodium carboxymethyl cellulose aqueous solution into the mixture to obtain green pellets with a particle size of 10-30mm, and the amount of sodium carboxymethyl cellulose aqueous solution is 12% of the mixture;

[0037] (5) Put the green pellets prepared in step (4) into a drying oven, and dry them at 120℃ for 2h to obtain dry pellets;

[0038] (6) Put the dry pellets into a muffle furnace, and roast them at 700℃ for 2.5h to obtain phosphate ore pellets.

[0039] Example 3

[0040] (1) Take 1.2kg of gravity separation tailings after flotation and spiral chute separation;

[0041] (2) Put sodium carboxymethyl cellulose into water, and stir it at 60℃ for 0.5h to fully dissolve it, and prepare sodium carboxymethyl cellulose aqueous solution, wherein the mass fraction of sodium carboxymethyl cellulose is 0.5%-1%;

[0042] (3) Take 48g of calcium oxide according to 4% of the weight of the gravity separation tailings, and mix it with the gravity separation tailings in the mixing machine to obtain a mixture;

[0043] (4) Put the mixture obtained in step (3) into a disc granulator, adjust the rotating speed to 40 rpm / min and the inclination angle to 50°, and conduct rolling granulation, while spraying sodium carboxymethyl cellulose aqueous solution into the mixture to obtain green pellets with a particle size of 10-30mm, and the amount of sodium carboxymethyl cellulose aqueous solution is 15% of the mixture;

[0044] (5) Put the green pellets prepared in step (4) into a drying oven, and dry them at 120℃ for 2h to obtain dry pellets;

[0045] (6) Put the dry pellets into a muffle furnace, and roast them at 800℃ for 2h to obtain phosphate ore pellets.

[0046] Example 4

[0047] (1) Take 1.2kg of gravity separation tailings after flotation and spiral chute separation;

[0048] (2) Take sodium carboxymethyl cellulose and put it in water, stir at 60℃ for 0.5h to make it fully dissolved, prepare sodium carboxymethyl cellulose aqueous solution, wherein the mass fraction of sodium carboxymethyl cellulose is 0.5%~1%;

[0049] (3) Take 48g cement according to 4% of the weight of the gravity separation tailings, put it in the mixing machine together with the gravity separation tailings in step (1) to mix evenly to obtain a mixture;

[0050] (4) Put the mixture obtained in step (3) into a disc granulator, adjust the rotation speed to 40rpm / min and the inclination angle to 50° to perform rolling granulation, spray sodium carboxymethyl cellulose aqueous solution into it while granulating, obtain green pellets with a particle size of 10-30mm, and the amount of sodium carboxymethyl cellulose aqueous solution is 15% of the mixture;

[0051] (5) Take the green pellets prepared in step (4) and put them in a drying box, dry at 120℃ for 2h to obtain dry pellets;

[0052] (6) Put the dry pellets into a muffle furnace and calcine at 800℃ for 2h, and naturally cool to obtain phosphate ore pellets.

[0053] Comparative Example 1

[0054] (1) Take 1.2kg of gravity separation tailings and 48g of calcium oxide, put them in a mixing machine to mix evenly to obtain a mixture;

[0055] (2) Put the mixture into a disc granulator, adjust the rotation speed to 40rpm / min and the inclination angle to 50° to perform rolling granulation, spray water into it while granulating, obtain green pellets with a particle size of 10-30mm, and the amount of water is 15% of the mixture.

[0056] (3) Put the green pellets prepared in step (2) into a drying box, dry at 120℃ for 2h to obtain dry pellets;

[0057] (4) Put the dry pellets into a muffle furnace and calcine at 800℃ for 2h, and naturally cool to obtain phosphate ore pellets.

[0058] Comparative Example 2

[0059] The method and steps are the same as Comparative Example 1, only 48g of calcium oxide is replaced by 12g of sodium carboxymethyl cellulose, and phosphate ore pellets are prepared.

[0060] Comparative Example 3

[0061] (1) Take 1.2kg of gravity separation tailings, 48g of calcium oxide and 6g of sodium carboxymethyl cellulose, put them in a mixing machine to mix evenly to obtain a mixture;

[0062] (2) The mixture is fed into a disc granulator, the rotation speed is adjusted to 40 rpm / min, the inclination angle is 50°, and rolling granulation is performed, while spraying water into the granulator, to obtain green pellets with a particle size of 10-30 mm, wherein the amount of water is 15% of the mixture.

[0063] (3) The green pellets prepared in step (2) are placed in a drying oven and dried at 120°C for 2 h to obtain dry pellets;

[0064] (4) The dry pellets are placed in a muffle furnace and calcined at 800°C for 2 h, and then naturally cooled to obtain phosphate pellets.

[0065] Result detection:

[0066] The green pellets, dry pellets and phosphate pellets prepared in the above examples and comparative examples are subjected to falling experiments to detect the falling strength and the strength of the pellets, and the results are as follows:

[0067]

[0068] The results show that the green pellets prepared by using only inorganic binder and without sodium carboxymethyl cellulose are broken after falling 2 times at a distance of 50 cm from the steel plate (Comparative Example 1), and the green pellet compression strength and the dry pellet compression strength are poor; the green pellets prepared by using only sodium carboxymethyl cellulose and without inorganic binder are broken after falling more than 40 times, the green pellet compression strength is 15 N / pellet, and the dry pellet compression strength is 152 N / pellet; the green pellets prepared by directly mixing sodium carboxymethyl cellulose with inorganic binder and gravity separation tailings and then disc granulation are broken after falling 3 times, the green pellet compression strength is 48 N / pellet, and the dry pellet compression strength is 138 N / pellet. In Examples 1-4, the gravity separation tailings are first mixed with inorganic binder, and then sodium carboxymethyl cellulose is prepared into an aqueous solution, which is added to the pellets in the form of spraying during granulation, and the falling strength of the prepared green pellets is increased to 7-12 times / pellet, and the green pellet compression strength and the dry pellet compression strength are also significantly improved; in Example 2, sodium silicate is used as inorganic binder and sodium carboxymethyl cellulose is used as organic binder, and the green pellet compression strength prepared thereby is higher than that prepared in the comparative examples, which is because the calcium oxide as a binder has a high compression strength of the pellets itself; at the same time, calcium oxide reacts with water to generate calcium hydroxide, which causes the compression strength of the dry pellets to increase to a certain extent, but the falling strength is only 2 times / pellet, and the pellets are brittle and not easy to use in subsequent yellow phosphorus production. For the phosphorus grade of phosphate pellets, when the amount of added inorganic binder is the same, the phosphorus grade of the phosphate pellets is not significantly different; the organic binder is volatilized and decomposed at high temperature during calcination, which has no effect on the phosphorus grade.

Claims

1. A phosphate ore pellet from phosphate ore gravity separation tailings, characterized in that: The phosphate rock pellets are composed of phosphate rock gravity separation tailings, pellet binder, and organic solution, wherein the mass ratio of phosphate rock gravity separation tailings to pellet binder is 100:1-4, and the amount of organic solution is 10-15% of the weight of the raw materials; The pellet binder is an inorganic binder, specifically one or more of calcium oxide, sodium silicate, and bentonite; the organic solution is a sodium carboxymethyl cellulose solution with a mass fraction of 0.5-1%; the phosphate rock gravity separation tailings are gravity separation tailings produced after phosphate rock has undergone flotation and spiral sluice gate, with a mass percentage of fineness <0.074mm of 80-90% and a phosphorus grade of 20%-25%.

2. A method for preparing phosphate rock pellets from phosphate rock gravity separation tailings as described in claim 1, characterized in that: Includes the following steps: (1) Phosphate ore is separated into gravity tailings by flotation and spiral sluice gravity separation; (2) Preparation of pellet binder: Dissolve sodium carboxymethyl cellulose in water to obtain an aqueous solution of sodium carboxymethyl cellulose; (3) Mix the gravity separation tailings obtained in step (1) with the inorganic binder in a certain proportion to obtain a mixture; (4) The mixture is granulated by disc and sprayed with the sodium carboxymethyl cellulose aqueous solution prepared in step (2), and rolled to form green pellets; (5) Dry the raw pellets at 100-120℃ for 1-4 hours to obtain dry pellets; (6) The dry pellets are roasted at 600-800℃ for 2-3 hours and then cooled to obtain phosphate rock pellets.

3. The preparation method according to claim 2, characterized in that: In step (2), the sodium carboxymethyl cellulose is dissolved by stirring at 50-60℃ for 0.5-1h to obtain an aqueous solution of sodium carboxymethyl cellulose, wherein the mass fraction of sodium carboxymethyl cellulose is 0.5%~1%; the amount of sodium carboxymethyl cellulose aqueous solution is 10-15% of the mass of the mixture.

4. The preparation method according to claim 2, characterized in that: In step (4), the rotation speed of the disc granulator is 30-40 rpm / min and the tilt angle is 45-50°; the particle size of the green pellets is 10-30 mm.

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