Method for processing fluorite concentrate containing monazite

Abstract

The present invention discloses a method for treating monazite-containing fluorite concentrate, comprising the following steps: 1) mixing the monazite-containing fluorite concentrate with iron ore concentrate, granulating the mixture, and then drying the mixture to obtain pretreated fluorite concentrate particles; wherein the mass ratio of the monazite-containing fluorite concentrate to the iron ore concentrate is 1:(0.007-0.2); 2) mixing the pretreated fluorite concentrate particles with sulfuric acid and conducting a preliminary reaction at 100-150°C to obtain a preliminary reaction mass; reacting the preliminary reaction mass at 200-270°C to obtain gas and calcined slag; and 3) leaching the calcined slag with water to obtain a leachate containing rare earth and niobium, as well as a water-leached slag. This method achieves a high leaching rate of rare earth and niobium.

Description

Technical Field

[0001] The present invention relates to a method for processing fluorite concentrate, in particular to a method for processing fluorite concentrate containing monazite. Background Art

[0002] Monazite is a phosphate mineral containing rare earth elements. Methods for decomposing monazite generally include alkaline decomposition and concentrated sulfuric acid roasting. The concentrated sulfuric acid roasting method involves mixing monazite concentrate with concentrated sulfuric acid and roasting it. The decomposed product is then cooled and leached with water to produce a rare earth sulfate solution.

[0003] Fluorite is primarily composed of calcium fluoride (CaF2). The Bayan Obo mine boasts the largest reserves of associated fluorite in China. However, due to the fine grains, complex dissemination, high inclusion content, and abundance of similarly floatable minerals, the quality of fluorite concentrate is low. For example, even fluorite concentrates containing small amounts of monazite still contain small amounts of valuable resources such as rare earth elements and niobium, but these resources are underutilized. Therefore, recovering these valuable metals and improving their leaching efficiency is of great importance.

[0004] CN109371239A discloses a method for treating low-grade fluorite ore containing rare earth elements. This method utilizes a temperature-programmed, staged slurry decomposition process using an absolute excess of sulfuric acid solution. The low-temperature stage prioritizes the decomposition of fluorite, while the temperature is increased to decompose rare earth elements. Hydrofluoric acid is recovered from the tail gas. The acid leaching residue is then used to leach rare earth elements, neutralize and remove thorium, and then recover rare earth elements and gypsum. This patent document does not mention monazite, but only the REO decomposition rate, without mentioning the leaching rates of rare earth elements and niobium.

[0005] CN113735062A discloses a method for recovering rare earths from fluorite to produce hydrogen fluoride. This method first processes fluorite into a powder and refines it into high-purity acid-grade fluorite concentrate, which is then reacted with industrial sulfuric acid to produce high-purity hydrogen fluoride. The raw material used is high-purity acid-grade fluorite concentrate. While the production process mentions the proportion of fuming acid, the specific value and reaction temperature are not mentioned. More importantly, the method does not involve monazite and does not consider the recovery of rare earths and niobium.

[0006] CN105441674A discloses a method for comprehensively recovering phosphorus and rare earths from monazite-containing phosphate ore. The method comprises the following steps: leaching the monazite-containing phosphate ore with phosphoric acid, separating the solid and liquid to obtain a rare earth-containing monocalcium phosphate solution and monazite-containing slag; adding an organic extractant solution to the rare earth-containing monocalcium phosphate solution to extract and recover the rare earths in the monocalcium phosphate solution, and obtaining a monocalcium phosphate-containing raffinate; and recovering the rare earths from the monazite-containing slag and phosphorus from the monocalcium phosphate-containing raffinate. This method is particularly suitable for treating minerals with high monazite content. Summary of the Invention

[0007] In view of this, an object of the present invention is to provide a method for treating fluorite concentrate containing monazite, which has a high leaching rate of rare earth and niobium.

[0008] The present invention adopts the following technical solutions to achieve the above-mentioned purpose.

[0009] The present invention provides a method for processing fluorite concentrate containing monazite, comprising the following steps:

[0010] 1) mixing fluorite concentrate containing monazite with iron ore concentrate, granulating the mixture, and then drying the mixture to obtain pretreated fluorite concentrate particles;

[0011] The monazite-containing fluorite concentrate has a CaF2 content greater than 75 wt%, a REO content of 4.5 to 9.5 wt%, a Nb2O5 content of 0.05 to 0.5 wt%, and a P content of 0.1 to 3.0 wt%.

[0012] Wherein, the mass ratio of the fluorite concentrate containing monazite to the iron ore concentrate is 1:(0.007-0.2);

[0013] 2) mixing the pretreated fluorite concentrate particles with sulfuric acid and reacting them at 100-150° C. to obtain a preliminary reaction material; reacting the preliminary reaction material at 200-270° C. to obtain gas and roasted slag;

[0014] 3) Leaching the roasted slag with water to obtain a leachate containing rare earth and niobium and a water-leached slag; wherein the mass ratio of water to roasted slag is 0.1 to 0.2:1.

[0015] According to the treatment method of the present invention, preferably, in step 1), the mass ratio of the monazite-containing fluorite concentrate to the iron ore concentrate is 1:(0.01-0.15).

[0016] According to the treatment method of the present invention, preferably, in step 2), the sulfuric acid is a mixture of 98 wt% concentrated sulfuric acid and 105 wt% fuming sulfuric acid; wherein the mass ratio of 98 wt% concentrated sulfuric acid to 105 wt% fuming sulfuric acid is 0.75-1.0:0.6-0.8.

[0017] According to the treatment method of the present invention, preferably, in step 2), the mass ratio of the pretreated fluorspar concentrate particles, 98wt% concentrated sulfuric acid and 105wt% oleum is 1:(0.75-1.0):(0.6-0.8).

[0018] According to the treatment method of the present invention, preferably, in step 2), the initial reaction temperature is 100-140° C.; and the initial reaction time is 4-8 min.

[0019] According to the treatment method of the present invention, preferably, in step 2), the preliminary reaction materials are reacted at 200-270° C. for 65-110 minutes to obtain hydrogen fluoride-containing gas and calcined slag.

[0020] According to the treatment method of the present invention, preferably, the following steps are further included: washing the hydrogen fluoride-containing gas through a washing tower, and then condensing and rectifying to obtain anhydrous hydrogen fluoride.

[0021] According to the processing method of the present invention, preferably, the following steps are further included:

[0022] The leaching solution containing rare earth and niobium obtained in step 3) is neutralized with magnesium oxide to obtain a neutralized leaching solution containing rare earth and niobium and a neutralized slag.

[0023] According to the processing method of the present invention, preferably, the following steps are further included:

[0024] The water-leached residue obtained in step 3) is subjected to magnetic separation using a magnetic separator to obtain calcium sulfate; wherein the magnetic separation intensity is 3.5 to 4.5T.

[0025] According to the processing method of the present invention, preferably, the pretreated fluorite concentrate particles are obtained by pretreatment comprising the following steps:

[0026] The fluorite concentrate containing monazite is mixed with iron ore concentrate and made into balls with a diameter of 2 to 5 mm. The prepared balls are dried at 90 to 125° C. for 16 to 40 hours to obtain pretreated fluorite concentrate particles.

[0027] The treatment method of the present invention can recover rare earth elements and niobium from monazite-containing fluorite concentrate, achieving high leaching rates for rare earth and niobium. The leaching rate for rare earth can reach over 99%, and for niobium over 87%. Furthermore, the method can produce gypsum with a purity exceeding 92% and anhydrous hydrogen fluoride. According to a preferred technical solution, the leaching rate of rare earth and niobium is increased by adding iron ore concentrate, controlling the ratio of concentrated sulfuric acid and oleum to the fluorite concentrate, and controlling the amount of water used during leaching. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0029] The present invention's method for processing monazite-containing fluorite concentrate comprises the following steps: 1) a pretreatment step; 2) a reaction step; and 3) a leaching step. Optionally, it also includes a neutralization step and a magnetic separation step. This is described in detail below.

[0030] <Preprocessing Steps>

[0031] Monazite-containing fluorite concentrate is mixed with iron ore concentrate, pelletized, and then dried to produce pretreated fluorite concentrate particles. The present inventors discovered that the addition of iron ore concentrate can fix phosphorus and fully decompose monazite. This helps increase the decomposition rate of rare earth and niobium, and thus the leaching rate of rare earth and niobium.

[0032] The CaF2 content in the monazite-containing fluorite concentrate is greater than 75 wt%, preferably greater than or equal to 78 wt%, more preferably greater than or equal to 80 wt% and less than 93 wt%, and even more preferably greater than or equal to 83 wt% and less than 87 wt%. The REO content can be 4.5-9.5 wt%, preferably 5.04-8 wt%, more preferably 5.3-7.0 wt%, and even more preferably 5.5-6.3 wt%. The Nb2O5 content can be 0.05-0.5 wt%, preferably 0.08-0.4 wt%, more preferably 0.1-0.2 wt%, and even more preferably 0.13-0.18 wt%. The P content (i.e., phosphorus content) is 0.1-3.0 wt%, preferably 0.5-2.5 wt%, more preferably 0.7-1.4 wt%, and even more preferably 0.9-1.1 wt%. Such a monazite-containing fluorite concentrate can achieve higher rare earth and niobium leaching rates when processed within the specific process and process parameter ranges of the present invention.

[0033] The mass ratio of monazite-containing fluorite concentrate to iron ore concentrate is 1:(0.007-0.2), preferably 1:(0.01-0.15), more preferably 1:(0.04-0.1), and even more preferably 1:(0.045-0.06). This is beneficial for improving the leaching rate of rare earth and niobium.

[0034] The monazite-containing fluorite concentrate is mixed with iron ore concentrate and then pelletized, preferably into balls. The diameter of the balls can be 2-5 mm, preferably 2-4 mm, and more preferably 3-4 mm. Such a diameter is conducive to the reaction and is also conducive to the recovery of the monazite-containing fluorite concentrate after drying.

[0035] In the present invention, a disc granulator can be used to form the pellets.

[0036] The drying temperature can be 90-125°C, preferably 90-110°C, and more preferably 100-110°C. The drying time can be 16-40 hours, preferably 20-36 hours, and more preferably 24-36 hours. The moisture content of the pretreated fluorite concentrate particles is less than 0.1 wt%. This helps to improve the decomposition rate of rare earth and niobium.

[0037] According to one embodiment of the present invention, the prepared balls are dried at 90-100° C. for 30-36 hours to obtain pretreated fluorite concentrate particles.

[0038] In the present invention, the rare earth minerals in the fluorite concentrate are mainly bastnaesite and monazite, and the niobium minerals are mainly one or more of niobite, calcite, pyrochlore and niobium rutile.

[0039] <Reaction Step>

[0040] The reaction steps include a primary reaction step and a secondary reaction step, which are described in detail below.

[0041] Initial reaction steps

[0042] The pretreated fluorite concentrate particles are mixed with sulfuric acid and subjected to a preliminary reaction at 100-150°C to obtain a preliminary reaction material. This is beneficial to increasing the decomposition rate of rare earth and niobium, thereby increasing the leaching rate of rare earth and niobium.

[0043] In the present invention, the sulfuric acid is a mixture of 98 wt% concentrated sulfuric acid and 105 wt% oleum. The mass ratio of 98 wt% concentrated sulfuric acid to 105 wt% oleum can be 0.75-1.0:0.6-0.8, preferably 0.8-1.0:0.6-0.8, and more preferably 0.8-0.9:0.7-0.8. The mass ratio of the pretreated fluorspar concentrate particles to the 98 wt% concentrated sulfuric acid and 105 wt% oleum can be 1:(0.75-1.0):(0.6-0.8), preferably 1:(0.8-1.0):(0.6-0.8), and more preferably 1:(0.8-0.9):(0.7-0.8).

[0044] The initial reaction temperature may be 100-150° C., preferably 100-140° C., more preferably 100-120° C. The initial reaction time may be 4-8 min, preferably 5-8 min, more preferably 5-7 min.

[0045] According to one embodiment of the present invention, pretreated fluorspar concentrate particles are mixed with sulfuric acid and preliminarily reacted at 100-105° C. for 5.5-6.5 minutes to obtain a preliminary reaction material; wherein the sulfuric acid is a mixture of 98 wt % concentrated sulfuric acid and 105 wt % fuming sulfuric acid; and the mass ratio of the pretreated fluorspar concentrate particles to the 98 wt % concentrated sulfuric acid and the 105 wt % fuming sulfuric acid is 1:(0.85-0.9):(0.75-0.8).

[0046] Secondary reaction step

[0047] The primary reaction materials react at 200-270°C to produce gas and calcined slag. This helps increase the decomposition rate of rare earth and niobium, and thus the leaching rate of rare earth and niobium. It also helps to obtain a higher yield of hydrogen fluoride gas.

[0048] The secondary reaction temperature may be 200-270° C., preferably 220-260° C., more preferably 230-250° C. The secondary reaction time may be 65-110 min, preferably 70-100 min, more preferably 80-90 min.

[0049] According to one embodiment of the present invention, the preliminary reaction materials are reacted at 230-240° C. for 85-90 minutes to obtain hydrogen fluoride-containing gas and calcined slag.

[0050] In the present invention, during the reaction, the generated hydrogen fluoride gas can be washed in a scrubber and then condensed and distilled to obtain anhydrous hydrogen fluoride. The recovered acid after washing can be returned to the raw material (dried fluorite concentrate particles) to continue participating in the reaction, which is conducive to the recycling of acid.

[0051] In the present invention, the calcined slag is a solid containing rare earth elements, niobium elements and calcium sulfate, and the gas is a gas containing hydrogen fluoride.

[0052] <Leaching Step>

[0053] The roasted slag is leached with water to obtain a leaching solution containing rare earth and niobium and a water-leached slag.

[0054] The mass ratio of water to calcined slag is 0.1-0.2:1, preferably 0.12-0.19:1, and more preferably 0.13-0.18:1. This helps increase the leaching rate of rare earth and niobium and improves their purity. In the present invention, the mass of the calcined slag is calculated based on the dry weight of the calcined slag. Through research and experimentation, the present invention has found that the mass ratio of water to calcined slag needs to be controlled within a specific range; otherwise, a high leaching rate of rare earth and niobium cannot be achieved.

[0055] According to one embodiment of the present invention, the roasted slag is leached with water to obtain a leachate containing rare earth and niobium and a water-leached slag; wherein the mass ratio of water to roasted slag is 0.13-0.14:1.

[0056] In the present invention, the leaching rate of rare earth is greater than or equal to 96%, preferably greater than or equal to 97%, more preferably greater than or equal to 98%, and even more preferably greater than or equal to 99%. The leaching rate of rare earth can reach 99.3%. The leaching rate of niobium is greater than or equal to 85.5%, preferably greater than or equal to 86%, and more preferably greater than or equal to 87%.

[0057] The calculation formula for the leaching rate of rare earth and niobium is as follows:

[0058] Leaching rate of rare earth = 100% - (mass of leaching residue × REO content in leaching residue / mass of fluorite concentrate containing monazite × REO content in fluorite concentrate containing monazite) × 100%.

[0059] Niobium leaching rate = 100% - (mass of leached slag × Nb2O5 content in leached slag / mass of fluorite concentrate containing monazite × Nb2O5 content in fluorite concentrate containing monazite) × 100%.

[0060] The invention can use an intelligent high-efficiency filter press to perform one-step leaching and filtration to obtain a leaching solution containing rare earth and niobium and a water-leached residue. The phosphorus content in the leaching solution containing rare earth and niobium is 0.02-0.05 wt%.

[0061] <Neutralization Step>

[0062] In the present invention, the leachate containing rare earth and niobium can be neutralized and impurities removed using magnesium oxide to produce a neutralized leachate containing rare earth and niobium and a neutralized slag. The neutralization step can be performed using methods known in the art and will not be described in detail here. The neutralized slag can be returned to the water leaching step for further leaching to recover residual rare earth and niobium.

[0063] <Magnetic separation step>

[0064] In the present invention, the resulting water-leached residue can be magnetically separated using a magnetic separator to obtain calcium sulfate. The magnetic separation intensity is 3.0 to 4.5 T, preferably 3.0 to 4.0 T, and more preferably 3.5 to 4.0 T. This can produce gypsum that meets practical needs. The purity of the resulting calcium sulfate is greater than or equal to 92 wt%.

[0065] <Analysis Method>

[0066] The analytical testing methods used in the embodiments and comparative examples are described below:

[0067] CaF2 content: tested by EDTA (ethylenediaminetetraacetic acid) volumetric method according to standard GB5195.1-85.

[0068] REO content: tested by gravimetric method according to GB / T 6730.25-2021.

[0069] Nb2O5 content: tested by weight method according to standard GB / T 3654.1-1983.

[0070] P content: using spectrophotometry, according to GB / T 5009.87-2003.

[0071] Purity of gypsum: tested by barium sulfate precipitation method in accordance with standard GB / T5484-2012.

[0072] Example 1

[0073] The monazite-containing fluorite concentrate used in this embodiment has a CaF2 content of 85.66 wt%, a REO content of 5.94 wt%, a Nb2O5 content of 0.16 wt%, and a P content of 1.02 wt%.

[0074] The fluorite concentrate containing monazite and the iron ore concentrate are mixed in a mass ratio of 1:0.05 and made into balls with a diameter of 2 to 5 mm. The prepared balls are dried at 90° C. for 36 hours to obtain pretreated fluorite concentrate particles.

[0075] The pretreated fluorspar concentrate particles were uniformly mixed with 98wt% concentrated sulfuric acid and 105wt% oleum in a mass ratio of 1:0.9:0.8 and reacted at 100°C for 6 minutes to obtain a preliminary reaction mass. The preliminary reaction mass was then reacted at 230°C for 90 minutes to produce hydrogen fluoride gas and roasted slag. During the reaction, the hydrogen fluoride gas was passed into a scrubbing tower for scrubbing, condensation, and rectification to obtain anhydrous hydrogen fluoride.

[0076] The calcined slag was subjected to a one-step leaching and filtration process using water in an intelligent high-efficiency filter press to obtain a leachate containing rare earth elements and niobium, as well as a water-leached slag. During the leaching process, the mass ratio of water to calcined slag was 0.13:1.

[0077] The rare earth and niobium-containing leachate is neutralized with magnesium oxide to obtain a neutralized rare earth and niobium-containing leachate and a neutralized slag, wherein the amount of magnesium oxide used is 6.0 wt% of the mass of the monazite-containing fluorite concentrate.

[0078] The water-leached residue was subjected to a superconducting strong magnetic separator at a magnetic field strength of 3.0 T to remove impurities such as iron and thorium, and obtain gypsum (i.e., calcium sulfate) of relatively high purity. The results are shown in Table 1.

[0079] Example 2

[0080] The monazite-containing fluorite concentrate used in this embodiment has a CaF2 content of 78.64 wt%, a REO content of 6.85 wt%, a Nb2O5 content of 0.15 wt%, and a P content of 1.36 wt%.

[0081] The fluorite concentrate containing monazite and the iron ore concentrate are mixed in a mass ratio of 1:0.07 and made into balls with a diameter of 2 to 5 mm. The prepared balls are dried at 100° C. for 24 hours to obtain pretreated fluorite concentrate particles.

[0082] The pretreated fluorspar concentrate particles were uniformly mixed with 98wt% concentrated sulfuric acid and 105wt% oleum in a mass ratio of 1:0.8:0.6 and reacted at 100°C for 5 minutes to obtain a preliminary reaction mass. The preliminary reaction mass was then reacted at 240°C for 80 minutes to produce hydrogen fluoride-containing gas and roasted slag. During the reaction, the hydrogen fluoride-containing gas was passed into a scrubbing tower for scrubbing, condensation, and rectification to obtain anhydrous hydrogen fluoride.

[0083] The calcined slag was subjected to a one-step leaching and filtration process using water in an intelligent high-efficiency filter press to obtain a leachate containing rare earth elements and niobium, as well as a water-leached slag. During the leaching process, the mass ratio of water to calcined slag was 0.12:1.

[0084] The rare earth and niobium-containing leachate is neutralized with magnesium oxide to obtain a neutralized rare earth and niobium-containing leachate and a neutralized slag, wherein the amount of magnesium oxide used is 6.9 wt% of the mass of the monazite-containing fluorite concentrate.

[0085] The water-leached slag is subjected to a superconducting strong magnetic separator at a magnetic field strength of 3.5T to remove impurities such as iron and thorium, and obtain gypsum of higher purity.

[0086] The results are shown in Table 1.

[0087] Example 3

[0088] In the monazite-containing fluorite concentrate used in this embodiment, the CaF2 content is 91.38 wt%, the REO content is 4.88 wt%, the Nb2O5 content is 0.106 wt%, and the P content is 0.73 wt%.

[0089] The fluorite concentrate containing monazite is mixed with iron ore concentrate in a mass ratio of 1:0.04 and made into balls with a diameter of 2 to 5 mm. The prepared balls are dried at 110° C. for 24 hours to obtain pretreated fluorite concentrate particles.

[0090] The pretreated fluorspar concentrate particles were uniformly mixed with 98wt% concentrated sulfuric acid and 105wt% oleum in a mass ratio of 1:0.9:0.8 and reacted at 120°C for 5 minutes to obtain a preliminary reaction mass. The preliminary reaction mass was then reacted at 240°C for 85 minutes to produce hydrogen fluoride-containing gas and roasted slag. During the reaction, the hydrogen fluoride-containing gas was passed into a scrubbing tower for scrubbing, condensation, and rectification to obtain anhydrous hydrogen fluoride.

[0091] The calcined slag was subjected to a one-step leaching and filtration process using water in an intelligent high-efficiency filter press to obtain a leachate containing rare earth elements and niobium, as well as a water-leached slag. During the leaching process, the mass ratio of water to calcined slag was 0.12:1.

[0092] The rare earth and niobium-containing leachate is neutralized with magnesium oxide to obtain a neutralized rare earth and niobium-containing leachate and a neutralized slag, wherein the amount of magnesium oxide used is 4.8 wt% of the mass of the monazite-containing fluorite concentrate.

[0093] The water-leached slag is subjected to a superconducting strong magnetic separator at a magnetic field strength of 4.0T to remove impurities such as iron and thorium, and obtain gypsum with higher purity.

[0094] The results are shown in Table 1.

[0095] Example 4

[0096] In the monazite-containing fluorite concentrate used in this embodiment, the CaF2 content is 90.34 wt%, the REO content is 5.74 wt%, the Nb2O5 content is 0.17 wt%, and the P content is 0.82 wt%.

[0097] The fluorite concentrate containing monazite and the iron ore concentrate are mixed in a mass ratio of 1:0.08 and made into balls with a diameter of 2 to 5 mm. The prepared balls are dried at 100° C. for 24 hours to obtain pretreated fluorite concentrate particles.

[0098] The pretreated fluorspar concentrate particles were uniformly mixed with 98wt% concentrated sulfuric acid and 105wt% oleum in a mass ratio of 1:1:0.8 and reacted at 120°C for 5 minutes to obtain a preliminary reaction mass. The preliminary reaction mass was then reacted at 250°C for 70 minutes to produce hydrogen fluoride-containing gas and roasted slag. During the reaction, the hydrogen fluoride-containing gas was passed into a scrubbing tower for scrubbing, condensation, and rectification to obtain anhydrous hydrogen fluoride.

[0099] The calcined slag was subjected to a one-step leaching and filtration process using water in an intelligent high-efficiency filter press to obtain a leachate containing rare earth elements and niobium, as well as a water-leached slag. During the leaching process, the mass ratio of water to calcined slag was 0.18:1.

[0100] The rare earth and niobium-containing leachate is neutralized with magnesium oxide to obtain a neutralized rare earth and niobium-containing leachate and a neutralized slag, wherein the amount of magnesium oxide used is 5.7 wt% of the mass of the monazite-containing fluorite concentrate.

[0101] The water-leached slag is subjected to a superconducting strong magnetic separator at a magnetic field strength of 3.8T to remove impurities such as iron and thorium, and obtain gypsum of higher purity.

[0102] The results are shown in Table 1.

[0103] Comparative Example 1

[0104] The difference from Example 1 is that no iron ore powder is added.

[0105] Comparative Example 2

[0106] The difference from Example 1 is that the mass ratio of the pretreated fluorite concentrate particles to 98 wt % concentrated sulfuric acid and 105 wt % fuming sulfuric acid is 1:1.1:0.4.

[0107] Table 1

[0108] serial number Leaching rate of rare earth % Niobium leaching rate % Purity of gypsum % Example 1 99.3 87.5 93.2 Example 2 97.3 86.4 92.0 Example 3 97.4 87.3 95.0 Example 4 96.1 86.3 93.8 Comparative Example 1 82.6 87.3 90.4 Comparative Example 2 91.7 83.6 89.6

[0109] The present invention is not limited to the above-mentioned embodiments. Any modification, improvement, or substitution that can be conceived by those skilled in the art without departing from the essential content of the present invention shall fall within the scope of the present invention.

Claims

1. A method for treating fluorite concentrate containing monazite, characterized in that: The steps include: 1) mixing fluorite concentrate containing monazite with iron ore concentrate, granulating the mixture, and then drying the mixture to obtain pretreated fluorite concentrate particles; The monazite-containing fluorite concentrate has a CaF2 content greater than 78 wt%, a REO content of 4.5 to 9.5 wt%, a Nb2O5 content of 0.08 to 0.2 wt%, and a P content of 0.5 to 1.4 wt%. Wherein, the mass ratio of the fluorite concentrate containing monazite to the iron ore concentrate is 1:(0.04-0.1); 2) mixing the pretreated fluorspar concentrate particles with sulfuric acid and conducting a preliminary reaction at 100-150° C. for 4-8 minutes to obtain a preliminary reaction mass; reacting the preliminary reaction mass at 220-250° C. for 70-100 minutes to obtain a gas and a roasted slag; wherein the sulfuric acid is a mixture of 98 wt% concentrated sulfuric acid and 105 wt% oleum; and the mass ratio of the pretreated fluorspar concentrate particles, 98 wt% concentrated sulfuric acid, and 105 wt% oleum is 1:(0.75-1.0):(0.6-0.8); 3) leaching the calcined slag with water to obtain a leaching solution containing rare earth and niobium and a water-leached slag; wherein the mass ratio of water to calcined slag is 0.1 to 0.2:1; neutralizing the rare earth and niobium-containing leachate obtained in step 3) with magnesium oxide to obtain a neutralized rare earth and niobium-containing leachate and a neutralized slag; The water-leached residue obtained in step 3) is subjected to magnetic separation using a magnetic separator to obtain calcium sulfate; wherein the magnetic separation intensity is 3.0 to 4.5 T; The leaching rate of rare earth is greater than or equal to 96%, and the leaching rate of niobium is greater than or equal to 85.5%; The purity of the obtained calcium sulfate is greater than or equal to 92wt%.

2. The processing method according to claim 1, characterized in that In step 1), the mass ratio of the monazite-containing fluorite concentrate to the iron ore concentrate is 1:(0.045-0.1).

3. The processing method according to claim 1, characterized in that In step 2), the initial reaction temperature is 100-140°C.

4. The processing method according to claim 1, characterized in that In step 2), the preliminary reaction materials are reacted at 230-250° C. for 70-90 minutes to obtain hydrogen fluoride-containing gas and calcined slag.

5. The processing method according to claim 4, characterized in that: The method further comprises the following steps: washing the hydrogen fluoride-containing gas through a washing tower, and then condensing and rectifying the gas to obtain anhydrous hydrogen fluoride.

6. The processing method according to claim 1, characterized in that The pretreated fluorspar concentrate particles are obtained by pretreatment comprising the following steps: The fluorite concentrate containing monazite is mixed with iron concentrate and made into balls with a diameter of 2 to 5 mm. The prepared balls are dried at 90 to 125° C. for 16 to 40 hours to obtain pretreated fluorite concentrate particles.