A rare earth tailings beneficiation and smelting combined comprehensive utilization process

Abstract

The present invention relates to the field of rare earth tailings recycling and utilization, and discloses a rare earth tailings beneficiation and smelting combined comprehensive utilization process. In view of the problem of low grade of valuable elements in ore samples, a flotation-gravity-magnetic combined process is used to obtain fluorite coarse ore, rare earth concentrate, and strontium-barium concentrate, and then an industrial-grade strontium carbonate product is prepared for the strontium-barium concentrate. In the beneficiation stage, the rare earth tailings are first subjected to gravity separation and desludging treatment, and then mixed flotation is performed to select fluorite, rare earth and strontium-barium ore, and then separation flotation is performed to obtain fluorite coarse ore, and finally rare earth concentrate and strontium-barium concentrate can be obtained after gravity separation and magnetic separation. The present invention combines the properties of rare earth tailings to efficiently enrich the valuable elements in the tailings, greatly improves the comprehensive utilization rate of rare earths, reduces the discharge of tailings, and improves resource utilization efficiency.

Description

Technical Field

[0001] The invention belongs to the field of rare earth tailings recovery and utilization, and specifically relates to a rare earth tailings dressing and smelting combined comprehensive utilization process. Background Art

[0002] my country is a country rich in rare earth resources. The main rare earth production areas in my country are the Bayan Obo mining area in Inner Mongolia, the Panxi mining area in Sichuan, and the Weishan mining area in Shandong. With the mining of rare earth mines in my country, a steady stream of mineral resources has been provided to the country, but long-term mining has also led to the loss of a large number of associated resources in the tailings; niobium, iron, and fluorite in the rare earth tailings in Bayan Obo; fluorite, strontium and barium in the rare earth tailings in Panxi have not been effectively utilized.

[0003] There are two main reasons for the underutilization of rare earth associated resources: First, the grade of rare earth associated resources is generally low, and its value is far lower than the value of rare earth or not up to the industrial grade, so it has no independent development value. Taking the rare earth mines in Panxi area as an example, the fluorite grade in Panxi rare earth mines is generally 10-15%, which is lower than the industrial grade of 20%; the strontium and barium content of rare earth mines is about 10-20%, which is also lower than the 25% lapis lazuli mining grade.

[0004] Secondly, the comprehensive recovery process is difficult. The associated elements can only have a good economic value if they are comprehensively recovered. However, comprehensive recovery involves multi-metal beneficiation. Multi-metal beneficiation is not just about opening an additional beneficiation production line. The impact between different minerals and the separation between minerals are all factors that need to be considered. At present, there are few mines in China that consider the comprehensive utilization of associated elements on the premise that the target minerals can be profitable. This situation directly leads to many problems such as waste of resources, increase in tailings, and environmental pollution.

[0005] At present, the comprehensive utilization of rare earth tailings mainly involves the recovery of fluorite, rare earth, barite, iron niobium and other minerals from rare earth tailings. For example, patent document CN201910099236.8 discloses a method for separating fluorite from rare earth tailings, which obtains CaF 2 Fluorite concentrate with a grade greater than 95%.

[0006] Patent document CN202010587745.8 discloses a method for efficiently recovering rare earth, fluorite and barite from rare earth tailings, specifically: (1) adding 100-600 g / t of water glass, 50-400 g / t of barite inhibitor, and 100-400 g / t of rare earth and fluorite collector to the tailings slurry, and stirring to adjust the slurry; (2) performing mixed flotation preliminary selection, scavenging and concentrating operations to obtain flotation concentrate and flotation tailings; (3) performing strong magnetic preliminary selection and scavenging operations on the flotation concentrate to obtain strong magnetic tailings, which is the final fluorite concentrate; (4) performing rare earth gravity separation roughing and scavenging operations on the strong magnetic concentrate to obtain a rare earth gravity concentration concentrate, which is the final rare earth concentrate; (5) performing barite gravity separation roughing, scavenging, concentrating and scavenging operations on the flotation tailings to obtain a barite gravity concentration concentrate, which is the final barite concentrate.

[0007] Patent document CN201310317707.0 discloses a method for comprehensive recovery of valuable minerals from rare earth tailings, which adopts the method of "rare earth tailings - grinding - weak magnetic separation - weak magnetic tailings into strong magnetic - strong magnetic tailings flotation fluorite - strong magnetic concentrate flotation separation of rare earths, iron and niobium - underflow reduction roasting, weak magnetic separation of iron and niobium - weak magnetic tailings flotation niobium" to efficiently and comprehensively recover rare earths, iron, niobium and fluorite from rare earth tailings.

[0008] However, a method for recovering rare earth concentrate, fluorite concentrate and strontium-barium concentrate from rare earth tailings and preparing industrial-grade strontium carbonate with the recovered strontium-barium concentrate has not been reported. Summary of the invention

[0009] The present invention takes rare earth tailings in a certain place in Panxi as the research object. In addition to rare earths, the rare earth ores in this area are also accompanied by valuable minerals such as fluorite, strontium and barium. The rare earth grade in the tailings is 0.6-0.8%, the fluorite grade is 13-15%, and the total amount of strontium and barium minerals is 18-20%. The grades of fluorite and strontium and barium minerals in the tailings are lower than the industrial mining grade. Combined with the properties of the tailings, only by comprehensively utilizing the fluorite, strontium and barium and rare earth in the tailings can the value of the tailings be maximized.

[0010] The technical difficulties of comprehensive utilization of tailings are mainly:

[0011] (1) Rare earth tailings are seriously muddied. During the rare earth beneficiation process, minerals such as fluorite, strontium and barium have been contaminated by rare earth beneficiation reagents;

[0012] (2) The amount of tailings slurry is large. If all tailings are processed for beneficiation, the production cost will be too high;

[0013] (3) The grades of fluorite and strontium-barium in the tailings are low, and the selectivity of rare earths in the tailings is poorer than that of the original ore, making it difficult to select the target minerals at one time;

[0014] (4) The isomorphism of strontium-barium minerals in the tailings is quite obvious, and the barium content in the selected strontium-barium concentrate is too high and cannot be sold as celestine concentrate;

[0015] In view of the deficiencies in the prior art and the above-mentioned problems, the present invention provides a rare earth tailings beneficiation and smelting combined comprehensive utilization process, which adopts a flotation-gravity-magnetic combined process to obtain fluorite coarse ore, rare earth concentrate, and strontium-barium concentrate, and then optimizes the double decomposition process of the strontium-barium concentrate to prepare an industrial-grade strontium carbonate product, which greatly improves the comprehensive utilization rate of rare earths, reduces the discharge of tailings, and improves resource utilization efficiency.

[0016] The objective of the present invention is achieved through the following technical solutions:

[0017] A rare earth tailings beneficiation and smelting combined comprehensive utilization process, comprising the following steps:

[0018] S1. Pretreatment: The rare earth tailings are subjected to gravity separation and desludging to obtain coarse ore and tailings;

[0019] S2. Mixed flotation: The coarse ore is mixed and flotated to obtain a mixed flotation concentrate and mixed flotation tailings;

[0020] The pH value of the mixed flotation pulp is 9-10, water glass, sodium carbonate and lignin are used as a combined inhibitor, sodium hydroxide is used as a pH adjuster, and cotton oleic acid is used as a collector;

[0021] S3. Separation flotation: The mixed flotation concentrate is separated by flotation to obtain fluorite coarse ore and separation tailings;

[0022] During the separation flotation, sulfuric acid is used to adjust the ore pulp to a pH value of 5.5-6, and the flotation reagents are tannin extract and strontium-barium inhibitor;

[0023] Wherein, the strontium barium inhibitor is compounded by lignosulfonic acid, sodium fluoride and dextrin;

[0024] S4. Gravity separation: performing a gravity separation operation on the separated tailings to obtain a gravity separation ore, a gravity separation concentrate and a gravity separation tailings, wherein the gravity separation ore is a strontium barium concentrate;

[0025] S5. Magnetic separation: subjecting the re-separated concentrate to magnetic rare earth separation to obtain rare earth concentrate and magnetic tailings, wherein the magnetic tailings are also strontium-barium concentrate.

[0026] Furthermore, in step S1, the desliming treatment includes two or more gravity desliming steps.

[0027] Furthermore, in step S1, the coarse ore obtained is ground before the second and subsequent gravity separation and desliming.

[0028] After the rare earth tailings are subjected to desliming I treatment, tailings I and coarse ore are obtained. The coarse ore is ground to a fineness of -200 mesh, 82-84%, and then desliming II step is performed to obtain tailings II and coarse ore.

[0029] Furthermore, in step S2, the mixed flotation includes at least one roughing selection, two cleaning selections and one scavenging selection;

[0030] During the rough selection, the amount of water glass used is 1200-1500 g / t, the amount of sodium carbonate used is 1000-1200 g / t, the amount of sodium hydroxide used is 300-400 g / t, the amount of lignin used is 50-80 g / t, and the amount of cottonseed acid used is 300-400 g / t.

[0031] Furthermore, in step S3, the fluorite crude ore is subjected to fluorite concentration operation to obtain fluorite concentrate;

[0032] and / or, in step S3, the separation flotation process comprises at least one roughing and seven cleaning processes;

[0033] During the roughing, the amount of tannin extract is 250-300 g / t, and the amount of strontium-barium inhibitor is 500-600 g / t.

[0034] Furthermore, in step S3, the mass ratio of the strontium barium inhibitor lignosulfonic acid, sodium fluoride and dextrin is 4-5:2:3-4.

[0035] Furthermore, in step S4, the re-selection operation adopts a shaking table method.

[0036] Furthermore, in step S5, the magnetic field strength of the rare earth magnetic separation operation is 1-1.3T.

[0037] Furthermore, the strontium-barium concentrate can be used to prepare industrial-grade strontium carbonate, and the steps of preparing industrial-grade strontium carbonate from the strontium-barium concentrate are:

[0038] 1) Pickling: using industrial concentrated hydrochloric acid to pickle the strontium barium concentrate to remove impurities, and filtering after pickling to obtain the pickled strontium barium concentrate and pickling waste liquid; the concentration of the ore pulp during the pickling is 55%-65%, the pH value is 2-2.5, and the pickling time is 25-30 minutes;

[0039] 2) Double decomposition reaction: Add Na to the acid washed strontium barium concentrate 2 CO 3 Perform double decomposition reaction and filter to obtain crude strontium carbonate and sodium sulfate waste liquid;

[0040] Among them, the Na 2 CO 3The molar amount is 1.2-1.3 times the molar amount of strontium in the acid-washed strontium barium concentrate, the concentration of the ore pulp during the double decomposition reaction is 45%-55%, the reaction temperature is 85-90°C, and the reaction time is 3-3.5 hours;

[0041] 3) Acid dissolution: The crude strontium carbonate is acid-dissolved using hydrochloric acid, and filtered after acid dissolution to obtain a filtrate and leached residue 1; the concentration of the ore pulp in the acid dissolution operation is 55%-65%, the pH value is 2.5-3, and the time of the acid dissolution operation is 0.5-1 hour;

[0042] 4) Removing metal ions: adjusting the pH value of the filtrate to 6-8 using ammonia water, and filtering to obtain strontium solution and leaching residue 2;

[0043] 5) Removing barium: adding ammonium sulfate to the strontium solution, filtering to remove strontium barium sulfate slag; the molar amount of the ammonium sulfate is 0.15-0.2 times the molar amount of barium in the acid-washed strontium barium concentrate;

[0044] 6) Precipitation of strontium carbonate: adding ammonium bicarbonate to the strontium solution, filtering to obtain strontium carbonate, and washing with deionized water to obtain a strontium carbonate product; wherein the molar amount of the ammonium bicarbonate is 0.9-1 times the molar amount of strontium in the acid-washed strontium barium concentrate.

[0045] Furthermore, in step 6), the number of times of washing with deionized water is 1-2 times.

[0046] In step S2 and step S3 of the present scheme, the reagents for mixed flotation and separation flotation only provide the dosage range for roughing. This is because the reagents for roughing and scavenging are generally adjusted on site and the dosage is very small. In production, blank roughing or scavenging is generally used directly.

[0047] In view of the slime formation of tailings, this scheme sets up at least two desliming operations in the mineral processing process. The first desliming operation is carried out before grinding. The main purpose is to remove the primary ore slimes such as clay in the tailings. Due to the high hardness of fluorite and the high specific gravity of strontium barium and rare earth minerals, the use of gravity separation desliming can ensure that the loss rate of the target minerals is small. The one-time desliming operation also reduces the processing volume of subsequent grinding and reduces production energy consumption. The grinding operation grinds the tailings to a fineness of -200 mesh, 78-85%, which is the flotation fineness. At the same time, it can also effectively remove the tailings after the first desliming. The secondary desliming operation after grinding can remove some secondary ore slimes and further remove residual reagents.

[0048] After pretreatment, the mud content and reagent residue of the tailings have been significantly improved. Since the mine is a rare earth tailing, it is not very meaningful to prioritize the flotation of rare earths. At the same time, the use of hydroxamic acid in rare earth flotation has a large environmental pollution. Therefore, mixed flotation is directly adopted, using water glass, sodium carbonate, and lignin as inhibitors, and sodium hydroxide as a pH adjuster. Among them, water glass has a good inhibitory effect on quartz and silicate minerals, and sodium carbonate has a certain inhibitory effect on carbonate minerals in minerals. The role of sodium hydroxide is to adjust the pulp to pH = 9.5. Lignin is a commonly used inhibitor, which inhibits more types of gangue, and cotton oleic acid is a collector. The mixed flotation process of one rough, one sweep and two fines is adopted, and the mixed flotation yield reaches 40-50%, which ensures the recovery rate of the target mineral. At the same time, the flotation tailings can be discarded earlier, further reducing the processing volume of subsequent operations.

[0049] This scheme separates and selects fluorite-strontium barium-rare earth in order. The rare earth content in the mixed concentrate is low, and the gangue minerals are mainly a small amount of carbonate minerals. Fluorite has good selectivity. The pulp is adjusted to weak acidity with sulfuric acid, and the amount of sulfuric acid is 1200-1500g / t. Tannin extract and strontium barium inhibitor can separate fluorite from the mixed concentrate. Among them, strontium barium inhibitor has a good inhibitory effect on strontium barium sulfate, and tannin extract has a good inhibitory effect on carbonates and rare earths. The pH value of the pulp is adjusted from alkaline to acidic, with the purpose of discarding a small amount of alkaline gangue with good floatability.

[0050] After the fluorite coarse ore is separated, the fluorite concentrate can be obtained by concentrating. At this time, rare earth, strontium barium and a small amount of carbonate are enriched in the separated tailings. Since the density of carbonate is relatively small, and the density of strontium barium and rare earth is relatively large, the above minerals can be separated by gravity separation. Using the shaking table operation, three products are obtained, among which the shaking table tailings are mainly carbonate minerals and can be directly discarded, the shaking table middlings are strontium barium concentrates, and the shaking table concentrates are strontium barium concentrates enriched with rare earths. The shaking table concentrates can be subjected to strong magnetic separation to obtain rare earth concentrates, and the magnetic separation tailings are also strontium barium concentrates.

[0051] At present, the mainstream processes for preparing strontium carbonate are carbon reduction method and double decomposition method, among which carbon reduction method is the mainstream industrial production method. Since the isomorphism of strontium barium minerals in the tailings of this scheme is relatively obvious, it is difficult to obtain high-purity strontium carbonate by carbon reduction method, so double decomposition method can only be used as the basic process for preparing strontium carbonate. Since there are still a small amount of carbonate minerals remaining in the strontium barium concentrate obtained by the shaking table and magnetic separation of this scheme, and the barium content in the separated strontium barium concentrate reaches more than 15%, even if the double decomposition method is used, the barium content of the final product will exceed the standard. Therefore, before the double decomposition process, this scheme carries out acid washing treatment on the strontium barium concentrate to achieve pre-impurity removal, and at the same time, after double decomposition, ammonium sulfate is used to remove barium, and the barium ions in the strontium solution are removed to ensure the purity of the final product strontium carbonate.

[0052] The beneficial effects of the present invention are:

[0053] 1. The pretreatment process of desliming-grinding-re-desliming is adopted to reduce the flotation processing capacity, remove a large amount of residual reagents, and improve the dissociation degree of the target mineral. The flotation processing capacity can also be stabilized by adjusting the desliming amount;

[0054] 2. Use mixed flotation to concentrate the valuable minerals in the tailings, achieve early tailings disposal, and reduce the subsequent processing volume;

[0055] 3. Utilizing the properties of each target mineral, we can flotate fluorite, re-select strontium and barium concentrate, and magnetically select rare earth concentrate;

[0056] 4. Based on the traditional double decomposition process, pre-impurity removal and barium removal are introduced to obtain qualified strontium carbonate products. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a flow chart of the principle of rare earth tailings beneficiation;

[0058] Figure 2 A process for preparing strontium carbonate from strontium barium concentrate. DETAILED DESCRIPTION

[0059] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0060] 10kg of rare earth tailings from Dechang County, Panxi were tested. The results showed that the fluorite grade in the tailings was 13.6%, the SrO+BaO grade was 10.45%, and the rare earth REO grade was 0.69%. (The main minerals of strontium and barium in the tailings are strontium sulfate and barium sulfate. For the convenience of calculation, the mineral processing operation is calculated according to the SrO+BaO grade)

[0061] Example 1: Pretreatment

[0062] Take 10kg of rare earth tailings and perform a shaking table desludging operation to obtain coarse ore (for grinding) and tailings I (desludging buckets or other equipment can also be used for desludging in actual production). The desludging results are shown in Table 1. The calculation formula for the recovery rate of the amount of ore entering the grinding is: (yield of ore entering the grinding * grade of ore entering the grinding) / (feed yield * feed grade).

[0063] Table 1 Results of a desludging test / %

[0064]

[0065] As shown in Table 1, about 21% of the tailings were removed by desludging, and 7 kg of ore was taken for grinding for subsequent tests:

[0066] 500g of the sample was taken for grinding test, and the grinding fineness was -200 mesh, 82-84%. After the grinding time was determined, 5kg of the sample was taken and divided into 10 groups, and all were ground to the appropriate fineness.

[0067] The coarse ore after grinding is subjected to secondary desludging by sedimentation desludging (in practice, it can also be carried out by desludging bucket or other desludging equipment) to obtain flotation ore (also coarse ore) and tailings II. The results of the secondary desludging operation are shown in Table 2. The calculation formula for the recovery rate of flotation ore is: (flotation ore yield*flotation ore grade) / (grinding ore yield*grinding ore grade).

[0068] Table 2 Secondary desludging test results / %

[0069]

[0070] As shown in Table 2, the operating yield of tailings in the secondary desludging operation is 12.87%, which is about 10% when calculated back to the original ore. The mineral fineness after desludging is between -200 mesh and 80-82%, which is the flotation fineness.

[0071] Through the desludging-grinding-desludging operation, about 30% of the tailings are discarded, of which the total recovery rate of fluorite is about 89.5%, the recovery rate of strontium and barium is about 92%, and the recovery rate of rare earth is about 89%. The loss of target minerals is not large. The desludging effect is good.

[0072] Example 2: Mixed flotation

[0073] The 10 groups of rough ores (float samples) in Example 1 were subjected to a mixed flotation closed-circuit test. The test process was one roughing, one sweeping and three fines. During the roughing, the pH value of the pulp was adjusted to 9.5 using sodium hydroxide. The inhibitor dosage was: 1200 g / t of water glass, 300 g / t of sodium hydroxide, and 60 g / t of lignin; the collector dosage was: 300 g / t of cotton oleic acid. The mixed flotation concentrate obtained in the test was not tested, and the mixed flotation tailings (tailings III) were tested to infer the concentrate results. The results given in Table 3 are the average test results of the mixed flotation tailings of groups 3-10 in the closed-circuit test.

[0074] Table 3 Mixed flotation test results / %

[0075]

[0076] Due to the low grade of rare earth ore, the recovery rate of rare earth is relatively low, but the enrichment effect is still relatively obvious.

[0077] Example 3: Separation of flotation, gravity separation and magnetic separation

[0078] The mixed flotation concentrate obtained in Example 2 was subjected to separation flotation operation. During roughing, sulfuric acid was first used to adjust the pH value of the pulp to 5.5-6, and the amount of sulfuric acid was 1200-1500 g / t. Strontium barium inhibitor and tannin extract were then added, and the amount of strontium barium inhibitor for roughing was 280 g / t, and the amount of strontium barium inhibitor was 500 g / t.

[0079] Fluorite coarse ore was separated and subjected to 8 fluorite concentration operations to obtain fluorite concentrate with a grade of 93.34%. Separated tailings were also obtained.

[0080] After fluorite flotation, the tailings are separated and shaken. The shaking table operation produces three products. Among them, carbonate minerals are mostly enriched in tailings IV (gravity separation tailings) due to their light weight. Tailings IV can be directly discarded. The shaking table middlings (gravity separation middlings) are strontium-barium concentrates. Rare earths are enriched in the shaking table concentrates (gravity separation concentrates) due to their large specific gravity. The shaking table concentrates are subjected to strong magnetic separation with a magnetic field strength of 1.2T to obtain a rare earth concentrate with a grade of about 30%. The magnetic separation tailings are still used as strontium-barium concentrates. The indicators of each product of the separation operation are shown in Table 4.

[0081] Table 4 Separation operation product indicators

[0082]

[0083] Example 4: Preparation of industrial grade strontium carbonate

[0084] The shaking table ore and magnetic tailings obtained in Example 3 were combined as strontium barium concentrate to prepare strontium carbonate. The grade of SrO+BaO in the strontium barium concentrate was calculated to be 51.52%. The SrO content in the strontium barium concentrate was 34.17%, the BaO content was 17.35%, and the total amount of strontium barium minerals was about 87%. Take 200g of strontium barium concentrate, add water to adjust the slurry to a concentration of 60%, add concentrated hydrochloric acid to adjust the pH value to 2-2.5, stir for 30 minutes, and completely remove the remaining carbonate in the mineral. After washing and filtering, adjust the slurry to a concentration of 50%, add 90g of sodium carbonate, and stir the reaction in a water bath at 90°C for 3h.

[0085] After the double decomposition reaction is completed, wash and filter, slurry the crude strontium carbonate ore to 60% concentration, add concentrated hydrochloric acid, adjust the pH value to 2.5-3, continue the reaction for 30 minutes, and filter out the leaching residue 1. Add ammonia water to the strontium chloride solution to adjust the pH value to 7-8, and filter to obtain the leaching residue 2. Add 5g of ammonium sulfate to the strontium chloride solution, stir to react fully, and filter to obtain strontium sulfate barium slag. Add 80g of ammonium bicarbonate to the strontium chloride solution, stir until completely precipitated, and filter to obtain strontium carbonate. Wash the strontium carbonate again with deionized water and filter to obtain the strontium carbonate product. The indicators of strontium carbonate products are shown in Table 5:

[0086] Table 5 Strontium carbonate product indicators

[0087] element <![CDATA[SrCO 3 ]]> <![CDATA[BaCO 3 ]]> <![CDATA[CaCO 3 ]]> <![CDATA[Na 2 The]]> Cl <![CDATA[Fe 2 THE 3 ]]> other content / % 97.23 1.17 0.89 0.27 0.24 0.02 0.1-0.2

[0088] The purity of strontium carbonate in the product is greater than 97%, which has reached the industrial strontium carbonate standard. A total of 80.76g of strontium carbonate was produced, and the recovery rate of strontium element reached 80.65%. The specific gravity of the leached residue 1 was measured to be 4.21, which can be used as a weighting agent.

[0089] Data collation of the embodiments: By calculating the operating efficiency of the above embodiments, it is found that 63.19% of fluorite, 70.45% of strontium barium, and 19.39% of rare earth can be recovered from the rare earth tailings through the ore dressing process. The low rare earth recovery rate is mainly because the rare earth grade in the tailings is only 0.69%, which is basically not worth re-selecting rare earths. However, the rare earths are simultaneously enriched during the ore dressing process, and some rare earths are still recovered.

[0090] In the process of preparing strontium carbonate from strontium barium concentrate, the recovery rate of strontium element exceeds 80%, and the yield is 40.38%. If the recovery rate of strontium in the ore dressing operation is also considered to be 70.45%, the overall recovery rate of strontium element is 56.82%.

[0091] Table 6 Rare earth tailings production rate and target mineral recovery rate

[0092]

[0093] Feasibility calculation of the scheme: Since the rare earth, fluorite and strontium barium in the original ore do not have the value of independent development and utilization, a preliminary economic estimate of the process is now carried out using the tailings as an example to verify the economic feasibility of the process.

[0094] According to the current daily tailings production of 2,000 tons in the mine, the output of each product is:

[0095] Fluorite: 2000×11.86%=237.2 tons.

[0096] Rare earth: 2000×0.34%=6.8 tons

[0097] Strontium carbonate: 2000×18.4%×40.38%=148.6 tons

[0098] The price of fluorite is 1,600 yuan / ton, the price of rare earth is 25,000 yuan / ton, and the price of strontium carbonate is currently around 12,000-14,000 yuan per ton. The benefits of each mineral are calculated at 10,000 yuan / ton:

[0099] Fluorite: 237.2×1600=379,500 yuan

[0100] Rare earth: 6.8×25000=170,000 yuan

[0101] Strontium carbonate: 148.6×10000=1.486 million yuan

[0102] Total 379,500+17+148,600=2,035,500 yuan

[0103] The cost of reagents and water and electricity per ton of strontium carbonate is calculated at 4,000 yuan, and the production cost of 148.6 tons of strontium carbonate is 594,400 yuan. The economic value can be generated daily 148.6-59.44 = 891,600 yuan. The economic benefit of each ton of tailings can be 445.8 yuan. At present, in the mineral processing production, the production cost of one ton of raw ore is mostly between 300-400 yuan, and the production cost of tailings reselection can be controlled between 200-300 yuan, which shows that the economic space is large. If strontium-barium mineral beneficiation is not carried out, the economic benefit generated by fluorite and rare earth is 549,500 yuan, which is equivalent to 2,747,500 yuan per ton of tailings. Even if the cost of desludging I is discarded, according to the calculation of 1,600 tons of tailings per day, the profit generated by each ton of ore is only 343.44 yuan. If the initial investment is too high, the economic benefit is also low.

[0104] The above economic budget verifies the technical feasibility and economic feasibility of the technology. The patented combined beneficiation and smelting process can maximize the economic benefits of the tailings. According to the concentrate yield, this process can reduce the tailings discharge rate by 30%. Under the premise of comprehensive resource utilization, the impact on the environment is reduced. It has good economic efficiency and feasibility.

[0105] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A rare earth tailings beneficiation and smelting combined comprehensive utilization process, It is characterized in that The following steps are involved: S1. Pretreatment: The rare earth tailings are subjected to gravity separation and desludging to obtain coarse ore and tailings; S2. Mixed flotation: The coarse ore is mixed and flotated to obtain a mixed flotation concentrate and mixed flotation tailings; The pH value of the mixed flotation pulp is 9-10, water glass, sodium carbonate and lignin are used as a combined inhibitor, sodium hydroxide is used as a pH regulator, and cotton oleic acid is used as a collector; S3. Separation flotation: The mixed flotation concentrate is separated by flotation to obtain fluorite coarse ore and separation tailings; During the separation flotation, sulfuric acid is used to adjust the ore pulp to a pH value of 5.5-6, and the flotation reagents are tannin extract and strontium-barium inhibitor; Wherein, the strontium barium inhibitor is compounded by lignosulfonic acid, sodium fluoride and dextrin; S4. Gravity separation: performing a gravity separation operation on the separated tailings to obtain a gravity separation ore, a gravity separation concentrate and a gravity separation tailings, wherein the gravity separation ore is a strontium barium concentrate; S5. Magnetic separation: subjecting the re-separated concentrate to magnetic rare earth separation to obtain rare earth concentrate and magnetic tailings, wherein the magnetic tailings are also strontium-barium concentrate.

2. A rare earth tailings dressing and smelting combined comprehensive utilization process according to claim 1, It is characterized in that In step S1, the desliming treatment includes two or more gravity desliming steps.

3. A rare earth tailings dressing and smelting combined comprehensive utilization process according to claim 2, It is characterized in that In step S1, the coarse ore obtained is ground before the second and subsequent gravity separation and desliming.

4. A rare earth tailings dressing and smelting combined comprehensive utilization process according to claim 1, It is characterized in that In step S2, the mixed flotation includes at least one roughing selection, two cleaning selections and one scavenging selection; Wherein, during the rough selection, the amount of water glass used is 1200-1500 g / t, the amount of sodium carbonate used is 1000-1200 g / t, the amount of sodium hydroxide used is 300-400 g / t, the amount of lignin used is 50-80 g / t, and the amount of cottonseed acid used is 300-400 g / t.

5. A rare earth tailings dressing and smelting combined comprehensive utilization process according to claim 1, It is characterized in that In step S3, the fluorite crude ore is subjected to fluorite concentration operation to obtain fluorite concentrate; and / or, in step S3, the separation flotation process comprises at least one roughing and seven cleaning processes; Wherein, during the rough selection, the amount of tannin extract is 250-300 g / t, and the amount of strontium barium inhibitor is 500-600 g / t.

6. A rare earth tailings dressing and smelting combined comprehensive utilization process according to claim 1, It is characterized in that In step S3, the mass ratio of the strontium-barium inhibitor lignosulfonic acid, sodium fluoride and dextrin is 4-5:2:3-4.

7. A rare earth tailings dressing and smelting combined comprehensive utilization process according to claim 1, It is characterized in that In step S4, the re-selection operation adopts a shaking table method.

8. A rare earth tailings dressing and smelting combined comprehensive utilization process according to claim 1, It is characterized in that In step S5, the magnetic field strength of the rare earth magnetic separation operation is 1-1.3T.

9. A rare earth tailings dressing and smelting combined comprehensive utilization process according to claim 1, It is characterized in that The strontium-barium concentrate can be used to prepare industrial-grade strontium carbonate. The steps of preparing industrial-grade strontium carbonate from the strontium-barium concentrate are as follows: 1) Pickling: using industrial concentrated hydrochloric acid to pickle the strontium barium concentrate to remove impurities, and filtering after pickling to obtain the pickled strontium barium concentrate and pickling waste liquid; the concentration of the ore pulp during the pickling is 55%-65%, the pH value is 2-2.5, and the pickling time is 25-30 minutes; 2) Double decomposition reaction: Add Na to the acid washed strontium barium concentrate 2 CO 3 Perform double decomposition reaction and filter to obtain crude strontium carbonate and sodium sulfate waste liquid; Among them, the Na 2 CO 3 The molar amount is 1.2-1.3 times the molar amount of strontium in the acid-washed strontium barium concentrate, the concentration of the ore pulp during the double decomposition reaction is 45%-55%, the reaction temperature is 85-90°C, and the reaction time is 3-3.5 hours; 3) Acid dissolution: The crude strontium carbonate is acid-dissolved using hydrochloric acid, and filtered after acid dissolution to obtain a filtrate and leached residue 1; the concentration of the ore pulp in the acid dissolution operation is 55%-65%, the pH value is 2.5-3, and the time of the acid dissolution operation is 0.5-1 hour; 4) Removing metal ions: adjusting the pH value of the filtrate to 6-8 using ammonia water, and filtering to obtain strontium solution and leaching residue 2; 5) Removing barium: adding ammonium sulfate to the strontium solution, filtering to remove strontium barium sulfate slag; the molar amount of the ammonium sulfate is 0.15-0.2 times the molar amount of barium in the acid-washed strontium barium concentrate; 6) Precipitation of strontium carbonate: adding ammonium bicarbonate to the strontium solution, filtering to obtain strontium carbonate, and washing with deionized water to obtain a strontium carbonate product; wherein the molar amount of the ammonium bicarbonate is 0.9-1 times the molar amount of strontium in the acid-washed strontium barium concentrate.

10. A rare earth tailings dressing and smelting combined comprehensive utilization process according to claim 9, It is characterized in that In step 6), the number of times of washing with deionized water is 1-2 times.

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