A heating and cleaning method for low-grade scheelite rough concentrate
By using sodium hydroxide, water glass, and molecular sieve activating powder as de-drying agents under high temperature conditions, and combining them with specific flotation equipment, the problem of separating scheelite from calcium-bearing gangue minerals was solved, achieving low-cost and high-efficiency scheelite recovery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LUOYANG ZHENBEI IND & TRADE CO LTD
- Filing Date
- 2023-12-05
- Publication Date
- 2026-06-23
AI Technical Summary
Existing technologies for scheelite recycling suffer from high energy consumption and high costs. In particular, the heating and beneficiation process makes it difficult to effectively separate scheelite from calcium-bearing gangue minerals. Furthermore, existing de-drying agents, such as 2D layered MoS2 nanosheets, affect the concentrate grade.
Under high temperature conditions, sodium hydroxide, water glass, and molecular sieve activation powder are added sequentially as desiccant. Through competitive adsorption and desorption, the desiccant efficiency is improved. Combined with flotation column and aerated stirring flotation machine, the flotation process is optimized.
While reducing production costs, it improved the grade and recovery rate of scheelite concentrate, ensuring the efficient recycling and utilization of scheelite.
Smart Images
Figure CN117463509B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of mineral processing technology, specifically to a heating and beneficiation method for low-grade scheelite rough concentrate. Background Technology
[0002] Scheelite is a primary target for tungsten resource development and utilization. However, due to its low ore grade, fine grain size, and complex gangue types, its recovery and utilization are challenging, especially the flotation separation of scheelite from calcium-bearing gangue minerals such as calcite and fluorite. Research has found that the difficulty in flotation separation of scheelite, fluorite, calcite, and other calcium-bearing minerals lies in the fact that they are all soluble salt minerals with similar calcium atom active sites and similar surface physicochemical properties. Furthermore, WO4 dissolved in the slurry... 2- F - CO3 2- Plasma can also adsorb and migrate on mineral surfaces, further complicating separation.
[0003] Currently, the main process for recovering and utilizing scheelite is "room temperature roughing followed by heated cleaning." Under high-temperature conditions, water glass and sodium oleate compete for adsorption on the mineral surface. The desorption rate of sodium oleate on fluorite and calcite surfaces increases, thus inhibiting the adsorption of fluorite and calcite. Meanwhile, a large amount of sodium oleate remains adsorbed on the scheelite surface, maintaining good floatability. However, the heated cleaning process is energy-intensive and requires a large amount of water glass, accounting for approximately 50% of the total cost of the flotation process. Taking Luanchuan, Henan Province as an example, the local molybdenum flotation tailings contain scheelite with a WO3 grade of 0.04–0.12%. Room temperature flotation in the roughing stage yields a rough scheelite concentrate with a WO3 grade of approximately 1%, a CaF2 grade of approximately 20%, and a CaCO3 grade of approximately 30%. This concentrate then enters the heated cleaning stage for further flotation, ultimately obtaining a scheelite concentrate with a WO3 grade greater than 20%. The recovery rate of the heated cleaning stage is over 90%, indicating that there is still room for further optimization of the heated cleaning indicators.
[0004] Chinese patent (CN 112676043 B) discloses a method for improving the effect of heated flotation of scheelite, using 2D layered MoS2 nanosheets as a de-removing agent. 2D layered MoS2 nanosheets, as a flotation de-removing agent, have a large specific surface area and abundant active sites, which can adsorb the residual reagents from the roughing flotation of scheelite, removing the influence of residual reagents on the heated flotation of scheelite, greatly improving the problem of poor separation between scheelite and gangue minerals in heated flotation of scheelite, and significantly reducing the amount of water glass used. However, in this technical solution, 2D layered MoS2 nanosheets are strongly hydrophobic materials, which can affect the final concentrate grade; and MoS2 nanosheets are also expensive.
[0005] Therefore, improving the efficiency of heating and beneficiation to reduce the cost of scheelite resource recovery and utilization, and stabilizing the recovery index of calcareous gangue scheelite, is of great significance for ensuring the development and utilization of tungsten resources. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide a heating and beneficiation method for low-grade scheelite rough concentrate, which can ensure the grade of scheelite concentrate, take into account the recovery rate of scheelite, and reduce production costs.
[0007] The technical solution of the present invention is as follows:
[0008] A heated beneficiation method for low-grade scheelite rough concentrate, wherein the WO3 grade of the low-grade scheelite rough concentrate is 0.8-2.0%, the heated beneficiation method includes the following steps:
[0009] Step S1: Concentrate the scheelite crude concentrate to 50-70 wt%, pump it into a mixing tank, and heat it with steam.
[0010] Step S2: Heat the scheelite rough concentrate to 85-95℃, and add sodium hydroxide, water glass, and molecular sieve activation powder in sequence under stirring. Continue to keep warm and stir for 25-45 minutes to remove the collector from the surface of the calcium-containing gangue minerals. The amount of sodium hydroxide is 0-300 g / t, the amount of water glass is 35-55 kg / t, and the amount of molecular sieve activation powder is 200-2000 g / t.
[0011] Step S3: After the reagent removal is completed, room temperature water is added to dilute the scheelite rough concentrate to 20-30 wt% and then it enters the flotation system. After one roughing, two cleaning and three scavenging processes, scheelite concentrate with WO3 grade of more than 30% is obtained, and the recovery rate of the whole process is more than 95%. The roughing and cleaning processes use flotation columns, and the scavenging process uses an aerated stirring flotation machine.
[0012] Furthermore, the molecular sieve activation powder is selected from one of 3A, 4A or 5A molecular sieves.
[0013] Furthermore, in low-grade scheelite rough concentrate, the grade of calcareous gangue CaF2 is 10-40%, and the grade of CaCO3 is 10-43%.
[0014] Furthermore, in step S2, the stirring time is 4-5 minutes after the addition of sodium hydroxide, 6-8 minutes after the addition of water glass, and 5-6 minutes after the addition of molecular sieve activation powder.
[0015] In the heated purification method of this invention, during the de-chemical treatment step, sodium hydroxide, water glass, and molecular sieve activation powder are added sequentially under high temperature conditions. The sodium hydroxide is added first to rapidly increase the pH of the slurry, followed by the addition of water glass. The synergistic effect of these two additives prevents the hydrolysis of water glass (Na₂SiO₃) to produce H₂SiO₃ colloids, while promoting the hydrolysis of water glass to produce more HSiO₃. - and SiO3 2- Silicon-containing monomers compete with sodium oleate adsorbed on the surface of calcium-containing gangue, causing most of the sodium oleate on the surface of calcium-containing gangue to desorb; at the same time, a hydrophilic surface is formed on the surface of gangue minerals, and the added molecular sieve activation powder adsorbs the desorbed sodium oleate. The fixative groups in sodium oleate interact with the molecular sieve activation powder to prevent secondary adsorption on the surface of gangue minerals.
[0016] The hydrolysis reaction of water glass is as follows:
[0017] SiO3 2- +H₂O=HSiO₃ - +OH -
[0018] HSiO3 - +H₂O=H₂SiO₃+OH -
[0019] Compared with existing technologies, the heating and beneficiation method for low-grade scheelite rough concentrate provided by this invention has the following advantages:
[0020] I. The heating and beneficiation method for low-grade scheelite rough concentrate provided by this invention involves sequentially adding sodium hydroxide, water glass, and molecular sieve activation powder as de-agents under high-temperature conditions. Water glass competes with sodium oleate adsorbed on the surface of calcareous gangue, causing sodium oleate to desorb. However, during stirring, sodium oleate may re-adsorb onto the calcareous gangue surface, reducing de-agent efficiency. Molecular sieve activation powder, with its porous structure, possesses excellent adsorption performance and a large specific surface area. Adding it during the heating and de-agent process adsorbs sodium oleate desorbed from the surfaces of fluorite and calcite, preventing re-adsorption onto the calcareous gangue surface and improving de-agent efficiency. Furthermore, the main chemical components of the molecular sieve activation powder are silicates or aluminosilicates; even if sodium oleate is adsorbed, it is easily suppressed by water glass, preventing it from floating and affecting the final scheelite concentrate grade.
[0021] II. The heating and beneficiation method for low-grade scheelite rough concentrate provided by the present invention involves adding sodium hydroxide in the descaling process under high temperature conditions, which can quickly synergistically react with water glass, thereby enhancing the desorption of sodium oleate and the inhibition of gangue minerals.
[0022] Third, the heating and beneficiation method for low-grade scheelite rough concentrate provided by this invention uses flotation columns for roughing and beneficiation, which helps to shorten the flotation process, increase the throughput, and reduce production costs; while the scavenging uses an aerated stirring flotation machine, which can increase the probability of collision between bubbles and mineral particles and the foam travel is short, ensuring that overly coarse and overly fine particles that are difficult to be beneficiated float effectively, and ensuring the recovery rate of heating and beneficiation. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a schematic flowchart of the heating and selection method of the present invention. Detailed Implementation
[0025] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, and to make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described below.
[0026] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0027] Example 1
[0028] The grade of wollastonite rough concentrate is 0.8% WO3, the grade of the main calcareous gangue CaF2 is 26%, and the grade of CaCO3 is 43%.
[0029] For the scheelite rough concentrate in this embodiment, the heating and beneficiation method includes the following steps:
[0030] Step S1: Concentrate the scheelite crude concentrate to 68 wt%, pump it into a mixing tank, and heat it with steam.
[0031] Step S2: Heat the scheelite concentrate to 90°C, and add sodium hydroxide, water glass, and molecular sieve activation powder sequentially under stirring. Continue stirring for 45 minutes to remove the collector from the surface of the calcium-containing gangue minerals. The amount of sodium hydroxide is 300 g / t, and the stirring time is 5 minutes after its addition. The amount of water glass is 55 kg / t, and the stirring time is 6 minutes after its addition. The molecular sieve activation powder is 4A molecular sieve activation powder, and the amount is 2000 g / t. The stirring time is 6 minutes after its addition.
[0032] Step S3: After the reagent removal is completed, room temperature water is added to dilute the scheelite rough concentrate to 25 wt% and enter the flotation system. After one roughing, two cleaning and three scavenging processes, the scheelite concentrate is obtained. The roughing and cleaning processes use flotation columns, and the scavenging process uses an aerated stirring flotation machine.
[0033] Comparative Examples 1-5
[0034] The grade of the scheelite rough concentrate was the same as in Example 1, but different heating and refining parameters were used to obtain Comparative Examples 1-5.
[0035] The heating and refining processes of Comparative Examples 1-5 are shown in Table 1, and the heating and refining effects of Example 1 and Comparative Examples 1-5 are shown in Table 1.
[0036] Table 1: Selected heating parameters and effects of Example 1 and Comparative Examples 1-5
[0037]
[0038]
[0039] As shown in Table 1:
[0040] In Comparative Example 1, the heating and desiccant removal process did not involve the addition of molecular sieve activating powder, resulting in low desiccant removal efficiency. The grade of the obtained scheelite concentrate was only 25%, and the recovery rate was also lower than that of Example 1.
[0041] In Comparative Example 2, without adding molecular sieve activating powder, increasing the amount of water glass increased the grade of scheelite concentrate to over 30%, but the recovery rate further decreased compared to Comparative Example 1.
[0042] Comparative Example 3: The entire flotation process was carried out using flotation machines, and all other conditions were exactly the same as in Example 1. However, the number of cleaning cycles was increased, the process was lengthened, and the grade and recovery rate of the obtained scheelite concentrate were lower than those in Example 1.
[0043] Comparative Example 4: The entire flotation process used flotation columns, and other conditions were exactly the same as in Example 1. The grade of the scheelite concentrate obtained was greater than 30%, but the recovery rate was less than 90%. The grade and recovery rate of the scheelite concentrate obtained were both lower than those in Example 1.
[0044] Comparative Example 5, where the heating temperature was reduced to 60°C while other conditions remained identical to Example 1, yielded a scheelite concentrate grade as low as 2.34%, and the recovery rate was also reduced. This is because at this temperature, descaling could not be completed, thus affecting the grade and recovery rate of the scheelite concentrate.
[0045] As can be seen from the analysis in Table 1, the heating and beneficiation process provided in this embodiment can ensure both the grade of scheelite concentrate and the recovery rate of scheelite.
[0046] Example 2
[0047] The scheelite rough concentrate has a WO3 grade of 2.0%, a main calcareous gangue CaF2 grade of 40%, and a CaCO3 grade of 10%.
[0048] For the scheelite rough concentrate in this embodiment, the heating and beneficiation method includes the following steps:
[0049] Step S1: Concentrate the scheelite crude concentrate to 50 wt%, pump it into a mixing tank, and heat it with steam.
[0050] Step S2: Heat the scheelite concentrate to 85°C, and add sodium hydroxide, water glass, and molecular sieve activation powder sequentially under stirring. Continue stirring for 25 minutes to remove the collector from the surface of the calcium-containing gangue minerals. The amount of sodium hydroxide is 100 g / t, and the stirring time is 4 minutes after its addition; the amount of water glass is 35 kg / t, and the stirring time is 8 minutes after its addition; the molecular sieve activation powder is 3A molecular sieve activation powder, and the amount is 200 g / t, and the stirring time is 5 minutes after its addition.
[0051] Step S3: After the reagent removal is completed, room temperature water is added to dilute the scheelite rough concentrate to 30 wt% and enter the flotation system. After one roughing, two cleaning and three scavenging processes, the scheelite concentrate is obtained. The roughing and cleaning processes use flotation columns, and the scavenging process uses an aerated stirring flotation machine.
[0052] Comparative Examples 6-10
[0053] The grade of the scheelite rough concentrate was the same as in Example 2, but different heating and refining parameters were used to obtain Comparative Examples 6-10.
[0054] The heating and refining processes of Comparative Examples 6-10 are shown in Table 2, and the heating and refining effects of Example 2 and Comparative Examples 6-10 are shown in Table 2.
[0055] Table 2: Selected heating parameters and effects of Examples 2 and Comparative Examples 6-10
[0056]
[0057]
[0058] As shown in Table 2:
[0059] In Comparative Example 6, the grade and recovery rate of the scheelite concentrate obtained without the addition of sodium hydroxide were both lower than those in Example 2.
[0060] In Comparative Example 7, without the addition of sodium hydroxide and molecular sieve activating powder, the descaling efficiency decreased, and the grade of the obtained scheelite concentrate was only 28.66%, with a recovery rate lower than that of Comparative Example 6.
[0061] Compared to Comparative Example 7, Comparative Example 8, without the addition of sodium hydroxide and molecular sieve activating powder, extended the stirring time and increased the heating and descaling temperature, resulting in a scheelite concentrate grade of 35%, but a recovery rate of approximately 92%.
[0062] Comparative Example 9, based on Comparative Example 7, increased the amount of water glass, raising the grade of scheelite concentrate to over 33%, but the recovery rate further decreased compared to Comparative Example 7.
[0063] Comparative Example 10, based on Example 2, omits the water glass component while keeping other conditions unchanged. As can be seen from Comparative Example 10, compared to the rough concentrate grade, the final scheelite concentrate grade shows a very small increase, and the recovery rate is less than 80%.
[0064] As can be seen from the analysis in Table 2, the heating and refining process provided in Example 2, which uses sodium hydroxide, water glass and molecular sieve activation powder as de-drug agents, can improve the de-drug effect and thus affect the heating and refining efficiency.
[0065] Example 3
[0066] The scheelite rough concentrate has a WO3 grade of 1.0%, a main calcareous gangue CaF2 grade of around 10%, and a CaCO3 grade of 35%.
[0067] For the scheelite rough concentrate in this embodiment, the heating and beneficiation method includes the following steps:
[0068] Step S1: Concentrate the scheelite crude concentrate to 70 wt%, pump it into a mixing tank, and heat it with steam.
[0069] Step S2: Heat the scheelite concentrate to 95°C, and add sodium hydroxide, water glass, and molecular sieve activation powder sequentially under stirring. Continue stirring for 30 minutes to remove the collector from the surface of the calcium-containing gangue minerals. The amount of sodium hydroxide is 100 g / t, and the stirring time is 4 minutes after its addition. The amount of water glass is 45 kg / t, and the stirring time is 6 minutes after its addition. The molecular sieve activation powder is 5A molecular sieve activation powder, and the amount is 1000 g / t. The stirring time is 5 minutes after its addition.
[0070] Step S3: After the reagent removal is completed, room temperature water is added to dilute the scheelite rough concentrate to 20 wt% and enter the flotation system. After one roughing, two cleaning and three scavenging processes, the scheelite concentrate is obtained. The roughing and cleaning processes use flotation columns, and the scavenging process uses an aerated stirring flotation machine.
[0071] Comparative Examples 11-13
[0072] The grade of the scheelite rough concentrate was the same as in Example 3, but different heating and refining parameters were used to obtain Comparative Examples 11-13.
[0073] The heating and refining processes of Comparative Examples 11-13 are shown in Table 3, and the heating and refining effects of Example 3 and Comparative Examples 11-13 are shown in Table 3.
[0074] Table 3: Selected heating parameters and effects of Examples 3 and Comparative Examples 11-13
[0075]
[0076] As shown in Table 3:
[0077] In Comparative Example 11, the heating and desiccant removal process did not involve the addition of molecular sieve activating powder, resulting in low desiccant removal efficiency. The grade of the obtained scheelite concentrate was only 29.17%, and the recovery rate was also lower than that of Example 3.
[0078] Comparative Example 12: The entire flotation process was carried out using a flotation machine, and all other conditions were exactly the same as in Example 3. However, the number of cleaning cycles was increased, the process was lengthened, and the grade and recovery rate of the obtained scheelite concentrate were lower than those in Example 3.
[0079] Comparative Example 13: The entire flotation process used flotation columns, and other conditions were exactly the same as in Example 3. The grade of the obtained scheelite concentrate was close to that of Example 3, but the recovery rate was significantly lower than that of Example 3.
[0080] As shown in Table 3, the addition of molecular sieve activating powder during heated de-drug treatment, the use of flotation columns for roughing and cleaning, and flotation machines for scavenging, combined with the other two methods, results in better performance indicators for heated cleaning.
[0081] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.
Claims
1. A method of heating and cleaning a low-grade crude scheelite concentrate, characterized in that, The WO3 grade in the low-grade scheelite rough concentrate is 0.8-2.0%, and the heating and beneficiation method includes the following steps: Step S1: Concentrate the scheelite crude concentrate to 50-70 wt%, pump it into a mixing tank, and heat it with steam. Step S2: Heat the scheelite rough concentrate to 85-95℃, and add sodium hydroxide, water glass, and molecular sieve activation powder in sequence under stirring. Continue to keep warm and stir for 25-45 minutes to remove the collector from the surface of the calcium-containing gangue minerals. The amount of sodium hydroxide is 0-300 g / t, the amount of water glass is 35-55 kg / t, and the amount of molecular sieve activation powder is 200-2000 g / t. Step S3: After the reagent removal is completed, room temperature water is added to dilute the scheelite rough concentrate to 20-30 wt% and then it enters the flotation system. After one roughing, two cleaning and three scavenging processes, scheelite concentrate with WO3 grade of more than 30% is obtained, and the recovery rate of the whole process is more than 95%. The roughing and cleaning processes use flotation columns, and the scavenging process uses an aerated stirring flotation machine.
2. The process for heating beneficiation of low grade white tungsten crude concentrate according to claim 1, characterized in that, The molecular sieve activation powder is selected from one of the molecular sieves: 3A, 4A, or 5A.
3. The process for heating beneficiation of low grade white tungsten crude concentrate according to claim 1, characterized in that, In low-grade scheelite rough concentrate, the grade of calcareous gangue CaF2 is 10-40%, and the grade of CaCO3 is 10-43%.
4. The heating and beneficiation method for low-grade scheelite rough concentrate according to claim 1, characterized in that, In step S2, the stirring time is 4-5 minutes after adding sodium hydroxide, 6-8 minutes after adding water glass, and 5-6 minutes after adding molecular sieve activation powder.