Quality-improving and impurity-reducing process for high-calcium refractory scheelite rough concentrate

Abstract

The invention provides a high-calcium refractory scheelite rough concentrate quality improvement and impurity reduction process, and belongs to the technical field of mineral separation processes. The process comprises the following steps: (1) concentrating ore pulp of scheelite rough concentrate to 50%-70% to obtain concentrated ore pulp, then heating the concentrated ore pulp to 60-90 DEG C, and keeping the temperature for 30-50 minutes; (2) after heat preservation is finished, an inhibitor and a collecting agent are sequentially added while stirring is conducted, and heat preservation stirring continues to be conducted for 15-30 min; and (3) after heat-preservation stirring is finished, water is added for dilution until the concentration of ore pulp is 25-20%, then the ore pulp enters a flotation system, and the quality improvement and impurity reduction process of the high-calcium refractory scheelite rough concentrate is completed through one-time roughing, two-time scavenging and two-time concentration processes. The quality-improving and impurity-reducing process for the high-calcium refractory scheelite rough concentrate provided by the invention can ensure the grade of the scheelite concentrate, also can consider the recovery rate of the scheelite, and can reduce the production cost.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of ore dressing, and in particular to a quality improvement and impurity reduction process for high-calcium and difficult-to-separate white tungsten rough concentrate. BACKGROUND

[0002] White tungsten resources in China generally have the characteristics of "poor, fine and impure", and the separation from calcium-containing gangue is a worldwide problem. High-calcium and difficult-to-separate white tungsten rough concentrate is often associated with fluorite (CaF2) and calcite (CaCO3) and other calcium-containing gangue minerals. Due to the similar surface properties of these minerals, it is extremely difficult to separate them by flotation, which has become a bottleneck for the comprehensive utilization of white tungsten resources.

[0003] Tungsten ore heating flotation technology (also known as "Peterlov method") is a classic white tungsten ore concentration process proposed by a Soviet expert, Peterlov, in the mid-20th century. Because white tungsten ore (CaWO4) is often associated with fluorite (CaF2) and calcite (CaCO3) and other calcium-containing gangue minerals, the physical and chemical properties of these minerals are similar, and their floatability is close, making it difficult to separate them efficiently by conventional flotation. In industrial production, the "Peterlov method" of heating flotation concentrates the rough concentrate to about 60-70%, adds 30-100 kg / t of water glass (Na2SiO3), and stirs it at a high temperature of 90-100℃ for at least 30-90 minutes. This causes the adsorption of different mineral surfaces to be desorbed at different speeds, thus amplifying the difference in floatability and achieving selective separation of white tungsten ore and calcium-containing gangue. This method has strong adaptability to ores, high and stable beneficiation indexes, and is particularly suitable for low-grade and complex symbiotic white tungsten resources, and has been used as the mainstream technology for the concentration of mixed black and white tungsten ore for a long time.

[0004] Various processes and reagent schemes have been developed for the quality improvement and impurity reduction of high-calcium and difficult-to-separate white tungsten rough concentrate, including normal and heating flotation, gravity separation-flotation combination, tailings reclamation, and the use of new types of collectors and combined depressants. These technologies have improved the grade and recovery rate of tungsten concentrate by optimizing the separation conditions and reagent system. However, the problems of high energy consumption, high reagent consumption, high investment cost, low comfort level, and metal loss are still prominent. In recent years, with the breakthroughs in metal complex collector and normal temperature flotation technology, some aspects of heating flotation have been simplified or replaced, but it is still irreplaceable in high-calcium and complex ore types. The disadvantages of "high energy consumption, high reagent consumption, high investment, low comfort level, and easy metal loss" have seriously restricted its economic efficiency and sustainability, prompting the industry to accelerate the transition to new processes such as normal or low temperature, low water glass consumption, and heating and reagent addition methods. SUMMARY

[0005] To address the issues of poor flotation efficiency, low concentrate grade, tungsten metal loss due to unstable froth, and poor adaptability to complex ores in room-temperature tungsten ore flotation, this invention provides a process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate. Compared with the traditional heated flotation process, the "Pedrof process," this invention features refined and innovative control over the optimization of reagent addition sequence, the innovation of heating method, and the combined use of highly efficient reagents, fundamentally enhancing separation selectivity and thus achieving high-efficiency grade improvement.

[0006] This invention provides a process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate, comprising the following steps:

[0007] (1) Concentrate the slurry of scheelite crude concentrate to 50% to 70% to obtain concentrated slurry. Then heat the concentrated slurry to 60-90℃ and keep it warm for 30-50 minutes.

[0008] (2) After the heat preservation is completed, add the inhibitor and the collector in sequence while stirring, and continue to heat preservation and stirring for 15-30 minutes;

[0009] (3) After the heat preservation and stirring are completed, water is added to dilute the slurry to a concentration of 25-20% and then it enters the flotation system. After one roughing, two scavenging and two cleaning processes, the process of upgrading and reducing impurities of high-calcium and difficult-to-select scheelite rough concentrate is completed.

[0010] Furthermore, in step (1), the WO3 grade in the scheelite rough concentrate is between 0.8% and 8.5%, the grade of calcareous gangue CaF2 in the scheelite rough concentrate is 10% to 40%, and the grade of CaCO3 is 10% to 43%.

[0011] Furthermore, during the heating and heat preservation process described in step (1), the stirring is continuously performed at a speed of 100-300 r / min.

[0012] Furthermore, the inhibitor in step (2) comprises water glass, and the collector comprises tungsten collector W-105.

[0013] Furthermore, the water glass is of a 2.2-2.6 mold, the amount of water glass used is 30-60 kg / t, and the amount of tungsten collector W-105 used is 600-1000 g / t.

[0014] Furthermore, the coarse selection and foaming time in step (3) is 3 to 6 minutes.

[0015] Furthermore, the two scavenging processes in step (3) are divided into scavenging 1 and scavenging 2. The amount of collector used in scavenging 1 is 200-400g / t, and the amount of collector used in scavenging 2 is 100-200g / t. The time for scraping bubbles in scavenging 1 is 2-4min, and the time for scraping bubbles in scavenging 2 is 2-3min.

[0016] Furthermore, the two selections in step (3) are divided into selection 1 and selection 2. The inhibitor dosage for selection 1 is 5-10 kg / t, and the inhibitor dosage for selection 2 is 3-5 kg / t. The foaming time for selection 1 is 2-4 min, and the foaming time for selection 2 is 2-3 min.

[0017] Furthermore, in step (3), a collector is used to adjust the slurry for 2-4 minutes during the scavenging process.

[0018] Furthermore, in step (3), the selection process involves adjusting the pulp with an inhibitor for 2-4 minutes.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. Technological Innovation, Significantly Improved Selectivity. Traditional processes involve mixing and heating the reagents and slurry in a single step, which easily leads to interference between the inhibitor and collector. This invention employs a revolutionary sequence of "selective heating with no load followed by reagent addition," prioritizing the cleaning and activation of the mineral surface. This creates ideal interfacial conditions for precise inhibition of water glass and efficient adsorption of the collector, fundamentally enhancing separation selectivity and achieving highly efficient product extraction.

[0021] 2. Synergistic effects of process and reagents create a technological barrier. The unique "two-stage heating" process is deeply coupled with the highly efficient "water glass + W-105" combined reagent system. Pretreatment lays the foundation for the efficient action of the reagents, while the highly effective reagent W-105 can accurately capture scheelite in the optimized environment, overcoming the problem of collectors being severely limited by high concentrations of inhibitors in traditional processes, forming an integrated technological advantage that is difficult to replicate.

[0022] 3. Cost reduction and efficiency improvement, with huge potential for industrial application. For tungsten concentrate samples with a tungsten content of approximately 6.0%, this invention achieves high grade (WO3 23.73%) and extremely high recovery rate (93.34%). Simultaneously, due to improved reagent efficiency, it significantly reduces the total consumption of inhibitors such as water glass, directly saving production costs and alleviating environmental pressure. Its process is stable and highly controllable, providing a reliable solution for the industrial and efficient utilization of similar high-calcium, difficult-to-process scheelite resources. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the heating mineral processing technology of the present invention. Detailed Implementation

[0024] This invention provides a process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate, comprising the following steps:

[0025] (1) Concentrate the slurry of scheelite crude concentrate to 50% to 70% to obtain concentrated slurry. Then heat the concentrated slurry to 60-90℃ and keep it warm for 30-50 minutes.

[0026] (2) After the heat preservation is completed, add the inhibitor and the collector in sequence while stirring, and continue to heat preservation and stirring for 15-30 minutes;

[0027] (3) After the heat preservation and stirring are completed, water is added to dilute the slurry to a concentration of 25-20% and then it enters the flotation system. After one roughing, two scavenging and two cleaning processes, the process of upgrading and reducing impurities of high-calcium and difficult-to-select scheelite rough concentrate is completed.

[0028] In this invention, the WO3 grade in the scheelite rough concentrate in step (1) is between 0.8% and 8.5%, preferably between 1% and 8%, and even more preferably between 5.9%.

[0029] In this invention, the grade of CaF2 in the scheelite rough concentrate in step (1) is 10-40%, and the grade of CaCO3 is 10-43%. Preferably, the grade of CaF2 in the scheelite rough concentrate in step (1) is 20%-30%, and the grade of CaCO3 is 20%-40%. More preferably, the grade of CaF2 in the scheelite rough concentrate in step (1) is 15.8%, and the grade of CaCO3 is 38.5%.

[0030] In this invention, preferably, step (1) involves heating to 90°C and holding for 50 minutes.

[0031] In this invention, during the heating and heat preservation process in step (1), the stirring is continuously performed at a speed of 100-300 r / min, preferably 150-250 r / min, and even more preferably 200 r / min.

[0032] In this invention, the inhibitor in step (2) includes any one of water glass, polymerized water glass, CA-1, F-01, and YC-2, preferably water glass.

[0033] CA-1, F-01, and YC-2 are calcium and magnesium carbonate inhibitors, whose main components are tannin and dextrin.

[0034] The collector includes any one of tungsten collectors W-105, W-104, W-103, 731, and ZL, preferably tungsten collector W-105.

[0035] In this invention, the water glass is of mold size 2.2-2.6, preferably of mold size 2.6.

[0036] In this invention, the amount of water glass used is 30-60 kg / t, preferably 50 kg / t.

[0037] In this invention, the dosage of the tungsten collector W-105 is 600-1000 g / t, preferably 1000 g / t.

[0038] In this invention, the coarse selection and foam scraping time in step (3) is 3 to 6 minutes, preferably 4 minutes.

[0039] In this invention, the two sweeps in step (3) are divided into sweep 1 and sweep 2. The amount of collector used in sweep 1 is 200-400 g / t, and the amount of collector used in sweep 2 is 100-200 g / t. Preferably, the amount of collector used in sweep 1 is 400 g / t, and the amount of collector used in sweep 2 is 200 g / t. No foaming agent is added.

[0040] In this invention, the time for scraping bubbles in sweeping selection 1 is 2-4 minutes, and the time for scraping bubbles in sweeping selection 2 is 2-3 minutes. Preferably, the time for scraping bubbles in sweeping selection 1 is 3 minutes, and the time for scraping bubbles in sweeping selection 2 is 2.5 minutes.

[0041] In this invention, the two selections in step (3) are divided into selection 1 and selection 2. The inhibitor dosage for selection 1 is 5-10 kg / t, and the inhibitor dosage for selection 2 is 3-5 kg / t. Preferably, the inhibitor dosage for selection 1 is 10 kg / t, and the inhibitor dosage for selection 2 is 5 kg / t.

[0042] In this invention, the foaming time for the first selection is 2-4 minutes, and the foaming time for the second selection is 2-3 minutes. Preferably, the foaming time for the first selection is 3 minutes, and the foaming time for the second selection is 2.5 minutes.

[0043] In this invention, the roughing, cleaning and scavenging processes adopt a process flow of one roughing, two cleaning and two scavenging processes.

[0044] In this invention, the slurry is prepared with a collector for 2-4 minutes during the scavenging process in step (3), preferably, the slurry is prepared with a collector for 2 minutes during the scavenging process.

[0045] In this invention, the selection process in step (3) uses an inhibitor to adjust the pulp for 2-4 minutes, preferably, the selection process uses an inhibitor to adjust the pulp for 3 minutes.

[0046] To address the issues of poor flotation efficiency, low concentrate grade, tungsten metal loss due to unstable froth, and poor adaptability to ores with complex properties in room-temperature tungsten ore flotation, this invention provides a process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate. Compared with the traditional heated flotation process, the "Pedrof process," this invention features refined and innovative control in aspects such as optimizing the order of reagent addition, innovating the heating method, and using a combination of highly efficient reagents.

[0047] I. Optimization of Reagent Addition Sequence: From "Passive Inhibition" to "Active Cleaning". In traditional processes, water glass is mixed and heated with the slurry in a single step. At this time, the water glass not only interacts with gangue minerals but also inevitably and indiscriminately adsorbs onto the surface of all mineral particles (including scheelite), forming an inhibitory film. During subsequent flotation, the collector must strongly "compete" or "penetrate" this film to recover scheelite, resulting in poor selectivity and easily leading to recovery loss or fluctuations in concentrate grade. The core advantage of this invention is its novel process of "heating first, then adding reagents." The slurry is first heated and stirred at 90°C for 50 minutes under no-load conditions; this process serves as a "physicochemical pretreatment."

[0048] 1. Cleaning mineral surfaces: The strong thermodynamic action and mechanical stirring can effectively desorb or weaken the unavoidable ions, residual agents or oxide layers pre-adsorbed on the surface of scheelite and calcium-bearing gangue.

[0049] 2. Activation interface differences: High temperature causes differential changes in the lattice energy, solubility, and electrical properties of different mineral surfaces, creating more favorable initial conditions for subsequent selective suppression / flotation;

[0050] 3. Avoid ineffective adsorption: This ensures that the water glass and collector added later act on the "clean" and "activated" target mineral surface, greatly improving the selectivity and efficiency of the reagents.

[0051] II. Innovation in Heating Methods: From "Condition Creation" to "Interfacial Modification". The main purpose of heating in traditional processes is to create a solution chemical environment with high alkalinity and high ionic strength, promoting the polymerization of water glass to form Ca2+. 2+ More sensitive colloidal calcium silicate, thus inhibiting the reaction of calcite and fluorite. Heating serves as a "means" to create a chemical environment. The novel process of this invention divides the heating process into two stages. The first stage, unloaded heating, focuses more on the "physical cleaning" and "thermal activation" of the mineral surface, altering the surface properties and reactivity. This is an active regulation of the mineral interface properties, its purpose going beyond simply creating a solution chemical environment.

[0052] III. Synergistic use of highly efficient combined reagents (especially water glass and tungsten collector W-105). No-load heating pretreatment cleans the surface of scheelite, removes impurities, and activates the Ca on its surface.2+ Active sites. This allows the subsequently added W-105 collector to adsorb more rapidly and firmly onto the "clean and activated" scheelite surface, significantly improving collection efficiency and selectivity. Simultaneously, the pretreatment also causes specific changes on the calcite and fluorite surfaces, making them more easily inhibited by water glass. The polymerization morphology and inhibitory efficacy of water glass as an inhibitor at high temperatures are crucial. Under optimized heating methods and sequences, water glass can more selectively form a hydrophilic and stable calcium silicate hydration film on the calcite and fluorite surfaces, while minimizing its adsorption on the scheelite surface. W-105 collector is a highly effective agent for scheelite, especially in high-temperature, high-alkalinity, and water glass-containing environments, maintaining high selectivity and collection ability. It undergoes a stronger chemical adsorption or complexation reaction with the pretreated scheelite surface, thereby "penetrating" or "circumventing" the inhibitory environment caused by water glass, achieving selective collection.

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0054] Unless otherwise specified, the test methods or experimental methods described in the following examples are all conventional methods; unless otherwise specified, the raw materials and additives are obtained from conventional commercial sources or prepared by conventional methods.

[0055] Example 1

[0056] A process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate, the specific steps of which are as follows:

[0057] (1) First, raw material preparation: the scheelite rough concentrate comes from the previous flotation operation. The scheelite rough concentrate has a tungsten grade of 5.9%, the calcareous gangue CaF2 grade of the scheelite rough concentrate is 15.8%, and the CaCO3 grade is 38.5%. The scheelite rough concentrate is first concentrated to a pulp concentration of 55% to obtain the concentrated pulp.

[0058] (2) Heat the concentrated slurry to 90°C, and stir continuously during the heating process. The speed of the mixer is 200 r / min, and the heating and stirring are continued for 50 minutes.

[0059] (3) After heating and stirring for 50 minutes, add water glass (2.6 mold) at a rate of 50 kg / t and tungsten collector W-105 at a rate of 1000 g / t while stirring in sequence. Then continue heating and stirring for 25 minutes to desorb the collector from the surface of gangue minerals at high temperature and enhance the selectivity of subsequent flotation.

[0060] (4) After heating and stirring, add room temperature water to dilute the slurry to a concentration of 27.27%, and then carry out a flotation process of one roughing, two scavenging, and two cleaning.

[0061] (5) No other reagents need to be added during the roughing process of tungsten; the slurry concentration can be adjusted and the slurry can be floated directly.

[0062] (6) During the scavenging process, the collector dosage for scavenging 1 is 400g / t, and the collector dosage for scavenging 2 is 200g / t. No foaming agent needs to be added.

[0063] (7) Water glass (2.6 mold) is added during the selection process to inhibit the reaction of calcium carbonate and calcium fluoride. The dosage for selection 1 is 10 kg / t, and the dosage for selection 2 is 5 kg / t.

[0064] (8) The preparation time for the inhibitor is 3 min, and the preparation time for the tungsten collector is 2 min;

[0065] (9) The time for scraping bubbles in roughing is 4 min, the time for scraping bubbles in cleaning 1 is 3 min, the time for scraping bubbles in cleaning 2 is 2 min, the time for scraping bubbles in scavenging 1 is 3 min, and the time for scraping bubbles in scavenging 2 is 2 min. A scheelite concentrate with a WO3 grade of 23.73% is obtained with a recovery rate of 93.34%.

[0066] Example 2

[0067] A process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate, the specific steps of which are as follows:

[0068] (1) First, raw material preparation: the scheelite rough concentrate comes from the previous flotation operation. The scheelite rough concentrate has a tungsten grade of 2.7%, the calcareous gangue CaF2 grade of the scheelite rough concentrate is 13.2%, and the CaCO3 grade is 26.4%. The scheelite rough concentrate is first concentrated to a pulp concentration of 50% to obtain the concentrated pulp.

[0069] (2) Heat the concentrated slurry to 80°C, and stir continuously during the heating process. The speed of the mixer is 200 r / min, and the heating and stirring are continued for 40 minutes.

[0070] (3) After heating and stirring for 40 minutes, add water glass (2.6 mold) at a rate of 50 kg / t and tungsten collector W-105 at a rate of 800 g / t while stirring in sequence. Then continue heating and stirring for 25 minutes to desorb the collector from the surface of gangue minerals at high temperature and enhance the selectivity of subsequent flotation.

[0071] (4) After heating and stirring, add room temperature water to dilute the slurry to a concentration of 30%, and then carry out a flotation process of one roughing, two scavenging and two cleaning.

[0072] (5) No other reagents need to be added during the roughing process of tungsten; the slurry concentration can be adjusted and the slurry can be floated directly.

[0073] (6) During the scavenging process, the collector dosage for scavenging 1 is 400g / t, and the collector dosage for scavenging 2 is 200g / t. No foaming agent needs to be added.

[0074] (7) Water glass (2.6 mold) is added during the selection process to inhibit the reaction of calcium carbonate and calcium fluoride. The dosage for selection 1 is 10 kg / t, and the dosage for selection 2 is 5 kg / t.

[0075] (8) The preparation time for the inhibitor is 3 min, and the preparation time for the tungsten collector is 2 min;

[0076] (9) The time for scraping bubbles in roughing is 4 min, the time for scraping bubbles in cleaning 1 is 3 min, the time for scraping bubbles in cleaning 2 is 2 min, the time for scraping bubbles in scavenging 1 is 3 min, and the time for scraping bubbles in scavenging 2 is 2 min. A scheelite concentrate with a WO3 grade of 20.81% is obtained with a recovery rate of 88.13%.

[0077] Example 3

[0078] A process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate, the specific steps of which are as follows:

[0079] (1) First, raw material preparation: the scheelite rough concentrate comes from the previous flotation operation. The scheelite rough concentrate has a tungsten grade of 5.2%, the calcareous gangue CaF2 grade of the scheelite rough concentrate is 20.4%, and the CaCO3 grade is 40%. The scheelite rough concentrate is first concentrated to a pulp concentration of 60% to obtain the concentrated pulp.

[0080] (2) Heat the concentrated slurry to 85°C, and stir continuously during the heating process. The speed of the mixer is 200 r / min, and the heating and stirring are continued for 50 minutes.

[0081] (3) After heating and stirring for 50 minutes, add water glass (2.6 mold) at a rate of 50 kg / t and tungsten collector W-105 at a rate of 900 g / t while stirring in sequence. Then continue heating and stirring for 25 minutes to desorb the collector from the surface of gangue minerals at high temperature and enhance the selectivity of subsequent flotation.

[0082] (4) After heating and stirring, add room temperature water to dilute the slurry to a concentration of 33%, and then carry out a flotation process of one roughing, two scavenging and two cleaning.

[0083] (5) No other reagents need to be added during the roughing process of tungsten; the slurry concentration can be adjusted and the slurry can be floated directly.

[0084] (6) During the scavenging process, the collector dosage for scavenging 1 is 400g / t, and the collector dosage for scavenging 2 is 200g / t. No foaming agent needs to be added.

[0085] (7) Water glass (2.6 mold) is added during the selection process to inhibit the reaction of calcium carbonate and calcium fluoride. The dosage for selection 1 is 10 kg / t, and the dosage for selection 2 is 5 kg / t.

[0086] (8) The preparation time for the inhibitor is 3 min, and the preparation time for the tungsten collector is 2 min;

[0087] (9) The time for scraping bubbles in roughing is 4 min, the time for scraping bubbles in cleaning 1 is 3 min, the time for scraping bubbles in cleaning 2 is 2 min, the time for scraping bubbles in scavenging 1 is 3 min, and the time for scraping bubbles in scavenging 2 is 2 min. A scheelite concentrate with a WO3 grade of 21.35% is obtained with a recovery rate of 92.72%.

[0088] Example 4

[0089] A process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate, the specific steps of which are as follows:

[0090] (1) First, raw material preparation: the scheelite rough concentrate comes from the previous flotation operation. The scheelite rough concentrate has a tungsten grade of 4.4%, the calcareous gangue CaF2 grade of the scheelite rough concentrate is 12.1%, and the CaCO3 grade is 27.6%. The scheelite rough concentrate is first concentrated to a pulp concentration of 55% to obtain the concentrated pulp.

[0091] (2) Heat the concentrated slurry to 85°C, and stir continuously during the heating process. The speed of the mixer is 200 r / min, and the heating and stirring are continued for 40 minutes.

[0092] (3) After heating and stirring for 40 minutes, add water glass (2.6 mold) at a rate of 50 kg / t and tungsten collector W-105 at a rate of 850 g / t while stirring in sequence. Then continue heating and stirring for 25 minutes to desorb the collector from the surface of gangue minerals at high temperature and enhance the selectivity of subsequent flotation.

[0093] (4) After heating and stirring, add room temperature water to dilute the slurry to a concentration of 35%, and then carry out a flotation process of one roughing, two scavenging and two cleaning.

[0094] (5) No other reagents need to be added during the roughing process of tungsten; the slurry concentration can be adjusted and the slurry can be floated directly.

[0095] (6) During the scavenging process, the collector dosage for scavenging 1 is 400g / t, and the collector dosage for scavenging 2 is 200g / t. No foaming agent needs to be added.

[0096] (7) Water glass (2.6 mold) is added during the selection process to inhibit the reaction of calcium carbonate and calcium fluoride. The dosage for selection 1 is 10 kg / t, and the dosage for selection 2 is 5 kg / t.

[0097] (8) The preparation time for the inhibitor is 3 min, and the preparation time for the tungsten collector is 2 min;

[0098] (9) The time for scraping bubbles in roughing is 4 min, the time for scraping bubbles in cleaning 1 is 3 min, the time for scraping bubbles in cleaning 2 is 2 min, the time for scraping bubbles in scavenging 1 is 3 min, and the time for scraping bubbles in scavenging 2 is 2 min. A 22.97% WO3 grade scheelite concentrate was obtained with a recovery rate of 92.88%.

[0099] Example 5

[0100] A process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate, the specific steps of which are as follows:

[0101] (1) First, raw material preparation: the scheelite rough concentrate comes from the previous flotation operation. The scheelite rough concentrate has a tungsten grade of 6.8%, the calcareous gangue CaF2 grade of the scheelite rough concentrate is 25.9%, and the CaCO3 grade is 36.7%. The scheelite rough concentrate is first concentrated to a pulp concentration of 50% to obtain the concentrated pulp.

[0102] (2) Heat the concentrated slurry to 90°C, and stir continuously during the heating process. The speed of the mixer is 200 r / min, and the heating and stirring are continued for 50 minutes.

[0103] (3) After heating and stirring for 50 minutes, add water glass (2.6 mold) at a rate of 50 kg / t and tungsten collector W-105 at a rate of 1000 g / t while stirring in sequence. Then continue heating and stirring for 25 minutes to desorb the collector from the surface of gangue minerals at high temperature and enhance the selectivity of subsequent flotation.

[0104] (4) After heating and stirring, add room temperature water to dilute the slurry to a concentration of 30%, and then carry out a flotation process of one roughing, two scavenging and two cleaning.

[0105] (5) No other reagents need to be added during the roughing process of tungsten; the slurry concentration can be adjusted and the slurry can be floated directly.

[0106] (6) During the scavenging process, the collector dosage for scavenging 1 is 400g / t, and the collector dosage for scavenging 2 is 200g / t. No foaming agent needs to be added.

[0107] (7) Water glass (2.6 mold) is added during the selection process to inhibit the reaction of calcium carbonate and calcium fluoride. The dosage for selection 1 is 10 kg / t, and the dosage for selection 2 is 5 kg / t.

[0108] (8) The preparation time for the inhibitor is 3 min, and the preparation time for the tungsten collector is 2 min;

[0109] (9) The time for scraping bubbles in roughing is 4 min, the time for scraping bubbles in cleaning 1 is 3 min, the time for scraping bubbles in cleaning 2 is 2 min, the time for scraping bubbles in scavenging 1 is 3 min, and the time for scraping bubbles in scavenging 2 is 2 min. A scheelite concentrate with a WO3 grade of 23.69% is obtained with a recovery rate of 92.04%.

[0110] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate, characterized in that, Includes the following steps: (1) Concentrate the slurry of scheelite crude concentrate to 50% to 70% to obtain concentrated slurry. Then heat the concentrated slurry to 60-90℃ and keep it warm for 30-50 minutes. (2) After the heat preservation is completed, add the inhibitor and the collector in sequence while stirring, and continue to heat preservation and stirring for 15-30 minutes; (3) After the heat preservation and stirring are completed, water is added to dilute the slurry to a concentration of 25-20% and then it enters the flotation system. After one roughing, two scavenging and two cleaning processes, the process of upgrading and reducing impurities of high-calcium and difficult-to-select scheelite rough concentrate is completed.

2. The process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate according to claim 1, characterized in that, In step (1), the WO3 grade in the scheelite rough concentrate is between 0.8% and 8.5%, the grade of calcareous gangue CaF2 in the scheelite rough concentrate is 10% to 40%, and the grade of CaCO3 is 10% to 43%.

3. The process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate according to claim 1, characterized in that, During the heating and heat preservation process in step (1), the stirring is carried out continuously at a speed of 100-300 r / min.

4. The process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate according to claim 1, characterized in that, The inhibitor in step (2) includes water glass, and the collector includes tungsten collector W-105.

5. The process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate according to claim 4, characterized in that, The water glass is of mold size 2.2-2.6, the amount of water glass used is 30-60 kg / t, and the amount of tungsten collector W-105 used is 600-1000 g / t.

6. The process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate according to claim 1, characterized in that, The coarse selection and foaming time in step (3) is 3 to 6 minutes.

7. The process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate according to claim 1, characterized in that, Step (3) involves two scavenging processes, namely scavenging 1 and scavenging 2. The amount of collector used in scavenging 1 is 200-400 g / t, and the amount of collector used in scavenging 2 is 100-200 g / t. The time for scraping bubbles in scavenging 1 is 2-4 min, and the time for scraping bubbles in scavenging 2 is 2-3 min.

8. The process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate according to claim 1, characterized in that, Step (3) The two selections are divided into selection 1 and selection 2. The inhibitor dosage for selection 1 is 5-10 kg / t, and the inhibitor dosage for selection 2 is 3-5 kg / t. The foam scraping time for selection 1 is 2-4 min, and the foam scraping time for selection 2 is 2-3 min.

9. The process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate according to claim 1, characterized in that, In step (3), a collector is used to adjust the slurry for 2-4 minutes during the scavenging process.

10. The process for upgrading and reducing impurities in high-calcium, difficult-to-process scheelite rough concentrate according to claim 1, characterized in that, In step (3), during the selection process, an inhibitor is used to adjust the pulp for 2-4 minutes.

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