Method for carrying out closed-loop reagent removal flotation on rare earth by utilizing backwater

Abstract

The invention provides a method for carrying out closed-loop reagent removal flotation on rare earth by utilizing backwater, and relates to the technical field of water treatment.The method comprises the steps that S1, primary desliming work is carried out on raw ore pulp, and upper-layer slurry and bottom-layer slurry are obtained; s2, roughing is conducted on the bottom layer ore pulp, and roughed foam and roughed ore pulp are obtained; s3, the ore pulp obtained after roughing is subjected to scavenging work, and scavenging tailings and scavenging foam are obtained; s4, the scavenging foam and the roughing foam are subjected to first concentration, and first middlings and first concentration foam are obtained; s5, secondary concentration is conducted on the first concentration foam, and second middlings and second concentration foam are obtained; s6, second desliming work is conducted on the second concentration foam, and concentrate desliming water and rare earth concentrate are obtained; and S7, the ore concentrate sludge removal water and the second middling are fed into the raw ore pulp in the step S1 of the next experiment to continue rare earth flotation, and a closed circuit is achieved. Flotation production is carried out by using backwater, and the quality and yield of rare earth produced concentrate are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, in particular to a method for flotation of rare earth by closed-circuit drug removal using return water. Background Art

[0002] The production indicators of rare earth flotation specified by Baosteel Baoshan Mining Company are rare earth concentrate grade REO ≥ 58% and operation recovery rate ≥ 50%. In the rare earth flotation production process, return water is usually used as production water for closed-circuit flotation. The advantages of using return water include: 1. Reducing the amount of new water added and reducing production costs; 2. The return water carries some rare earth flotation reagents, which can reduce the use of new reagents after returning to the system and reduce production costs; 3. Circulating water can reduce the discharge of mineral processing wastewater, which is beneficial to environmental protection.

[0003] The return water of Baoshan Mining Company is the total return water of the whole process of "iron-rare earth-fluorite" selection, specifically the overflow water and filtered water generated by the operation of each concentration equipment, grinding equipment and filtering equipment in the process of "iron-rare earth-fluorite" beneficiation. This part of water flows to the tailings pond with the tailings in the process, and then forms production return water after standing and clarifying, and returns to the "iron-rare earth-fluorite" beneficiation system through pipelines for recycling. The whole process of "iron-rare earth-fluorite" selection is that the original ore is first selected for iron, and the tailings of iron selection are used to select rare earths, and the tailings of rare earth selection are used to select fluorite. Some middlings and fluorite tailings are finally discharged. The quality of production return water is unstable, which is affected by whether the production is normal, evaporation, acid-base level, etc. Table 1 shows the quality of return water taken at a certain time point.

[0004] Table 1 Water quality indicators of production return water taken at a certain time point

[0005]

[0006]

[0007] The reagents added in the whole process of "iron-rare earth-fluorite" beneficiation include reverse flotation iron reagents, such as oxidized paraffin soap, modified starch, etc.; positive flotation rare earth reagents: hydroxamic acid, etc.; positive flotation fluorite reagents: fatty acids such as oleic acid and linoleic acid. As the process operation time increases, the residual reagents and suspended solids in the return water continue to increase, resulting in changes in the return water quality, which directly affects the separation production indicators. Among them, the main factor affecting rare earth flotation is the collector of fluorite flotation. The residual reagents in the collector exist freely in the ore pulp water and continue to interfere with flotation. Practice has shown that using the existing process and existing reagents, using return water for rare earth flotation on site, or the concentrate grade REO≤55%, or the operation recovery rate ≤50%, it is difficult to achieve the specified production indicators. In the absence of significant changes in other conditions, the continuous accumulation of other types of residual reagents in the return water is the main factor interfering with rare earth flotation, and the residual reagents exist freely in the return water and are difficult to remove.

[0008] In order to improve the quality of return water and enhance the flotation separation index, the present invention is specially proposed. Summary of the invention

[0009] The purpose of the present invention is to provide a method for flotation of rare earths by closed-circuit de-drugation using return water. In a certain embodiment of the present invention, after desludging the raw ore pulp, water glass, KYR-1 rare earth collector, and 2# oil are used to conduct a flotation test of "one roughing-one scavenging-two concentrating", and the desludging water of the selected foam of the middling ore is combined and returned to the ore to realize closed-circuit flotation, and the separation index can stably reach the concentrate grade REO ≥ 58%, and the operation recovery rate ≥ 55%. It solves the current difficult problem of not being able to use return water for flotation production, ensures the quality and output of rare earth concentrate production, and at the same time reduces the cost of water and drug use, reduces wastewater discharge, and has extremely significant economic and social benefits.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] The present invention provides a method for flotation of rare earth by closed-circuit de-drugation using return water, comprising the following steps:

[0012] S1: Perform the first desludging operation on the raw ore slurry to obtain upper ore slurry and bottom ore slurry;

[0013] S2: adding water glass, a collector and a frother to the bottom pulp obtained in step S1, performing roughing work, and obtaining roughing foam and roughing pulp;

[0014] S3: adding collector and frother to the pulp after roughing, and performing scavenging to obtain scavenging tailings and scavenging foam;

[0015] S4: adding water glass and a collector to the scavenging foam and the roughing foam to perform the first concentration to obtain the first intermediate ore and the first concentrated foam;

[0016] S5: performing a second concentration on the first concentrated foam to obtain a second intermediate ore and a second concentrated foam;

[0017] S6: performing a second desludging operation on the second concentrated foam to obtain concentrate desludging water and rare earth concentrate;

[0018] S7: the concentrate desludging water obtained in step S6 and the second intermediate ore obtained in step S5 are fed into the raw ore slurry in step S1 to continue rare earth flotation, thus realizing a closed circuit.

[0019] Further, on the basis of the above technical solution, the collector in step S2, step S3 and step S4 is a rare earth collector, and the rare earth collector includes a KYR-1 collector or a LF8# collector;

[0020] And / or, the foaming agent in step S2 and step S3 includes one or more of 2# oil, H103 or J102, preferably 2# oil.

[0021] Further, based on the above technical solution, the preparation method of the KYR-1 type collector comprises the following steps:

[0022] The fatty acid methyl ester and hydroxylamine hydrochloride are heated and mixed to obtain a KYR-1 type collector;

[0023] Preferably, the mass ratio of the fatty acid methyl ester to hydroxylamine hydrochloride is (1-3): (1-3);

[0024] Preferably, the heating and mixing temperature is 50-80° C., and the heating and mixing time is 2-4 hours.

[0025] Further, on the basis of the above technical solution, the ore slurry concentration of the raw ore slurry in step S1 is 60-65%, and the temperature is 20-30° C.;

[0026] Screening and analysis of raw ore pulp includes the following steps:

[0027] Multi-element testing and particle size analysis are carried out on the raw ore slurry to obtain the content ratio of each element in the raw ore and the distribution of minerals of different particle sizes in the raw ore.

[0028] Further, based on the above technical solution, in step S1, the first desludging operation includes:

[0029] The raw ore pulp is placed in a container, and production return water is added and stirred. After the stirring is completed, the ore pulp is allowed to stand to obtain an upper layer of ore mud and a bottom layer of ore pulp;

[0030] The production return water is the total return water of the whole process of “iron-rare earth-fluorite” separation;

[0031] The mass volume ratio of raw ore slurry and production return water is 1.6g:1mL;

[0032] The stirring time is 3 min to 5 min, and the stirring paddle speed is 150 to 200 rad / min; after the stirring is completed, let it stand for 8 to 12 min.

[0033] Further, on the basis of the above technical solution, in step S2, the rough selection process includes:

[0034] The bottom pulp obtained in step S1 is poured into the flotation tank, and then water glass, a collector and a frother are added in sequence, and roughing frothing is started after an interval of 2 to 3 minutes to obtain roughing froth and roughing pulp;

[0035] Among them, the roughing temperature is 60-65°C, the pulp concentration of the bottom pulp is 60-65%, and the pH is 8-9;

[0036] The addition time of water glass, collector and frother is 3-5min respectively;

[0037] The addition amount of water glass is 10000-15000mL / t, the addition amount of collector is 50000~70000mL / t, and the addition amount of foaming agent is 100~150mL / t;

[0038] The time for the rough selection and scraping of bubbles is 2 to 3 minutes.

[0039] Further, based on the above technical solution, in step S3, the scanning and selection work includes:

[0040] Collectors and frothers are added to the pulp after roughing in sequence, and scavenging and scraping foaming are started after an interval of 2 to 3 minutes to obtain scavenging foam and scavenging tailings;

[0041] Among them, the scavenging temperature is 60-65°C, the pulp concentration of the ore pulp after roughing is 50-55%, and the pH is 8-9;

[0042] The time interval between adding the collector and the foaming agent is 1 to 2 minutes;

[0043] The amount of collector added is 30000~4000mL / t, and the amount of foaming agent added is 50~100mL / t;

[0044] The time for sweeping and scraping bubbles is 2 to 3 minutes.

[0045] Further, based on the above technical solution, in step S4, the first selection includes:

[0046] Pour the scavenging foam and the roughing foam into the flotation tank, add water glass and collector in turn, and then start the first cleaning and scraping foam after an interval of 1 to 2 minutes to obtain the first intermediate ore and the first cleaned foam;

[0047] Among them, the first concentration temperature is 60-65°C, the pulp concentration of the scavenging foam and the roughing foam is 50-55%, and the pH is 8-9;

[0048] The time interval between adding water glass and collector is 1 to 2 minutes;

[0049] The addition amount of water glass is 1000~1200mL / t, and the addition amount of collector is 15000~20000mL / t;

[0050] The time for the first selective scraping is 3 to 4 minutes.

[0051] Further, based on the above technical solution, in step S5, the second selection includes:

[0052] The first selected foam is poured into a flotation tank, and the foam is scraped for the second time to obtain the second intermediate ore and the second selected foam;

[0053] The temperature of the second concentration is 60-65°C, the pulp concentration of the first concentration foam is 40-45%, and the pH is 8-9;

[0054] The time for the second selective scraping is 2 to 3 minutes.

[0055] Further, based on the above technical solution, in step S6, the second desludging operation includes:

[0056] Pour the second selected foam into a container, add production return water, stir, and let stand after stirring to obtain concentrate desludging water and rare earth concentrate;

[0057] Among them, the volume ratio of the second selected foam and the production return water is 1mL:3mL;

[0058] The stirring refers to stirring with a JJ-1 type electric mechanical stirrer;

[0059] The stirring time is 3 to 5 minutes, and the stirring paddle speed is 150 to 200 rad / min; after the stirring is completed, let it stand for 5 to 10 minutes.

[0060] The present invention provides a method for flotation of rare earth by closed-circuit de-drugation using return water, which has the following beneficial effects:

[0061] 1. The rare earth collector contained in the closed-loop return water and the concentrate desludging water in the process provided by a specific embodiment of the present invention can interact with the fluorite flotation collector remaining in the original ore pulp (i.e., the tailings after iron selection) and the fluorite flotation collector in the return water used to dilute the original ore pulp, producing substances that are easy to float. In the first desludging work, the residual fluorite flotation collector is dynamically removed by manually pouring out the upper layer of ore mud (laboratory method) or discharging it by overflow of the thickener (actual production method), thereby reducing the interference of the residual fluorite flotation collector on flotation. After the original ore is desludified, water glass, KYR-1 type rare earth collector, and 2# oil are used to carry out a flotation test of "one roughing selection-one scavenging selection-two concentrating selections", and the desludging water of the selected foam of the middling ore is combined and returned to the ore to realize closed-loop flotation, and the separation index can stably reach the concentrate grade REO ≥ 58%, and the operation recovery rate ≥ 55%.

[0062] 2. In the present invention, the residual KYR-1 rare earth collector in the closed-circuit returned pulp, concentrate desludging water, etc. can act with the fluorite flotation collector and iron flotation residual medicine in the original ore pulp, and remove the residual medicine by overflow to reduce the interference of the residual medicine on flotation. At the same time, it can also be combined with the ore mud in the original ore, and remove the ore mud in the original ore by overflow to reduce the interference of the ore mud on flotation, taking into account the role of flotation desludging and desludging, improving the flotation water quality, and ensuring that the production indicators are achieved under closed-circuit conditions. The method of the present invention is simple and effective, easy to implement by industrial organizations, and can effectively solve the problem of poor rare earth closed-circuit flotation production indicators.

[0063] 3. Through the process provided by the present invention, after the production return water is subjected to dynamic drug removal treatment, it is used for rare earth closed-circuit flotation, and the concentrate grade REO ≥ 58%, the operation recovery rate ≥ 50%, and both key indicators can meet the standards. It can be promoted and applied to rare earth ore dressing production, solving the current difficult problem of not being able to use return water for flotation production, ensuring the quality and output of rare earth production concentrate, while reducing water and drug costs, reducing wastewater discharge, and having extremely significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0065] Figure 1 A process flow chart for removing drugs in a closed circuit with return water to improve rare earth flotation indicators is provided for a specific embodiment of the present invention. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. The process parameters of the following embodiments that do not specify specific conditions are usually based on conventional conditions.

[0067] The endpoints and any values ​​of the ranges disclosed in the present invention 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0068] According to a first aspect of the present invention, a method for flotation of rare earth by closed-circuit de-doping using return water is provided, which specifically comprises the following steps:

[0069] S1: Perform the first desludging operation on the raw ore slurry to obtain upper ore slurry and bottom ore slurry;

[0070] Among them, the raw ore refers to the rare earth raw ore slurry, which is also the tailings after iron selection. In the iron selection process, return water is needed for grinding, flotation and other processes, so the obtained raw ore slurry contains fluorite flotation collectors and other reagents remaining in the return water.

[0071] S2: adding water glass, a collector and a frother to the bottom pulp obtained in step S1, performing roughing work, and obtaining roughing foam and roughing pulp;

[0072] S3: adding collector and frother to the pulp after roughing, and performing scavenging to obtain scavenging tailings and scavenging foam;

[0073] S4: adding water glass and a collector to the scavenging foam and the roughing foam to perform the first concentration to obtain the first intermediate ore and the first concentrated foam;

[0074] S5: performing a second concentration on the first concentrated foam to obtain a second intermediate ore and a second concentrated foam;

[0075] S6: performing a second desludging operation on the second concentrated foam to obtain concentrate desludging water and rare earth concentrate.

[0076] S7: the concentrate desludging water obtained in step S6 and the second intermediate ore obtained in step S5 are fed into the raw ore slurry in step S1 to continue rare earth flotation, thus realizing a closed circuit.

[0077] Specifically, the present invention feeds the concentrate desludging water obtained in step S6 into the original ore pulp in the next test step S1 because the rare earth collector contained in the concentrate desludging water can interact with the residual fluorite flotation fatty acid collector in the production return water to produce substances that are easy to float. In the first desludging work, the upper layer of ore mud is manually poured out (laboratory method) or discharged by thickener overflow (actual production method), thereby avoiding the residual fluorite flotation fatty acid collector in the return water from affecting the subsequent rare earth flotation process.

[0078] Furthermore, the present invention feeds the second intermediate ore obtained in step S5 into the original ore slurry in the next test step S1 because the rare earth content in the second intermediate ore is relatively high, and the rare earth in the second intermediate ore is not selected in the roughing work and the first concentration due to coarse particle size or because it is a conjoined body. Therefore, feeding the second intermediate ore into the original ore slurry in the next test step S1 can increase the total rare earth metal content of the next test, thereby improving the operation recovery rate.

[0079] As an optional embodiment of the present invention, the collector in step S1, step S3 and step S4 is a rare earth collector, and the rare earth collector includes a KYR-1 collector or a LF8# collector.

[0080] Specifically, LF8# collector was purchased from Baotou Steel Linfeng Rare Earth Technology Co., Ltd.

[0081] As an optional embodiment of the present invention, the preparation method of the KYR-1 type collector comprises the following steps:

[0082] The fatty acid methyl ester and hydroxylamine hydrochloride are heated and mixed to obtain a KYR-1 type collector;

[0083] Preferably, the mass ratio of the fatty acid methyl ester to hydroxylamine hydrochloride is (1-3): (1-3), such as 1:1, 1:1.5, 1:2, 1:2.5, 1.5:2, 2:2, 2.5:2, 2.5:2.5, 3:1, 3:1.5, 1:3, 3:2.5, etc.;

[0084] Preferably, the heating and mixing temperature is 50-80°C (such as 55°C, 60°C, 65°C, 70°C, 75°C, etc.), and the heating and mixing time is 2-4h (such as 2.5h, 3h, 3.5h, etc.).

[0085] Specifically, the surface of the mineral particles of the original ore is adsorbed with residual fatty acid reagents for fluorite flotation, which affects the process of rare earth flotation with return water. Rare earth collectors contain hydroxamic acid, which has a stronger adsorption force with the rare earth mineral particles in the original ore. In the competitive adsorption process, the fatty acid reagents are forced to desorb due to their weak adsorption force with the surface of the mineral particles, so that the fatty acid reagents are separated from the rare earth mineral particles and float on the surface of the slurry. In the first desludging work, the upper layer of ore mud is manually poured out (laboratory method) or discharged by overflow of the thickener (actual production method) to avoid interference with the process of rare earth flotation using return water.

[0086] As an optional embodiment of the present invention, the foaming agent in step S1, step S3 and step S4 includes one or more of 2# oil (pine oil), H103 or J102, preferably 2# oil.

[0087] Specifically, water glass, as a regulator, mainly functions to suppress the floatability of certain minerals. During the flotation process, it can suppress the floatability of gangue minerals of rare earth ores, such as pyrite, fluorite, barite, calcite, feldspar and quartz, thereby increasing the recovery rate of the target minerals;

[0088] The KYR-1 collector or LF8# collector used in the present invention is a rare earth collector, which is a hydroxamic acid preparation and can be selectively adsorbed on the surface of the target mineral, thereby enhancing the hydrophobicity of the target mineral surface, so that the mineral particles can be more easily attached to the bubbles and float to the surface of the slurry with the bubbles;

[0089] The frothers such as 2# oil, H103 or J102 used in the present invention are frothers specially used in rare earth flotation, and their function is to reduce the surface tension of the water-air interface and promote the formation of a large number of stable tiny bubbles in the slurry. These bubbles will adhere to the mineral particles with strong hydrophobicity, help them float to the surface of the slurry, form a foam layer, and thus separate from the gangue minerals.

[0090] As an optional embodiment of the present invention, the ore slurry obtained before the first desludging work has a slurry concentration of 60-65% (for example, 61%, 62%, 63%, 64%, etc.), and a temperature of 20-30°C (for example, 22°C, 24°C, 26°C, 28°C, etc.).

[0091] As an optional embodiment of the present invention, screening and analyzing the raw ore pulp includes the following steps:

[0092] Multi-element testing and particle size analysis are carried out on the raw ore slurry to obtain the content ratio of each element in the raw ore and the distribution of minerals of different particle sizes in the raw ore.

[0093] As an optional embodiment of the present invention, in step S1, the first desludging operation includes:

[0094] The raw ore pulp is placed in a container, and production return water is added and stirred. After the stirring is completed, the ore pulp is allowed to stand to obtain an upper layer of ore mud and a bottom layer of ore pulp;

[0095] Specifically, in the first desludging work, the desludging water of the second intermediate ore and concentrate obtained in the previous test is added to the original ore slurry and mixed to simulate the desludging process of the original ore large well. After stirring and standing, the upper layer of ore mud is poured out or discharged through the overflow of the thickener. The removed residual drug exists in this part of the upper layer of ore mud or overflow. In actual production, the overflow is directly discharged into the tailings.

[0096] The production return water is the total return water of the whole process of “iron-rare earth-fluorite” separation;

[0097] The mass volume ratio of raw ore slurry and production return water is 1.6g:1mL;

[0098] In one embodiment of the present invention, the stirring is performed using a JJ-1 type electric mechanical stirrer; in actual production, other large-scale stirring equipment may also be used to achieve sufficient mixing of the added production return water and the original ore pulp, so that the fluorite flotation collector and other reagents remaining in the return water can be combined with the middle ore mud of the original ore pulp to facilitate the desludging of the original ore pulp.

[0099] The stirring time is 3min to 5min (such as 3.5min, 4min, 4.5min, etc.), and the speed of the stirring paddle is 150 to 200rad / min (such as 160rad / min, 170rad / min, 180rad / min, 190rad / min, etc.); after the stirring is completed, let it stand for 8 to 12min (such as 9min, 10min, 11min, etc.).

[0100] As an optional implementation manner of the present invention, in step S2, the rough selection process includes:

[0101] Pour the bottom pulp obtained in step S1 into the flotation tank, then add water glass, collector and frother in sequence, and start roughing and scraping foam after an interval of 2 to 3 minutes (such as 2.2 minutes, 2.4 minutes, 2.6 minutes, 2.8 minutes, etc.) to obtain roughing foam and roughing pulp;

[0102] Among them, the roughing temperature is 60-65°C (such as 61°C, 62°C, 63°C, 64°C, etc.), the slurry concentration of the bottom slurry is 60-65% (such as 61%, 62%, 63%, 64%, etc.), and the pH is 8-9;

[0103] The addition time of water glass, collector and frother is 3-5min (e.g. 3.5min, 4min, 4.5min, etc.);

[0104] The addition amount of water glass is 10000-15000mL / t (such as 11000mL / t, 12000mL / t, 13000mL / t, 14000mL / t, etc.), the addition amount of collector is 50000-70000mL / t (55000mL / t, 60000mL / t, 65000mL / t, etc.), and the addition amount of frother is 100-150mL / t (such as 110mL / t, 120mL / t, 130mL / t, 140mL / t, etc.);

[0105] The time for rough selection and scraping bubbles is 2 to 3 minutes (such as 2.2 minutes, 2.4 minutes, 2.6 minutes, 2.8 minutes, etc.).

[0106] As an optional implementation manner of the present invention, in step S3, the scanning operation includes:

[0107] Collectors and frothers are added to the pulp after roughing in sequence, and scavenging and scraping foaming are started after an interval of 2 to 3 minutes (such as 2.2 minutes, 2.4 minutes, 2.6 minutes, 2.8 minutes, etc.) to obtain scavenging foam and scavenging tailings;

[0108] Among them, the scavenging temperature is 60-65°C (such as 61°C, 62°C, 63°C, 64°C, etc.), the pulp concentration of the slurry after roughing is 50-55% (such as 51%, 52%, 53%, 54%, etc.), and the pH is 8-9;

[0109] The time interval between adding the collector and the frother is 1 to 2 minutes (e.g. 1.2 minutes, 1.4 minutes, 1.6 minutes, 1.8 minutes, etc.);

[0110] The amount of collector added is 30000-4000mL / t (such as 32000mL / t, 34000mL / t, 36000mL / t, 38000mL / t, etc.), and the amount of frother added is 50-100mL / t (such as 60mL / t, 70mL / t, 80mL / t, 90mL / t, etc.);

[0111] The time for sweeping and scraping bubbles is 2 to 3 minutes (such as 2.2 minutes, 2.4 minutes, 2.6 minutes, 2.8 minutes, etc.).

[0112] Specifically, the purpose of scavenging is to continue to float the rare earth in the ore pulp remaining in the flotation tank after roughing. Most of the gangue minerals that need to be suppressed have been suppressed in the first roughing step, so there is no need to add water glass in step S3.

[0113] As an optional implementation of the present invention, in step S4, the first selection includes:

[0114] Pour the scavenging foam and the roughing foam into the flotation tank, add water glass and collector in sequence, and then start the first cleaning and scraping foam after an interval of 1 to 2 minutes (such as 1.2 minutes, 1.4 minutes, 1.6 minutes, 1.8 minutes, etc.) to obtain the first intermediate ore and the first cleaned foam;

[0115] Among them, the first concentration temperature is 60-65°C (such as 61°C, 62°C, 63°C, 64°C, etc.), the pulp concentration of the scavenging foam and the roughing foam is 50-55% (such as 51%, 52%, 53%, 54%, etc.), and the pH is 8-9;

[0116] Among them, the main components of scavenging foam and roughing foam are rare earth minerals;

[0117] The time interval between adding water glass and collector is 1 to 2 minutes (e.g. 1.2 minutes, 1.4 minutes, 1.6 minutes, 1.8 minutes, etc.);

[0118] The addition amount of water glass is 1000-1200mL / t (such as 1050mL / t, 1100mL / t, 1120mL / t, 1140mL / t, 1160mL / t, 1180mL / t, etc.), and the addition amount of collector is 15000-20000mL / t (such as 16000mL / t, 17000mL / t, 18000mL / t, 19000mL / t, etc.);

[0119] The time for the first selection and scraping of bubbles is 3 to 4 minutes (for example, 3.2 minutes, 3.4 minutes, 3.6 minutes, 3.8 minutes, etc.).

[0120] Specifically, frothers such as 2# oil are helpful for mineral capture but have poor selectivity and are prone to capture gangue minerals together. They are suitable for the roughing step but not for the fine step with higher product purity. Therefore, no frother is added in step S4.

[0121] As an optional implementation mode of the present invention, the scavenged tailings and the first intermediate ore are used as feed materials for the next step of comprehensive recovery of fluorite.

[0122] As an optional implementation of the present invention, in step S5, the second selection includes:

[0123] The first selected foam is poured into a flotation tank, and the foam is scraped for the second time to obtain the second intermediate ore and the second selected foam;

[0124] Among them, the second concentration temperature is 60-65°C (such as 61°C, 62°C, 63°C, 64°C, etc.), the pulp concentration of the first concentration foam is 40-45% (such as 41%, 42%, 43%, 44%, etc.), and the pH is 8-9;

[0125] Among them, the main component of the first selected foam is rare earth minerals;

[0126] The time for the second selection and scraping of bubbles is 2 to 3 minutes (for example, 2.2 minutes, 2.4 minutes, 2.6 minutes, 2.8 minutes, etc.).

[0127] As an optional embodiment of the present invention, in step S6, the second desludging operation includes:

[0128] Pour the second selected foam into a container, add production return water, stir, and let stand after stirring to obtain concentrate desludging water and rare earth concentrate;

[0129] Among them, the volume ratio of the second selected foam and the production return water is 1mL:3mL;

[0130] The stirring refers to stirring with a JJ-1 type electric mechanical stirrer;

[0131] The stirring time is 3 to 5 minutes (for example, 3.5 minutes, 4 minutes, 4.5 minutes, etc.), and the speed of the stirring paddle is 150 to 200 rad / min (for example, 160 rad / min, 170 rad / min, 180 rad / min, 190 rad / min, etc.); after the stirring is completed, let it stand for 5 to 10 minutes (for example, 6 minutes, 7 minutes, 8 minutes, 9 minutes, etc.).

[0132] As an optional implementation mode of the present invention, the scavenged tailings and the first intermediate ore are used as feed materials for the next step of comprehensive recovery of fluorite.

[0133] The present invention will be further described in detail below with reference to specific embodiments and comparative examples.

[0134] The preparation method of the KYR-1 collector used in the embodiments of the present invention and the comparative examples is as follows:

[0135] Fatty acid methyl ester and hydroxylamine hydrochloride were mixed in a mass ratio of 1:1, and reacted at 70°C for 4 hours to obtain a KYR-1 collector.

[0136] Example 1

[0137] Take 1L of circulating raw ore slurry (i.e. tailings after iron separation) from the rare earth separation box of Baosteel Baoshan Mining Company. The slurry concentration is ≈65% and the temperature is ≈25℃. Screen and analyze the raw ore slurry:

[0138] Multi-element testing and particle size analysis are carried out on the raw ore slurry to obtain the content ratio of each element in the raw ore and the distribution of minerals of different particle sizes in the raw ore.

[0139] The analysis results of the content of each element in the original ore are shown in Table 2:

[0140] Table 2 Results of chemical multi-element analysis of raw ore

[0141] Components REO TFe F P S CaO MgO <![CDATA[K2O]]> content / % 8.40 13.22 6.899 1.56 1.120 22.00 2.55 0.71 Components <![CDATA[Na2O]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> <![CDATA[Nb2O5]]> <![CDATA[Sc2O3]]> <![CDATA[TiO2]]> BaO <![CDATA[ThO2]]> content / % 1.25 0.58 17.43 0.16 290.66ppm 0.35 3.28 0.010

[0142] According to Table 2, the mass percentage of rare earth oxide REO in the raw ore is 8.4%.

[0143] The distribution of minerals of different particle sizes in the original ore is shown in Table 3:

[0144] Table 3 Screening analysis results of minerals with different particle sizes in the original ore

[0145] Particle size Yield / % REO / % Distribution rate / % -500 mesh 48.71 10.12 59.18 -400~+500 mesh 9.10 9.82 10.68 -300~+400 mesh 12.67 9.20 14.05 -200~+300 mesh 12.85 6.35 9.84 +200 mesh 16.67 3.11 6.25 total 100.00 8.33 100.00

[0146] According to Table 3, the purpose of analyzing the particle size of the raw ore in Table 3 is to ensure that the particle size of the raw ore is within the particle size range that is most conducive to recovery. Usually, when rare earth flotation is performed, the raw ore -200 mesh ≥85% is required. Under this particle size, the degree of dissociation of rare earth mineral monomers is better, and the flotation index is good under the same conditions. It can be used as a general requirement for ore feeding for rare earth flotation.

[0147] A method for flotation of rare earth by closed circuit de-doping using return water comprises:

[0148] S1: Perform the first desludging on the raw ore slurry to obtain upper ore slurry and bottom ore slurry:

[0149] The raw ore pulp was placed in a 5000ml glass beaker, 1000ml of production return water was added, and a JJ-1 electric mechanical stirrer was used to stir for 3min, with the stirring blade speed of 180rad / min. After stirring, it was allowed to stand for 10min to obtain the upper layer of ore mud and the bottom layer of ore pulp, and the upper layer of ore mud was manually poured out;

[0150] S2: The bottom ore pulp obtained in step S1 is subjected to roughing work to obtain roughing foam and roughing pulp:

[0151] The bottom pulp obtained in step S1 is poured into a 1L plastic flotation tank for roughing, the roughing temperature is 60°C, the concentration is 65%, the pH is ≈ 8.5, 13ml of water glass is added, after an interval of 3min, 60ml of KYR-1 collector is added, after an interval of 5min, 2 drops of 2# oil are added, and after an interval of 2min, roughing foaming is started, and the foaming time is 2min to obtain roughing foam and roughing pulp.

[0152] S3: Sweep the pulp after roughing to obtain scavenging tailings and scavenging foam:

[0153] Pour the pulp after roughing into the flotation tank, add 30ml KYR-1 collector to the pulp in the flotation tank, add 1 drop of 2# oil after 1min, and start scavenging and scraping foam after 2min, the scraping time is 2min30s, and obtain scavenging foam and scavenging tailings.

[0154] S4: The scavenging foam and the roughing foam are subjected to the first concentration to obtain the first intermediate ore and the first concentrated foam:

[0155] Combine the scavenging foam and the roughing foam and pour them into a 0.75L plastic flotation tank for the first selection. The selection temperature is 60℃, the concentration is 50%, and the pH is ≈ 8.5. Add 1ml of water glass. After a 1min interval, add 15ml of KYR-1 collector. After a 1min interval, start the first selection and scraping foam. The scraping time is 3min. The first intermediate ore and the first selected foam are obtained. The first intermediate ore and the scavenging tailings can be used as feed for the next step of comprehensive fluorite recovery.

[0156] S5: The first selected foam is subjected to a second selection to obtain a second intermediate ore and a second selected foam:

[0157] Pour the first selected foam into a 0.5L plastic flotation tank for the second selection, with a selection temperature of 60°C, a concentration of 40%, and a pH value of 8.5. Start the second selection and scraping foam for 2min30s to obtain the second intermediate ore and the second selected foam. Pour all the second intermediate ore into the original ore pulp of step S1.

[0158] S6: Perform the second desludging work in the second concentration foam to obtain concentrate desludging water and rare earth concentrate:

[0159] Pour the second concentration foam into a 2000ml glass beaker, add 500ml of production return water, use JJ-1 electric mechanical stirrer to stir for 3min, the stirring paddle speed is 180rad / min, and stand for 8min after stirring to obtain concentrate desludging water and rare earth concentrate, the concentrate grade REO ≥ 58%.

[0160] S7: The concentrate desludging water obtained in step S6 and the second intermediate ore obtained in step S5 are fed into the raw ore slurry in step S1 to realize a closed circuit.

[0161] According to the above-mentioned closed-loop water return and drug removal experimental method and conditions, four groups of experiments were carried out, wherein the first group of experiments only included steps S1-S6, and the concentrate desludging water obtained in step S6 of the first group of experiments and the second intermediate ore obtained in step S5 were fed into the original ore slurry of the second group of experiments; then, the concentrate desludging water obtained in step S6 of the second group of experiments and the second intermediate ore obtained in step S5 were fed into the original ore slurry of the third group of experiments; finally, the concentrate desludging water obtained in step S6 of the third group of experiments and the second intermediate ore obtained in step S5 were fed into the original ore slurry of the fourth group of experiments to achieve a closed circuit.

[0162] The experimental results of the second to fourth groups of experiments are shown in Table 4 below:

[0163] Table 4 Closed circuit stability test data

[0164]

[0165] Comparative Example 1

[0166] The difference between this comparative example and Example 1 is that the concentrate desludging water obtained in the first group of experimental steps S6 and the second intermediate ore obtained in step S5 are fed into the second group of steps S4 for re-concentration; the concentrate desludging water obtained in the second group of experimental steps S6 and the second intermediate ore obtained in step S5 are fed into the third group of steps S4 for re-concentration; the concentrate desludging water obtained in the third group of experimental steps S6 and the second intermediate ore obtained in step S5 are fed into the fourth group of steps S4 for re-concentration, and the remaining steps and technical parameters are the same as those in Example 1. The measured experimental results are shown in Table 5:

[0167] Table 5 Comparative Example 1 Test Results

[0168]

[0169] According to Table 5, in the first to fourth groups of experiments in Comparative Example 1, the concentrate desludging water obtained in step S6 and the second intermediate ore obtained in step S5 were fed into step S4 for re-concentration, and the interference of residual drugs in the return water was not completely eliminated, resulting in the rare earth concentrate grade REO and recovery rate indicators unable to meet the requirements at the same time.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for flotation of rare earth by closed circuit de-doping using return water, characterized in that: The steps include: S1: Perform the first desludging operation on the raw ore slurry to obtain upper ore slurry and bottom ore slurry; S2: adding water glass, a collector and a frother to the bottom pulp obtained in step S1, performing roughing work, and obtaining roughing foam and roughing pulp; S3: adding collector and frother to the pulp after roughing, and performing scavenging to obtain scavenging tailings and scavenging foam; S4: adding water glass and a collector to the scavenging foam and the roughing foam to perform the first concentration to obtain the first intermediate ore and the first concentrated foam; S5: performing a second concentration on the first concentrated foam to obtain a second intermediate ore and a second concentrated foam; S6: performing a second desludging operation on the second concentrated foam to obtain concentrate desludging water and rare earth concentrate; S7: the concentrate desludging water obtained in step S6 and the second intermediate ore obtained in step S5 are fed into the raw ore slurry in step S1 to continue rare earth flotation, thus realizing a closed circuit.

2. The method for flotation of rare earth by closed-circuit de-drugation using return water according to claim 1, characterized in that: The collector in step S2, step S3 and step S4 is a rare earth collector, and the rare earth collector includes a KYR-1 collector or a LF8# collector; And / or, the foaming agent in step S2 and step S3 includes one or more of 2# oil, H103 or J102, preferably 2# oil.

3. The method for flotation of rare earth by closed-circuit de-drugation using return water according to claim 2, characterized in that: The preparation method of the KYR-1 type collector comprises the following steps: The fatty acid methyl ester and hydroxylamine hydrochloride are heated and mixed to obtain a KYR-1 type collector; Preferably, the mass ratio of the fatty acid methyl ester to hydroxylamine hydrochloride is (1-3): (1-3); Preferably, the heating and mixing temperature is 50-80° C., and the heating and mixing time is 2-4 hours.

4. The method for flotation of rare earth by closed-circuit de-drugation using return water according to claim 1, characterized in that: The ore slurry of the raw ore in step S1 has a slurry concentration of 60-65% and a temperature of 20-30° C.; Screening and analysis of raw ore pulp includes the following steps: Multi-element testing and particle size analysis are carried out on the raw ore slurry to obtain the content ratio of each element in the raw ore and the distribution of minerals of different particle sizes in the raw ore.

5. The method for flotation of rare earth by closed-circuit de-doping using return water according to claim 1, characterized in that: In step S1, the first desludging operation includes: The raw ore pulp is placed in a container, and production return water is added and stirred. After the stirring is completed, the ore pulp is allowed to stand to obtain an upper layer of ore mud and a bottom layer of ore pulp; The production return water is the total return water of the whole process of "iron-rare earth-fluorite" separation; The mass volume ratio of raw ore slurry and production return water is 1.6g:1mL; The stirring time is 3 min to 5 min, and the stirring paddle speed is 150 to 200 rad / min; after the stirring is completed, let it stand for 8 to 12 min.

6. The method for flotation of rare earth by closed-circuit de-doping using return water according to claim 1, characterized in that: In step S2, the rough selection process includes: The bottom pulp obtained in step S1 is poured into the flotation tank, and then water glass, a collector and a frother are added in sequence, and roughing frothing is started after an interval of 2 to 3 minutes to obtain roughing froth and roughing pulp; Among them, the roughing temperature is 60-65°C, the pulp concentration of the bottom pulp is 60-65%, and the pH is 8-9; The addition time of water glass, collector and frother is 3-5min respectively; The addition amount of water glass is 10000-15000mL / t, the addition amount of collector is 50000~70000mL / t, and the addition amount of foaming agent is 100~150mL / t; The time for the rough selection and scraping of bubbles is 2 to 3 minutes.

7. The method for flotation of rare earth by closed-circuit de-doping using return water according to claim 1, characterized in that: In step S3, the scanning operation includes: Collectors and frothers are added to the pulp after roughing in sequence, and scavenging and scraping foaming are started after an interval of 2 to 3 minutes to obtain scavenging foam and scavenging tailings; Among them, the scavenging temperature is 60-65°C, the pulp concentration of the ore pulp after roughing is 50-55%, and the pH is 8-9; The time interval between adding the collector and the foaming agent is 1 to 2 minutes; The amount of collector added is 30000~4000mL / t, and the amount of foaming agent added is 50~100mL / t; The time for sweeping and scraping bubbles is 2 to 3 minutes.

8. The method for flotation of rare earth by closed-circuit de-doping using return water according to claim 1, characterized in that: In step S4, the first selection includes: Pour the scavenging foam and the roughing foam into the flotation tank, add water glass and collector in turn, and then start the first cleaning and scraping foam after an interval of 1 to 2 minutes to obtain the first intermediate ore and the first cleaned foam; Among them, the first concentration temperature is 60-65°C, the pulp concentration of the scavenging foam and the roughing foam is 50-55%, and the pH is 8-9; The time interval between adding water glass and collector is 1 to 2 minutes; The addition amount of water glass is 1000~1200mL / t, and the addition amount of collector is 15000~20000mL / t; The time for the first selective scraping is 3 to 4 minutes.

9. The method for flotation of rare earth by closed-circuit de-doping using return water according to claim 1, characterized in that: In step S5, the second selection includes: The first selected foam is poured into a flotation tank, and the foam is scraped for the second time to obtain the second intermediate ore and the second selected foam; The temperature of the second concentration is 60-65°C, the pulp concentration of the first concentration foam is 40-45%, and the pH is 8-9; The time for the second selective scraping is 2 to 3 minutes.

10. The method for flotation of rare earth by closed circuit de-doping using return water according to claim 1, characterized in that: In step S6, the second desludging operation includes: Pour the second selected foam into a container, add production return water, stir, and let stand after stirring to obtain concentrate desludging water and rare earth concentrate; Among them, the volume ratio of the second selected foam and the production return water is 1mL:3mL; The stirring refers to stirring with a JJ-1 type electric mechanical stirrer; The stirring time is 3 to 5 minutes, and the stirring paddle speed is 150 to 200 rad / min; after the stirring is completed, let it stand for 5 to 10 minutes.

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