Multi-stage ultra-pulse countercurrent washing, deacidification, iron extraction and phosphorus reduction process for high-phosphoric-acid iron-washed concentrate

Abstract

The invention provides a multi-stage ultra-pulse countercurrent washing, deacidification, iron extraction and phosphorus reduction process for high-phosphoric-acid washed iron ore concentrate, which comprises the following steps: sequentially carrying out first-stage washing, second-stage washing, third-stage washing and fourth-stage washing on the washed iron ore concentrate pulp, and filtering to obtain iron ore concentrate; the effluent of the fourth-stage washing is used as the washing water of the third-stage washing, the effluent of the third-stage washing is used as the washing water of the second-stage washing, the effluent of the second-stage washing is used as the washing water of the first-stage washing, and the effluent of the first-stage washing is used as the washing water of the fourth-stage washing after being neutralized. According to the method, four-stage elutriation is adopted, residual acid in the acid-washed iron ore concentrate can be efficiently removed, the pH value of the acid-washed iron ore concentrate is increased to 6.3 or above from 0.5-0.8, meanwhile, impurities of the acid-washed iron ore concentrate can be further removed, the P content is reduced to 0.15% or below, the TFe grade is increased to 64% or above, and the mFe recovery rate is 98% or above.

Description

Technical Field

[0001] This application relates to the field of mineral processing technology, and in particular to a multi-stage superpulse countercurrent washing process for deacidification, iron extraction and phosphorus reduction of high-phosphate washed iron concentrate. Background Technology

[0002] High-phosphorus oolitic hematite is a type of iron ore with relatively large reserves in my country. It is characterized by its fine grain size, complex mineral composition, high content of harmful phosphorus impurities, and frequent close association with hematite, making it complex and difficult to beneficiate. Excessive phosphorus content in iron ore leads to phosphorus entering the metal during ironmaking and steelmaking processes, causing the steel to become brittle upon cooling and severely affecting the quality of pig iron and steel. Dephosphorization of high-phosphorus iron ore is a major technical challenge currently being explored and solved in China.

[0003] Currently used phosphorus removal methods mainly include mineral processing, chemical leaching, bioleaching, and blast furnace metallurgical phosphorus removal. For example, Chinese patent CN102168174B discloses a method for dephosphorizing high-phosphorus hematite. First, the high-phosphorus hematite is crushed and ground to obtain high-phosphorus hematite powder with a particle size of less than 0.1 mm. Then, the high-phosphorus hematite powder is mixed with organic acid, and distilled water is added at a certain weight ratio. The mixture is stirred, separated, washed, and dried to obtain hematite with a phosphorus content of less than 0.2%. This method is simple, has a short production cycle, and low cost, but the phosphorus content in the hematite remains relatively high. Summary of the Invention

[0004] In view of this, this application provides a multi-stage superpulse countercurrent washing process for deacidification, iron extraction and phosphorus reduction of high phosphoric acid washed iron concentrate. The process provided by this application can further remove phosphorus and impurities from the iron concentrate after acid washing of high phosphorus hematite, thereby improving the grade of the iron concentrate.

[0005] This application provides a multi-stage ultra-fast countercurrent washing process for deacidification, iron extraction, and phosphorus reduction of high-phosphate iron concentrate, comprising the following steps:

[0006] The pickled iron concentrate slurry was subjected to first-stage washing, second-stage washing, third-stage washing and fourth-stage washing in sequence, and then filtered to obtain iron concentrate;

[0007] The effluent from the fourth stage of rinsing is used as the rinsing water for the third stage of rinsing, the effluent from the third stage of rinsing is used as the rinsing water for the second stage of rinsing, the effluent from the second stage of rinsing is used as the rinsing water for the first stage of rinsing, and the effluent from the first stage of rinsing, after being neutralized, is used as the rinsing water for the fourth stage of rinsing.

[0008] In some specific implementations, the effluent from the first stage of rinsing is neutralized and mixed with fresh water to serve as the rinsing water for the fourth stage of rinsing.

[0009] In some specific implementations, the effluent from the first-stage washing is neutralized with lime slurry.

[0010] In some specific implementations, the effluent from the first stage of rinsing is neutralized, concentrated, and then mixed with fresh water to serve as the rinsing water for the fourth stage of rinsing.

[0011] In some specific implementations, the acid-washed iron concentrate has a TFe grade of 61%~63%, a P content of 0.18%~0.22%, a pulp concentration of 30%~40%, and a pH value of 0.5~0.8.

[0012] In some specific implementations, the acid-washed iron concentrate is acid-washed iron concentrate leached with concentrated sulfuric acid.

[0013] In some specific implementations, during the first stage of rinsing, the pressure of the rinsing water is 0.2 MPa to 0.3 MPa, the pH value of the rinsing water is 6.5 to 7.5, and the suspended solids concentration of the rinsing water is less than 250 ppm.

[0014] In the second stage of rinsing, the pressure of the rinsing water is 0.2MPa~0.3MPa, the pH value of the rinsing water is 6.5~7.5, and the suspended solids concentration of the rinsing water is less than 250ppm;

[0015] In the third stage of rinsing, the pressure of the rinsing water is 0.2MPa~0.3MPa, the pH value of the rinsing water is 6.5~7.5, and the suspended solids concentration of the rinsing water is less than 250ppm;

[0016] In the fourth stage of rinsing, the pressure of the rinsing water is 0.2MPa~0.3MPa, the pH value of the rinsing water is 6.5~7.5, and the suspended solids concentration of the rinsing water is less than 250ppm.

[0017] The washing-to-water ratio for the first, second, third, and fourth stages of rinsing is 5 to 7.

[0018] In some specific implementations, the first-stage washing is carried out under the action of a magnetic field; the strength of the magnetic field is 300 Gs to 350 Gs.

[0019] The second-stage washing is carried out under the action of a magnetic field; the strength of the magnetic field is 300 Gs to 350 Gs.

[0020] The third-stage washing is carried out under the action of a magnetic field; the strength of the magnetic field is 300 Gs to 350 Gs.

[0021] The fourth stage of washing is carried out under the action of a magnetic field; the strength of the magnetic field is 300 Gs to 350 Gs.

[0022] In some specific implementations, the first-stage washing is performed under the action of ultrasound; the intensity of the ultrasound is 560 W / m. 2~720W / m 2 ;

[0023] The second-stage washing is performed under the action of ultrasound; the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 ;

[0024] The third stage of washing is performed under the action of ultrasound; the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 ;

[0025] The fourth stage of washing is performed under the action of ultrasound; the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 .

[0026] In some specific implementations, the first-stage washing is performed using an ultra-pulse machine;

[0027] The second stage of washing is carried out using an ultra-pulse machine;

[0028] The third-stage washing is performed using an ultra-pulse machine;

[0029] The fourth stage of washing is carried out using an ultra-pulse machine.

[0030] In some specific implementations, the undercurrent concentration of the ultrapulse generator is 68%~70%.

[0031] This application provides a multi-stage superpulse countercurrent washing process for deacidification, iron extraction, and phosphorus reduction of high-phosphate washed iron concentrate, comprising the following steps: The acid-washed iron concentrate slurry is sequentially subjected to a first-stage washing, a second-stage washing, a third-stage washing, and a fourth-stage washing, followed by filtration to obtain iron concentrate. The effluent from the fourth-stage washing is used as the rinsing water for the third-stage washing, the effluent from the third-stage washing is used as the rinsing water for the second-stage washing, the effluent from the second-stage washing is used as the rinsing water for the first-stage washing, and the effluent from the first-stage washing is neutralized and used as the rinsing water for the fourth-stage washing. This application employs a four-stage washing process, which can efficiently remove residual acid from the acid-washed iron concentrate, increasing its pH value from 0.5-0.8 to above 6.3. Simultaneously, it can further remove impurities from the acid-washed iron concentrate, reducing the P content to below 0.15%, increasing the TFe grade to above 64%, and achieving an mFe recovery rate of over 98%. Moreover, this application uses countercurrent washing, and only introduces fresh water during the fourth stage of rinsing, resulting in a lower water consumption of 30% to 60% and reduced treatment costs. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the ultrasound pulse machine provided in this application;

[0033] Figure 2This is a schematic diagram of the deacidification, iron extraction, and phosphorus reduction process for high-phosphate washed iron concentrate provided in this application. Detailed Implementation

[0034] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0035] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0036] It should be understood that the order of steps or the sequence of actions is not important as long as this application remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0037] The use of any and all instances or exemplary language such as “e.g.” or “including” herein is merely intended to better illustrate the application and does not constitute a limitation on the scope of the application unless the claims are made. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of this application.

[0038] Furthermore, the numerical ranges and parameters used to define this application are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any numerical value inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise explicitly stated, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately." Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0039] This application provides a multi-stage ultra-fast countercurrent washing process for deacidification, iron extraction, and phosphorus reduction of high-phosphate iron concentrate, comprising the following steps:

[0040] The pickled iron concentrate slurry was subjected to first-stage washing, second-stage washing, third-stage washing and fourth-stage washing in sequence, and then filtered to obtain iron concentrate;

[0041] The effluent from the fourth stage of rinsing is used as the rinsing water for the third stage of rinsing, the effluent from the third stage of rinsing is used as the rinsing water for the second stage of rinsing, the effluent from the second stage of rinsing is used as the rinsing water for the first stage of rinsing, and the effluent from the first stage of rinsing, after being neutralized, is used as the rinsing water for the fourth stage of rinsing.

[0042] This application describes the processing of acid-washed iron concentrate, wherein the acid-washed iron concentrate is a slurry obtained by acid leaching of iron ore, followed by acid washing, preferably a slurry obtained by concentrated sulfuric acid leaching followed by acid washing. In some specific implementations, the iron ore is a high-phosphorus iron ore, such as high-phosphorus hematite or high-phosphorus oolitic hematite. In this case, the acid-washed iron concentrate is preferably a product obtained by roasting and magnetic separation followed by concentrated sulfuric acid leaching, followed by acid washing. In some specific implementations, the TFe grade of the acid-washed iron concentrate is 61%~63%, for example, 61%, 62%, or 63%; the P content of the acid-washed iron concentrate is 0.18%~0.22%, for example, 0.18%, 0.19%, 0.20%, 0.21%, or 0.22%; the slurry concentration of the acid-washed iron concentrate is 30%~40%, for example, 30%, 33%, 35%, 37%, or 40%; and the pH value of the acid-washed iron concentrate is 0.5~0.8, for example, 0.5, 0.6, 0.7, or 0.8.

[0043] This application first performs a first-stage washing of the pickled iron concentrate. The rinsing water used in the first-stage washing comes from the overflow water after the second-stage washing (i.e., the effluent from the second-stage washing). This process removes acid and iron impurities from the pickled iron concentrate simultaneously. In some specific implementations, the first-stage washing involves bottom-feeding rinsing water, meaning the rinsing water is added to the washing equipment from bottom to top and discharged through the overflow device at the top of the washing equipment after washing. The pickled iron concentrate is added to the washing equipment from top to bottom and discharged from the bottom of the washing equipment after washing.

[0044] In some specific implementations, the pressure of the rinsing water in the first-stage washing is 0.2 MPa to 0.3 MPa, for example, 0.2 MPa, 0.25 MPa, or 0.3 MPa; the pH value of the rinsing water is 6.5 to 7.5, for example, 6.5, 7.0, or 7.5; and the suspended solids concentration of the rinsing water is below 250 ppm, for example, 200 ppm or 150 ppm. In some specific implementations, the first-stage washing is performed under the influence of a magnetic field. In some specific implementations, the strength of the magnetic field is 300 Gs to 350 Gs, for example, 300 Gs, 320 Gs, or 350 Gs. In some specific implementations, the first-stage washing is performed under the influence of ultrasound. In some specific implementations, the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 For example, it can be 560W / m 2 640W / m 2 720W / m 2 wait.

[0045] Specifically, the first-stage washing can be carried out using an ultrasonic pulse separator, which is a longitudinally high-gradient pulsed ultrasonic combined with magnetic gravity separation device with a weak magnetic field. It has advantages such as high washing efficiency, good separation effect, low equipment investment, and small footprint. It can not only clean the acid in the iron concentrate but also remove impurities mixed in, further improving the grade of the iron concentrate. This application can use a commercially available ultrasonic pulse separator with the characteristics of longitudinally high-gradient pulsed ultrasonic combined with magnetic gravity for washing, or an ultrasonic pulse separator with the following structure. See [link to relevant documentation]. Figure 1 , Figure 1 The diagram below shows the structure of the ultrasonic pulse generator provided in this application, in which 1 is the separation cylinder, 2 is the ultrasonic vibrating rod, 3 is the electromagnetic coil, 4 is the vertical feed pipe, 5 is the material blocking column, 51 is the material chamber, 11 is the tailings outlet, 12 is the feed inlet, 13 is the water inlet pipe, 14 is the concentrate outlet, 9 is the diaphragm, 10 is the pulse generator, and 15 is the pulse tube.

[0046] The ultrasonic pulse machine includes a separation cylinder 1, with a tailings outlet 11 and a feed inlet 12 at the top of the separation cylinder, and a water inlet pipe 13 and a concentrate outlet 14 at the bottom of the separation cylinder. Multiple ultrasonic vibrating rods 2 are evenly distributed and fixed along the circumference of the separation cylinder wall, and multiple electromagnetic coils 3 are wound around the separation cylinder wall. The ultrasonic vibrating rods are located between two adjacent electromagnetic coils.

[0047] The ultra-pulse machine includes a vertical feed pipe 4, which is located in the middle of the separation cylinder 1. One end of the vertical feed pipe is connected to the feed port 12, and the other end is a closed end that extends downward. Multiple first vortex discharge ports are evenly distributed along the circumference of the outer wall of the vertical feed pipe near the closed end.

[0048] The super-pulse machine includes a material blocking column 5, which is vertically arranged at the bottom inside the separation cylinder 1 and directly below the other end of the vertical feed pipe. A material cavity 51 is provided at the top of the material blocking column, and a plurality of second swirl outlets are evenly distributed along the circumference of the outer wall of the material cavity. The closed end of the vertical feed pipe extends through the top of the material blocking column into the material cavity.

[0049] The ultrapulse machine also includes a tympanic membrane 9 disposed on the side wall of the separation cylinder 1, and the pulsation motor 10 is connected to the tympanic membrane 9 through the pulsation tube 15.

[0050] Using an ultrasonic pulse mill to wash acid-washed iron concentrate can achieve better washing results under the action of ultrasound, and a magnetic field can be applied to increase the grade of TFe. In some specific implementations, the ultrasonic pulse mill is equipped with an underflow concentration control system to control the underflow concentration at 68%~70%, such as 68%, 69%, or 70%.

[0051] After the first stage of washing, the washed iron concentrate undergoes a second stage of washing. The effluent from this second stage is neutralized and used as the rinse water for the fourth stage of washing. In some specific implementations, lime slurry is preferably used to neutralize the effluent from the first stage of washing. In some specific implementations, the neutralized rinse water is mixed with fresh water and used as the rinse water for the fourth stage of washing. In some specific implementations, the neutralized rinse water is thickened before being mixed with fresh water. In some specific implementations, the rinse water is treated using a thickener to remove tailings and sediments, resulting in neutralized circulating water.

[0052] In one specific implementation of this application, the rinsing water used in the second-stage washing comes from the overflow water after the third-stage washing (i.e., the effluent obtained after the third-stage washing), which further deacidifies, extracts iron, and removes impurities from the acid-washed iron concentrate. In some specific implementations, the second-stage washing involves bottom-feeding rinsing water, meaning the rinsing water is added to the washing equipment from bottom to top and discharged from the overflow device at the top of the washing equipment after washing. The acid-washed iron concentrate is added to the washing equipment from top to bottom and discharged from the bottom of the washing equipment after washing.

[0053] In some specific implementations, the pressure of the rinsing water in the second-stage washing is 0.2 MPa to 0.3 MPa, for example, 0.2 MPa, 0.25 MPa, or 0.3 MPa; the pH value of the rinsing water is 6.5 to 7.5, for example, 6.5, 7.0, or 7.5; and the suspended solids concentration of the rinsing water is below 250 ppm, for example, 200 ppm or 150 ppm. In some specific implementations, the second-stage washing is performed under the influence of a magnetic field. In some specific implementations, the strength of the magnetic field is 300 Gs to 350 Gs, for example, 300 Gs, 320 Gs, or 350 Gs. In some specific implementations, the second-stage washing is performed under the influence of ultrasound. In some specific implementations, the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 For example, it can be 560W / m 2 640W / m 2 720W / m 2 wait.

[0054] Specifically, the second-stage washing can be carried out using an ultrasonic pulse separator. An ultrasonic pulse separator is a longitudinal, high-gradient, pulsed, weak-magnetic-field combined ultrasonic and magnetic-gravity separation device. It has advantages such as high washing efficiency, good separation effect, low equipment investment, and small footprint. It can not only clean the acid in the iron concentrate but also remove impurities mixed in with the iron concentrate, further improving the grade of the iron concentrate. The ultrasonic pulse separator can be a commercially available product or can have the structure described above, which will not be elaborated further in this application. Using an ultrasonic pulse separator to wash acid-washed iron concentrate can achieve better washing results under the action of ultrasound, and at the same time, a magnetic field can be applied to improve the grade of TFe. In some specific implementations, the ultrasonic pulse separator is equipped with an underflow concentration control system, controlling the underflow concentration to 68%~70%, such as 68%, 69%, or 70%.

[0055] After the second stage of washing is completed, the washed iron concentrate undergoes a third stage of washing, and the effluent from the third stage is returned to the first stage of washing as the rinsing water.

[0056] In one specific implementation of this application, the rinsing water used in the third-stage washing comes from the overflow water after the fourth-stage washing (i.e., the effluent after the fourth-stage washing), which further deacidifies and removes impurities from the acid-washed iron concentrate. In some specific implementations, the third-stage washing involves bottom-feeding rinsing water, meaning the rinsing water is added to the washing equipment from bottom to top and discharged through the overflow device at the top of the washing equipment after washing. The acid-washed iron concentrate is added to the washing equipment from top to bottom and discharged from the bottom of the washing equipment after washing.

[0057] In some specific implementations, the pressure of the rinsing water in the third-stage washing is 0.2 MPa to 0.3 MPa, for example, 0.2 MPa, 0.25 MPa, or 0.3 MPa; the pH value of the rinsing water is 6.5 to 7.5, for example, 6.5, 7.0, or 7.5; and the suspended solids concentration of the rinsing water is below 250 ppm, for example, 200 ppm or 150 ppm. In some specific implementations, the third-stage washing is performed under the influence of a magnetic field. In some specific implementations, the strength of the magnetic field is 300 Gs to 350 Gs, for example, 300 Gs, 320 Gs, or 350 Gs. In some specific implementations, the third-stage washing is performed under the influence of ultrasound. In some specific implementations, the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 For example, it can be 560W / m 2 640W / m 2 720W / m 2 wait.

[0058] Specifically, the third-stage washing can be performed using an ultrasonic pulse separator. An ultrasonic pulse separator is a longitudinal, high-gradient, pulsed, weak-magnetic-field combined ultrasonic and magnetic-gravity separation device. It has advantages such as high washing efficiency, good separation effect, low equipment investment, and small footprint. It can not only clean the acid in the iron concentrate but also remove impurities, further improving the grade of the iron concentrate. The ultrasonic pulse separator can be a commercially available product or have the structure described above, which will not be elaborated further in this application. Using an ultrasonic pulse separator to wash acid-washed iron concentrate can achieve better washing results under the action of ultrasound, and a magnetic field can be applied to improve the TFe grade. In some specific implementations, the ultrasonic pulse separator is equipped with an underflow concentration control system, controlling the underflow concentration to 68%~70%, such as 68%, 69%, or 70%.

[0059] After the third stage of washing is completed, the washed iron concentrate undergoes a fourth stage of washing, and the effluent from the fourth stage is returned to the second stage as the rinsing water for the second stage of washing.

[0060] In one specific implementation of this application, the rinsing water used in the fourth-stage washing comes from the overflow water after the first-stage washing (i.e., the effluent obtained after the first-stage washing), and is used to further deacidify and remove impurities from the acid-washed iron concentrate. As mentioned above, the rinsing water used in the fourth-stage washing comes from the overflow water after the first-stage washing, which has been neutralized and concentrated, and then mixed with fresh water; this will not be elaborated further here. In some specific implementations, the fourth-stage washing involves bottom-feeding rinsing water, meaning the rinsing water is added to the washing equipment from bottom to top, and discharged through the overflow device at the top of the washing equipment after washing. The acid-washed iron concentrate is added to the washing equipment from top to bottom, and discharged from the bottom of the washing equipment after washing.

[0061] In some specific implementations, the pressure of the rinsing water in the fourth-stage washing is 0.2 MPa to 0.3 MPa, for example, 0.2 MPa, 0.25 MPa, or 0.3 MPa; the pH value of the rinsing water is 6.5 to 7.5, for example, 6.5, 7.0, or 7.5; and the suspended solids concentration of the rinsing water is below 250 ppm, for example, 200 ppm or 150 ppm. In some specific implementations, the fourth-stage washing is performed under the influence of a magnetic field. In some specific implementations, the strength of the magnetic field is 300 Gs to 350 Gs, for example, 300 Gs, 320 Gs, or 350 Gs. In some specific implementations, the fourth-stage washing is performed under the influence of ultrasound. In some specific implementations, the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 For example, it can be 560W / m 2 640W / m 2720W / m 2 wait.

[0062] Specifically, the fourth-stage washing can be performed using an ultrasonic pulse separator. An ultrasonic pulse separator is a longitudinal, high-gradient, pulsed, weak-magnetic-field combined ultrasonic and magnetic-gravity separation device. It has advantages such as high washing efficiency, good separation effect, low equipment investment, and small footprint. It can not only clean the acid in the iron concentrate but also remove impurities, further improving the grade of the iron concentrate. The ultrasonic pulse separator can be a commercially available product or have the structure described above, which will not be elaborated further in this application. Using an ultrasonic pulse separator to wash acid-washed iron concentrate can achieve better washing results under the action of ultrasound, and a magnetic field can be applied to improve the TFe grade. In some specific implementations, the ultrasonic pulse separator is equipped with an underflow concentration control system, controlling the underflow concentration to 68%~70%, such as 68%, 69%, or 70%.

[0063] When using an ultra-pulse washing machine for rinsing, the washing water ratio of the first, second, third, and fourth stages of rinsing, i.e., the ratio of the unit rinsing water volume of the fourth stage ultra-pulse washing machine to the unit solids volume of the first stage ultra-pulse washing machine, is 5 to 7.

[0064] After the fourth stage of washing, the washed iron concentrate is filtered to obtain refined iron ore. The effluent from the fourth stage is returned to the third stage as the rinse water. This application does not impose any special limitations on the filtration process; simply separating the iron concentrate from the water is sufficient. The filtered water can be mixed with the overflow water from the first stage of washing (i.e., the rinse water obtained after the first stage of washing) for neutralization and concentration.

[0065] In some specific implementations, when the first-stage washing, second-stage washing, third-stage washing, and fourth-stage washing all employ an ultra-pulse mill, the forward flow of the acid-washed iron concentrate slurry is as follows: the underflow concentrate from the first-stage ultra-pulse mill is fed into the second-stage ultra-pulse mill; the underflow concentrate from the second-stage ultra-pulse mill is fed into the third-stage ultra-pulse mill; the underflow concentrate from the third-stage ultra-pulse mill is fed into the fourth-stage ultra-pulse mill, where the underflow is high-grade iron concentrate. The reverse flow of the flushing water is as follows: the flushing water is fed into the water supply pipe of the fourth-stage ultra-pulse mill; the overflow from the fourth-stage ultra-pulse mill is fed into the third-stage ultra-pulse mill; the overflow from the third-stage ultra-pulse mill is fed into the second-stage ultra-pulse mill; the overflow from the second-stage ultra-pulse mill is fed into the first-stage ultra-pulse mill; and the overflow from the first-stage ultra-pulse mill is fed into the neutralization mixing tank for neutralization.

[0066] See Figure 2 , Figure 2This is a flow chart of the deacidification, iron extraction, and phosphorus reduction process for high-phosphate washed iron concentrate provided in this application. The acid-washed iron concentrate is sequentially washed through a first-stage washing, a second-stage washing, a third-stage washing, and a fourth-stage washing. After filtration, a high-grade iron concentrate with low phosphorus content is obtained. During the washing process, the effluent from the fourth-stage washing is returned to the third-stage washing, the effluent from the third-stage washing is returned to the second-stage washing, and the effluent from the second-stage washing is returned to the first-stage washing. The effluent from the first-stage washing and the filtered water are mixed, neutralized, concentrated, and then mixed again with fresh water to serve as the rinsing water for the fourth-stage washing.

[0067] After the above treatment, the pH value of the iron concentrate product is higher than 6.3, the TFe grade is higher than 64%, the P content is lower than 0.15%, and the washing recovery rate of mFe reaches more than 98%.

[0068] The present application is further illustrated below with reference to embodiments. The scope of protection of the present application is not limited to the following embodiments.

[0069] Example 1

[0070] In this embodiment, the acid-washed iron concentrate is a concentrate product obtained by leaching roasted magnetic separation products with concentrated sulfuric acid and then acid washing. Its TFe grade is 61%, P content is 0.2%, pulp concentration is 33%, and pH value is 0.6.

[0071] The pickled iron concentrate slurry is sequentially washed through four stages of ultrafiltration (UHV) washing. The flow direction of the pickled iron concentrate slurry is as follows: the underflow concentrate from the first stage UHV is fed into the second stage UHV, the underflow concentrate from the second stage UHV is fed into the third stage UHV, and the underflow concentrate from the third stage UHV is fed into the fourth stage UHV. The flushing water is fed in a counter-current manner: the fourth stage UHV uses fresh water and neutral circulating water as flushing water, and its overflow is fed into the third stage UHV; the overflow from the third stage UHV is fed into the second stage UHV; the overflow from the second stage UHV is fed into the first stage UHV; and the overflow from the first stage UHV is fed into the neutralization mixing tank. The pressure of the flushing water for each stage of washing is 0.2 MPa, the pH value is 6.8, and the suspended solids concentration is 250 ppm.

[0072] After filtration, the concentrate obtained from the fourth-stage ultrafiltration mill yields high-grade iron concentrate and filtered water. The filtered water is fed into a neutralization mixing tank. The iron concentrate has a pH of 6.5, a TFe grade of 64.2%, and a P content of 0.13%.

[0073] In the neutralization mixing tank, lime slurry is added as a neutralizing agent to adjust the pH to neutral. Then, after thickening, the thickener underflow (washing tailings and neutralized sediment) and overflow (neutral circulating water) are obtained. The thickener underflow is discharged to the tailings pond, and the neutral circulating water and fresh water are mixed and fed into the fourth-stage superpulse machine.

[0074] In this embodiment, the magnetic field strength of the ultrasonic transducer is set to 300 Gs, and the intensity of the ultrasonic wave is 560 W / m. 2 The underflow concentration is controlled at 68%, and the wash water ratio is controlled at 5:1.

[0075] Using the deacidification, iron extraction, and phosphorus reduction process of this embodiment, the TFe grade in the acid-washed iron concentrate increased by 3.2 percentage points, and the P content decreased by 0.07 percentage points, meeting the requirements for high-quality iron concentrate. The pH value was increased to 6.5, and the washing recovery rate of mFe reached 98.5%, achieving the purpose of deacidification, iron extraction, and impurity reduction.

[0076] Example 2

[0077] In this embodiment, the acid-washed iron concentrate is a concentrate product obtained by leaching roasted magnetic separation products with concentrated sulfuric acid and then acid washing. Its TFe grade is 62%, P content is 0.21%, pulp concentration is 35%, and pH value is 0.7.

[0078] The pickled iron concentrate slurry is sequentially washed through four stages of ultrafiltration (UHV) washing. The flow direction of the pickled iron concentrate slurry is as follows: the underflow concentrate from the first stage UHV is fed into the second stage UHV, the underflow concentrate from the second stage UHV is fed into the third stage UHV, and the underflow concentrate from the third stage UHV is fed into the fourth stage UHV. The flushing water is fed in a counter-current manner: the fourth stage UHV uses fresh water and neutral circulating water as flushing water, and its overflow is fed into the third stage UHV; the overflow from the third stage UHV is fed into the second stage UHV; the overflow from the second stage UHV is fed into the first stage UHV; and the overflow from the first stage UHV is fed into the neutralization mixing tank. The pressure of the flushing water for each stage of washing is 0.25 MPa, the pH value is 7.0, and the suspended solids concentration is 250 ppm.

[0079] After filtration, the concentrate obtained from the fourth-stage ultrafiltration mill yields high-grade iron concentrate and filtered water. The filtered water is fed into a neutralization mixing tank. The iron concentrate has a pH of 6.61, a TFe grade of 64.5%, and a P content of 0.138%. In the neutralization mixing tank, lime slurry is added as a neutralizing agent to adjust the pH to neutral. Then, after thickening, thickener underflow (washing tailings and neutralized sediment) and overflow (neutral circulating water) are obtained. The thickener underflow is discharged to the tailings pond, and the neutral circulating water is mixed with fresh water and fed into the fourth-stage ultrafiltration mill.

[0080] In this embodiment, the magnetic field strength of the ultrasonic transducer is 325 Gs, and the intensity of the ultrasound is 640 W / m. 2 The underflow concentration is controlled at 69%, and the wash water ratio is 6:1.

[0081] Using the deacidification, iron extraction, and phosphorus reduction process of this embodiment, the TFe grade in the acid-washed iron concentrate increased by 2.5 percentage points, and the P content decreased by 0.063 percentage points, meeting the requirements for high-quality iron concentrate. The pH value increased to 6.61, and the washing recovery rate of mFe reached 98.8%, achieving the purpose of deacidification, iron extraction, and impurity reduction.

[0082] Example 3

[0083] In this embodiment, the acid-washed iron concentrate is a concentrate product obtained by leaching roasted magnetic separation product with concentrated sulfuric acid and then acid washing. Its TFe grade is 62.8%, P content is 0.19%, pulp concentration is 40%, and pH value is 0.8.

[0084] The pickled iron concentrate slurry is sequentially washed through four stages of ultrafiltration (UHV) washing machines. The flow direction of the pickled iron concentrate slurry is as follows: the underflow concentrate from the first stage UHV is fed into the second stage UHV, the underflow concentrate from the second stage UHV is fed into the third stage UHV, and the underflow concentrate from the third stage UHV is fed into the fourth stage UHV. The flushing water is fed in a counter-current manner: the fourth stage UHV uses fresh water and neutral circulating water as flushing water, and its overflow is fed into the third stage UHV; the overflow from the third stage UHV is fed into the second stage UHV; the overflow from the second stage UHV is fed into the first stage UHV; and the overflow from the first stage UHV is fed into the neutralization mixing tank. The pressure of the flushing water for each stage of washing is 0.3 MPa, the pH value is 7.5, and the suspended solids concentration is 250 ppm.

[0085] After filtration, the concentrate obtained from the fourth-stage ultrafiltration mill yields high-grade iron concentrate and filtered water. The filtered water is fed into a neutralization mixing tank. The iron concentrate has a pH of 6.64, a TFe grade of 64.8%, and a P content of 0.13%.

[0086] In the neutralization mixing tank, lime slurry is added as a neutralizing agent to adjust the pH to neutral. Then, after thickening, the thickener underflow (washing tailings and neutralized sediment) and overflow (neutral circulating water) are obtained. The thickener underflow is discharged to the tailings pond, and the neutral circulating water and fresh water are mixed and fed into the fourth-stage superpulse machine.

[0087] In this embodiment, the magnetic field strength of the ultrasonic transducer is 350 Gs, and the intensity of the ultrasonic wave is 720 W / m. 2 The underflow concentration is controlled at 70%, and the wash water ratio is 7:1.

[0088] Using the deacidification, iron extraction, and phosphorus reduction process of this embodiment, the TFe grade in the acid-washed iron concentrate increased by 2.0 percentage points, and the P content decreased by 0.06 percentage points, meeting the requirements for high-quality iron concentrate. The pH value increased to 6.64, and the washing recovery rate of mFe reached 98.7%, achieving the purpose of deacidification, iron extraction, and impurity reduction.

[0089] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and application concept of this application, should be included within the scope of protection of this application.

Claims

1. A multi-stage ultra-high-phosphorus iron concentrate washing, countercurrent washing, deacidification, iron extraction, and phosphorus reduction process, comprising the following steps: The pickled iron concentrate slurry was subjected to first-stage washing, second-stage washing, third-stage washing and fourth-stage washing in sequence, and then filtered to obtain iron concentrate; The effluent from the fourth stage of rinsing is used as the rinsing water for the third stage of rinsing, the effluent from the third stage of rinsing is used as the rinsing water for the second stage of rinsing, the effluent from the second stage of rinsing is used as the rinsing water for the first stage of rinsing, and the effluent from the first stage of rinsing, after being neutralized, is used as the rinsing water for the fourth stage of rinsing.

2. The process according to claim 1, characterized in that, The effluent from the first stage of rinsing is neutralized and mixed with fresh water to serve as the rinsing water for the fourth stage of rinsing.

3. The process according to claim 1 or 2, characterized in that, The effluent from the first stage of rinsing is neutralized, concentrated, and then mixed with fresh water to serve as the rinsing water for the fourth stage of rinsing.

4. The process according to any one of claims 1 to 3, characterized in that, The acid-washed iron concentrate has a TFe grade of 61%~63%, a P content of 0.18%~0.22%, a pulp concentration of 30%~40%, and a pH value of 0.5~0.

8.

5. The process according to claim 4, characterized in that, The acid-washed iron concentrate is an acid-washed iron concentrate leached with concentrated sulfuric acid.

6. The process according to any one of claims 1 to 5, characterized in that, In the first stage of rinsing, the pressure of the rinsing water is 0.2MPa~0.3MPa, the pH value of the rinsing water is 6.5~7.5, and the suspended solids concentration of the rinsing water is less than 250ppm; In the second stage of rinsing, the pressure of the rinsing water is 0.2MPa~0.3MPa, the pH value of the rinsing water is 6.5~7.5, and the suspended solids concentration of the rinsing water is less than 250ppm; In the third stage of rinsing, the pressure of the rinsing water is 0.2MPa~0.3MPa, the pH value of the rinsing water is 6.5~7.5, and the suspended solids concentration of the rinsing water is less than 250ppm; In the fourth stage of rinsing, the pressure of the rinsing water is 0.2MPa~0.3MPa, the pH value of the rinsing water is 6.5~7.5, and the suspended solids concentration of the rinsing water is less than 250ppm. The washing-to-water ratio for the first, second, third, and fourth stages of rinsing is 5 to 7.

7. The process according to any one of claims 1 to 6, characterized in that, The first stage of washing is carried out under the action of a magnetic field; the strength of the magnetic field is 300 Gs to 350 Gs. The second-stage washing is carried out under the action of a magnetic field; the strength of the magnetic field is 300 Gs to 350 Gs. The third-stage washing is carried out under the action of a magnetic field; the strength of the magnetic field is 300 Gs to 350 Gs. The fourth stage of washing is carried out under the action of a magnetic field; the strength of the magnetic field is 300 Gs to 350 Gs.

8. The process according to any one of claims 1 to 6, characterized in that, The first stage of washing is carried out under the action of ultrasound; the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 ; The second-stage washing is performed under the action of ultrasound; the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 ; The third stage of washing is performed under the action of ultrasound; the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 ; The fourth stage of washing is performed under the action of ultrasound; the intensity of the ultrasound is 560 W / m. 2 ~720W / m 2 .

9. The process according to claim 8, characterized in that, The first stage of washing is carried out using an ultra-pulse machine; The second stage of washing is carried out using an ultra-pulse machine; The third-stage washing is performed using an ultra-pulse machine; The fourth stage of washing is carried out using an ultra-pulse machine.

10. The process according to claim 9, characterized in that, The underflow concentration of the ultra-pulse machine is 68%~70%.

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