Disclosure of Invention
The invention aims to provide a magnetite full-particle-size pre-selection waste-throwing method, which solves the problem that the prior art cannot realize pre-selection waste-throwing of powder ore with the particle size of below 5 mm.
The technical scheme of the invention is as follows: a magnetite full-particle-level pre-selection waste-throwing method is characterized by comprising the following steps: the method is characterized in that magnetite with the particle size fraction of below 5mm is subjected to three-stage pre-selection waste disposal by adopting a fully-sealed spiral dry magnetic separator, and specifically comprises the following steps:
A. carrying out particle size classification on magnetite with the particle size of less than 50mm, wherein the magnetite is divided into three particle size ranges of less than 5mm, 5-15mm and 15-50 mm;
B. d, performing three-stage pre-selection waste disposal on the magnetite with the particle size of less than 5mm obtained in the step A by adopting a fully-sealed spiral dry magnetic separator, wherein the primary magnetic field strength is 1000-grade 1200GS, the secondary magnetic field strength is 1400-grade 1600GS, and the tertiary magnetic field strength is 2000-grade 2200 GS; the first level is rough concentration, and the second level and the third level are tailing scavenging;
C. b, performing two-stage pre-selection waste disposal on the magnetite with the size of 5-15mm obtained in the step A by adopting a magnetic pulley;
D. and D, performing primary pre-selection waste disposal on the magnetite with the particle size of 15-50mm obtained in the step A by adopting a magnetic pulley.
Because fine fraction magnetite of below 5mm has fine granularity and large dust emission, the magnetite cannot be effectively thrown by a strong magnetic pulley, through a large number of tests, a fully-sealed spiral dry magnetic separator is selected to carry out three-stage pre-selection waste throwing treatment, the fully-sealed spiral dry magnetic separator mainly comprises a shell, magnetic rollers with a built-in 360-degree wrap angle fixed magnetic system, 3 primary magnetic rollers, 2 secondary magnetic rollers, 1 tertiary magnetic rollers and a magnetic system outer barrel skin welded spiral conveying blade, the rotating speed of the rollers is controlled by frequency conversion, when the magnetite of below 5mm is fed into a primary magnetic roller sorting area from a feeding port, the magnetite with the grade higher than the geological grade is adsorbed on the roller body and is pushed to move forwards by the spiral blades, and the magnetite and surrounding rocks with the grade equal to or lower than the geological grade are overturned outside under the action of the fixed magnetic system during moving, throwing the magnetite out by the centrifugal force rotating at a high speed to fall into a secondary magnetic roller grading area, performing the same high-speed rotating operation of the secondary magnetic roller to grade the magnetite at geological grade, throwing the magnetite and surrounding rocks with the grade lower than the geological grade into a tertiary magnetic roller grading area, performing the same high-speed rotating operation of the tertiary magnetic roller to grade the magnetite with the grade lower than the geological grade, throwing the surrounding rocks into a bottom box, discharging the magnetite from a tailing discharge port, and discharging the concentrate from a concentrate port. Six magnetic drums of tertiary of totally enclosed spiral dry-type magnet separator are installed in same totally enclosed shell, and rougher flotation, scavenging are accomplished in same casing, and the magnetic drum rotational speed is controlled by frequency conversion system, sets for according to selected ore nature and index requirement, has the advantage of reaching index such as control rough concentrate grade, metal recovery rate and tailing grade through adjusting the drum rotational speed. The magnetite with the particle size of less than 5mm can be recovered to geological grade by rough concentration and scavenging treatment through a fully-sealed spiral dry magnetic separator, the tailing discarding grade is controlled to be less than 1 percentage point higher than the grade of surrounding rock, and the problem of difficult fine-particle magnetite pre-concentration discarding is solved.
As a further improvement of the invention, the specific magnetization coefficient of magnetite is not less than 92000X 10-9m3/kg。
As a further improvement of the method, in the step C, the primary magnetic field intensity is 1400-1600GS, the secondary magnetic field intensity is 2000-2200GS, the primary magnetic field intensity is roughing, and the secondary magnetic field intensity is tailing scavenging. Through a large number of tests, the magnetite with the size fraction of 5-15mm is subjected to pre-concentration and waste disposal by adopting a spiral dry magnetic separator, the magnetite has large particles, and the magnetite cannot be effectively separated by completely throwing out the magnetite when the magnetic roller rotates at a high speed; or the waste is pre-selected and thrown by adopting a magnetic pulley together with 15-50mm size fraction magnetite, so that the problem that large-particle iron ore blocks small-particle surrounding rock and cannot be thrown out exists. A large number of tests prove that only 5-15mm size fraction magnetite is screened out separately, and the waste is discarded by adopting a magnetic pulley for pre-selection, so that the index requirement can be met. The magnetic pulley pre-selection waste throwing is to tile magnetite with the particle size of 5-15mm on a belt, a belt head wheel is a magnetic pulley, the magnetite with the particle size of 5-15mm rotates along with the belt, surrounding rocks are thrown out by means of inertia force and fall into a tailing outlet, the magnetite is attracted by the magnetic pulley field intensity and falls into a concentrate outlet below the belt away from the magnetic field attraction, the main reasons are that the particle size of the selected material is small, the distribution thickness is thin, the inertia force of the small-particle magnetite rotating along with the belt is smaller than the magnetic field attraction to ores, the magnetite with the grade at geological grade is selected by the primary strong magnetic pulley rough selection, the magnetite with the grade lower than the geological grade and the surrounding rocks are selected by the secondary magnetic pulley scavenging, the magnetite with the grade lower than the geological grade is selected, and the. The magnetite with the grain size of 5-15mm is treated by a magnetic pulley primary roughing and secondary scavenging process, the output ore can be recovered to the geological grade, and the grade of the pre-selected tailings is controlled to be lower than 1 percentage point higher than the grade of surrounding rock.
As a further improvement of the invention, in the step D, the magnetic field intensity is 2400-2600 GS. A large amount of test data prove that the effect of pre-selecting and discarding the magnetite magnetic pulley with the particle size of more than 15mm is better, because the inertia force of coarse particle materials rotating along with the belt is smaller than the magnetic field suction force, therefore, the ores are sucked to the range of being separated from the magnetic field force by the magnetic pulley magnetic field suction force and fall down when rotating along with the belt, and the waste rocks are directly discarded, thereby realizing mineral separation. The magnetic pulley pre-selection waste disposal is to tile 15-50mm size fraction magnetite on a belt, a belt head wheel is a magnetic pulley, the 15-50mm size fraction magnetite rotates along with the belt, surrounding rock is thrown out by means of inertia force and falls into a tailing outlet, the magnetite is attracted by the magnetic pulley field intensity and falls into a concentrate outlet below the belt away from the magnetic field attraction, and the goal that the pre-selection concentrate is restored to the geological grade and the pre-selection tailing grade is higher than the surrounding rock grade by less than 0.5 percentage point can be achieved.
The invention has the beneficial effects that: according to the invention, the magnetite ore with the size fraction below 50mm is classified into magnetite ore with the size fraction below 5mm, magnetite ore with the size fraction below 5-15mm and magnetite ore with the size fraction below 15-50mm, and according to the characteristics of the magnetite ore with different size fraction ranges, the magnetite ore with the size fraction below 50mm is subjected to pre-selection waste disposal by adopting different devices, so that the whole size fraction pre-selection waste disposal of the magnetite ore with the size fraction below 50mm is finally realized, the selected magnetite ore is recovered to the geological grade, and the surrounding rock is reduced to the maximum extent and. Compared with the existing pre-selection waste throwing process of the magnetite magnetic pulley with the size fraction of only 5-50mm, the waste throwing level is reduced by more than 3.25 percent, the metal recovery rate is improved by more than 4.4 percent, the selected surrounding rock quantity is reduced, the selected grade is improved, the ore dressing cost is reduced, the quality of the iron ore concentrate is improved, and the benefit is obvious.
Detailed Description
The following examples further illustrate the invention but are not intended to limit the invention in any way.
The magnetite in the following examples is derived from wine-steel four-channel iron ore, and the iron ore belongs to one of magnetite, wherein the raw ore grade of the sampling is 31%, the mixing proportion of the surrounding rock is 10%, and the geological grade is 34%. The process flow is shown in figure 1.
Examples 1,
A. Carrying out particle size classification on magnetite with the particle size of less than 50mm, wherein the magnetite is divided into three particle size ranges of less than 5mm, 5-15mm and 15-50mm, the particle size of less than 5mm accounts for 20%, the particle size of 5-15mm accounts for 25%, and the particle size of 15-50mm accounts for 55%;
B. magnetite of grain size below 5mm is subjected to three-stage pre-selection waste disposal by adopting a fully-sealed spiral dry magnetic separator with a primary magnetic field strength of 1000GS, a secondary magnetic field strength of 1500GS and a tertiary magnetic field strength of 2000GS, wherein the primary is rough concentration, and the secondary and tertiary are tailing scavenging, so that indexes of 34.36% of pre-selection waste disposal concentrate grade, 89.6% of concentrate yield, 2% of waste disposal surrounding rock grade, 10.4% of surrounding rock yield and 99.31% of metal recovery rate are obtained;
C. the magnetite of 5-15mm size fraction is subjected to two-stage pre-selection waste disposal by adopting a magnetic pulley with 1500GS (magnetic field strength) of primary magnetic field and 2000GS of secondary magnetic field, wherein the primary magnetic field is roughing, and the secondary magnetic field is tailing scavenging, so that indexes of 34.33% of pre-selection waste disposal concentrate grade, 89.7% of concentrate yield, 2% of waste disposal surrounding rock grade, 10.3% of surrounding rock yield and 99.33% of metal recovery rate are obtained;
D. the magnetite with the size fraction of 15-50mm is subjected to primary pre-selection waste disposal by adopting a magnetic pulley with the magnetic field intensity of 2500GS, and the indexes of 34.35% of the concentrate grade of the pre-selection waste disposal, 89.8% of the concentrate yield, 1.5% of the waste disposal surrounding rock grade, 10.2% of the surrounding rock yield and 99.5% of the metal recovery rate are obtained.
The embodiment finally realizes the whole-size-fraction pre-selection waste disposal of the magnetite with the size fraction of less than 50mm, restores the selected magnetite to the geological grade of 34.35 percent, and obtains the indexes of 10.26 percent of the yield of the discarded surrounding rock, 1.75 percent of the grade of the surrounding rock and 99.4 percent of the recovery rate of pre-selected concentrate metal. Compared with the existing pre-selection waste throwing process of the magnetite magnetic pulley with the size fraction of only 5-50mm, the waste throwing position is reduced to 1.75% from 5%, the waste throwing position is reduced by more than 3.25%, the metal recovery rate is improved to 99.4% from 95%, the metal recovery rate is improved by more than 4.4%, the amount of surrounding rocks entering and selecting is reduced, the entering grade is improved, the ore dressing cost is reduced, the quality of iron ore concentrate is improved, and the benefit is remarkable.
Examples 2,
A. And (3) carrying out particle size classification on the magnetite with the particle size of less than 50mm, wherein the magnetite is divided into three particle size ranges of less than 5mm, 5-15mm and 15-50mm, and the particle size of less than 5mm accounts for 20%, the particle size of 5-15mm accounts for 25% and the particle size of 15-50mm accounts for 55%.
B. Magnetite of grain size below 5mm is subjected to three-stage pre-selection waste disposal by adopting a fully-sealed spiral dry magnetic separator with a primary magnetic field strength of 1000GS, a secondary magnetic field strength of 1400GS and a tertiary magnetic field strength of 2000GS, wherein the primary is rough separation, and the secondary and tertiary are tailing scavenging, so that indexes of 34.50% of pre-selection waste disposal concentrate grade, 89.25% of concentrate yield, 2.1% of waste disposal surrounding rock grade, 10.75% of surrounding rock yield and 99.33% of metal recovery rate are obtained;
C. 5-15mm size fraction magnetite carries out two-stage pre-selection waste disposal by adopting a magnetic pulley with a first-stage magnetic field intensity of 1400GS and a second-stage magnetic field intensity of 2000GS, wherein the first stage is roughing and the second stage is tailing scavenging, and indexes of 34.51% of pre-selection waste disposal concentrate grade, 89.32% of concentrate yield, 1.9% of waste disposal surrounding rock grade, 10.68% of surrounding rock yield and 99.43% of metal recovery rate are obtained;
D. and (3) carrying out primary pre-selection waste disposal on 15-50mm size fraction magnetite by adopting a magnetic field intensity 2400GS magnetic pulley to obtain indexes of 34.58% of pre-selection waste disposal concentrate grade, 89.16% of concentrate yield, 1.6% of waste disposal surrounding rock grade, 10.84% of surrounding rock yield and 99.46% of metal recovery rate.
The embodiment finally realizes the whole-size-fraction pre-selection waste disposal of the magnetite with the size fraction of less than 50mm, restores the selected magnetite to the geological grade of 34.53%, and obtains the indexes of 10.76% of the yield of the discarded surrounding rock, 1.82% of the grade of the surrounding rock and 99.41% of the recovery rate of pre-selected concentrate metal. Compared with the existing pre-selection waste throwing process of the magnetite magnetic pulley with the size fraction of only 5-50mm, the waste throwing position is reduced to 1.82% from 5%, the waste throwing position is reduced by more than 3.18%, the metal recovery rate is improved to 99.41% from 95%, the metal recovery rate is improved by more than 4.41%, the amount of surrounding rocks entering and selecting is reduced, the entering grade is improved, the ore dressing cost is reduced, the quality of iron ore concentrate is improved, and the benefit is remarkable.
Examples 3,
A. And (3) carrying out particle size classification on the magnetite with the particle size of less than 50mm, wherein the magnetite is divided into three particle size ranges of less than 5mm, 5-15mm and 15-50mm, and the particle size of less than 5mm accounts for 20%, the particle size of 5-15mm accounts for 25% and the particle size of 15-50mm accounts for 55%.
B. Magnetite of grain size below 5mm is subjected to three-stage pre-selection waste disposal by adopting a full-sealed spiral dry magnetic separator with a primary magnetic field strength of 1200GS, a secondary magnetic field strength of 1600GS and a tertiary magnetic field strength of 2200GS, wherein the primary magnetic field strength is roughing, and the secondary magnetic field strength and the tertiary magnetic field strength are tailing scavenging, so that indexes of 34.29% of pre-selection waste disposal concentrate grade, 89.85% of concentrate yield, 1.66% of waste disposal surrounding rock grade, 10.15% of surrounding rock yield and 99.39% of metal recovery rate are obtained;
C. magnetite of 5-15mm size fraction is subjected to two-stage pre-selection waste disposal by adopting a magnetic pulley with 1600GS (gas-liquid) of primary magnetic field intensity and 2200GS (gas-liquid) of secondary magnetic field intensity, wherein the primary magnetic field intensity is rough concentration, and the secondary magnetic field intensity is tailing scavenging, so that indexes of 34.48% of pre-selection waste disposal concentrate grade, 89.29% of concentrate yield, 1.91% of waste disposal surrounding rock grade, 10.71% of surrounding rock yield and 99.31% of metal recovery rate are obtained;
D. magnetite of 15-50mm size fraction is subjected to primary pre-selection waste disposal by adopting a field intensity 2600GS magnetic pulley, and indexes of 34.19% of concentrate grade, 89.58% of concentrate yield, 2.09% of waste disposal surrounding rock grade, 10.42% of surrounding rock yield and 98.80% of metal recovery rate are obtained.
The embodiment finally realizes the whole-size-fraction pre-selection waste disposal of the magnetite with the size fraction of less than 50mm, restores the selected magnetite to the geological grade of 34.32 percent, and obtains the indexes of 10.43 percent of the yield of the discarded surrounding rock, 1.89 percent of the grade of the surrounding rock and 99.17 percent of the recovery rate of pre-selected concentrate metal. Compared with the existing pre-selection waste throwing process of the magnetite magnetic pulley with the size fraction of only 5-50mm, the waste throwing position is reduced to 1.89% from 5%, the waste throwing position is reduced by more than 3.11%, the metal recovery rate is improved to 99.17% from 95%, the metal recovery rate is improved by more than 4.17%, the amount of surrounding rocks entering and selecting is reduced, the entering grade is improved, the ore dressing cost is reduced, the quality of iron ore concentrate is improved, and the benefit is remarkable.