阅读说明：本技术 一种弱磁性难选铁矿石磁化焙烧-智能预选联合抛废方法 (Magnetized roasting-intelligent pre-selection combined discarding method for weakly magnetic refractory iron ore ) 是由 宋嘉 展仁礼 边立国 郭忆 王欣 池永沁 于 2019-10-18 设计创作，主要内容包括：本发明公开了一种弱磁性难选铁矿石磁化焙烧-智能预选联合抛废方法,属于矿物加工技术领域,解决了弱磁性难选铁矿石预选抛废难的问题。本发明方法是：将100mm以下铁矿石分为三个粒级；对15mm以下粒级难选铁矿石采用回转窑进行磁化焙烧,焙烧矿冷却至常温时,焙烧矿采用全密封螺旋干式磁选机进行预选抛废；对15-50mm和50-100mm粒级弱磁性难选铁矿石采用不同型号的X射线透射智能选别设备分别进行一级预选抛废。本发明采用不同工艺方法对各粒级范围难选铁矿石进行预选抛废处理,从而实现弱磁性难选铁矿石全粒级有效抛废处理,将入选弱磁性难选铁矿石恢复到地质品位,最大限度地减少了入选围岩量,提高了入选品位。(The invention discloses a magnetized roasting-intelligent pre-selection combined discarding method for weakly magnetic refractory iron ores, belongs to the technical field of mineral processing, and solves the problem that the pre-selection discarding of the weakly magnetic refractory iron ores is difficult. The method of the invention comprises the following steps: dividing iron ore with the particle size of less than 100mm into three size fractions; magnetizing and roasting refractory iron ore with the grain size of below 15mm by using a rotary kiln, and performing pre-selection and waste disposal on the roasted ore by using a fully-sealed spiral dry magnetic separator when the roasted ore is cooled to normal temperature; and respectively carrying out primary pre-selection waste disposal on 15-50mm and 50-100mm size grade weak magnetic refractory iron ores by adopting different types of X-ray transmission intelligent sorting equipment. The invention adopts different process methods to carry out pre-selection waste disposal on the refractory iron ores in each size range, thereby realizing the effective waste disposal of the weak-magnetism refractory iron ores in the whole size range, restoring the selected weak-magnetism refractory iron ores to the geological grade, reducing the amount of the selected surrounding rocks to the maximum extent and improving the selected grade.)

1. A weak-magnetism refractory iron ore magnetizing roasting-intelligent preselection combined waste throwing method is characterized by comprising the following steps:

A. grading the weak-magnetic refractory iron ore with the size fraction of less than 100mm into three size fractions of less than 15mm, 15-50mm and 50-100 mm;

B. b, magnetically roasting the refractory iron ore with the size fraction of below 15mm obtained in the step A by adopting a rotary kiln, and when the roasted ore is cooled to normal temperature, pre-selecting and discarding the roasted ore by adopting a fully-sealed spiral dry magnetic separator;

C. and D, respectively carrying out primary pre-selection waste disposal on the 15-50mm and 50-100mm size grade weak magnetic refractory iron ores obtained in the step A by adopting different types of X-ray transmission intelligent sorting equipment.

2. The weak-magnetism refractory iron ore magnetizing roasting-intelligent pre-selection combined waste disposal method according to claim 1, characterized in that: in the step B, the roasting temperature is 650-700 ℃, the coal powder is used as a reducing agent, the addition amount of the reducing agent is 1.5-2% of the weight of the ore, and the roasting time is 45-60 min.

3. The weak-magnetism refractory iron ore magnetizing roasting-intelligent pre-selection combined waste disposal method according to claim 2, characterized in that: in the step B, the magnetic field intensity of 2000-2200 GS is adopted for pre-selecting the waste disposal, and the pre-selected tailings are discharged.

4. The weak-magnetism refractory iron ore magnetizing roasting-intelligent pre-selection combined waste disposal method according to any one of claims 1 to 3, characterized in that: the weakly magnetic refractory iron ore comprises specularite, hematite, limonite or complex paragenic ore.

Technical Field

The invention belongs to the technical field of mineral processing, and particularly relates to a weak-magnetism refractory iron ore magnetizing roasting-intelligent pre-selection combined waste disposal method.

Background

The lean ore and the magnetic ore of iron ore resources in China are more, the less weak-magnetic refractory iron ore accounts for more than 70% of the total reserve, the pre-selection and waste disposal of the weak-magnetic iron ore is always a big problem for mine enterprises, the annual production of specularite birch ditch ore areas of wine and steel companies is less than 100mm, the grain-size weak-magnetic specularite of about 450 ten thousand tons, due to the limited geographical environment position of the specularite ore, the ore dressing plant cannot be built, and the low-magnetic separation-reverse flotation process is adopted to obtain 58-60% iron ore concentrate after the magnetic roasting of the specularite ore dressing, so the ore dressing plant is built in a wine and steel metallurgical area 78km away from the mine by the wine and steel companies, the ore output and transportation cost is 25 yuan/t, the roasting cost is 32 yuan/t, the birch ditch ore area is underground mining, the content of the ore surrounding rock is 8-12%, wherein the content of part of the surrounding rock of the ore body is as high as 30, in order to save the cost of ore output transportation and roasting, a wine and steel company builds a strong magnetic induction roller preselection system in 2002, specularite with the grain size of less than 100mm is divided into three grain size ranges of less than 15mm, 15-50mm and 50-100mm for preselection and waste disposal, the geological grade of the wine and steel specularite birch ditch specularite is 34%, surrounding rocks belong to iron-containing phyllite and iron-containing jade, the grade is 4-8%, the grade of the preselection design waste disposal tailings is 15%, after operation, the grade of the specularite with the grain size of less than 15mm reaches more than 20%, the waste disposal tailings still contain 70% of ores, the waste disposal effect is poor, and the main reason is that when refractory ores with the grain size of less than 15mm leave a magnetic roller, part of fine-grained ores are thrown out along with the surrounding rocks, so that the grade of the; the specularite with the grain size of 15-50mm and 50-100mm cannot be discarded, and the main reason is that the inertia force of the ore rotating along with the belt is larger than the suction force of the magnetic roller to the ore, so that the ore and the surrounding rock cannot be effectively separated and are stopped all the time. Therefore, the low-magnetism refractory iron ore is difficult to pre-select and discard, and the ore mixed in the surrounding rock increases the ore transportation, roasting and sorting costs, so that the development of a low-magnetism refractory ore pre-selecting and discarding process technology is urgently needed.

Disclosure of Invention

The invention aims to provide a weak-magnetism refractory iron ore magnetizing roasting-intelligent pre-selection combined waste disposal method, which aims to solve the problem that the weak-magnetism refractory iron ore is difficult to pre-select and dispose waste.

The technical scheme of the invention is as follows: a weak-magnetism refractory iron ore magnetizing roasting-intelligent preselection combined waste throwing method is characterized by comprising the following steps:

A. grading the weak-magnetic refractory iron ore with the size fraction of less than 100mm into three size fractions of less than 15mm, 15-50mm and 50-100 mm;

B. b, magnetically roasting the refractory iron ore with the size fraction of below 15mm obtained in the step A by adopting a rotary kiln, and when the roasted ore is cooled to normal temperature, pre-selecting and discarding the roasted ore by adopting a fully-sealed spiral dry magnetic separator;

C. and D, respectively carrying out primary pre-selection waste disposal on the 15-50mm and 50-100mm size grade weak magnetic refractory iron ores obtained in the step A by adopting different types of X-ray transmission intelligent sorting equipment. The pre-separation waste throwing achieves the aims that the pre-separation concentrate is restored to the geological grade, and the pre-separation tailings are higher than the grade of the surrounding rock by less than 0.5 percent.

A large amount of test data prove that the waste of the refractory iron ore with the particle size fraction of more than 15mm and weak magnetism cannot be effectively discarded by adopting the strong magnetic induction roller because the inertia force of coarse particle materials rotating along with the belt is greater than the magnetic field suction force, so the ores are discarded along with surrounding rocks, and the mineral separation cannot be realized. Therefore, the iron ore with the size fraction of more than 15mm and weak magnetism and difficult separation is selected by X-ray transmission intelligent sorting equipment to carry out pre-selection and waste disposal. The difference of the types of the preselection and waste-removal selecting machine for the weak-magnetism refractory iron ores with the grain sizes of 15-50mm and 50-100mm is mainly that the air spray guns have different sizes, and the spray guns with large grain sizes are also large. The working principle of the X-ray transmission intelligent sorting equipment is a mineral separation method for separating minerals by combining machinery and electricity by simulating the action of hand selection. The method is characterized in that pre-selection throwing waste materials are flatly paved on a 3m/s high-speed rotating belt through a vibrating feeder, X rays transmit and recognize each material above the belt, differences of photoelectric signals are fed back through different mineral components and properties, various ores and surrounding rock information bases are established through computer recognition, during production, an ultrahigh-speed X-ray detector acquisition system transmits and recognizes each material, signals are transmitted to a computer, the computer judges whether the material belongs to ore or waste rock through background quick calculation, an instruction is given to start a spraying execution mechanism to act, waste rock or ore is set through accurate spraying, and minerals are separated. The method is characterized in that X-ray transmission intelligent sorting equipment is selected for pre-selecting and discarding 15-50mm and 50-100mm size fraction weak-magnetism refractory iron ores, and the target that the pre-selected tailing grade is controlled within the iron-containing grade of surrounding rocks can be achieved.

As a further improvement of the invention, in the step B, the roasting temperature is 650-700 ℃, coal powder is used as a reducing agent, the addition amount of the reducing agent is 1.5-2% of the weight of the ore, and the roasting time is 45-60 min.

As a further improvement of the invention, in the step B, the magnetic field intensity of the pre-selection waste disposal is 2000-2200 GS, the grade of the pre-selection tailings is controlled to be below 8%, and the pre-selection tailings are discharged. Because the roasted ore of the 0-15mm fine-grained weak-magnetic refractory iron ore has fine granularity and large dust emission, the waste can not be effectively thrown by adopting a magnetic pulley and an intelligent sorting device, through a large number of tests, a fully-sealed spiral dry magnetic separator is selected for carrying out pre-sorting and waste-throwing treatment, the fully-sealed spiral dry magnetic separator mainly comprises a shell, 2 magnetic rollers with a 360-degree wrap angle fixed magnetic system arranged inside, and spiral conveying blades welded on the outer barrel skin of the magnetic system, the rotating speed of the rollers is controlled by frequency conversion, when the 0-15mm weak-magnetic refractory iron ore roasted ore is fed into a magnetic roller sorting area from a feeding port, the spiral magnetic rollers rotate at high speed, the magnetized refractory iron ore roasted ore is adsorbed on the magnetic rollers and is pushed by the spiral blades to move forwards, and is subjected to magnetic rolling adsorption for a plurality of times under the action of the fixed magnetic system while moving, surrounding rocks are thrown into a bottom box and discharged from a tailing discharge port, and the concentrate separated by the magnetic roller is discharged from a concentrate port. 2 magnetic rollers of the full-sealed spiral dry magnetic separator are arranged in the same full-sealed outer shell, the rotating speed of the rollers is controlled by a frequency conversion system, the rotating speed is set according to the property and index requirements of selected ores, and the full-sealed spiral dry magnetic separator has the advantage of controlling indexes such as rough concentrate grade, metal recovery rate and tailing grade by adjusting the rotating speed of the rollers. The roasted ore of the 0-15mm size fraction weak-magnetism refractory iron ore is subjected to pre-selection waste disposal by a fully-sealed spiral dry magnetic separator, the tailing disposal grade can be controlled to be higher than the iron-containing grade range of the surrounding rock, the magnetism of the weak-magnetism refractory iron ore is increased by magnetization roasting, so that the magnetism of the weak-magnetism refractory iron ore is obviously different from that of the surrounding rock, and the pre-selection waste disposal is performed by the fully-sealed spiral dry magnetic separator, so that the problem of difficulty in pre-selection waste disposal of the fine-size fraction weak-magnetism refractory iron ore can be solved.

As a further improvement of the invention, the weakly magnetic refractory iron ore comprises specularite, hematite, limonite or complex paragenetic ore.

Compared with the prior art, the invention has the following beneficial effects: according to the invention, after the particle sizes of the low-magnetism refractory iron ore with the particle size of less than 100mm are classified into three particle sizes of less than 15mm, 15-50mm and 50-100mm, the refractory iron ore with different particle size ranges is subjected to pre-selection waste disposal by adopting different process methods according to the characteristics of the low-magnetism refractory iron ore with different particle size ranges, so that the full-particle-size effective waste disposal of the low-magnetism refractory iron ore is realized, the selected low-magnetism refractory iron ore is recovered to the geological grade, the selected surrounding rock amount is reduced to the maximum extent, the selected grade is improved, the ore dressing cost is reduced, the iron ore concentrate quality is improved, and the benefit is remarkable; compared with the existing multistage pre-selection waste throwing process only adopting the strong magnetic induction roller, the waste throwing level is reduced by 7 percent, and the metal recovery rate is improved by more than 20 percent. Because of mining mode and resource depletion, refractory iron ore usually contains about 10% of waste rock or surrounding rock, refractory iron ore below 15mm is usually treated by adopting a levigating and strong magnetic separation mode, and the problems of low concentrate grade and low metal recovery rate exist. The method is characterized in that the waste of the refractory special ore with the grain size of 15-100mm is thrown in advance by adopting an intelligent preselector, and then the refractory special ore is subjected to subsequent treatment, so that the concept of 'early selection and early throwing' in the ore dressing boundary is met, and the dumping cost, the roasting, grinding and dressing cost and the like can be saved. Therefore, the whole-grain-level pre-selection of the refractory iron ore can be realized in advance, and the waste rocks or the surrounding rocks are prevented from entering a grinding and separation system, so that the production cost is reduced.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The following examples further illustrate the invention but are not intended to limit the invention in any way.

Generally, iron ores other than magnetite are weakly magnetic iron ores; the grade is below 40%, the properties are complex, and the iron ore which is difficult to be processed by simple magnetic separation is the difficultly selected iron ore. Specularite belongs to one of weak-magnetism refractory iron ores, and is derived from a betula alnifolia ditch ore area in the following examples, the quality of a sampled raw ore is 32%, the mixing proportion of surrounding rocks is 10-15%, and the iron content of the surrounding rocks is below 5%. The process flow of the present invention is shown in FIG. 1.