CN111215219A

CN111215219A - Production process system for sand making of vertical mill preparation machine

Info

Publication number: CN111215219A
Application number: CN201911173468.XA
Authority: CN
Inventors: 宋留庆; 何小龙; 聂文海; 徐达融; 赵剑波; 杜鑫
Original assignee: Sinoma Tianjin Powder Technology & Equipment Co ltd; Tianjin Cement Industry Design and Research Institute Co Ltd
Current assignee: Sinoma Tianjin Powder Technology & Equipment Co ltd; Tianjin Cement Industry Design and Research Institute Co Ltd
Priority date: 2019-11-26
Filing date: 2019-11-26
Publication date: 2020-06-02

Abstract

The invention discloses a production process system for making sand by a vertical mill preparation machine, which comprises a raw material bin, a machine-made sand vertical mill, a combined type powder concentrator, a vibrating screen, a cyclone cylinder and a circulating fan, wherein an outlet of the raw material bin is connected with a material inlet of the machine-made sand vertical mill; the conical angle of each grinding roller of the machine-made sand vertical mill is not more than 20 degrees, and the total projection area of the grinding rollers on the grinding disc is 20-35% of the area of the grinding disc; the material blocking ring is a through type screening material blocking assembly or a crossing type material blocking ring, an auxiliary material discharging assembly is arranged on the grinding disc, and the auxiliary material discharging assembly is located behind each grinding roller along the rotating direction of the grinding disc. The process system has simple flow and is beneficial to large-scale production; the environment-friendly effect is better, and ultra-clean discharge can be realized.

Description

Production process system for sand making of vertical mill preparation machine

Technical Field

The invention belongs to the technical field of vertical mill sand making, and particularly relates to a production process system for making sand by a vertical mill preparation machine.

Background

With the continuous development of economy, consciousness of environmental protection is gradually deepened, and concrete is one of materials applied in a large scale in the field of building materials. The sandstone is used as the aggregate of the concrete and plays a role of a framework in the concrete. The aggregate is divided into coarse aggregate and fine aggregate, wherein the coarse aggregate is the aggregate with the particle size of more than 5mm and mainly comprises natural rock or pebble; the fine aggregate is aggregate with the particle size of below 4.75mm, and mainly comprises river sand and machine-made sand. Generally, river sand or machine-made sand with different particle sizes is called fine sand with the particle size of 0.075-1.18 mm, medium sand with the particle size of 1.18-2.36 mm and coarse sand with the particle size of 2.36-4.75 mm. The particle sizes of different sands can meet the requirements of different products, for example, dry-mixed mortar mainly comprises fine sand and medium sand, and common concrete mainly comprises medium sand and coarse sand. The fine aggregate commonly used in the prior common concrete is mainly river sand, but through continuous mining for many years, the natural river sand resource is rapidly reduced. In order to protect the ecological environment, the national regulations strictly prohibit the exploitation of natural river sand. In the concrete field, practical mechanism sand is encouraged vigorously. Therefore, the prosperity of the construction market promotes the rapid development of the machine-made sand market, and the machine-made sand gradually replaces the natural sand market and becomes one of the best sources of construction materials.

The prior machine-made sand production technology mainly adopts equipment such as a jaw crusher, a cone crusher, a ball mill, a double-rotor sand making machine, a vertical shaft type impact crusher and the like as main crushing equipment. Production of mechanism sand is realized through multistage breakage, but jaw breaker, cone crusher rely on the impact to be broken with the granule, and the effort that the granule received is little, and granule selectivity is broken, and the mechanism sand granule circularity of production is relatively poor, mostly is the needle slice. The influence of the gill-rod-shaped content of the aggregate on the strength of the gelled sand gravel (Henan water conservancy and south-to-north water conservancy, 76-7 pages in 6 th of 2018) is researched by Jinxianli, and the research is considered as follows: the needle-shaped sand stone in the concrete is harmful particles, so that the fluidity and the strength of the concrete can be greatly reduced, and the quantity of the needle-shaped sand stone should be reduced to the greatest extent. Therefore, the quality deviation of the products of the jaw crusher and the cone crusher for preparing the machine-made sand is not beneficial to engineering application. The ball mill is used as crushing equipment, the produced machine-made sand particles have good circularity, but the ball mill has the main function of grinding, and a large amount of fine powder (the fine powder refers to powdery particles with the particle size of less than 0.075mm) can be generated in the production process. Liu war ao et al, in the research on harmfulness and evaluation of fine powder in machine-made sand (journal of building materials, 2015, 150-155 p. 2), consider that: the fine powder is also a harmful particle to the machine-made sand, which causes the water requirement of concrete to be increased and the durability to be deteriorated, and the content of the fine powder in the machine-made sand needs to be strictly controlled. In addition, the production energy consumption of the ball mill is very high, and the large-scale and large-scale production is not facilitated. Therefore, the high fine powder content in the product and the high energy consumption of production and operation result in that the sand preparation of the ball mill preparation machine is not popularized and applied in a large area.

The vertical mill is used as an energy-saving and efficient material bed grinding device, is widely applied to cement grinding and metallurgical slag treatment, and adopts the mutual movement of grinding rolls and grinding discs, after particles form a material bed on the grinding discs and are subjected to extrusion force, the particles are crushed by extrusion and shearing force, the materials are repeatedly ground in the rolling process of the grinding discs, the particle roundness is better, and the energy utilization efficiency of the crushing and grinding of the vertical mill is higher than that of the selective crushing of a cone crusher and that of the single particle crushing of a ball mill, so that the vertical mill is widely accepted and applied as grinding equipment for producing fine powder. Chinese patent publication No. CN109277146A discloses a vertical mill sand making machine, which comprises a transmission device, a milling device, a pressurizing device, a limiting device, a feeding device, a lower shell and a discharging device, and the technology can basically realize the production of machine-made sand, but because of adopting the traditional vertical mill structure, the following defects exist:

1. the content of fine powder (less than 0.075mm) in the manufacturing process is too high, so that the sand forming rate is low, the energy consumption is high, the resource waste is caused, and the efficiency is low;

2. the extension of the grinding disc has fine powder accumulation, excessive grinding is caused in an accumulation area, the operation stability of the vertical mill is poor, the reliability of equipment is poor, and the shutdown maintenance frequency is high;

3. in the existing vertical mill, the tire roller is adopted, and an upward arc transition surface exists on a grinding disc of the grinding structure, so that the flowability of materials on the grinding disc is poor;

4. auxiliary discharge is not involved, resulting in too high a fine content in the machine-made sand.

As more efficient and energy-saving grinding equipment, the grinding equipment is feasible in principle when used for producing machine-made sand, but the granularity of a product is increased from less than 0.075mm to less than 4.75mm, the original vertical mill needs to be redesigned, and the problems of high fine powder content, poor product circularity and high production energy consumption of the traditional machine-made sand crushing equipment are solved.

In addition, the machine-made sand production system adopting the crusher at present has poor sphericity of the prepared machine-made sand, poor field dust collection effect, serious ash emission in production and no compliance with the requirement of green production. Therefore, it is urgently needed to develop a novel machine-made sand production process system using a vertical mill, so as to improve the product quality of machine-made sand, improve the environmental protection quality of a machine-made sand production line, and realize green, efficient and large-scale production.

Disclosure of Invention

The invention aims to provide a production process system for preparing sand by a vertical mill preparation machine, which reduces the content of needle-shaped particles in a product, reduces the fine powder content of machine-made sand, improves the product quality of the machine-made sand, improves the energy utilization rate of sand preparation, reduces the production energy consumption, is beneficial to large-scale production and improves the resource utilization rate.

The invention is realized in this way, a vertical mill prepares the productive technology system of the sand, including raw materials storehouse, machine-made sand vertical mill, combined powder concentrator, oscillating screen and powder removing organization, the said powder removing organization includes cyclone and circulating fan, the outlet port of raw materials storehouse couples to vertical mill material entrance of machine-made sand, the material outlet of the vertical mill of machine-made sand couples to material entrance of the combined powder concentrator, the discharge gate of the bottom of the combined powder concentrator couples to oscillating screen, the oscillating screen returns the oversize to the machine-made sand vertical mill, the air outlet of the combined powder concentrator couples to cyclone, the air outlet of the cyclone couples to circulating fan;

the machine-made sand vertical mill comprises a grinding disc, at least two grinding rollers and a material blocking ring, wherein the conical angle of each grinding roller is not more than 20 degrees, and the total projection area of the grinding rollers on the grinding disc is 20-35% of the area of the grinding disc; the material blocking ring is a through type screening material blocking assembly or a crossing type material blocking ring, an auxiliary material discharging assembly is arranged on the grinding disc, and the auxiliary material discharging assembly is located behind each grinding roller along the rotation direction of the grinding disc.

Preferably, the material blocking ring is a through-type screening material blocking assembly, the through-type screening material blocking assembly comprises a material blocking ring and a fastening support piece, the material blocking ring is fixed on the grinding disc through the fastening support piece, and a hollow structure is formed between the material blocking ring and the grinding disc.

Further preferably, the duty cycle of the hollow structure is 1: (0.4-0.7), and the total height of the through type screening material blocking assembly is 2-6% of the diameter of the grinding disc.

Further preferably, the height of the hollow structure is 30-200 mm, the height of the material blocking ring is 5-100 mm, a protective sleeve is sleeved outside the fastening support piece at the position of the hollow structure, and the protective sleeve supports the material blocking ring on the upper layer.

Preferably, the material blocking ring is a cross material blocking ring, a plurality of material discharging openings are formed in the upper portion of the cross material blocking ring, the material blocking ring is made to form a concave-convex structure, the total area of the material discharging openings is 40-60% of the total area of the cross material blocking ring, the height of the concave portion of the cross material blocking ring is 55-95% of the height of the convex portion, and the interval between every two adjacent material discharging openings is 100-800 mm.

Preferably, the auxiliary discharge assembly comprises a pneumatic blowing device and/or a mechanical discharge device.

Preferably, the pneumatic injection device is fixed on the vertical mill shell and used for timely discharging fine powder generated after grinding, a nozzle of the pneumatic injection device extends into the upper portion of the grinding disc and faces the material blocking ring side or the grinding disc side, the height of the nozzle of the pneumatic injection device from the surface of the grinding disc is 20-100 mm, and the radial distance of the nozzle from the material blocking ring is 5-80 mm.

Preferably, the mechanical discharging device is a shovel plate which is arranged downwards and slantwise towards the grinding disc and is used for discharging the ground materials in time, one end of the shovel plate is fixed on the vertical mill shell, and the other end of the shovel plate extends to the position above the grinding disc; the shovel plate comprises a material guiding section and a material shoveling section, and the shovel plate is in arc transition at the joint of the material shoveling section and the material guiding section; the distance between the part of the shovel plate above the grinding disc and the grinding roller is 5-30 mm, the distance between the shovel plate and the grinding disc is 5-60 mm, and the distance between the shovel plate and the material retaining ring is 5-80 mm.

Preferably, the outlet of the circulating fan is also sequentially provided with a dust collector and a tail exhaust fan.

Preferably, the materials from the raw material bin can be directly fed into the combined powder concentrator through a belt conveyor.

The invention has the following advantages and beneficial effects:

1. the machine-made sand production process system can prepare mixed sand, has simple flow, convenient operation and maintenance and high equipment intellectualization degree, and is beneficial to large-scale production; the machine-made sand vertical mill adopts the relative motion of a grinding roller and a grinding disc to crush particles, the energy efficiency utilization rate is higher than that of a traditional crusher, the energy consumption can be saved by 15-45%, and the obvious energy-saving effect is achieved; the machine-made sand adopts a material bed grinding structure, the raw materials are crushed by extrusion and shearing acting forces in a machine-made sand vertical mill, the circularity of the crushed particles is higher than that of the crushed particles due to impact crushing of a crusher, and the finished product particles have fewer needle-shaped particles and are better in quality; the machine-made sand vertical mill is of a totally enclosed structure, operates under micro negative pressure, has no dust leakage in the production process, and has good production environmental protection effect.

2. According to the material blocking ring of the machine-made vertical sand mill, the content of fine powder of the obtained mill material is only 10-20%, the content of fine powder is reduced, only 20-30% of large particles which are not ground enter the mill material, the energy consumption of an auxiliary machine is reduced by 5-10%, and the material blocking efficiency of the large particles is improved; and in addition, auxiliary discharge is used, so that auxiliary discharge can be better performed.

Drawings

FIG. 1 is a flow chart of a machine-made sand production process system provided in accordance with an embodiment of the present invention;

figure 2 is a schematic structural view of a through screen dam assembly provided in accordance with one embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a pneumatic blowing device and a mechanical discharging device according to a first embodiment of the present invention;

fig. 4 is a schematic structural diagram of a striding type tail ring provided by a second embodiment of the invention;

FIG. 5 is a flow chart of a machine-made sand production process system provided by the third embodiment of the invention;

fig. 6 is a flow chart of a machine-made sand production process system provided by the fourth embodiment of the invention.

In the figure: 100-machine-made sand vertical mill; 110-grinding rolls; 120-grinding disc; 130-through screening stop assemblies; 131-a material blocking ring; 132-a fastening support; 133-a protective sleeve; 134-a cap; 140-crossing material blocking ring; 141-a discharge port; 150-a pneumatic blowing device; 151-a nozzle; 152-a gas delivery pipe; 160-mechanical discharge device; 161-a material guiding section; 162-material shoveling section; 170-vertical mill shell;

200-a raw material bin;

300-combined powder concentrator;

400-vibrating screen;

500-a pollen removal mechanism; 510-a cyclone; 520-a circulating fan;

600-a dust collector;

700-tail exhaust fan.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example 1

Referring to fig. 1, the present embodiment provides a production process system for producing sand by using a vertical mill preparation machine, including a raw material bin 200, a machine-made sand vertical mill 100, a combined type powder concentrator 300, a vibrating screen 400 and a powder removing mechanism 500, where the powder removing mechanism 500 includes a cyclone 510 and a circulating fan 520, an outlet of the raw material bin 200 is connected to a material inlet of the machine-made sand vertical mill 100, a material outlet of the machine-made sand vertical mill 100 is connected to a material inlet of the combined type powder concentrator 300 through a hoisting machine, a bottom discharge port of the combined type powder concentrator 300 is connected to the vibrating screen 400, the vibrating screen 400 returns oversize material to the machine-made sand vertical mill 100, an air outlet of the combined type powder concentrator 300 is connected to the cyclone 510, and an air outlet of the cyclone 510 is connected to.

The material is crushed and ground by the machine-made sand vertical mill 100 and enters the screening equipment such as the combined powder concentrator 300 and the vibrating screen 400, and the high-efficiency, low-energy-consumption and clean production of the machine-made sand is realized.

Raw materials enter a machine-made sand vertical mill 100 from a raw material bin 200 through a conveying belt, the ground materials are discharged outside the machine-made sand vertical mill 100 and enter a lifting machine, the materials coming out of the lifting machine enter a combined powder concentrator 300, fine powder smaller than 0.075mm passes through the combined powder concentrator 300 and moves upwards under the driving action of gas, coarse particles move downwards under the action of gravity, the fine powder passes through the combined powder concentrator 300 and then is collected by a cyclone cylinder 510 and enters the next working section, the materials after powder removal enter a vibrating screen 400, the vibrating screen 400 is provided with screen holes with a certain size, and the particles meeting the size requirement enter finished products through the vibrating screen 400 to form finished product sand; the vibrating screen 400 of this example can be provided with three sizes of screen holes according to different requirements, for example: the aperture of the sieve pore is 4.75mm, 2.36mm or 1.18mm, correspondingly, the granules with the diameter less than or equal to 4.75mm, 2.36 or 1.18mm are used as finished sand; the particles which do not meet the requirements and are larger than the sieve opening size of the vibrating screen 400 are returned to the machine-made sand vertical mill 100 for grinding and then are circulated for the next step. The gas carrying fine powder enters the cyclone 510 from the combined powder separator 300, the cyclone 510 separates the fine powder from the gas, the fine powder enters the next process, the gas enters the circulating fan 520, a part of the gas passing through the circulating fan 520 returns to enter the combined powder separator 300, and a part of the gas is exhausted to the atmosphere through a chimney, so that the powder removal is completed. The embodiment is suitable for the process system with the material moisture of less than 2.5 percent.

The sand is produced by a vertical mill, and the ground material enters the combined powder concentrator 300 through a lifter. The combined powder concentrator 300 is composed of a dynamic powder concentrator on the upper part and a static sieving machine on the lower part. The fine powder is driven by the airflow to move upwards, and the harmful fine powder is separated under the action of the dynamic powder separator and enters the next working procedure; the coarse particles passing through the combined type powder concentrator 300 move downwards under the action of gravity, are discharged from a discharge port at the bottom of the combined type powder concentrator 300, enter the vibrating screen 400, and are screened by the vibrating screen 400, so that a mixed machine sand making product with a particle size smaller than a certain particle size is obtained.

The machine-made sand vertical mill 100 comprises a grinding disc 120, at least two grinding rollers 110 and a material stop ring, wherein the conical angle of each grinding roller 110 is not more than 20 degrees, and the total projection area of the grinding rollers 110 on the grinding disc 120 is 20-35% of the area of the grinding disc. The increase of the projection area can increase the yield of the grinding roller for one-time grinding, and the generation amount of fine powder is reduced by matching with the increase of the rotating speed and discharging the ground material out of the grinding machine in time; the machine-made sand vertical mill of the embodiment adopts a rocker arm roll turning structure, and can directly turn the grinding roll out of the mill for maintenance; the grinding roller sleeve is made of surfacing materials, so that online surfacing is convenient to realize. The material blocking ring is a through-type screening material blocking assembly 130 or a cross-type material blocking ring 140, an auxiliary material discharging assembly is arranged on the grinding disc 120, and the auxiliary material discharging assembly is positioned behind each grinding roller along the rotation direction of the grinding disc. The through type screening material blocking assembly or the crossing type material blocking ring is adopted, so that the content of fine powder of the milled material can be reduced, the energy consumption of an auxiliary machine is reduced, and auxiliary material discharge is additionally arranged, so that the content of the fine powder is further reduced.

Preferably, referring to fig. 2, the material blocking ring is a through-type screening material blocking assembly 130, the through-type screening material blocking assembly 130 includes a material blocking ring 131 and a fastening support 132, the material blocking ring 131 is fixed on the grinding disc 120 through the fastening support 132, and a hollow structure is formed between the material blocking ring 131 and the grinding disc 120. The hollow structure of the lower layer ensures that the materials can be discharged in time after being extruded, reduces the excessive grinding of the vertical mill and reduces the generation amount of fine powder; the material blocking ring 131 of the upper solid structure effectively blocks large particles which are not ground, so that the large particles stay on the grinding disc, the large particles are guaranteed to be discharged outside the grinding machine after being ground, and the circulating load of the system and the production energy consumption are reduced.

Further preferably, the duty cycle of the hollow structure is 1: (0.4 to 0.7); adopt in this embodiment the hollow structure height is 30 ~ 200mm, keep off material ring 131 height and be 5 ~ 100mm, the clearance between per two fastening support piece 132 is 20 ~ 600mm for the material that is less than 50mm can both pass through, prevents that the material from excessively grinding. The total height of the through-type screening material blocking assembly 130 is 2-6% of the diameter of the grinding disc 120, and reasonable matching is conducted according to feeding amount.

100% of materials of the material blocking ring structure of the original vertical mill pass through the upper part of the material blocking ring, and the content of fine powder of the milled materials reaches 20-30%; 70-90% of materials pass through the hollow part at the lower part of the through type screening material blocking assembly 130, the content of fine powder of the ground materials is only 10-20%, and the content of the fine powder is reduced. In addition, in the material blocking ring structure of the original vertical mill, about 35-45% of large particles which are not ground enter the milled materials, so that the system load and the energy consumption are increased; by adopting the through-type screening material blocking assembly 130 structure, only 20-30% of large particles which are not ground enter a ground material, the energy consumption of an auxiliary machine is reduced by 5-10%, and the material blocking efficiency of the large particles is improved.

It is further preferable that a protection sleeve 133 is sleeved outside the fastening support 132 at the hollow structure, and the protection sleeve 133 supports the material stopping ring 131 of the upper solid structure. The fastening support 132 in this embodiment is made of a bolt, and the cap 134 is sleeved on the bolt head above the material stop ring 131, and the cap 134 and the protection sleeve 133 are sleeved up and down respectively, so as to prevent the fastening support 132 from being worn and damaged due to long-term use, and not easy to screw.

Preferably, the auxiliary discharge assembly comprises a pneumatic blowing device 150 and/or a mechanical discharge device 160.

When the auxiliary discharging device combining the pneumatic blowing device 150 and the mechanical discharging device 160 is adopted, the mechanical discharging device 160 has a certain height from the grinding disc 120, so that the upper material is mainly scooped up, the lower fine powder is blown out by the pneumatic blowing device 150, and the combination of the two can better perform auxiliary discharging.

Preferably, referring to fig. 3, the conveying air pipe 152 of the pneumatic blowing device 150 is fixed on the vertical mill housing 170 for discharging the fine powder generated after grinding in time, and the nozzle 151 of the pneumatic blowing device 150 extends above the grinding disc 120 and faces the material stop ring side or the grinding disc 120 side. The compressed air flow rate of the pneumatic injection device 150 is 35-85 m/s, the pneumatic injection device 150 is arranged in the mill, and fine powder generated after grinding is discharged in time, so that the fine powder cannot be ground again, and the amount of the fine powder is reduced. The nozzle 151 of the present embodiment may be a divergent fan nozzle, fine material is blown out in time under the combined action of centrifugal force, and coarse material is left on the grinding disc 120 for further grinding.

The height of the nozzle 151 of the pneumatic blowing device 150 from the surface of the grinding disc 120 is 20-100 mm, the radial distance of the nozzle 151 from the material retaining ring is 5-80 mm, and reasonable matching is carried out according to the feeding amount.

Preferably, referring to fig. 3, the mechanical discharging device 160 is a shovel plate disposed obliquely downward toward the grinding disc 120 for discharging the ground material in time, and one end of the shovel plate is fixed on the vertical mill housing 170, and the other end extends to above the grinding disc 120. The mechanical discharging device 160 is arranged in the mill, so that the ground material is discharged in time, the retention time of the ground material in the grinding disc 120 is reduced, the material cannot be ground twice, and the generation amount of fine powder is reduced. The scoops impart a force to the material and the scooped material is thrown out of the grinding disc 120.

The shovel plate comprises a material guiding section 161 and a material shoveling section 162, and the shovel plate is in circular arc transition at the connecting position of the material shoveling section 162 and the material guiding section 161. The shoveling section 162 is used for shoveling the materials and guiding the materials out of the mill through the guiding section 161. The cross section of the shovel plate in this embodiment may be arc-shaped or L-shaped or other shapes.

The distance between the part of the shovel plate above the grinding disc 120 and the grinding roller 110 is 5-30 mm, the distance between the shovel plate and the grinding disc 120 is 5-60 mm, the distance between the shovel plate and the material retaining ring is 5-80 mm, and reasonable matching is carried out according to the feeding amount.

In the process of producing machine-made sand, the main factors influencing the quality of the machine-made sand product are the grinding disc rotating speed of the machine-made sand vertical mill, the centrifugal force of materials on the grinding disc, the grinding pressure and the like.

Wherein, 1) the grinding disc rotating speed of the machine-made sand vertical mill is calculated by adopting the following formula:

wherein: n is the rotation speed of the grinding disc, r/min;

k is an empirical coefficient and is dimensionless, and the value of K is 48-60;

d is the diameter of the grinding disc of the vertical mill, m.

The grinding disc rotating speed of the machine-made sand vertical mill is 1.05-1.35 times of that of the traditional vertical mill, and the grinding disc rotating speed of the traditional vertical mill is 25-35 r/min. The increase of the rotating speed can shorten the retention time of material particles in the grinding disc, reduce the times of grinding the particles and reduce the generation of fine powder.

2) The centrifugal force of the material on the grinding disc is calculated by adopting the following formula:

F＝mV²/R

wherein: f is the centrifugal force on the grinding disc of the material, N;

m is the mass of the particles, kg;

v is the peripheral speed of the grinding disc, m/s;

radius of R-disc, m.

It can be seen that when V is larger, the centrifugal force on the material is larger, the residence time of the grinding disc is shorter, the material can be discharged out of the grinding disc in time after being ground once, and the number and degree of over-grinding of the material are reduced.

3) The grinding pressure of the material is calculated by adopting the following formula:

P＝F×S₁÷S₂÷k

wherein: p is grinding pressure, MPa;

f is the grinding pressure of the hydraulic cylinder, and N is the grinding pressure of the hydraulic cylinder;

S₁is the effective area of the hydraulic oil in the hydraulic cylinder, m²；

S₂Is the projected area of a single grinding roller on the grinding disc, m²；

K is the rocker coefficient of the machine-made sand vertical mill, is dimensionless and is a structural space design value, and the value of K is 0.6-0.8.

It is clear that the greater the grinding pressure to which the material is subjected, the more easily it is crushed.

The diameter of the grinding disc is selected according to the actual yield and different raw materials, the grinding disc is used as a traditional vertical mill cement or raw material product, the traditional vertical mill cannot be directly used for producing the machine-made sand, the detailed description is provided in the background art, for the purpose, the diameter of the grinding disc, the pressure and the rotating speed of the grinding roller and the design of the material stop ring of the vertical mill for producing the machine-made sand need to be redesigned and matched according to the characteristics of the machine-made sand product, the diameter of the grinding disc 120 of the vertical mill for producing the machine-made sand is preferably 1.2m, the pressure of the grinding roller 110 is preferably 5MPa, and the rotating speed of the grinding disc 120 is preferably 43.8 r/min; in order to prove that the invention can realize the production of the machine-made sand with the expected specification by using the vertical mill, the applicant takes limestone as a raw material to carry out experiments to produce the machine-made sand with the grain size specification of 0.15-2.36 mm, and the production machine-made sand experiments are carried out on the diameter of the grinding disc 120, the pressure of the grinding roller 110 and the rotating speed of the grinding disc 120 in the embodiment and are compared with the existing double-rotor sand making machine and a vertical shaft type impact crusher.

The specific contents are as follows: the limestone is used as a raw material for carrying out an experiment, a machine-made sand vertical mill with a grinding disc 120 and a diameter of 1.2m is adopted, the rotating speed of the grinding disc 120 is 43.8r/min, the grinding pressure is 5MPa, the through type screening material blocking assembly 130 is hollow and has a height of 30mm, the height of the material blocking ring 131 is 8mm, the grinding time is 50min, machine-made sand with a thickness of 0.15-2.36 mm is produced, and 6 tons of the machine-made sand are produced. The sphericity coefficient pair of the machine-made sand produced by the machine-made sand vertical mill of the invention and the machine-made sand prepared by the existing double-rotor sand making machine and the vertical shaft type impact crusher is shown in table 1:

TABLE 1 production test results

From the above table, the quality of the machine-made sand vertical mill is better than that of a double-rotor sand making machine and a vertical shaft type impact crusher.

The vertical mill in the machine-made sand production process system replaces the original cone crusher, double-rotor sand making machine, vertical shaft impact crusher and the like, reduces the content of needle-shaped particles in a product, reduces the content of fine powder of machine-made sand, improves the product quality of machine-made sand, improves the utilization rate of sand making energy, reduces the production energy consumption, is beneficial to large-scale production, improves the resource utilization rate, is beneficial to improving the performance of concrete and is beneficial to the engineering quality.

Example 2

Different from the embodiment 1, referring to fig. 4, the material blocking ring of the embodiment is a striding type material blocking ring 140, the upper portion of the striding type material blocking ring 140 is provided with a plurality of material discharging openings 141, so that the striding type material blocking ring 140 forms a concave-convex structure, and the total area of the material discharging openings 141 is 40-60% of the total area of the striding type material blocking ring 140.

The crossing structure enables partial materials to be discharged and partially blocked, reduces the escape amount of the non-ground materials, and improves the content of qualified products in the ground materials. After the material is ground by the grinding roller 110 for a certain time, fine powder is accumulated at the corner at the bottom of the material retaining ring to form a slope, the slope can be used as a stable material layer, and the ground material can be milled through the formed slope after grinding.

The height of the concave part of the striding type material blocking ring 140 is 55-95% of the height of the convex part, and reasonable selection and matching are carried out according to the feeding amount.

The interval between two adjacent discharge ports 141 is 100-800 mm, and reasonable selection and matching are carried out according to the feeding amount.

Example 3

Different from embodiment 1, referring to fig. 5, a dust collector 600 and a tail exhaust fan 700 are further sequentially disposed at an outlet of the circulation fan 520 in this embodiment.

A part of the gas after passing through the circulating fan 520 enters the dust collector 600, is dedusted by the dust collector 600, and is exhausted to the atmosphere through the tail exhaust fan 700 and the chimney. By adopting a double-fan system consisting of the circulating fan 520 and the tail exhaust fan 700, the on-site dust collection effect is improved, and the dust collector 600 can reduce the dust emission concentration to 5mg/m³And the ultra-clean emission is realized, and the environment protection is facilitated. Meanwhile, the arrangement of the tail exhaust fan 700 is beneficial to the adjustment of the circulating air volume, and particularly when the moisture of the grinding material is more than 2.5%, the finished product has high requirement on the moisture content (for example, machine-made sand for dry powder mortar with the moisture of less than 0.5%), wet air can be discharged, the dewing of the wet air in a system is reduced, and the service life of a pipeline is prolonged. Hot air can be connected in series before separation, the materials ground by the vertical mill are dried, and the whole circulating system is prevented from being influenced by water vapor condensation.

Example 4

Unlike embodiment 1, referring to fig. 6, in this embodiment, the material from the raw material bin 200 may be directly fed into the combined powder concentrator 300 through a belt conveyor.

When the content of finished sand in the raw materials is high, the raw materials can directly enter the combined type powder concentrator 300 for powder concentration, so that the grinding efficiency of the vertical mill is improved, the operation load of auxiliary machines in the system is reduced, the energy consumption of the auxiliary machines is saved, and the operation safety of auxiliary machine equipment is improved. Raw materials get into combined powder concentrator 300 from raw materials storehouse 200 through conveyor belt, the farine that is less than 0.075mm through combined powder concentrator 300 is upward movement under the effect of gas carrying, be greater than 0.075mm coarse particle and receive the downward movement of action of gravity, the farine is collected by cyclone 510 after passing through combined powder concentrator 300 and gets into next process, be greater than 0.075mm coarse particle and get into shale shaker 400, shale shaker 400 is provided with the screen cloth that the sieve mesh size is 4.75mm, 0.075 ~ 4.75 mm's granule passes through shale shaker 400 and gets into the finished product, it gets back to the mechanism sand again and grinds vertical mill 100 to be greater than 4.75mm granule, the material after the grinding gets into the lifting machine, enter combined powder concentrator 300 through the lifting machine, carry out circulation on next step. The gas carrying fine powder enters the cyclone 510 from the combined powder separator 300, the cyclone 510 separates the fine powder from the gas, the fine powder enters the next process, the gas enters the circulating fan 520, a part of the gas passing through the circulating fan 520 returns to the combined powder separator 300, a part of the gas enters the dust collector 600, the dust is removed by the dust collector 600, and the gas is exhausted to the atmosphere through the tail exhaust fan 700 and the chimney.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: it is to be understood that modifications may be made to the technical solutions described in the foregoing embodiments, or some or all of the technical features may be equivalently replaced, and the modifications or the replacements may not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A production process system for producing sand by a vertical mill preparation machine is characterized by comprising a raw material bin, a machine-made sand vertical mill, a combined type powder concentrator, a vibrating screen and a powder removing mechanism, wherein the powder removing mechanism comprises a cyclone and a circulating fan;

2. The production process system for preparing sand by using the vertical mill according to claim 1, wherein the material blocking ring is a through-type screening material blocking assembly, the through-type screening material blocking assembly comprises a material blocking ring and a fastening support piece, the material blocking ring is fixed on the grinding disc through the fastening support piece, and a hollow structure is formed between the material blocking ring and the grinding disc.

3. The system of claim 2, wherein the duty cycle of the hollow structure is 1: (0.4-0.7), and the total height of the through type screening material blocking assembly is 2-6% of the diameter of the grinding disc.

4. The sand production process system of the vertical mill preparation machine as claimed in claim 3, wherein the height of the hollow structure is 30-200 mm, the height of the material blocking ring is 5-100 mm, a protective sleeve is sleeved outside the fastening support member at the hollow structure, and the protective sleeve supports the material blocking ring at the upper layer.

5. The production process system for preparing the sand by the vertical mill preparation machine according to claim 1, wherein the material blocking ring is a cross-over material blocking ring, a plurality of material discharging ports are formed in the upper portion of the cross-over material blocking ring, so that the material blocking ring forms a concave-convex structure, the total area of the material discharging ports is 40-60% of the total area of the cross-over material blocking ring, the height of the concave portion of the cross-over material blocking ring is 55-95% of the height of the convex portion, and the interval between every two adjacent material discharging ports is 100-800 mm.

6. The system for the sand production process by the vertical mill preparation machine as claimed in claim 1, wherein the auxiliary discharge assembly comprises a pneumatic blowing device and/or a mechanical discharge device.

7. The production process system for preparing the sand by the vertical mill preparation machine according to claim 6, wherein the pneumatic blowing device is fixed on the vertical mill shell and used for timely discharging fine powder generated after grinding, a nozzle of the pneumatic blowing device extends into the upper part of the grinding disc and faces the side of the material blocking ring or the side of the grinding disc, the height of the nozzle of the pneumatic blowing device from the surface of the grinding disc is 20-100 mm, and the radial distance of the nozzle from the material blocking ring is 5-80 mm.

8. The system for the production process of the sand by the vertical mill preparation machine according to claim 7, wherein the mechanical discharging device is a shovel plate which is arranged obliquely downwards towards the grinding disc and is used for discharging the ground material in time, one end of the shovel plate is fixed on the vertical mill shell, and the other end of the shovel plate extends to the position above the grinding disc; the shovel plate comprises a material guiding section and a material shoveling section, and the shovel plate is in arc transition at the joint of the material shoveling section and the material guiding section; the distance between the part of the shovel plate above the grinding disc and the grinding roller is 5-30 mm, the distance between the shovel plate and the grinding disc is 5-60 mm, and the distance between the shovel plate and the material retaining ring is 5-80 mm.

9. The sand production process system of the vertical mill preparation machine according to claim 1, wherein the outlet of the circulating fan is further provided with a dust collector and a tail exhaust fan in sequence.

10. The system of claim 1, wherein the materials from the raw material bin can be directly fed to the combined powder concentrator through a belt conveyor.