RU2812103C2 - Technological complex for production of metal powders of scaly shape - Google Patents

Abstract

FIELD: material processing.

SUBSTANCE: invention relates to the production of powder materials, namely to copper powder of a scaly shape, used in chemical purification and for production of paints. The complex contains a supplier for loading of granules, a supplier for loading of protective lubricant for granules, a mill with milling balls, a centrifugal fan, a pumping pipeline for air supply to an inner cavity of the mill from the centrifugal fan, equipped with an adjustable flap, an aspiration unit, a powder unloading unit, and a system of pipelines connecting listed units to a single aerodynamic ring consisting of parallel operating main and auxiliary contours for air circulation and transfer of a produced product. At the same time, its is equipped with an exhaust fan for direction of incoming surrounding air contaminated with fine dust-like particles for further purification and an exhaust probe connected to it by means of the pipeline, installed above the centrifugal fan unit and both flaps. The aspiration unit contains a primary purification cyclone and a secondary purification cyclone connected in series with pipelines, each of which communicates with a corresponding receiving hopper for collection of produced powder.

EFFECT: regulation of a fraction composition of produced powder and removal of fine dust-like particles of produced powder coming to an air medium.

2 cl, 2 dwg

Description

The invention relates to a technological complex of equipment for the production of flake-shaped metal powders, in particular, flake-shaped copper powders used in the chemical purification of titanium chloride from impurities, as well as for the production of paints.

The most advanced technology is the production of copper or copper-containing flake powder from a copper charge with particles of spherical or polyhedral shape, including applying a water-repellent lubricant to the charge particles, flattening and grinding the particles in a ball mill to form a mixture in the form of flakes from the original powder with a water-repellent lubricant located along the boundaries of the flakes lubricant, followed by extraction of the required parameters from the resulting product mixture. The implementation of this technology is carried out through the use of the main equipment that forms the technological complex, ensuring the implementation of the listed operations, and auxiliary equipment that performs related operations. The design of the technological complex is known (Yu.I. Khimchenko, L.S. Radkevich, A.V. Leshchenko, Z.V. Litvishko, L.N. Degtyareva, N.A. Likhacheva and E.A. Khainakova. Method of production metal powder of scaly form. Automatic certificate of the USSR SU 1395427 A1. 05.15.88. Bull. 11 18 (71)), representing a steel drum rotating on the rollers of a ball mill and at room temperature at a speed of 100 rpm for up to 20 hours, where the powder of the crushed metal is loaded, a solvent (ethanol, acetone) in a ratio of 1:1, steel balls with a diameter of 1-8 mm in a ratio of 6:1 to the weight of the powder, salt of a two-quaternary ammonium base in an amount of 0.02-0.14 to the weight of the metal powder . The powder processed in the drum, manually or using small-scale mechanization, is unloaded onto a metal sieve, separated from the balls and washed with an organic solvent until the salt is completely removed. This technical solution makes it possible to reduce the oxide content on the powder particles and increase the degree of dispersion of the resulting flake-shaped powder, which is characterized by an increase in the specific surface area several times compared to the specific surface area of the original powders taken as a charge. This makes it possible to obtain highly dispersed flake-shaped metal powder with a low oxide content and an increased shelf life.

The disadvantages of this design of equipment of the technological complex are low productivity due to the discrete technological operations of unloading, separation from grinding balls and washing with solvent, a large amount of manual labor and the associated relatively high cost of the powder. The design of the technological complex is known (Budakov O.V., Vargasov D.D., Kozitsin A.A., Plekhanov K.A. A method for producing copper or copper-containing flake powder from copper or copper-containing powder with spherical particles and an installation for its implementation. RF Patent No. 2051009. From 03/20/1993. Published on 12/27/1997), containing a feeder for raw materials, a lubricant feeder, a centrifugal ball mill with grinding balls located on a horizontal shaft, a device for classifying crushed powder, an inert gas supply unit in the cavity of the installation and a system of communicating pipelines, an impact centrifugal mill on a horizontal shaft, located between the ball mill and a device for classifying crushed powder, made in the form of a linear-inertial separator and a centrifugal separator, the cavities of which are connected to each other and with the cavity of the feeder of the original powder, and a cyclone, with In this case, the gas outlet pipe from the cyclone is connected to the cavity of the impact centrifugal mill, its discharge hole is connected to the pipe for introducing the flake mixture into the linear-inertial separator, and the pipe for outputting the highly dispersed fraction of the flake mixture from the centrifugal separator is connected to the pipe for its input into the cyclone. In the technological complex under consideration, the transfer of the resulting powder from one unit to another is ensured by air circulating inside it.

The disadvantages of this design are:

1. - the complexity of the equipment of the complex, the presence of two grinding devices, the last of which is expected to have intensive wear of the rotating parts due to interaction with the mixture of air and the produced powder, the presence of two types of separators of different design to separate the product of the required fraction;

2. - low productivity in terms of product volume due to two reasons:

a) - the presence of a closed pipeline system in which the air circulation provided by the centrifugal fan is difficult. It is characterized by low air flow velocities due to the large internal volumes of the complex units connected into a single aerodynamic ring, as well as the high aerodynamic resistance of its individual elements, which reduce the air pressure difference between adjacent sections of the aerodynamic ring. This makes it difficult to transfer flaky powder particles formed in the mill, reducing the efficiency of the technological complex and its productivity;

b) - the impossibility of changing the speed of rotation of the mill drum, which makes it optimal to use the complex equipment only for processing raw materials of a certain brand. Switching to raw materials with other parameters will also lead to a decrease in equipment productivity;

3. - the inability to change the amount of flake powder produced by grinding, taking into account the possibility of its transfer within the complex by the air circulating there, which leads during the operation of the complex to additional grinding of powder particles, which is undesirable from the point of view of the consumer properties of the resulting product.

The closest in technical essence of the invention is the design of the technological complex (Alekseev V.D., Vershinin S.V., Yudin A.D., Slukin E.Yu., Motovilov P.A., Belov V.V., Khatyanov A. L. Technological complex for the production of metal powders of flake form. RF Patent No. 2736121. From 04/03/2019. Published on 11/11/2020), which includes a feeder for loading granules, a feeder for loading protective lubricant of granules, a mill with grinding balls, rotating by means of an electric drive with a constant unregulated frequency around its horizontal axis, an air supply unit into the internal cavity of the mill, an aspiration unit, a powder unloading unit, a pipeline system connecting the above units into a single aerodynamic ring through which air circulates and the transfer of the produced product is carried out, consisting of working in parallel main and auxiliary circuits, characterized in that the pipeline connecting the suction part of the air supply unit to the mill and the aspiration unit at the outlet has the possibility of controlled supply of outside air into it (adjustable suction of outside air), and the pipeline connecting the discharge part of the air supply unit and the mill , equipped with a damper, the amount of air supplied to the internal cavity of the mill; The mill drive for regulating its rotation frequency is equipped with a device that allows you to change the stepless speed control of the electric motor.

The disadvantages of this design are:

- the inability to regulate the fractional composition of the produced powder during the operation of the complex;

- during the operation of the complex, at the suction section of the main fan, the release of small dust-like particles of the produced powder, which enter in small quantities through the slightly open damper into the air during operation of the technological complex, which requires the operating personnel to use individual respiratory protection.

The technical challenge is to provide the ability to regulate the fractional composition of the produced powder during the operation of the complex and to remove small dust particles of the produced powder that enter the air from the internal space of the technological complex during its operation. The problem is solved by the fact that: 1. a technological complex for the production of metal powders of flake form, containing a feeder for loading granules, a feeder for loading protective lubricant of granules, a mill with grinding balls, configured to rotate by means of an electric drive with an adjustable frequency around its horizontal axis, a centrifugal fan, the suction part of which is configured to regulate the amount of air supplied to it by means of a damper for adjustable suction of outside air, a discharge pipeline for supplying air into the internal cavity of the mill from a centrifugal fan, equipped with an adjustable damper, an aspiration unit, a powder unloading unit and a piping system, connecting the listed units into a single aerodynamic ring, consisting of main and auxiliary circuits operating in parallel for air circulation and transfer of the produced product, characterized in that it is equipped with an exhaust fan to direct the ambient air entering it, contaminated with small dust particles for further cleaning, and an exhaust probe connected to it through a pipeline, installed above the centrifugal fan assembly and both dampers, while the aspiration assembly contains a primary purification cyclone and a secondary purification cyclone connected in series by pipelines, each of which communicates with a corresponding receiving hopper for collecting the produced powder;

2. technological complex, characterized in that it is designed to produce mechanically activated metal powders of scaly form.

A diagram of the technological complex for the production of flake-shaped metal powders, including mechanically activated ones, is shown in Fig. 1 and Fig. 2.

The technological complex consists of a drum-type mill with a horizontal axis 1, equipped with an external gear rim and capable of rotating by means of an electric drive, including an electric motor with the possibility of steplessly variable speed control 2, a gearbox 3 and a drive gear 4 meshed with the rim of the mill, connected into a single kinematic chain. Mill 1 is preloaded with grinding balls, the number and dimensions of which are determined by the characteristics of the charge and the requirements for the finished powder. The centrifugal fan 5 located above the mill is connected to its internal cavity by a pipeline 6 passing from the side of the gear rim through an end 7 that is stationary relative to the specified pipeline, equipped with a sealing device that interacts with the rotating drum of the mill 1. The feeder 8 with the charge is a hopper equipped with a vibrator for to prevent the charge from sticking in it, and a dispenser located in the lower part of the hopper to ensure the required amount of charge supplied to the mill through pipeline 9. The charge in the form of granules is loaded into the feeder hopper 8 located on the service platform 11. A mixer 10 is also located on the platform 11 , designed for possible mixing of the original granules and stearin in proportions determined by the production technology. Pipeline 9 for better distribution of the supplied powder in the mill at the entrance to the mill drum passes inside pipeline 6, which has a larger diameter, forcing air from the fan into the mill.

Passing from the side opposite the gear rim through end 13, which is stationary relative to the pipelines, equipped with a sealing device and interacting with the rotating drum of the mill 1, pipeline 14 is connected to the aspiration unit 15. The aspiration unit 15 includes a primary cleaning cyclone, in which the primary cleaning of the air flow occurs with metal powder removed from mill 1 and a secondary purification cyclone installed after it to further purify the air flow. After the aspiration unit 15, the purified air enters the main fan and is then pumped back into the mill 1.

Fine copper powder, caught by the primary purification cyclone, is a finished product and, through the flow of this cyclone 12, enters the prepared container. The powder collected by the secondary purification cyclone is a finer fraction and is suitable as a finished product. It is also packaged in a separate container for further mixing with the bulk of the powder. Both cyclones are connected in series with each other by a pipeline and are located on a separate platform or other supporting metal structure above the top of the mill drum. The pipeline 6 is connected to the pipeline 14 by a pipeline of a smaller cross-section 16 to allow better circulation of air moving through the mill drum. The pipe of purified air leaving the cyclone of the aspiration unit 15 is connected to the suction part of the centrifugal fan 5 of the air supply unit to the mill by pipeline 17, in the side surface of which there is a pipe, to the end of which an adjustable damper 18 is attached to change the ratio of the amount of air supplied to the fan 5 from aspiration unit 15 and mixed outside air (to change the adjustable suction of outside air). Each cyclone of the aspiration unit 15, with its lower part, communicates with the corresponding receiving hopper for collecting the produced powder. Each receiving hopper is equipped with its own shutter: 12 for the primary purification cyclone and 19 for the secondary purification cyclone, which shuts off the supply of powder to the prepared container once it is filled. The pipeline 6 pumping air into the mill directly behind the point of its connection with the centrifugal fan 5 is equipped with an adjustable damper 20 that regulates the pressure of the air directed by the centrifugal fan 5 into the mill 1. The space above the centrifugal fan 5 and the dampers 18 and 20 on top is under the exhaust probe 21, which is connected by a pipeline 22 to the exhaust fan 23, which directs the air entering it from the surrounding main fan and both dampers 18 and 20 for further cleaning.

The device works as follows. Before launching the complex, based on the accumulated experience and available recommendations, the rotation speed of the mill drum 1 is set for each type of charge using its electric drive, which includes an electric motor with the possibility of steplessly variable speed control 2, a gearbox 3 and a drive gear 4 meshed with the rim of the mill, connected into a single kinematic chain. When the mill starts, the drum with the grinding balls in it begins to rotate at a given frequency, and the balls roll inside the drum, which ensures subsequent grinding of the charge. After starting the electric motor of the mill 1, the centrifugal fan 5 is sequentially started, providing air circulation inside the working space of the complex, and the exhaust fan 23, which ensures the capture and removal of outside air contaminated with grinding products.

1. Loading of mill 1 with charge is carried out from the service platform 11, located above the upper part of the drum of mill 1 through feeder 8, which is a hopper into which the prepared charge is loaded, equipped with a vibrator to prevent the charge from sticking together in the hopper, and a dispenser located at the bottom of the hopper, providing the required amount of charge supply to mill 1 through pipeline 9. Pipeline 9 for better distribution of the supplied powder in the mill at the entrance to the mill drum passes inside pipeline 6, which forces air from the fan into the mill, having a larger diameter, which ensures a more uniform distribution of the charge inside the mill drum . To prepare the charge, preliminary mixing of the original charge granules and stearin can be used in proportions determined by the production technology, carried out in a rotating mixer 10, where in this case the source product is loaded. The mixer 10 is located with the feeder 8 on the same service platform 11 and ensures the preparation of the mixture with stearin for feeding into the latter. The prepared charge is supplied from feeder 6 to mill 1 through a stationary end 9 equipped with a sealing device on the side of the gear rim, interacting with the rotating drum of mill 1. The charge loaded into the rotating ball mill 1 is ground by grinding balls with an air flow constantly moving inside the drum. In this case, the amount of air pressure is ensured by adjusting the position of the valve 20, and pipeline 16, operating in parallel with pipeline 6, the mill cavity and pipeline 14, stabilizes the air circulation inside the aerodynamic contour during operation of the complex, regardless of the degree of filling of the cyclones of the aspiration unit 15 with the resulting powder. The pipeline 14 passes through the fixed end 13, located on the side opposite the gear rim of the mill 1, and is equipped with a sealing device that interacts with its rotating drum. Through the slightly open damper 20, it is possible that the smallest particles of powder that are not captured by the aspiration unit 15 from the internal cavity of the aerodynamic contour can enter the surrounding air.

2. Upon reaching a certain size of flake-shaped particles ground in mill 1, they are captured by the air flow passing through the mill drum 1 and generated by a centrifugal fan 5 with an adjustable valve 20, through pipeline 14 they enter the primary cleaning cyclone of the aspiration unit 15, where separation from the mixture occurs particles of the required fraction and accumulating them in the bunker of this cyclone. Smaller powder particles with moving air enter the secondary cleaning cyclone of the aspiration unit 15, where they are accumulated in the corresponding hopper. The air, cleared of powder, moving further along the air duct, which is pipeline 17, is directed by a centrifugal fan again into the mill 1, while an additional volume of air is taken from the environment by a centrifugal fan 5 through an adjustable cross-section by a valve 18 in the inlet connecting the cyclone to the fan , pipeline 17, which makes it possible for the smallest particles of powder not captured by the aspiration unit 15 to enter the surrounding air from the internal cavity of the aerodynamic contour of the device in question. 3. The large fraction of powder separated from the separator of the aspiration unit 15 enters the unloading hopper, equipped with a shutter 12, of the unloading unit, from where, as it accumulates, it is poured by the personnel into the finished container. The powder collected by the secondary purification cyclone is a smaller fraction suitable for use as a finished product. It also enters the unloading hopper of this cyclone, equipped with a shutter 19, of the unloading unit, from where, as it accumulates, it is poured by personnel into finished containers for further mixing with the bulk of the produced powder.

4. The smallest powder particles that are not collected by the aspiration unit 15, which have entered the ambient air through the dampers 18 and 20, located close to the centrifugal fan 5, which are slightly open during operation of the complex, under the influence of the vacuum created by the exhaust fan 23, fall into the exhaust probe 21 located above them. and through pipeline 22 they pass together with the outside air sucked from under the probe 21 through the exhaust fan 23 for subsequent cleaning with devices that are more effective than cyclones.

The technical result is the regulation of the fractional composition of the produced powder and the removal of small dust particles of the produced powder that enter the air environment from the internal space of the technological complex during its operation through the dampers on the suction and discharge units of the centrifugal fan.

To expand the technological capabilities of the complex, it can be equipped with a system for supplying inert gas inside the mill, which will reduce the oxidation of particles of the produced powder.

To operate the complex in a temperature range that is favorable from the point of view of obtaining its highest productivity (from +5 to +30 degrees Celsius) and to remove excess heat generated during grinding of the charge, it is advisable to equip the complex with an autonomous cooling system for the outer surface of the rotating drum of the mill.

Claims (2)

1. A technological complex for the production of flake-shaped metal powders, containing a feeder for loading granules, a feeder for loading protective lubricant of granules, a mill with grinding balls, configured to rotate by means of an electric drive with adjustable frequency around its horizontal axis, a centrifugal fan, the suction part of which is with the ability to regulate the amount of air supplied to it by means of a damper for adjustable suction of outside air, a discharge pipeline for supplying air into the internal cavity of the mill from a centrifugal fan, equipped with an adjustable damper, an aspiration unit, a powder unloading unit and a pipeline system connecting the above units into a single aerodynamic ring , consisting of main and auxiliary circuits operating in parallel for air circulation and transfer of the produced product, characterized in that it is equipped with an exhaust fan to direct the ambient air entering it, contaminated with small dust particles for further cleaning, and an exhaust probe connected to it through a pipeline , installed above the centrifugal fan unit and both dampers, while the aspiration unit contains a primary purification cyclone and a secondary purification cyclone connected in series by pipelines, each of which communicates with a corresponding receiving hopper for collecting the produced powder. 2. The technological complex according to claim 1, characterized in that it is designed to produce mechanically activated metal powders of scaly form.