RU2186637C2 - Method of recycling spent materials - Google Patents

Abstract

FIELD: recycling of spent materials formed from industrial wastes mainly on base of granite and marble. SUBSTANCE: method includes crushing of wastes, preliminary aerodynamic classification of raw material at moisture content of up to 5.0 % and rate of air flow of 1 to 50 m/s for separation of fine fraction (3 to 0.001) mm from coarse fraction. Splitting remaining coarse fraction s effected through screening into fractions of 10-2 mm. Fine fraction 3-0.001 mm is classified for the second time in aerodynamic flows at rates of 0.01-30 m/s into fractions 3-1; 2-0.4; 0.8-0.1 and 0.2-0.001 mm at continuous introduction of fraction of 3-0.1 mm obtained after screening. Fractions thus obtained are used for manufacture of building and decorative materials. EFFECT: reduced power requirements for processing wastes; extended range of fractions; enhanced ecology. 18 cl, 4 dwg, 1 tbl

Description

The invention relates to the technology of recycling waste from the mining industry (OGPP) resulting from human production activities, and can be used by returning them to the production cycle of other industries. There is a method of recycling waste from the mining industry, mainly granite raw materials (patent 2575 RB), which consists in the fact that particles less than 5 mm in size are extracted directly from the dumps, particles larger than 5 mm are subjected to crushing, and classification is carried out to the following particle size distribution: 1 2-5 mm; 0.63-1.2 mm; 0.16-0.63 mm; 0.005-0.16 mm [1]:
- a 1.2-5 mm fraction is introduced into the formulation for the preparation of mortars, cement-sand products, anti-icing mixtures;
- the fraction of 0.63-1.2 mm is introduced into the formulation for booking roofing material;
- a fraction of 0.16-0.63 mm is introduced into the formulation of building sealants as a mineral filler;
- a fraction of 0.005-0.16 mm is introduced into the recipe for the preparation of abrasive pastes, cleaning and polishing materials, construction putties, as a filler for paints.

 A disadvantage of the known object is uneconomical, since particles less than 5 mm in size are directly extracted from the dumps. When extracting particles of more than 5 mm, all dumps and the entire particle size spectrum of the 0.001-5 mm fraction are screened, which is not economically feasible. Particles larger than 5 mm are subjected to crushing, and then they are allowed for further classification.

 The closest technical solution, adopted as a prototype, is a method for recycling dumps formed from industrial waste, mainly based on granite and marble rocks, obtained on the basis of marble sawing, in which waste is crushed, preliminary aerodynamic classification of raw materials with humidity up to 5.0% for removal of a small fraction, dividing the remaining large fraction into a small one and subsequent use of the obtained fractions.

 The disadvantage of the prototype as well as the well-known object, is uneconomical, as directly from the dumps to remove particles less than 0-300 mm in size to obtain a dust-free fraction of 0.3-10 mm Screenings (0-5) mm are sent to the blade. Partial dedusting of products is mainly carried out by means of vibration dedusters. More complete dedusting is carried out according to the "wet" hydromechanized technology. Air classification as incomplete aerodynamic is of secondary importance and it is used for preliminary screening of part of the sand from gravel-sand material, while “dry” dust removal is not observed. When extracting particles of more than 5 mm, all dumps are screened and the whole particle size spectrum of the 0.001-5 mm fraction according to the prototype is not economically feasible.

 The basis of the invention is the task of improving the environmental situation in the exclusion zones of waste from the mining industry with the simultaneous expansion of the fractions of useful products while reducing energy costs for processing.

 This goal is achieved by the fact that in the method of recycling dumps formed from industrial waste, mainly based on granite and marble rocks, in which the waste is crushed, preliminary raw materials are aerodynamically classified with a moisture content of up to 5.0% to remove the fine fraction, the division of the remaining coarse fraction and the subsequent use of the obtained fractions, according to the invention, aerodynamic classification is carried out at air flow rates of 1-50 m / s, separating the fine fraction (3.0-0.001) mm from the coarse, the large fraction is divided into fractions (10-2) mm by screening, and the small fraction (3-0.001) mm is classified a second time in aerodynamic flows at speeds (0.01-30) m / s of air per fraction (3-1); (2-0.4); (0.8-0.1); (0.2-0.001) mm, with the constant introduction into it of a fraction (3-0.1) mm obtained from screening.

 In the method, the obtained fractions are introduced into the production technology of building and finishing materials.

 In the method of fraction (10-4); (6-2); (3-1); (2-0.4); (0.8-0.1); (0.2-0.001) mm is introduced as a mineral filler in the formulation for high-strength concrete, thin-walled concrete structures, in dry mixes, asphalt, brick and finishing materials, as well as when sprinkling roads as a strengthening surface layer.

 In the fraction method (0.8-0.1); (0.2-0.001) mm is introduced as a clay cleaner in the formulation in the manufacture of bricks and ceramic tiles.

 In the method, a fraction (0.2-0.001) mm is introduced as a binder (melt) into the formulation in the manufacture of ceramic tiles and bricks.

 In the method, a fraction (0.2-0.001) mm is introduced as an abrasive into the formulation in the manufacture of cleaning products, pastes and polishing powders.

 In the method of fraction (3-1); (2-0.4); (0.8-0.1); (0.2-0.001) mm is used as a strengthening surface layer and color pigment in the formulation in the production of concrete flooring with the addition of cement.

 In the fraction method (2-0.4); (0.8-0.1); (0.2-0.001) is used as nutrient layers, mixed in certain proportions with each other depending on plants, for hydroponics.

 In the method, a fraction of (0.2-0.001) mm is introduced as structure-forming in the formulation during deoxidation of soils.

 In the method, a fraction of (0.2-0.001) mm is used to obtain a dust cloud scattering a laser beam, as well as to extinguish fires.

 In the method of fraction (10-4); (6-2); (3-1); (2-0.4); (0.8-0.1) mm is added as a decorative material in the formulation for walkways and aquariums.

 In the method, a fraction of (2-0.4) mm is used as a sprinkle for booking a roofing material.

 In the method, a fraction of (0.2-0.001) mm is used as a cushioning material when rolling ruberoid into coils and as a cushioning damping layer during road construction and laying of rubble stone.

 In the method of fraction (10-4); (6-2); (3-1); (0.8-0.1) mm is introduced into the composition to obtain sand by mixing them with each other in certain proportions to obtain a given, as well as the optimum modulus of the size of the sand.

In the fraction method (0.8-0.1); (0.2-0.001) mm is preliminarily subjected to heat treatment at t> 600 ^° C for 0.9-1.5 hours, and then used as a dry colored pigment.

In the method of fraction (6-2); (3-1); (2-0.4); (0.8-0.1); (0.2-0.001) mm is introduced into the composition for the production of paving blocks and slabs with the following optimal ratio in volume%:
Fraction (6-1) mm - 20-50
Fraction (2-0.4) mm - 10-30
Fraction (0.8-0.1) mm - 15-30
Fraction (0.2-0.001) mm - 1.5-3.0
In the method, a fraction of (0.2-0.001) mm is used to create dust clouds in the atmosphere to prevent hail.

 In the method of fraction (6-2); (3-1); (2-0.4) mm is used as filtering and precipitating elements in city water treatment plants, water deferrization stations, pools, filters, etc.

The invention is illustrated by drawings, where:
figure 1 - dependence of energy loss and the total cost of the screening process on particle size;
FIG. 2 - dependence of energy losses and the total cost of aerodynamic classification on particle size;
FIG. 3 - dependence of energy losses and the total cost of classification by the combined method.

 The recycling method is carried out according to the following technology. From the dumps or immediately after the operating equipment of the enterprise, the raw materials are delivered and put into the pre-distributor. The moisture content of the feed is measured by any of the known methods, for example, by calcination and subsequent weighing. Before classification, the raw material of the dumps is brought to 0.01-5.0% moisture.

 After measuring moisture, the raw materials are distributed in streams. At a moisture content of up to 5%, the raw material is fed to a primary classifier, for example, an inert one, where mainly a small fraction of less than 3-2 mm is blown, which is carried away with the air stream for further processing. Large particles, more than 3-2 mm, fall down and are fed to a screen, for example, two-product, in which they are divided into fractions, for example, (10-4); (6-2). Moreover, the air flow through the raw materials varies from 1 to 50 m / s depending on the density of the processed material, the individual characteristics of the classifier, the fractional composition of the starting material, the place of supply of the raw materials into it, the requirements for the quality of separation into fractions and compliance with a number of other requirements.

 At a humidity of more than 5%, aerodynamic classification is difficult, since it does not provide an effective separation of conglomerates of particles, therefore, the classification is also ineffective. Therefore, from the pre-distributor, the feed is sent through a different stream to further drying, for example, in rotary dryers. After drying, moisture measurements are carried out by any of the known methods and adjusted to the required one, and then the raw materials are aerodynamically classified at a moisture content of less than 5% by blowing fractions of less than (3-2) mm from the raw materials, as mentioned earlier, with a fraction of (0.2 -0.001) is blown almost completely with the permissible presence of small particles of not more than 0.1%. Thus, energy losses are reduced at the first stage of classification, since the remaining fraction (10-2) mm is screened by additional separation, for example, into two fractions (10-4) and (6-2) without fine particles, thereby improving the screening process itself. The resulting fractions go to finished goods warehouses. Since the aerodynamic classification is probabilistic in nature, there will always be the remainder of the fraction (3-0.1) in the large fraction (10-2) after preliminary aeration. Therefore, the remainder of the fraction (3-0.1) is isolated by screening and fed for further processing together with the fraction (3-0.001), which was obtained at the stage of aeration of raw materials. On this preliminary aeration and screening is completed.

 After aeration, the fraction (3-0.001) is fed into the device, where it is divided into two streams, while separating the dust-like fraction (0.2-0.001) mm for subsequent storage in the form of finished products. The aerodynamic flow is divided into two for the possibility of a wider regulation of the air velocity of the air, which can vary in the range of 0.01-30 m / s. With this adjustment of air velocities, it becomes possible to change the boundaries of the fractions and their quantity by order of consumers, as well as to classify the product in a wide range of densities.

 A fraction of (3-0.001) mm mm cleaned from dust by 70-75% is fed to the classifier (for example, inertial, where it is divided into fractions of (3-1) mm and (2-0.4) mm in the air stream, which are subsequently supplied for storage of finished products.The remaining fraction (0.8-0.001) mm is fed by air flow for further separation into another classifier (for example, centrifugal), as a result of which a fraction (0.8-0.1) mm is released, which is also fed a finished product (0.2-0.001) mm fine fraction is precipitated from the air stream, for example, using a cyclone and The residues of the ultrafine fraction are captured, for example, by electrostatic precipitation (this is a fraction of less than 30-20 microns) and transferred to the user either as a fraction (0.03-0.001) mm as, for example, a filler for paints, or other purposes, or it is mixed with a fraction of (0.2-0.001) mm.

 After passing the dust cleaning devices, the cleaned air enters the atmosphere. The entire technological cycle is under vacuum, thereby eliminating dust from the places of transfer and transportation.

 With this method of processing dumps, the crushing process is not required, and when screening, an additional fraction (10-4) mm is allocated, which is fine crushed stone according to GOST and has its own consumption market.

 The use of combined classification: screening on screens and aerodynamic separation, due to the need to reduce energy costs for processing. Dry screening of the entire volume of raw material dumps on these fractions is not only energetically disadvantageous due to the increase in screening time, but also technically difficult. To increase productivity with this classification method, the use of water is necessary. The screening time per unit volume of the material of the dumps is inversely proportional to the square of the particle size, therefore, the classification cost on the sieves is also inversely proportional to the square of the particle size and is shown in Fig. 1.

 With decreasing particle size of the material, screening time, cost, costs and energy grow exponentially.

 An increase in the screening time by 2–3 times and a sharp increase in energy costs and, accordingly, the cost of processing occurs at the border of 2–3 mm (an increase in the screening time of particles 1 mm in size compared with 5 mm particles increases 25 times).

 The inverse dependence of the classification cost in the aerodynamic processing method is an increase in energy consumption with an increase in the particle size of the classified material. The nature of this curve is proportional to the cubic dependence of the deposition rate (wandering) of particles of a given size.

 The table shows the values of the deposition rates for different particle sizes at different air flow rates and the dependence of the deposition rate on the particle diameter is plotted, shown in Fig.4.

 The particle diameters at which the particle hangs in the air stream (hovers) for the given flow rates are also calculated.

 The value of the equilibrium velocity, for example, for a particle with a diameter of d = 1.3 mm is the flow velocity V = 8 m / s, and for a particle d = 5.5 mm the equilibrium velocity is V = 20 m / s. This means that in order to separate particles d = 1.3 mm and d = 5.5 mm, it is enough to create an air flow of more than 8 m / s. The particle d = 1.3 mm is carried away with the air flow, and the particle d = 5.5 mm remains to be in place.

где K = (ξρS/2) - энергетический коэффициент устройства, характеризующий его аэродинамические качества. Для скоростей от 8 до 20 м/с правомерно принять его постоянным, хотя на самом деле коэффициент К в диапазоне скоростей 0,01-50 м/с имеет более сложную зависимость, так как ξ нелинейная функция. Тогда, например, отношение
E_d=5,5/E_d=1,3=V_d=5,5/V_d=1,3=20³/8³=15,6 раза.The energy costs of creating an air flow are proportional to the product of the differential pressure and air flow rate W = Δp • Q in devices that carry out the classification. The pressure drop is proportional to Δp = ξ (ρv ² ) / 2, where ξ is the hydraulic resistance coefficient, ρ is the air density, v is the flow rate. Air consumption Q = S • v, where S is the cross-sectional area of the device, v is the flow rate. The energy needed to classify

where K = (ξρS / 2) is the energy coefficient of the device, characterizing its aerodynamic qualities. For speeds from 8 to 20 m / s, it is legitimate to take it constant, although in fact the coefficient K in the speed range 0.01–50 m / s has a more complex dependence, since ξ is a nonlinear function. Then, for example, the ratio
_{E d = 5,5 / E d =} 1,3 = V d = 5,5 / V d = 1,3 = 20 ^{3/8 3} = 15.6 times.

 Thus, the ratio of energy expenditures on particle sizes is approximately close to a quadratic dependence on their diameters.

 Figure 2 - the graph shows, thus, that with increasing particle size increases the cost of aerodynamic classification of a unit volume of material depending on the quadratic.

 When analyzing these graphs and calculating absolute values, we conclude that the energy costs for screening and aerodynamic classification are the same within the linear sizes (diameters) of particles of 3-2 mm. This means that the boundary of the energy feasibility of a particular type of classification is at the border of 3-2 mm, therefore it is energetically more profitable to classify small particles by the aerodynamic method, and large ones by screening.

 However, the content of the fine fraction adversely affects the screening time (time increases), therefore it is preferable to isolate this fraction from the large one by aeration or preliminary classification at the border of 3-2 mm before the screening process.

 Therefore, dividing at the first stage into two fractions (10-2) mm and (3-0.001) mm, we achieve that we do not spend additional energy on creating the speeds of coarse particles, but by separating the small fraction from the coarse one, we create favorable conditions for screening on sieves of a large fraction.

 The total energy consumption when combining the processes of aerodynamic classification and screening are presented in figure 3.

 The graph in figure 3 shows the total energy loss for the classification of screenings crushing rocks in a combined way the entire range of sizes of screenings.

 Experience shows, for example, that to obtain a fraction of less than 0.16 mm, it is necessary to spend 40 kWh of electricity when grinding from a fraction of 10-5 mm, and with a combined method of classification from dumps the same 1 t of a fraction of less than 0.16 mm can be obtained by only 8 kWh of electricity, which is 5 times less than the traditional method. At the same time, three tons of a fraction of 10-5, three tons of a fraction of 5-2.5, two tons of a fraction of 2.5-1.25, one ton of seven hundred kilograms of a fraction of 1.25-0.63 and one ton of a fraction of 0.63 are obtained -0.16.

 From the graph in figure 1 it can be seen that in order to obtain a fraction, for example, 0.16-0.001 mm by the screening method, it is necessary to spend tens of times more energy than in the proposed method. And vice versa, with aerodynamic classification, the cost of processing, for example, obtaining fractions 10-15 also increase tenfold compared with screening (figure 2).

 Thus, when implementing this method, we achieve significant savings in energy costs, and hence the cost of processing.

 The fractions obtained according to the invention from the dumps are sent to the consumer and used: for the production of building and finishing materials (as a mineral filler for concrete and dry mixes, a clay cleaner and a binder in the manufacture of ceramics, in the production of roofing material for booking the surface layer and cushioning material when rolling the finished material in rolls, as building sand with a given modulus of fineness, as a coloring pigment after appropriate treatment); in road construction (when sprinkling roads as a reinforcing surface layer, when arranging territories as decorative sprinkling of paths); in land management (as a deoxidizing agent for improving the structure of clay soils); in hydroponics as a carrier layer; in water treatment plants as filtering and precipitation elements; in household chemicals and household products (in the production of cleaning and polishing powders and pastes, when decorating aquariums); in the military field, for example, to create a dust cloud scattering a laser beam; in meteorological centers, for example, to create dust clouds in the atmosphere to prevent hail.

 More specifically, it looks as follows.

 Fractions (10-4), (6-2), (3-1), (2-0.4), (0.8-0.1), (0.2-0.001) mm are used in the production of building materials in as a mineral filler for high-strength concrete, asphalt, brick, in dry mixes and finishing materials, and also when sprinkling roads as a strengthening surface layer.

 Fractions (0.8-0.1); and (0.2-0.001) mm are used in the recipe as a clay cleaner in industrial ceramics in the manufacture of bricks and tiles.

 The fraction (0.2-0.001) mm is used in the formulation as a binder (flux) in the manufacture of ceramic tiles and bricks.

 The fraction (0.2-0.001) mm is used as an abrasive material in the production of cleaning products, pastes, as well as polishing powders.

 The fraction (0.8-0.1) mm is used in the formulation as a mineral filler for thin-walled concrete structures.

 Fractions (3-1); (2-0.4); (0.8-0.1) mm is used as a reinforcing surface layer for concrete flooring and as a color pigment in the same place.

 Fractions (2-0.4); (0.8-0.1); (0.2-0.001) mm are used in the formulation as nutrient layers in hydroponics, mixed in certain proportions with each other depending on the plants.

 The fraction (0.2-0.001) mm is used in the formulation as a deoxidizing agent and to improve soil structure.

 The fraction (0.2-0.001) mm is used to obtain a dust cloud scattering a laser beam, as well as to extinguish fires.

 Fractions (10-4); (6-2); (3-1); (2-0.4); (0.8-0.1) mm is used as a decorative material, for example for walkways and aquariums.

 A fraction of (2-0.4) mm is used for booking roofing material, as a sprinkle that increases the strength of the surface layer of the material, as well as increasing the resistance of the roofing material to weather conditions.

 The fraction (0.2-0.001) mm is used as a cushioning material when rolling roofing material into rolls and as a cushioning damping layer during road construction and laying of rubble stone.

 Mixing fractions (10-4); (6-2); (3-1); (2-0.4); (0.8-0.1) mm between themselves in certain proportions, get the specified, as well as the optimal modulus of the size of the sand.

Previously heat-treated at t> 600 ^o C for at least 1 hour, fractions (0.8-0.1); (0.2-0.001) mm is used as a dry colored pigment.

 Fractions (6-2); (3-1); (2-0.4); (0.8-0.1); (0.2-0.001) is used in the formulation of compositions in the production of paving blocks and plates.

 The most optimal ratio of fractions in the production of paving blocks and slabs is as follows, volume%: fractions (6-2); (3-1) mm taken together - 20-50%; fraction (2-0.4) mm - 10-30%; fraction (0.8-0.1) - 15-30%; fraction (0.2-0.001) mm - 1.5-3.0%.

 The fraction (0.2-0.001) mm is used to create dust clouds in the atmosphere in order to prevent hail.

 Fraction (6-2); (3-1); (2-0.4) mm is used as filtering and precipitating elements in city water treatment plants, water deferrization stations, basins, filters, etc.

 Industrial use of the claimed technology is based on the manufacture of a pilot plant by the applicant.

Sources of information
1. Patent BY 2575, IPC B 01 V 1/00, 1999.

 2. Olyunin VV Processing of non-metallic building materials. - M .: Nedra, 1988, p. 166 and 167, 189-201.

Claims (17)

 1. The method of recycling dumps formed from industrial waste, mainly based on granite and marble rocks, which carry out crushing waste, preliminary aerodynamic classification of raw materials with a moisture content of up to 5.0% to remove the fine fraction, dividing the remaining large fraction and the subsequent use of the obtained fractions, characterized in that the aerodynamic classification is carried out at air flow rates of 1-50 m / s highlighting a small fraction (3.0-0.001) mm from a large fraction, then a large fraction is divided into fractions from (10-2) mm put m of screening, and a small fraction (3-0.001) mm is classified a second time in aerodynamic flows at speeds (0.01-30) m / s of air into fractions (3-1), (2-0.4), (0.8 -0.1), (0.2-0.001) mm with the constant introduction of a fraction of (3-0.1) mm obtained from screening into it.  2. The method according to p. 1, characterized in that the obtained fractions are introduced into the production technology of building and finishing materials.  3. The method according to claim 2, characterized in that the fraction (10-4), (6-2), (3-1), (2-0.4), (0.8-0.1), ( 0.2-0.001) mm is introduced as a mineral filler in the formulation for high-strength concrete, thin-walled concrete structures, in dry mixes, asphalt, brick and finishing materials, as well as when sprinkling roads as a strengthening surface layer.  4. The method according to claim 2, characterized in that the fraction (0.8-0.1), (0.2-0.001) mm is introduced as a clay cleaner in the formulation in the manufacture of bricks and ceramic tiles.  5. The method according to claim 2, characterized in that the fraction (0.2-0.001) mm is introduced as a binder (fluff) into the formulation in the manufacture of ceramic tiles and bricks.  6. The method according to claim 1, characterized in that the fraction (0.2-0.001) mm is introduced as an abrasive material into the formulation in the manufacture of cleaning products, pastes and polishing powders.  7. The method according to claim 1, characterized in that the fraction (3-1), (2-0.4), (0.8-0.1), (0.2-0.001) mm is used as a strengthening surface layer and color pigment in the formulation for the production of concrete flooring with cement.  8. The method according to p. 1, characterized in that the fraction (2-0.4), (0.8-0.1), (0.2-0.001) mm is used as nutrient layers, mixed in certain proportions each with another depending on the plants, for hydroponics.  9. The method according to claim 1, characterized in that the fraction (0.2-0.001) mm is introduced as structure-forming in the formulation during deoxidation of soils.  10. The method according to p. 1, characterized in that the fraction (0.2-0.001) mm is used to obtain a dust cloud scattering the laser beam, as well as when fighting fires.  11. The method according to claim 1, characterized in that the fraction (10-4), (6-2), (3-1), (2-0.4), (0.8-0.1) mm is introduced as a decorative material in the recipe for walkways and aquariums.  12. The method according to claim 1, characterized in that the fraction (2-0.4) mm is used as a topping for booking roofing material.  13. The method according to p. 1, characterized in that the fraction (0.2-0.001) mm is used as a cushioning material for coiling the ruberoid in rolls and as a cushioning damping layer for road construction and laying of rubble stone.  14. The method according to claim 1, characterized in that the fraction (10-4), (6-2), (3-1), (0.8-0.1) mm is introduced into the composition to obtain sand by mixing them among themselves in certain proportions to obtain a given, as well as the optimal modulus of fineness of sand. 15. The method according to claim 1, characterized in that the fraction (0.8-0.1), (0.2-0.001) mm is preliminarily subjected to heat treatment at t> 600 ^o C for 0.9-1.5 h, and then used as a dry colored pigment. 16. The method according to claim 1, characterized in that the fraction (6-2), (3-1), (2-0.4), (0.8-0.1), (0.2-0.001) mm is introduced into the composition for the production of paving blocks and slabs in the following optimal ratio, vol.%:
Fraction (6-1) mm - 20-50
Fraction (2-0.4) mm - 10-30
Fraction (0.8-0.1) mm - 15-30
Fraction (0.2-0.001) mm - 1.5-3.0
17. The method according to p. 1, characterized in that the fraction (0.2-0.001) mm is used to create dust clouds in the atmosphere to prevent hail.  18. The method according to claim 1, characterized in that the fraction (6-2), (3-1), (2-0.4) mm is used as filtering and precipitating elements in water treatment plants in cities, iron removal stations, pools filters, etc.

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