Comprehensive utilization method of steel mill fly ash

Abstract

The invention discloses a comprehensive utilization method of steel mill fly ash, and relates to the technical field of blast furnace ash utilization. According to the spiral chute, reverse separation is carried out according to the difference of gravity, inertia centrifugal force, water flow acting force, groove face friction force and the like borne by light ore particles and heavy ore particles in water flow downward along the spiral inclined face; the spiral chute is simple in equipment structure and low in manufacturing cost; the space utilization rate is high and the occupied area is small; operation and maintenance are convenient; the productivity is high; according to the spiral chute, reverse separation is carried out according to the difference of gravity, inertia centrifugal force, water flow acting force, groove surface friction force and the like borne by light ore particles and heavy ore particles in water flow downward along the spiral inclined surface.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace ash utilization, and in particular to a comprehensive utilization method of steel plant dust removal ash. Background Art

[0002] Blast furnace ash is a by-product produced during the blast furnace ironmaking process. It specifically refers to the charge powder brought out by the blast furnace gas. It is mainly composed of mineral powder, coke powder and alkaline oxides (such as CaO), and also contains a small amount of iron, carbon and other elements. Blast furnace ash has great utilization value. After recycling, it can be sorted into iron powder, coke powder and tailings. Iron powder can be used directly for ironmaking, coke powder can be used as ironmaking fuel, and tailings can be used as raw materials for cement production. The temperature of blast furnace ash when it is collected from the blast furnace into the dust collector is about 300°C. It needs to be sprayed with water to cool it down when it is transported from the dust collector to the blast furnace ash silo. The moisture content of blast furnace ash entering the silo is about 20%. The moisture content of blast furnace ash when it leaves the silo and is loaded into the external tank truck is about 15%. The moisture content is about 5% when it is unloaded into the raw material area of ​​the workshop after entering the factory.

[0003] There are three main methods for comprehensive utilization of blast furnace ash as solid waste: 1. Direct storage, which is likely to cause environmental pollution and waste of resources; 2. As a sintering ingredient, it directly enters the blast furnace to recover Fe and C. This method easily leads to the circulation and enrichment of zinc in the blast furnace, resulting in the blast furnace being unable to operate normally; 3. Pyrometallurgy and hydrometallurgy, the main purpose of which is to recover zinc in blast furnace ash. The pyrometallurgy adds coke to reduce zinc to vapor and volatilize it, while iron remains in the slag to achieve zinc-iron separation. This method consumes a lot of energy and can also cause some environmental pollution. When using hydrometallurgy, acid leaching or alkali leaching is usually used. This method will produce new waste acid, waste liquid and other wastes. For this reason, we propose a comprehensive utilization method for steel plant dust removal ash. Summary of the invention

[0004] The purpose of the present invention is to solve the problems mentioned in the above background technology, and provide a method for comprehensive utilization of dust from a steel plant.

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0006] A method for comprehensive utilization of steel plant dust removal ash, comprising the following steps:

[0007] Step 1: Loading: conveying the raw materials into the mixing tank;

[0008] Step 2, add water and stir evenly. After the blast furnace ash is sent to the mixing tank, it is stirred evenly with water and a foaming agent in the tank to make it in a uniform liquid state, so that the iron powder, tail powder and coke powder in the tank are separated into three layers at the bottom, middle and top;

[0009] Step 3, flotation, using spiral chute flotation integrated equipment for flotation work, in which iron has a high specific gravity and sinks to the lower layer, carbon has a low specific gravity and floats to the upper layer, and calcium and other impurities are located in the middle, thereby separating;

[0010] Step 4, dehydration, dehydration is carried out by a rotary spin dryer, the dehydrated water enters the production water circulation pool, after precipitation, it is reused in the water adding and stirring process, and continues to be recycled, and the sediment in the water circulation pool is the tail powder;

[0011] Step 5: The product is fished out regularly and then dehydrated to become tail powder product.

[0012] Furthermore, a spraying device is arranged during the feeding process to control dust by spraying water, and the raw material used for the feeding is purchased blast furnace ash.

[0013] Furthermore, the material loading method is through pit feeding + corridor transportation in the workshop, using a forklift to push the raw materials into the feeding pit, and then enter the fully enclosed conveying corridor, and then send them into the mixing tank through the conveying corridor.

[0014] Furthermore, water needs to be added during the stirring process, but no water needs to be added during flotation.

[0015] Furthermore, the main components of the foaming agent in the water-added stirring are longifolene and its isomers and terpineol and its isomers, wherein the content of longifolene and its isomers is 25.0%, and the content of terpineol and its isomers is 15.0%.

[0016] Furthermore, the material water flow of the flotation is the material liquid in the mixing tank, which is pumped into the spiral chute separator by the delivery pump. Under the action of the material water flow and gravity, the material flow is driven. The mixing water will escape in the dehydration process and be collected into the circulating water pool. After sedimentation, it is reused in the mixing process and used as mixing water to achieve recycling.

[0017] Furthermore, the spiral chute flotation integrated equipment is composed of a ore separator, a feed chute, a spiral chute, an ore intercepting chute, an ore receiving bucket and a chute bracket.

[0018] Further, the ore distributor is used to distribute the pulp. It is located at the uppermost part of the spiral chute. By means of the reaction force of the pulp flow discharged through the feed pipe, it drives the ore distribution cylinder to rotate, and evenly distributes the pulp into the four-flow guide chute; the feed chute is located between the ore distributor and the spiral chute, and is used to evenly and slowly feed the pulp from the ore distributor into the spiral chute along the convex tongue-shaped feed weir plate after buffering and stabilizing; the spiral chute is used to separate minerals. The spiral chute is composed of multiple spiral plates connected to each other by bolts; the ore cutting chute is connected to the discharge end at the lower part of the spiral chute. The pulp sorted by the spiral chute forms ore belts with different grades at the discharge end and is intercepted as products with different grades when passing through the ore cutting chute; the ore receiving hopper is a concentric annular cylinder, which can collect the different-grade flows intercepted by the four ore cutting chutes by category and guide them to the next operation; the chute support is used to support the spiral chute, and the chute support is composed of columns installed around the spiral chute and a cross-shaped frame at the upper part.

[0019] Further, the flotation includes the following steps:

[0020] Step 31: Layering. The longitudinal flow of the pulp flow rotating around the vertical axis of the spiral chute and flowing downward along the chute surface is the main flow. The transverse flow rotating around a certain equilibrium layer of the ore flow itself is the transverse circulation or secondary flow. The flow velocity of the upper layer of the longitudinal flow is large, and the flow velocity of the lower layer is small. The upper layer of the transverse circulation flows towards the outer edge of the chute, and the lower layer flows towards the inner edge of the chute. The ore particles given to the spiral chute surface, under the combined action of the longitudinal main flow and the transverse circulation, due to differences in density, particle size, shape, etc., produce differences in the longitudinal and transverse movement speeds and trajectories along the spiral chute, resulting in the layering phenomenon of ore particles according to density and particle size.

[0021] Step 32: Zoning. After layering, the light ore particles are in the upper layer. Under the action of the longitudinal main flow with a larger velocity and the transverse circulation with the direction towards the outer edge, they gradually flow towards the outer edge of the chute along the expanding spiral; while the heavy ore particles in the lower layer are less affected by the longitudinal main flow. Under the action of gravity and the transverse circulation with the direction towards the inner edge, they gradually move towards the inner edge along the converging spiral, causing the layered ore particles to be zoned.

[0022] Step 33: Separation. After the above two stages, the ore cutting chute and the ore receiving hopper discharge the sorted products with different grades from the chute. The iron powder, coke powder, and tail powder respectively enter their respective iron powder chutes, coke powder chutes, and tail powder chutes to enter the next process.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. The spiral chute of the present invention performs reverse separation by taking advantage of the differences in the gravity, inertial centrifugal force, water flow force, and chute surface friction force of light and heavy ore particles in the water flow along the spiral slope downward.

[0025] 2. The spiral chute of the present invention has the advantages of simple equipment structure, low cost, high space utilization, small footprint, convenient operation and maintenance, high productivity and wide processing particle size range (0.02-0.3mm). The spiral chute uses the different gravity, inertial centrifugal force, water flow force and chute surface friction of light and heavy ore particles in the downward water flow along the spiral slope to perform reverse selection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a work flow chart of the present invention;

[0027] Figure 2 It is the work flow chart of flotation in the present invention. DETAILED DESCRIPTION

[0028] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0029] See also Figure 1 - Figure 2 The present invention provides a method for comprehensive utilization of steel plant dust, comprising the following steps:

[0030] Step 1: Loading: conveying the raw materials into the mixing tank;

[0031] Step 2, add water and stir evenly. After the blast furnace ash is sent to the mixing tank, it is stirred evenly with water and a foaming agent in the tank to make it in a uniform liquid state, so that the iron powder, tail powder and coke powder in the tank are separated into three layers at the bottom, middle and top;

[0032] Step 3, flotation, using spiral chute flotation integrated equipment for flotation work, in which iron has a high specific gravity and sinks to the lower layer, carbon has a low specific gravity and floats to the upper layer, and calcium and other impurities are located in the middle, thereby separating;

[0033] Step 4, dehydration, dehydration is carried out by a rotary spin dryer, the dehydrated water enters the production water circulation pool, after precipitation, it is reused in the water adding and stirring process, and continues to be recycled, and the sediment in the water circulation pool is the tail powder;

[0034] Step 5: The product is fished out regularly and then dehydrated to become tail powder product.

[0035] In this embodiment, preferably, a spraying device is provided during the feeding process to control dust by spraying water, and the raw material used for feeding is purchased blast furnace ash.

[0036] In this embodiment, preferably, the feeding method is to use the method of feeding through the pit + conveying through the corridor in the workshop. The forklift is used to push the raw materials into the feeding pit, and then enter the fully enclosed feeding corridor, and the feeding corridor sends the materials into the mixing tank.

[0037] In this embodiment, preferably, water needs to be added during the mixing process of adding water and mixing, and no water needs to be added during flotation.

[0038] In this embodiment, preferably, the main components of the foaming agent in adding water and mixing are longifolene and its isomers and terpineol and its isomers. Among them, the content of longifolene and its isomers is 25.0%, and the content of terpineol and its isomers is 15.0%.

[0039] In this embodiment, preferably, the material water flow for flotation is the material liquid in the mixing tank, which is pumped into the spiral chute ore splitter by a conveying pump. Under the action of the material water flow and gravity, the material is pushed to flow. The mixing water will be removed during the dehydration process, collected and sent into the circulating water tank, and after precipitation, it will be reused in the mixing process and used as mixing water again to achieve circular use.

[0040] In this embodiment, preferably, the spiral chute flotation integrated equipment is composed of an ore splitter, a feeding trough, a spiral chute, a cut-off trough, a receiving hopper and a trough support. The spiral chute has the advantages of simple equipment structure, low cost; high space utilization rate, small floor area; convenient operation and maintenance; high productivity; wide processing particle size range (0.02 - 0.3mm). The spiral chute is used for reverse selection by the different gravity, inertial centrifugal force, water flow force and trough surface friction force of light and heavy ore particles in the downward water flow along the spiral slope.

[0041] In this embodiment, preferably, the ore splitter is used to realize the distribution of pulp. It is located at the top of the spiral chute. With the help of the reaction force of the discharged pulp flow through the feeding pipe, the ore splitter cylinder is pushed to rotate, and the pulp is evenly distributed into the four-flow guide trough; the feeding trough is located between the ore splitter and the spiral chute, and is used to evenly and slowly feed the pulp from the ore splitter trough into the spiral chute along the convex tongue type feeding weir plate after buffering and stabilizing; the spiral chute is used to realize the separation of minerals, and the spiral chute is composed of multiple spiral sheets connected by bolts; the cut-off trough is connected to the discharge end at the lower part of the spiral chute. After the pulp is separated by the spiral chute, ore belts with different grades are formed at the discharge end, and different grade products are intercepted when passing through the cut-off trough; the receiving hopper is a concentric annular cylinder, which can collect the different grade flows intercepted by the four cut-off troughs by category and guide them to the next operation; the trough support is used to support the spiral chute, and the trough support is composed of columns installed around the spiral chute and a cross-shaped frame at the upper part to ensure the safe support of the spiral chute.

[0042] In this embodiment, preferably, the flotation includes the following steps:

[0043] Step 31. Layering: The longitudinal flow of the pulp flowing around the vertical axis of the spiral chute and downward along the chute surface is the main flow, and the transverse flow rotating around a certain balance layer of the ore flow itself is the transverse circulation or secondary flow. The flow velocity of the upper layer of the longitudinal flow is large, while that of the lower layer is small. The upper layer of the transverse circulation flows towards the outer edge of the chute, and the lower layer flows towards the inner edge of the chute. The ore particles fed onto the spiral chute surface, under the combined action of the longitudinal main flow and the transverse circulation, due to differences in density, particle size, shape, etc., generate differences in the longitudinal and transverse movement speeds and trajectories along the spiral chute, resulting in the layering of ore particles according to density and particle size.

[0044] Step 32. Zoning: After layering, the light ore particles are in the upper layer. Under the action of the longitudinal main flow with a relatively large velocity and the transverse circulation with the direction towards the outer edge, they gradually flow towards the outer edge of the chute along the expanding spiral line; while the heavy ore particles in the lower layer are less affected by the longitudinal main flow. Under the action of gravity and the transverse circulation with the direction towards the inner edge, they gradually move towards the inner edge along the converging spiral line, causing the layered ore particles to be zoned.

[0045] Step 33. Sorting: After the above two stages, the intercepting trough and the receiving hopper discharge the sorting products with different grades from the chute. The iron powder, coke powder, and tail powder enter their respective iron powder troughs, coke powder troughs, and tail powder troughs respectively to enter the next process.

[0046] The working principle and usage process of the present invention:

[0047] Step 1. Feeding: The raw materials are transported into the mixing tank; a spraying device needs to be set up to control dust by water spraying. The raw materials selected for feeding are purchased blast furnace ash, and the feeding method is through pit feeding + corridor transportation in the workshop. A forklift is used to push the raw materials into the feeding pit of the ground pit, and then they enter the fully enclosed feeding corridor, and the feeding corridor sends them into the mixing tank.

[0048] Step 2. Adding water and mixing evenly: After the blast furnace ash is fed into the mixing tank, it is mixed evenly with water and foaming agent in the tank to make it in a uniform liquid state, so that the iron powder, tail powder, and coke powder in the tank are separated into three layers of upper, middle, and lower layers; water needs to be added during the mixing process of adding water and mixing evenly, and no water needs to be added during flotation. The main components of the foaming agent in adding water and mixing evenly are longifolene and its isomers and terpineol and its isomers. Among them, the content of longifolene and its isomers is 25.0%, and the content of terpineol and its isomers is 15.0%. The material water flow for flotation is the material liquid in the mixing tank, which is pumped into the spiral chute ore splitter by a delivery pump. Under the action of the material water flow and gravity, the material is pushed to flow. The mixing water will be removed during the dehydration process, collected and sent into the circulating water tank, and after precipitation, it will be reused as mixing water for the mixing process, realizing circular use.

[0049] Step 3: Flotation. A spiral chute flotation integrated device is selected for the flotation work. Among them, iron has a large specific gravity and sinks to the lower layer, carbon has a small specific gravity and floats to the upper layer, and calcium and other impurities are in the middle, thus achieving separation.

[0050] The flotation includes the following steps:

[0051] Step 31: Layering. The longitudinal flow of the pulp flow rotating around the vertical axis of the spiral chute and flowing downward along the chute surface is the main flow, and the transverse flow rotating around a certain equilibrium layer of the ore flow itself is the transverse circulation or secondary flow. The flow velocity in the upper layer of the longitudinal flow is large, and the flow velocity in the lower layer is small. The upper layer of the transverse circulation is towards the outer edge of the chute, and the lower layer is towards the inner edge of the chute. The ore particles fed onto the spiral chute surface, under the combined action of the longitudinal main flow and the transverse circulation, due to differences in density, particle size, shape, etc., generate differences in the longitudinal and transverse movement velocities and trajectories along the spiral chute, resulting in the layering phenomenon of ore particles according to density and particle size.

[0052] Step 32: Zoning. After layering, the light ore particles are in the upper layer. Under the action of the longitudinal main flow with a larger velocity and the transverse circulation with the direction towards the outer edge, they gradually flow towards the outer edge of the chute along the expanding spiral; while the heavy ore particles in the lower layer are less affected by the longitudinal main flow and, under the action of gravity and the transverse circulation with the direction towards the inner edge, gradually move towards the inner edge along the converging spiral, causing the already layered ore particles to be zoned.

[0053] Step 33: Separation. After the above two stages, the intercepting trough and the receiving hopper discharge the separation products of different grades from the chute. The iron powder, coke powder, and tail powder respectively enter their respective iron powder troughs, coke powder troughs, and tail powder troughs to enter the next process.

[0054] The spiral chute flotation integrated device consists of a ore distributor, a feed trough, a spiral chute, an intercepting trough, a receiving hopper, and a trough support.

[0055] The ore distributor is used to achieve pulp distribution. It is located at the uppermost part of the spiral chute. By means of the reaction force of the discharged pulp flow through the feed pipe, it pushes the ore distribution cylinder to rotate and evenly distributes the pulp into the four-flow guide troughs; the feed trough is located between the ore distributor and the spiral chute and is used to evenly and slowly feed the pulp from the ore distribution trough into the spiral chute after buffering and stabilizing along the convex tongue-type feed weir plate; the spiral chute is used to achieve the separation of minerals. The spiral chute is composed of multiple spiral plates connected to each other by bolts; the intercepting trough is connected to the discharge end at the lower part of the spiral chute. The pulp sorted by the spiral chute forms ore belts with different grades at the discharge end and is intercepted as products of different grades when passing through the intercepting trough; the receiving hopper is a concentric annular cylinder that can collect the different-grade flows intercepted by the four intercepting troughs by category and guide them to the next operation; the trough support is used to support the spiral chute, and the trough support is composed of columns installed around the spiral chute and a cross-shaped frame at the upper part to ensure the safe support of the spiral chute.

[0056] The spiral chute has the advantages of simple equipment structure and low cost; high space utilization rate and small floor area; convenient operation and maintenance; high productivity; and a relatively wide processing particle size range (0.02 - 0.3 mm). The spiral chute separates materials by the different gravitational, inertial centrifugal, water flow, and trough surface friction forces acting on light and heavy ore particles in the downward water flow along the spiral slope.

[0057] Step 4: Dehydration. Dehydration is carried out through a rotating spin dryer. The discharged water enters the production water circulation pool. After precipitation, it is reused in the water addition and mixing process and continues to circulate. The sediment in the water circulation pool is tail powder.

[0058] Step 5: Product. After being regularly fished out, it is processed for dehydration as tail powder to become a tail powder product.

[0059] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A comprehensive utilization method for steel plant dust removal ash, characterized in that, It includes the following steps: Step 1, feeding: Transport the raw materials into the homogenizing tank. Step 2, adding water and homogenizing: After the blast furnace ash is fed into the homogenizing tank, it is homogenized with water and foaming agent in the tank to make it in a uniform liquid state, and the iron powder, tail powder, and coke powder in the tank are separated into three layers, upper, middle, and lower. Step 3, flotation: Select a spiral chute flotation integrated device for flotation. Among them, iron has a large specific gravity and sinks to the lower layer, carbon has a small specific gravity and floats to the upper layer, and calcium and other impurities are in the middle, so as to carry out separation. Step 4, dehydration: Dehydrate through a rotary drying centrifuge. The discharged water enters the production water circulation pool. After precipitation, it is reused in the water addition and homogenizing process and continues to be recycled. The sediment in the water circulation pool is tail powder. Step 5, product: Regularly fish out and dehydrate and process it as tail powder to become a tail powder product.

2. The comprehensive utilization method of steel plant dust removal ash according to claim 1, characterized in that: During the feeding process, a spraying device is set up to control dust by water spraying, and the raw materials selected for feeding are purchased blast furnace ash.

3. A comprehensive utilization method of steel plant dust removal ash according to claim 1, characterized in that: The feeding method is to use a pit feeding + corridor conveying method in the workshop. A forklift is used to push the raw materials into the feeding pit, and then it enters the fully enclosed conveying corridor, and the conveying corridor sends it to the homogenizing tank.

4. A comprehensive utilization method of steel plant dust removal ash according to claim 1, characterized in that: During the water addition and homogenizing process, water needs to be added, and no water needs to be added during flotation.

5. A comprehensive utilization method for steel plant dust removal ash according to claim 1, characterized in that: The main components of the foaming agent in the water addition and homogenizing are longifolene and its isomers and terpineol and its isomers. Among them, the content of longifolene and its isomers is 25.0%, and the content of terpineol and its isomers is 15.0%.

6. The comprehensive utilization method of steel plant dust removal ash according to claim 1, characterized in that: The material water flow for flotation is the material liquid in the homogenizing tank, which is pumped into the spiral chute ore splitter by a conveying pump. Under the action of the material water flow and gravity, the material is pushed to flow. The homogenizing water will be discharged during the dehydration process, collected and entered the circulation pool, and after precipitation, it is reused in the homogenizing process and used as homogenizing water again to achieve recycling.

7. A comprehensive utilization method of steel plant dust removal ash according to claim 1, characterized in that: The spiral chute flotation integrated device is composed of an ore splitter, a feed tank, a spiral chute, a cut-off ore chute, a receiving hopper, and a chute support.

8. A comprehensive utilization method of steel plant dust removal ash according to claim 6, characterized in that: The ore splitter is used to achieve pulp distribution. It is located at the top of the spiral chute. With the help of the reaction force of the discharged pulp flow through the feed pipe, the ore splitter cylinder is pushed to rotate, and the pulp is evenly distributed into the four-flow guide chute; the feed tank is located between the ore splitter and the spiral chute, and is used to evenly and slowly feed the pulp from the ore splitter tank into the spiral chute along the convex tongue type feed weir plate after buffering and stabilizing; the spiral chute is used to achieve the separation of minerals. The spiral chute is composed of multiple spiral sheets connected by bolts; the cut-off ore chute is connected to the discharge end at the lower part of the spiral chute. After the pulp is sorted by the spiral chute, ore belts with different grades are formed at the discharge end, and different grade products are intercepted when passing through the cut-off ore chute; the receiving hopper is a concentric annular cylinder, which can collect the different grade flows intercepted by the four cut-off ore chutes by category and guide them to the next operation; the chute support is used to support the spiral chute, and the chute support is composed of columns installed around the spiral chute and a cross-shaped frame at the upper part.

9. The comprehensive utilization method of steel plant dust removal ash according to claim 1, characterized in that: The flotation includes the following steps: Step 31: Layering. The longitudinal flow of the pulp flowing around the vertical axis of the spiral chute and downward along the chute surface is the main flow. The transverse flow rotating around a certain balance layer of the ore flow itself is the transverse circulation or secondary flow. The flow velocity of the upper layer of the longitudinal flow is large, while that of the lower layer is small. The upper layer of the transverse circulation flows towards the outer edge of the chute, and the lower layer flows towards the inner edge of the chute. The ore particles fed onto the spiral chute surface, under the combined action of the longitudinal main flow and the transverse circulation, due to differences in density, particle size, shape, etc., generate differences in the longitudinal and transverse movement speeds and trajectories along the spiral chute, resulting in the layering phenomenon of ore particles according to density and particle size. Step 32: Zoning. After layering, the light ore particles are in the upper layer. Under the action of the longitudinal main flow with a relatively large velocity and the transverse circulation with the direction towards the outer edge, they gradually flow towards the outer edge of the chute along the expanding spiral. The heavy ore particles in the lower layer are less affected by the longitudinal main flow. Under the action of gravity and the transverse circulation with the direction towards the inner edge, they gradually move towards the inner edge along the converging spiral, causing the zonal separation of the layered ore particles. Step 33: Sorting. After the above two stages, the cut-off chute and the ore receiving hopper discharge the sorting products of different grades from the chute. The iron powder, coke powder, and tail powder respectively enter their respective iron powder chutes, coke powder chutes, and tail powder chutes to enter the next process.

Images