Process for producing casting molding sand from Yellow River sediment and scrubbing device

Abstract

The invention relates to a process for producing foundry sand from Yellow River silt and a scrubbing device, which is characterized in that firstly, the Yellow River silt is subjected to rotational flow washing and mechanical scrubbing to remove organic matters in the silt and feldspar substances on the surfaces of silt particles, and secondly, wet silt is subjected to drying treatment through drying equipment; and finally, iron oxide and other magnetic minerals are removed in a magnetic separation mode, the silt treated through the technology can be processed into casting molding sand, the high-value utilization way of the Yellow River silt is widened, and the Yellow River silt deposition treatment cost can be effectively reduced. A scrubber used in the process enables silt to be fully scrubbed and collided in a cylinder in a rotational flow feeding and mechanical stirring mode, and the silt sinking due to collision of a scrubbing unit is washed at a high speed in a reverse washing mode through an annular pipe. According to the scrubber, scrubbing sewage is discharged upwards in an overflow mode, so that the box body below the cylinder body is kept in a clear water covering state.

Description

Technical Field

[0001] The invention relates to the field of high-value utilization of Yellow River sediment, and in particular to a process for producing foundry sand from Yellow River sediment and a scrubbing device. Background Art

[0002] Molding sand is the primary material used in the casting process. Each ton of casting consumes an average of 1.5 tons of sand. Currently, the national annual consumption of molding sand is approximately 50 million tons, and this amount is increasing year by year. Currently, Zhongmu County in Henan Province consumes approximately 2 million tons of Yellow River sediment annually to process molding sand.

[0003] The Yellow River, one of the world's most sediment-laden rivers, has an average annual sediment load of up to 1.6 billion tons. Sedimentation has long been a key technical challenge for flood control, the maintenance of effective reservoir capacity, and the safe operation of irrigation areas. The Yellow River sediment, eroded by long-term water flow, has become round or oval in particle shape, with particle sizes primarily below 0.25 mm. As a silicate resource, it offers potential as foundry sand. Its high-value utilization is crucial for reducing sediment disposal costs and addressing ecological and environmental challenges. The particle shape of Yellow River sediment meets the requirements for natural silica sand in "Silica Sand for Foundry" (GB / T 9442-2010). However, due to limitations in previous processing techniques, foundry sand prepared from Yellow River sediment suffers from low SiO2 content, feldspar impurities, and residual magnetic materials. This leads to defects such as pores, mechanical and chemical sand adhesion during the casting process, limiting its application in the foundry industry. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes a process for producing foundry sand from Yellow River sediment and a scrubbing device.

[0005] The technical solution of the present invention is: The scrubbing device includes a platform bracket and a multi-layer scrubbing unit. The platform bracket is provided with several equally spaced platform plates, a cyclone is provided on the top platform plate, and a scrubbing unit is provided on each platform plate below, forming a multi-stage series processing structure. The scrubbing unit includes a conical box, a cylindrical body and a conical bracket. The conical box is vertically fixed in the conical bracket by a flange, and the conical bracket is welded to the outer side of the circular through hole of the platform plate; the upper port of the conical box is provided with an overflow trough, and the lower port is a discharge port; the cylindrical body is coaxially arranged in the conical box, and a grid plate is provided at its bottom port, and a joint pipe is provided along the tangent direction of the side wall; the bottom flow port of the cyclone is connected to the joint pipe of the first-layer scrubbing unit through the main material pipe, and the discharge port of the upper scrubbing unit is connected to the joint pipe of the lower scrubbing unit through the discharge pipe, forming a multi-stage series; a flushing water pipe is provided along the tangent direction at the top of the cylindrical body, and its water spraying direction is opposite to the direction of the sediment cyclone, which is used to flush the surface of the grid plate to prevent material blockage.

[0006] Preferably, the main body of the flushing mechanism is a circular ring tube, and a plurality of circles of water spray holes are evenly distributed on the side of the circular ring tube along the circumference. One side is radially fixedly connected to the water inlet pipe, and the other side is radially fixedly connected to the support pipe. The water inlet pipe and the support pipe are both fixedly connected to the conical box through flanges. A main water pipe is vertically arranged on the side of the platform bracket. The main water pipe is connected to the water inlet pipe of the scrubbing unit on each layer through a branch pipe. A valve is provided on the water inlet pipe. The inner diameter of the circular ring tube is smaller than the diameter of the lower port of the cylinder, and the spray direction of the water spray hole is inclined upward, forming a counter-flow with the flow direction of the sinking sediment, so as to enhance the stripping effect of impurities on the surface of the sediment particles.

[0007] Preferably, a support plate is provided at the overflow trough port, a reduction motor is mounted on the support plate, an agitator is provided in the cylinder, the agitator consists of a main rod body and a gear rod radially welded to its side surface, the upper end of the main rod body is connected to the output shaft of the reduction motor, and the rotation direction of the gear rod is opposite to the direction of the sediment vortex to enhance the mechanical scrubbing effect on the sediment particles and promote the removal of surface impurities.

[0008] Preferably, an extension groove is provided on the side of the overflow groove, and a sewage pipe is connected to the bottom of the extension groove. The sewage pipes on the adjacent scrubbing units are connected to the sewage main pipe through a U-shaped elbow. The lower end of the sewage main pipe extends to the sewage trough provided at the bottom of the platform bracket. The sewage main pipe and the sewage trough are connected by a flange, and a silicone sealing ring is provided on the contact surface.

[0009] Preferably, at least three lower ribs are evenly distributed on the inner side of the conical box body, and at least three upper ribs are evenly distributed on the outer side of the cylindrical body. Diagonal support rods are connected between the upper and lower ribs. The circumferential positions of the lower ribs and the upper ribs correspond one to one, and the axis of the diagonal support rods is coplanar with the central axis of the conical box body.

[0010] Preferably, a storage tank is provided at the bottom of the platform bracket, and the discharge port of the conical box on the lowest platform plate is connected to the storage tank through a recovery pipe. The recovery pipe and the storage tank are connected by a flange, and a silicone sealing ring is provided on the contact surface.

[0011] Preferably, the conical bracket includes an upper ring body, a lower ring body and a connecting assembly, and a number of connecting rods are evenly distributed between the upper ring body and the lower ring body. The upper ring body is sleeved on the upper part of the conical box body, and the lower ring body is sleeved on the lower part of the conical box body. The connecting rods are supported on the side of the conical box body, and a number of vertical support legs are evenly distributed on the upper ring body, and the lower ends of the support legs are fixedly connected to the platform plate.

[0012] A process for producing foundry sand from Yellow River silt, comprising the following steps: (a) Using a hydrocyclone to wash and screen the Yellow River sediment, sieving out sediment with a particle size of 0.075 mm or larger. Sediment with smaller particle sizes enters a sedimentation tank; (b) The washed sediment is fed into a scrubbing device, where the organic matter and feldspar on the surface of the sediment particles are removed by mechanical scrubbing and water impact; (c) Drying the sediment using an electromagnetic dryer; (d) The dried and cooled sediment is conveyed to a roller magnetic separator via a belt conveyor to remove magnetic minerals from the sediment.

[0013] The beneficial technical effects of the present invention are: (1) The multi-layer scrubbing unit of the present invention uses cyclonic feeding and mechanical stirring to fully scrub and collide the silt in the cylinder, and uses an annular pipe to reversely flush the silt that has been scrubbed, collided, and sunk at high speed. At the same time, the scrubber discharges the scrubbing wastewater upward in an overflow manner to keep the box below the cylinder covered with clean water, avoiding secondary pollution. It can completely remove organic matter and feldspar substances on the surface of silt particles, thereby ensuring the production quality of molding sand.

[0014] (2) The present invention fully removes organic matter and feldspar substances on the surface of the Yellow River sediment by swirling flushing and mechanical scrubbing, and removes magnetic minerals such as iron oxide by magnetic separation, so that the silicon dioxide content in the sediment is increased to more than 80%, and the iron oxide content and mud content are reduced to less than 0.5%, meeting the requirements of "Silica Sand for Casting" (GB / T 9442-2010).

[0015] (3) The use of Yellow River silt to prepare foundry sand has broadened the high-value utilization of Yellow River silt, reduced the cost of Yellow River silt accumulation control and ecological protection, and provided the foundry industry with a low-cost, high-performance sustainable material solution, achieving the coordinated progress of economic benefits, environmental protection and resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 It is a schematic diagram of the main structure of the present invention; Figure 3 yes Figure 2 Schematic diagram of the three-dimensional structure after horizontal sectioning in the middle; Figure 4 It is a structural diagram of the interconnected relationship of multiple scrubbers; Figure 5 It is a schematic diagram of the three-dimensional structure of the scrubber; Figure 6 It is a schematic diagram of the internal structure of the scrubber; Figure 7 yes Figure 6 Schematic diagram of the gear rod being replaced by a spiral blade.

[0017] Figure 8 It is a process flow diagram of the present invention.

[0018] In the figure, 1. Scrubbing unit, 11. Conical box, 111. Overflow trough, 12. Cylinder, 121. Mesh plate, 122. Connector pipe, 123. Feed pipe, 13. Annular pipe, 131. Spray hole, 132. Water inlet pipe, 133. Main water pipe, 134. Branch pipe, 135. Valve, 141. Support plate, 142. Reducer motor, 143. Main rod, 144. Rack, 145. Mixing blade, 15. Extension trough, 151. Sewage pipe, 152. Sewage main pipe, 153. Sewage trough, 161. Lower rib, 162. Upper rib, 163. Diagonal brace, 17. Storage tank, 2. Cyclone, 21. Main material pipe, 3. Platform plate, 31. Conical bracket, 311. Upper ring, 312. Lower ring, 313. Connecting rod, 314. Support leg. DETAILED DESCRIPTION

[0019] Example 1, see attached Figure 7 A process for producing foundry sand from Yellow River silt, the process steps are as follows: (a) Using a hydrocyclone 2 to wash and screen the Yellow River sediment, separating out sediment with a particle size of 0.075 mm or larger. Sediment with smaller particle sizes is then passed into a sedimentation tank. This process serves to initially increase the silica content of the Yellow River sediment and reduce its ferric oxide content and mud content. (b) The washed sediment is fed into a scrubbing device, where mechanical scrubbing and water impact are used to remove organic matter firmly attached to the sediment surface and feldspar from the sediment particle surface. During this scrubbing process, chemical additives may be added to the scrubbing device to reduce the adhesion of organic matter and feldspar to the sediment particle surface. (c) Drying the sediment using an electromagnetic dryer; (d) The dried and cooled sand is conveyed to a roller magnetic separator via a belt conveyor to remove magnetic minerals from the sand to obtain molding sand for casting.

[0020] After treatment in step (a), the silica content in the sediment increases to 65-70%, the ferric oxide content decreases to 3-4%, and the mud content decreases to 1-2%. After treatment in step (b), the silica content in the sediment increases to 70-80%, the ferric oxide content decreases to 2-3%, and the mud content decreases to below 0.5%. After treatment in step (d), the silica content in the sediment reaches more than 80%, and the ferric oxide content decreases to below 0.5%.

[0021] Table 1 shows the chemical composition changes during the production of foundry sand from Yellow River sediment. Sample 1 shows the chemical composition of untreated Yellow River sediment, and Sample 2 shows the chemical composition of treated Yellow River sediment.

[0022] It can be seen that after the Yellow River sediment is cyclone-flushed, mechanically scrubbed and magnetically separated, the silicon dioxide content in the sediment reaches more than 80%, and the iron oxide content and mud content are both reduced to below 0.5%, meeting the process requirements of "Silica Sand for Casting" (GB / T 9442-2010).

[0023] Table 1 Comparison of chemical composition of Yellow River sediment under different treatment processes Element <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> <![CDATA[TiO2]]> <![CDATA[K2O]]> MgO CaO Sample 1 63.82 14.14 4.15 1.03 3.42 2.06 3.94 Sample 2 81.40 10.50 0.42 0.10 3.51 0.34 1.15 Example 2, see attached Figure 1-3 , a scrubbing device for the casting sand production process of Yellow River silt, the scrubbing device includes a platform bracket and a multi-layer scrubbing unit 1, a plurality of equally spaced platform plates 3 are arranged in the platform bracket, a cyclone 2 is arranged on the top platform plate 3, and a scrubbing unit 1 is arranged on each platform plate 3 below, forming a multi-stage series processing structure, the scrubbing unit 1 includes a conical box 11, a cylindrical body 12 and a conical bracket 31, the conical box 11 is vertically fixed in the conical bracket 31 through a flange, and the conical bracket 31 is welded to the outside of the circular through hole of the platform plate 3; the upper port of the conical box 11 is provided with an overflow groove 111, and the lower port is a discharge port, and a certain distance is provided between the lower port of the cylindrical body 12 and the lower port of the conical box 11, so that a flushing space is formed at the lower part of the conical box 11; the cylindrical body 12 is coaxially arranged on the conical box Inside the cylinder 11, a mesh plate 121 is installed at the bottom port, and a joint pipe 122 is installed tangentially along the side wall. The mesh plate 121 is used to reduce the sinking velocity of sediment, increasing the time it collides and scrubs within the cylinder 12. The bottom flow outlet of the cyclone 2 is connected to the joint pipe 122 of the first scrubbing unit 1 via the main feed pipe 21. The discharge port of the upper scrubbing unit 1 is connected to the joint pipe 122 of the lower scrubbing unit 1 via a feed pipe 123, forming a multi-stage series connection. Sediment enters through the joint pipe 122 along the tangential direction of the inner wall of the cylinder 12, where it forms a swirling flow. The swirling force causes the sediment particles to collide and scrub against each other. A flushing water pipe is installed tangentially at the top of the cylinder 12. The water spray direction of the flushing water pipe is opposite to the swirling direction of the sediment, which is used to flush the surface of the mesh plate 121 to prevent material clogging. The principle of the cyclone 2 can be found in the applicant's authorized patent (Grant Announcement No. CN116393240B).

[0024] At least three lower ribs 161 are evenly distributed on the inner side of the conical box 11, and at least three upper ribs 162 are evenly distributed on the outer side of the cylindrical body 12. Diagonal support rods 163 are connected between the upper ribs 162 and the lower ribs 161. The cylindrical body 12 is fixed to the center of the conical box 11 through the ribs and the diagonal support rods 163, so that it has sufficient scrubbing support strength.

[0025] A storage tank 17 or a material storage box is provided at the bottom of the platform bracket. The storage tank 17 or the material storage box is provided with a drain valve to drain the water remaining in the mud and sand after scrubbing, reduce its humidity, and facilitate the subsequent drying process. The discharge port of the conical box body 11 on the lowest platform plate 3 is connected to the storage tank 17 through a recovery pipe.

[0026] Example 3, see attached Figure 5-6 Based on the second embodiment, this embodiment designs the main body of the flushing mechanism as a circular tube 13, and a plurality of circles of water spray holes 131 are evenly arranged on the side of the circular tube 13. A water inlet pipe 132 fixedly connected to the conical box body 11 is provided radially on one side of the circular tube 13, and a support pipe fixedly connected to the conical box body 11 is provided on the other side. A main water pipe 133 is vertically provided on the side of the platform bracket. The main water pipe 133 is connected to each water inlet pipe 132 through a branch pipe 134, and a valve 135 is provided on the water inlet pipe 132.

[0027] The size of the annular tube 13 is slightly smaller than that of the lower port of the cylindrical body 12. After collision and scrubbing in the cylindrical body 12, the mud and sand sink and flow out from the lower port. At this time, the water spray holes 131 on the annular tube 13 intensively spray high-pressure water jets to flush the mud and sand. The impurities on the surface of the mud and sand that have been collided, scrubbed and flushed can be fully removed.

[0028] Example 4, see attached Figure 6-7 This embodiment is based on the third embodiment. A support plate 141 is provided at the port of the overflow trough 111. A reduction motor 142 is installed on the support plate 141. A stirrer is provided in the cylinder 12. The stirrer consists of a main rod 143 and a gear rod 144 vertically connected to the main rod 143. The upper end of the main rod 143 is connected to the output shaft of the reduction motor 142. The stirrer is driven by the reduction motor 142. The gear rod 144 stirs the sediment inside the cylinder 12. The sediment continuously collides and scrubs against each other, removing organic matter and feldspar attached to the surface of the sediment particles. When the mud concentration is greater than 350 kg / m 3 When the mud concentration is less than 350kg / m 3 When the toothed rod in this embodiment can be replaced by a stirring blade 145.

[0029] Example 5, see attached Figure 4On the basis of the third embodiment, this embodiment is provided with an extension groove 15 on the side of the overflow groove 111, and a sewage pipe 151 is provided on the bottom surface of the extension groove 15. The lower ends of the sewage pipes 151 on adjacent scrubbing units 1 are connected to the sewage main pipe 152 through a U-shaped elbow. The lower end of the sewage main pipe 152 extends into the sewage trough 153 provided at the bottom of the platform bracket. The overflowing scrubbing sewage is concentrated from the sewage pipe 151 into the sewage main pipe 152, and then enters the sewage trough 153 on the ground from the sewage main pipe 152, and the sewage is centrally treated to meet the discharge requirements.

[0030] The working process and principle of this embodiment are as follows: the Yellow River sediment enters the scrubber below from the cyclone 2, and the sediment enters from the joint pipe 122 along the tangential direction of the inner wall of the cylindrical body 12. When entering, the sediment is in a swirling state. The swirling power can cause the sediment to collide and scrub each other. At the same time, the reduction motor 142 drives the agitator to rotate, and the gear rod 144 on the agitator stirs the sediment inside the cylindrical body 12. The stirring power combined with the swirling power causes the sediment to continuously collide and scrub each other, separating the sediment particles and the organic matter and feldspar substances on their surface. During the process of mud and sand collision and scrubbing, sedimentation continues to occur and the sediment flows out from the lower port of the cylinder 12. The grid plate 121 can reduce the sinking speed of the sediment and increase the time of its collision and scrubbing in the cylinder 12. When the sediment sinks and flows out, the water spray holes 131 on the annular tube 13 densely spray high-pressure water columns to flush the sediment. The sewage generated during the flushing process enters the overflow trough 111 under the driving action of the upward water flow, and the sewage pipe 151 enters the sewage main pipe 152 in a centralized manner, and then enters the sewage tank 153 from the sewage main pipe 152. After collision, scrubbing and flushing, the impurities on the surface of the sediment can be fully removed. The fully cleaned sediment enters the scrubber below from the discharge pipe 123 for the second and third scrubbing. The sediment that has undergone multi-stage scrubbing enters the storage tank 17 below.

[0031] Example 6, see attached Figure 3 The conical bracket 31 in the second embodiment includes an upper ring body 311 and a lower ring body 312. Several connecting rods 313 are evenly distributed between the upper ring body 311 and the lower ring body 312. The upper ring body 311 is sleeved on the upper part of the conical box body 11, and the lower ring body 312 is sleeved on the lower part of the conical box body 11. The connecting rods 313 are supported on the side of the conical box body 11. Several supporting legs 314 with lower ends connected to the platform plate 3 are evenly distributed on the upper ring body 311. The lower ends of the supporting legs 314 are welded and fixed to the platform plate 3. The conical bracket 31 can stably support the conical box body 11 and is easy to install and disassemble, which is beneficial to subsequent maintenance.

Claims

1. A scrubbing device for foundry sand, characterized by: The scrubbing device includes a platform bracket and a multi-layer scrubbing unit. The platform bracket is provided with several equally spaced platform plates, a cyclone is provided on the top platform plate, and a scrubbing unit is provided on each platform plate below, forming a multi-stage series processing structure. The scrubbing unit includes a conical box, a cylindrical body and a conical bracket. The conical box is vertically fixed in the conical bracket by a flange, and the conical bracket is welded to the outer side of the circular through hole of the platform plate; the upper port of the conical box is provided with an overflow groove, and the lower port is a discharge port; the cylinder is coaxially arranged in the conical box, and a grid plate is provided at its bottom port, and a joint pipe is provided on the side wall along the tangent direction; the bottom flow port of the cyclone is connected to the joint pipe of the first-layer scrubbing unit through the main material pipe, and the discharge port of the upper scrubbing unit is connected to the joint pipe of the lower scrubbing unit through the discharge pipe, forming a multi-stage series; a flushing water pipe is provided along the tangent direction on the top of the cylinder, and the water spraying direction of the flushing water pipe is opposite to the direction of the sediment cyclone, which is used to flush the surface of the grid plate to prevent material blockage.

2. The scrubbing device according to claim 1, wherein: The main body of the flushing mechanism is a circular ring tube, and a plurality of circles of water spray holes are evenly distributed on the side of the circular ring tube along the circumference. One side is radially fixedly connected to the water inlet pipe, and the other side is radially fixedly connected to the support pipe. The water inlet pipe and the support pipe are both fixedly connected to the conical box through flanges. A main water pipe is vertically arranged on the side of the platform bracket. The main water pipe is connected to the water inlet pipe of the scrubbing unit on each layer through a branch pipe. A valve is provided on the water inlet pipe. The inner diameter of the circular ring tube is smaller than the diameter of the lower port of the cylinder, and the spray direction of the water spray hole is inclined upward, forming a hedge with the flow direction of the sinking sediment, so as to enhance the stripping effect of impurities on the surface of the sediment particles.

3. The scrubbing device according to claim 1, wherein: A support plate is provided at the overflow trough port, and a reduction motor is installed on the support plate. An agitator is provided in the cylinder, and the agitator consists of a main rod body and a gear rod radially welded to its side surface. The upper end of the main rod body is connected to the output shaft of the reduction motor. The rotation direction of the gear rod is opposite to the direction of the sediment vortex to enhance the mechanical scrubbing effect on the sediment particles and promote the removal of surface impurities.

4. The scrubbing device according to claim 1, wherein: An extension groove is provided on the side of the overflow groove, and a sewage pipe is connected to the bottom of the extension groove. The sewage pipes on the adjacent scrubbing units are connected to the sewage main pipe through a U-shaped elbow. The lower end of the sewage main pipe extends to the sewage trough provided at the bottom of the platform bracket. The sewage main pipe and the sewage trough are connected by a flange, and a silicone sealing ring is provided on the contact surface.

5. The scrubbing device according to claim 1, wherein: The inner side of the conical box body is evenly distributed with at least three lower ribs, and the outer side of the cylindrical body is evenly distributed with at least three upper ribs. Diagonal braces are connected between the upper and lower ribs. The circumferential positions of the lower ribs and the upper ribs correspond one to one, and the axes of the diagonal braces are coplanar with the central axis of the conical box body.

6. The scrubbing device according to claim 1, wherein: A storage tank is provided at the bottom of the platform bracket, and the discharge port of the conical box on the lowest platform plate is connected to the storage tank through a recovery pipe. The recovery pipe and the storage tank are connected by a flange, and a silicone sealing ring is provided on the contact surface.

7. The scrubbing device according to claim 1, wherein: The conical bracket includes an upper ring body, a lower ring body and a connecting assembly. Several connecting rods are evenly distributed between the upper ring body and the lower ring body. The upper ring body is sleeved on the upper part of the conical box body, and the lower ring body is sleeved on the lower part of the conical box body. The connecting rods are supported on the side of the conical box body. Several vertical support legs are evenly distributed on the upper ring body, and the lower ends of the support legs are fixedly connected to the platform plate.

8. A process for producing foundry sand from Yellow River silt, characterized by: The steps include: (a) Using a hydrocyclone to wash and screen the Yellow River sediment, sieving out sediment with a particle size of 0.075 mm or larger. Sediment with smaller particle sizes enters a sedimentation tank; (b) feeding the washed sediment into the scrubbing device of claim 1, and removing organic matter and feldspar on the surface of the sediment particles by mechanical scrubbing and water impact of the scrubbing device; (c) Drying the sediment using an electromagnetic dryer; (d) The dried and cooled sediment is conveyed to a roller magnetic separator via a belt conveyor to remove magnetic minerals from the sediment.

Images