阅读说明：本技术 一种砂模铸造废砂回收再利用的方法 (Method for recycling waste sand from sand mold casting ) 是由 杨大东 于 2019-08-07 设计创作，主要内容包括：本发明涉及砂模铸造技术领域,为一种砂模铸造废砂回收再利用的方法,具体是将结块的筛上废砂破碎成细砂；之后采用喷淋将细砂与酸性溶液混合充分；采用研磨机将混合充分的细砂研磨；使用离心机进行分离,将离心处理后的固形物进行干燥处理,干燥至含水量≤0.5-1%；将干燥后的细砂进行风选和磁选去除其中的杂质后,得到成品；本发明生产过程中减少了废水和废气的排放,实现对废砂的回收利用,提高了经济效益。(The invention relates to the technical field of sand mould casting, in particular to a method for recycling waste sand produced in sand mould casting, which comprises the following steps of crushing agglomerated waste sand on a sieve into fine sand; then, spraying to fully mix the fine sand and the acid solution; grinding the fine sand fully mixed by adopting a grinder; separating with centrifuge, drying the centrifuged solid until the water content is not more than 0.5-1%; performing air separation and magnetic separation on the dried fine sand to remove impurities in the fine sand to obtain a finished product; the invention reduces the discharge of waste water and waste gas in the production process, realizes the recycling of waste sand and improves the economic benefit.)

1. A method for recycling waste sand from sand mold casting is characterized by comprising the following steps:

a) crushing the agglomerated waste sand on the screen into fine sand by a crusher;

b) fully mixing the fine sand with 0.2-0.25mol/L acid solution in a spraying manner;

c) grinding the fully mixed fine sand for 10-20min by a grinder;

d) separating the ground fine sand by using a centrifugal machine, and sending the separated liquid into a waste liquid treatment device for treatment;

e) drying the solid after the centrifugal treatment until the water content is less than or equal to 0.5-1%;

f) and (4) carrying out air separation and magnetic separation on the dried fine sand to remove impurities in the fine sand, thus obtaining a finished product.

2. The method of claim 1, wherein the crushed fine sand is passed through a 2 x 2mm mesh.

3. The method for recycling waste sand from sand casting according to claim 1, wherein the acidic solution is hydrochloric acid solution.

4. The method for recycling the waste sand from sand mold casting according to claim 1, wherein the fine sand is dried, cooled, and then subjected to air separation and magnetic separation to remove impurities.

5. The method for recycling the waste sand from the sand mold casting according to claim 1, wherein the equipment used in the method comprises a crusher, a spraying device, a grinder, a centrifuge, a drying device and a wind separation magnetic separation device, wherein a discharge port of the crusher is provided with a belt conveying device, a discharge port of the belt conveying device is connected with a feed port of the spraying device, the bottom of the spraying device is a soaking and stirring area, the top of the spraying device is a spraying area, the spraying area is connected with a corrosion-resistant spraying pipe, and the spraying pipe is connected with a weakly acidic solution feed pipe; the infiltration stirring area is provided with a spiral stirring device; the discharge gate of spraying equipment with the pan feeding mouth of grinding the machine is connected, the discharge gate of grinding the machine and connecting centrifugal device, centrifugal device's discharge gate with drying device is connected, and the material among the drying device gets into wind after the cooling and selects the magnetic separation device.

6. The method for recycling waste sand from sand mold casting according to claim 5, wherein the crusher is a plate-impact crusher, and a discharge port of the plate-impact crusher is provided with a funnel-type feed opening.

7. The method for recycling waste sand from sand casting according to claim 5, wherein a flow regulator and a pressure control valve are arranged on the corrosion-resistant spray pipe.

8. The method for recycling the waste sand from sand mold casting according to claim 5, wherein the infiltration stirring area is provided with a waste water outlet, and the waste water outlet is connected with a waste water treatment device.

9. The method for recycling the waste sand from sand mold casting according to claim 5, wherein the drying device is connected with a cooling device, and the cooling device cools the waste sand in the treatment process through heat exchange.

10. The method for recycling the waste sand from the sand mold casting according to claim 5, wherein the material in the drying device is cooled and then is conveyed to the air separation and magnetic separation device through a lifting machine.

Technical Field

The invention relates to the technical field of sand mould casting, in particular to a method for recycling waste sand produced in sand mould casting.

Background

Sand casting is a widely used form of casting. Sand casting requires placing a finished part pattern or wooden pattern in sand, filling the pattern with sand, opening the box to remove the pattern and then forming a mold from the sand, which is made in two or more pieces in order to remove the pattern prior to casting the metal. During the casting process, holes and vents must be left for casting metal into the mold to complete the casting system. After the casting mold is filled with the molten metal for a suitable time until the metal solidifies and the part is removed, the mold is destroyed and a new mold must be made for each casting. Like this at whole casting in-process, can waste a lot of sand material, to the resource lack of times now, the waste of sand material then causes the processing degree of difficulty height on the producer, the problem that the manufacturing cost improves, consequently needs at whole foundry in-process, carries out the setting of energy saving.

Some existing recovery methods only recover undersize materials after the waste sand is screened, oversize materials are discarded without being recovered, oversize materials are generally agglomerated waste sand, the oversize materials have a utilization value, and if the oversize materials are not recycled, the problems that the waste sand is not thoroughly recycled and the sand material recycling rate is low are caused. The waste sand on these screens is mostly attached with a failed or non-failed binder and cannot be directly used for secondary casting. The prior waste sand regenerating device on the screen only removes the coated binder through simple vibration friction, has poor removing effect and low recovery efficiency.

Disclosure of Invention

The invention overcomes the defects of the prior art, provides a method for recycling waste sand from sand mold casting, has compact and reasonable process design and arrangement, simple and convenient operation and high regeneration rate, and reduces the discharge of waste water in the production process, wherein the waste sand from casting is inorganic precoated sand and/or organic resin sand core.

The technical scheme adopted by the invention for solving the technical problem is as follows.

A method for recycling waste sand from sand mold casting comprises the following steps:

a) and crushing the agglomerated waste sand on the screen into fine sand by using a crusher.

b) And fully mixing the fine sand with 0.2-0.25mol/L acid solution in a spraying mode.

c) And grinding the fully mixed fine sand for 10-20min by adopting a grinder.

d) And separating the ground fine sand by using a centrifugal machine, and sending the separated liquid into a waste liquid treatment device for treatment.

e) Drying the solid after centrifugal treatment until the water content is less than or equal to 0.5-1%.

f) And (4) carrying out air separation and magnetic separation on the dried fine sand to remove impurities in the fine sand, thus obtaining a finished product.

Preferably, the crushed fine sand is able to pass through a 2 x 2mm mesh.

Preferably, the acidic solution is a hydrochloric acid solution.

Preferably, the fine sand is dried and then cooled, and then air separation and magnetic separation are carried out to remove impurities.

The equipment used by the method for recycling the sand mould casting waste sand comprises a crusher, a spraying device, a grinding machine, a centrifugal machine, a drying device and an air separation magnetic separation device, wherein a belt conveying device is arranged at a discharge port of the crusher, a feed port of the belt conveying device is connected with a feed port of the spraying device, the bottom of the spraying device is an infiltration stirring area, the top of the spraying device is a spraying area, the spraying area is connected with a corrosion-resistant spraying pipe, and the spraying pipe is connected with a weakly acidic solution feed pipe; the infiltration stirring area is provided with a spiral stirring device; the discharge gate of spraying equipment with the pan feeding mouth of grinding the machine is connected, the discharge gate of grinding the machine and connecting centrifugal device, centrifugal device's discharge gate with drying device is connected, and the material among the drying device gets into wind after the cooling and selects the magnetic separation device.

Furthermore, the crusher is a sheet impact crusher, and a discharge port of the sheet impact crusher is provided with a funnel type feed opening.

Furthermore, a flow regulator and a pressure control valve are arranged on the corrosion-resistant spray pipe.

Furthermore, the infiltration stirring area is provided with a wastewater outlet which is connected with a wastewater treatment device.

Furthermore, the drying device is connected with a cooling device, and the cooling device cools the waste sand in the treatment process through heat exchange.

Further, the materials in the drying device are conveyed to the winnowing and magnetic separation device through a lifter after being cooled. Compared with the prior art, the invention has the beneficial effects that.

The production process is compact and reasonable in arrangement, the waste sand is treated by adopting the spraying process, the amount of waste water generated in the process of neutralizing alkaline substances on the surface of the waste sand is effectively reduced, green production is facilitated, the two steps of grinding and centrifuging are combined, the defect of less neutralization and incompleteness of a dissolving solution is overcome, the characteristic of effectively removing the alkaline substances on the surface of the waste sand by a wet method is achieved by combining the processes of spraying, stirring and dissolving, the drying and air separation magnetic separation are utilized for further screening and selection, the screening process is reduced, the working efficiency is improved, and meanwhile, the standard-meeting production molding sand is obtained.

The invention reduces the discharge of waste water and waste gas in the production process, avoids the pollution to the surrounding environment and the land after stacking the solid waste by recycling and treating the waste sand, and simultaneously avoids the environmental damage to the surrounding mineral products in the mining process by recycling and regenerating. The discharge amount of waste gas and waste water in the whole process is obviously reduced, and the aim of environmental protection is fulfilled.

The reclaimed sand prepared by the equipment of the invention is partially or completely used for replacing new sand, so that the consumption of the new sand can be greatly reduced, the discharge of waste foundry sand is reduced, the purchase cost of the new sand and the discharge and stacking cost of the waste sand are reduced, the warehouse construction and occupation cost are saved, and the production cost of a casting enterprise is reduced. Realizes the cyclic utilization of resources, and ensures that the waste sand can be regenerated to obtain good economic benefit.

The reclaimed sand produced by the process can partially or completely replace new sand to be reused in casting production, so that the consumption of increasingly deficient silica sand resources is reduced, and the resource protection aspect plays a positive role.

Drawings

Fig. 1 is a schematic structural diagram of the embodiment of the present invention.

In the figure, 1 is a sheet impact crusher, 2 is a spray tower, 3 is a vibration type grinder, 4 is a horizontal spiral discharge sedimentation centrifuge, 5 is a tower dryer, 6 is a winnowing magnetic separation separator, 7 is a belt conveyor, 8 is a spray pipe, 9 is a flow regulator, 10 is a pressure control valve, 11 is a spiral stirring rod, 12 is a motor, 13 is a lifter, and 14 is a cooling tank.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail with reference to the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solution of the present invention is described in detail below with reference to the embodiments and the drawings, but the scope of protection is not limited thereto.

As shown in fig. 1, the recovery processing device for sand mould casting waste sand is used for recovering sand mould casting waste sand, and the specific implementation steps are as follows:

a) the agglomerated oversize waste sand is crushed by a plate crusher 1 into fine sand that can pass through 2 x 2mm mesh.

b) The fine sand is sent into a spray tower 2 through a belt conveyor 7, 0.2mol/L hydrochloric acid solution is uniformly sprayed on the fine sand in a spraying mode, and the fine sand and the hydrochloric acid solution are fully mixed.

c) The mixed fine sand was ground for 20min by a vibration type grinder 3.

d) And separating the ground fine sand by using a horizontal spiral discharge sedimentation centrifuge 4, and sending the separated liquid into a waste liquid treatment device for treatment.

e) Drying the solid after the centrifugal treatment until the water content is less than or equal to 1%; then, cooling the dried fine sand, and removing impurities in the fine sand by using a winnowing magnetic separation separator 6 after the fine sand is cooled to room temperature; and bagging to obtain the finished product.

The equipment adopted in the process comprises: the device comprises a sheet impact crusher 1, a spray tower 2, a vibration type grinding machine 3, a horizontal spiral discharging sedimentation centrifuge 4, a tower type dryer 5 and an air separation magnetic separator 6, wherein the air separation magnetic separator 6 combines two separation processes of air separation and magnetic separation, waste sand with small particle size is screened in the air separation separator at a feed inlet, and further enters the magnetic separator to remove magnetic substances; a discharge port of the sheet impact crusher 1 is connected with a belt conveyor 7, the belt conveyor 7 is provided with a funnel-shaped feed opening, the feed opening is connected with a feed opening of a spray tower 2 through a feed pipeline, the bottom of the spray tower 2 is a soaking and stirring area, the top of the spray tower 2 is a spray area, the spray area is connected with a spray pipe 8 resistant to acid corrosion, the spray pipe 8 is connected with a weakly acidic solution feed pipe, and 0.2mol/L hydrochloric acid solution is introduced through the weakly acidic solution feed pipe; a hydrochloric acid solution enters an infiltration stirring area through a spray pipe 8, the spray pipe 8 is connected with a flow regulator 9 and a pressure control valve 10, the pressure and the flow of the hydrochloric acid solution in the spraying process are effectively regulated, the flow meter pressure of the hydrochloric acid solution is controlled in the spraying operation according to the volume ratio of the waste sand to be infiltrated to the hydrochloric acid solution of 2-3.5:1, the bottom of the infiltration stirring area is connected with a spiral stirring rod 11, the spiral stirring rod 11 drives a spiral blade on the spiral stirring rod 11 to stir the infiltrated waste sand through a motor 12 arranged outside a spray tower 2, so that alkaline substances on the surface of the waste sand are neutralized with the hydrochloric acid solution, and the dissolution of the alkaline substances is further improved through stirring shear force; spraying is different from wet soaking, the usage amount of the acidic solution can be effectively reduced by spraying, a wastewater outlet is arranged in the soaking and stirring area, and the wastewater outlet is connected with a wastewater treatment device for treating discharged wastewater. A discharge port of the spray tower 2 is connected with a feed port of the vibration type grinding machine 3, and a frosting layer is attached to the inner wall of a grinding barrel of the vibration type grinding machine 3; a sanding mechanism and a sanding disc are connected in the grinding barrel. The discharge port of the vibrating type grinding machine 3 is connected with a horizontal spiral discharging sedimentation centrifuge 4, the discharge port of the horizontal spiral discharging sedimentation centrifuge 4 is connected with a tower type dryer 5, the discharge port of the tower type dryer 5 is connected with a cooling tank 14, the cooling tank 14 cools waste sand entering the cooling tank 14 through cooling water introduced into a heat exchange pipe, the waste sand enters a winnowing magnetic separation separator 6 through a lifting machine 13 after being cooled, and casting molding sand after recovery processing is obtained through final winnowing and magnetic separation. The winnowing magnetic separation separator 6 is connected with a fan and is provided with a dust suction port.

The production process is compact and reasonable in arrangement, the spray tower 2 is applied to waste sand treatment, the amount of wastewater generated in the process of neutralizing alkaline substances on the surface of waste sand is effectively reduced, green production is facilitated, two steps of grinding and centrifugation are combined, the defect of incomplete neutralization of a dissolving solution is overcome, the characteristic that the alkaline substances on the surface are effectively removed by a waste sand wet method is achieved by combining the process of spraying, stirring and dissolving, the drying and air separation magnetic separation are utilized for further screening and selection, the screening process is reduced, and the production molding sand meeting the standard is obtained while the working efficiency is improved.

The discharge of waste water and waste gas is reduced in the production process, waste sand is recycled, the pollution to the surrounding environment and the land after solid waste is stacked is avoided, and meanwhile, the environmental damage to surrounding mineral products during mining is avoided through recycling. The discharge amount of waste gas and waste water in the whole process is obviously reduced, and the aim of environmental protection is fulfilled.

The reclaimed sand prepared by the process is partially or completely used for replacing new sand, so that the consumption of the new sand can be greatly reduced, the emission of waste foundry sand is reduced, the purchase cost of the new sand and the discharge and stacking cost of the waste sand are reduced, the warehouse construction and occupation cost are saved, and the production cost of a foundry enterprise is reduced. Realizes the cyclic utilization of resources, and ensures that the waste sand can be regenerated to obtain good economic benefit.

The reclaimed sand produced by the equipment can partially or completely replace new sand to be reused in casting production, so that the consumption of increasingly deficient silica sand resources is reduced, and the resource protection plays a positive role.

While the invention has been described in further detail with reference to specific preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.