CN107470555A - A kind of alkaline sewage recovery method of used sodium silicate sand wet reclamation - Google Patents

Abstract

The invention belongs to the field of water glass old sand regeneration and sewage treatment, and discloses an alkaline sewage recovery method for wet regeneration of water glass old sand. The method comprises the following steps: pretreating the old sodium silicate sand in a treatment tank, then washing and dehydrating several times to obtain regenerated sand and sewage, detecting whether the Na ₂ O content is lower than a preset value, and when the Na ₂ O content is lower than Preset value, carry out drying, and complete the regeneration treatment of the old sodium silicate sand. When the Na ₂ O content is higher than the preset value, the regenerated sand is scrubbed and regenerated, dehydrated and dried again; among them, the high-concentration alkali that was removed several times before The alkaline sewage is returned to the treatment pool until the alkalinity of the solution in the treatment pool is greater than the preset value of alkalinity. At this time, the high-concentration alkaline sewage in the treatment pool is pumped out, and then the low-concentration alkaline sewage that has been taken off several times is added to the The old sand continues to be regenerated in the treatment pond. Through the invention, high-quality regenerated sand can be obtained with less water consumption, and most of the alkaline substances can be recovered from regenerated sewage.

Description

Alkaline sewage recovery method for wet regeneration of sodium silicate old sand

technical field

The invention belongs to the field of water glass old sand regeneration and sewage treatment, and more specifically relates to an alkaline sewage recovery method for wet regeneration of water glass old sand.

Background technique

Sodium silicate sand is one of the three most widely used large-scale sands in foundry production. It is widely used in cast steel and iron castings because of its non-toxic, tasteless, good fluidity, high strength, and low cost. Hundreds of millions of tons of water glass used sand, the abandonment of a large amount of water glass used sand is not only a great waste of resources, but also brings great harm to the environment. Therefore, the efficient recycling of water glass used sand is particularly important .

At present, the most commonly used regeneration methods of used water glass sand in industrial applications are dry regeneration, thermal regeneration, and wet regeneration. Dry regeneration is to use air or mechanical methods to make the old sand and metal components or between the sand particles collide and friction to remove the residual adhesive film on the surface of the old sand to realize the regeneration of the old sand. This regeneration method has simple equipment and low cost. , but the regeneration effect is not good, the stripping rate is low, and the reclaimed sand can only be used as back sand; thermal regeneration is a regeneration method that heats the old sand to a certain temperature through a roasting furnace to remove combustible residues in the old sand. Regenerated organic binder old sand has better effect and higher quality regenerated sand, but it consumes a lot of energy and costs high; wet regeneration uses water dissolution, scrubbing and mechanical stirring to regenerate old sand, and this method has a good regeneration effect , The regenerated sand is of high quality and can be used as surface sand or single sand, but the equipment system is more complicated, the water consumption and energy consumption are high, and a large amount of sewage needs to be treated. The residual binder film on the surface of the old water glass sand is very soluble in water. The wet regeneration of the old water glass sand can obtain high-quality recycled sand, which can be used instead of new sand. Compared with other regeneration methods, the wet regeneration method is more suitable for the old water glass sand of recycling. At present, the biggest challenge facing the wet regeneration of used water glass sand is the difficult problem of sewage treatment. Many scientific workers have done related research on the treatment of wet recycled sewage of used water glass sand.

CN102974757A discloses a combined treatment method for the regeneration of water glass old sand and the concentration of regeneration treatment liquid. In the method, the water glass old sand is placed in a regeneration device, and the water glass old sand treatment liquid is added to the concentration device. Regeneration of the old water glass sand and concentration of the regenerated treatment solution are achieved by leaching the old water glass sand. This method uses steam at or above 100°C to evaporate and concentrate the water glass old sand treatment solution, and the actual energy consumption is relatively high. And it is not easy to realize industrial application. CN204138473U discloses a water glass old sand wet regeneration sewage treatment system, the system includes a sewage tank, a mixer, a sewage processor, a dosing tank and a sludge treatment device, and realizes sewage flocculation and precipitation by sewage flocculation and acid-base neutralization Purification, the result of this method of treating sewage is judged by the pH value and the clarity of the water, while the salt in the sewage continues to accumulate beyond the discharge standard.

Contents of the invention

Aiming at the above defects or improvement needs of the prior art, the present invention provides a method for recovering alkaline sewage through wet regeneration of used sodium silicate sand, through the recycling of sewage and the recovery of alkaline substances in the regeneration process, thus It solves the technical problems of large water consumption and high cost of sewage treatment in the wet regeneration of sodium silicate old sand.

In order to achieve the above object, according to the present invention, a kind of alkaline sewage recovery method of water glass old sand wet regeneration is provided, it is characterized in that, this method comprises the following steps:

The old water glass sand is pretreated in the treatment tank, and then washed and dehydrated several times to obtain reclaimed sand and alkaline sewage. Check whether the Na ₂ O content is lower than the preset value. When the Na ₂ O content is lower than the preset value, Drying the regenerated sand, when the Na2O content is higher _than the preset value, scrubbing and regenerating the regenerated sand, dehydrating and drying again, thus completing the regeneration treatment of the used water glass sand;

Wherein, part of the alkaline sewage is recycled to the treatment pool until the alkalinity of the solution in the treatment pool is greater than the preset value of alkalinity, then the solution in the treatment pool is extracted, and the other part of the alkaline Sewage is supplemented to the treatment pool to continue to be reused. Further preferably, the pretreatment adopts one or a combination of vibration friction, mechanical stirring or microwave oscillation.

Further preferably, the multiple rinsing and dehydration are performed at least three times, the rinsing uses a water distributor for rinsing, and the dehydration uses air pressure or vacuum dehydration.

Further preferably, during the pretreatment, the ratio of water glass old sand to water is 1:0.3-1.

Further preferably, the part of the alkaline sewage is the alkaline sewage obtained from the first and second dehydration, and the other part of the alkaline sewage is the alkaline sewage obtained from the third and subsequent dehydration.

Further preferably, the amount of water used for rinsing in the leaching accounts for 5% to 30% of the weight of the sand, and the water content in the regenerated sand is not higher than 5%.

Further preferably, when scrubbing and regenerating, the ratio of regenerated sand to water is 1:0.8-2.

Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

1. The present invention keeps the alkalinity in the regeneration treatment pool by continuously reusing the removed sewage during the wet regeneration process of the old sodium silicate sand, and extracts the high-concentration alkaline sewage in the treatment pool, which can be used as a by-product recovery of alkaline substances;

2. The present invention recycles the low-concentration sewage after the second and subsequent leaching and removes it, and replenishes it into the regeneration treatment pool instead of clear water, so as to save water and reduce production costs;

3. The present invention has simple steps, easy control of the operation process, high product quality after regeneration, basically no sewage to be treated after regeneration treatment, low water consumption, low energy consumption, simple equipment required in the operation process, and is suitable for industrial production .

Description of drawings

Fig. 1 is the flowchart of water glass old sand wet process regenerated sewage recycling and alkaline substance recovery constructed according to the preferred embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

Fig. 1 is the flow chart of the water glass old sand wet method regeneration of reclaiming alkaline matter built according to the preferred embodiment of the present invention, as shown in Fig. 1, this method specifically comprises the following steps:

(1) Mix the old water glass sand and water into the regeneration treatment pool according to a certain ratio, and carry out wet regeneration treatment;

(2) The regenerated wet sand is taken out of the treatment tank for dehydration, and then rinsed and dehydrated several times;

(3) The removed high-concentration sewage is filtered and returned to the treatment tank to make the next batch of old sand regeneration water until the alkalinity of the sewage in the treatment tank exceeds the preset value of alkalinity, which is set according to empirical values 2mol/L, the high-concentration alkaline sewage in the pool is pumped out, and the alkaline raw material is recovered after filtration;

(4) The removed low-concentration sewage is filtered and added to the treatment tank to make up for the high-concentration sewage that has been taken out to continue to regenerate the old sand;

(5) If the Na ₂ O content of the reclaimed sand after repeated washing and dehydration is higher than the preset value, the preset value is set to 0.05% according to actual needs, then strong scrubbing, regeneration and dehydration are required;

(6) Wet reclaimed sand with Na ₂ O content less than 0.05% should be dried directly for use.

The present invention will be further described in detail below with reference to the flow chart of FIG. 1 and in conjunction with the following multiple embodiments.

Example 1

(1) Mix the old water glass sand and water according to a certain ratio (the mass ratio of sand to water is 1:0.3) and add them into the regeneration treatment pool for vibration and friction treatment for 15 minutes;

(2) After vibration and friction treatment, take out the regenerated wet sand from the treatment tank for dehydration, and then perform multiple leaching and dehydration. The water consumption for each leaching is 15% of the quality of the regenerated sand. higher than 4%;

(3) The sewage removed before the wet sand leaching and after the first leaching is filtered and directly returned to the regeneration treatment pool to make the next batch of used sand regeneration water until the alkalinity of the sewage in the regeneration treatment pool exceeds 2mol /L, pump out the sewage in the regeneration treatment pool, and make alkaline raw materials after filtration;

(4) The sewage removed after the second and third leaching of the regenerated sand is filtered and treated, and then enters the low-concentration sewage reuse pool. Take the same amount of water from the pool and add it to the treatment pool to continue to regenerate the old sand;

(5) If the Na ₂ O content of the reclaimed sand after repeated washing and dehydration is higher than 0.05%, it needs to be regenerated by strong scrubbing (the mass ratio of sand to water is 1:2) and dehydrated;

(6) Wet reclaimed sand with Na ₂ O content less than 0.05% should be dried directly for use.

Example 2

(1) Mix the old water glass sand and water in a certain proportion (the mass ratio of sand to water is 1:0.5) and add them into the regeneration treatment pool for vibration and friction treatment for 10 minutes;

(2) After vibration and friction treatment, take out the regenerated wet sand from the treatment tank for dehydration, and then perform multiple leaching and dehydration. The water consumption for each leaching is 10% of the quality of the regenerated sand. higher than 4%;

(3) The sewage removed before the wet sand leaching and after the first leaching is filtered and directly returned to the regeneration treatment pool to make the next batch of used sand regeneration water until the alkalinity of the sewage in the regeneration treatment pool exceeds 2mol /L, pump out the sewage in the regeneration treatment pool, and make alkaline raw materials after filtration;

(4) The sewage removed after the second and third leaching of the regenerated sand is filtered and treated, and then enters the low-concentration sewage reuse pool. Take the same amount of water from the pool and add it to the treatment pool to continue to regenerate the old sand;

(5) If the Na ₂ O content of the reclaimed sand after repeated washing and dehydration is higher than 0.05%, it needs to be regenerated by strong scrubbing (the mass ratio of sand to water is 1:1.5) and dehydrated;

(6) Wet reclaimed sand with Na ₂ O content less than 0.05% should be dried directly for use.

Example 3

(1) Mix the old water glass sand and water in a certain proportion (the mass ratio of sand to water is 1:0.7) and add them to the regeneration treatment pool for vibration and friction treatment for 8 minutes;

(2) After vibration and friction treatment, take out the regenerated wet sand from the treatment tank for dehydration, and then perform multiple leaching and dehydration. The water consumption for each leaching is 5% of the quality of the regenerated sand. higher than 4%;

(3) The sewage removed before the wet sand leaching and after the first leaching is filtered and directly returned to the regeneration treatment pool to make the next batch of used sand regeneration water until the alkalinity of the sewage in the regeneration treatment pool exceeds 2mol /L, pump out the sewage in the regeneration treatment pool, and make alkaline raw materials after filtration;

(4) The sewage removed after the second and third leaching of the regenerated sand is filtered and treated, and then enters the low-concentration sewage reuse pool. Take the same amount of water from the pool and add it to the treatment pool to continue to regenerate the old sand;

(5) If the Na ₂ O content of reclaimed sand after repeated washing and dehydration is higher than 0.05%, it needs to be regenerated by strong scrubbing (the mass ratio of sand to water is 1:1) and dehydrated;

(6) Wet reclaimed sand with Na ₂ O content less than 0.05% should be dried directly for use.

Example 4

(1) Mix the old water glass sand and water in a certain proportion (the mass ratio of sand to water is 1:0.8) and add them into the regeneration treatment tank for mechanical stirring treatment for 15 minutes;

(2) After the mechanical stirring treatment, take out the regenerated wet sand from the treatment tank for dehydration, and then perform multiple leaching and dehydration. higher than 5%;

(3) The sewage removed before the wet sand leaching and after the first leaching is filtered and directly returned to the regeneration treatment pool to make the next batch of used sand regeneration water until the alkalinity of the sewage in the regeneration treatment pool exceeds 2mol /L, pump out the sewage in the regeneration treatment pool, and make alkaline raw materials after filtration;

(4) The sewage removed after the second and third leaching of the regenerated sand is filtered and treated and then enters the low-concentration sewage reuse pool. Take the same amount of water from the pool and add it to the treatment pool to continue to regenerate the old sand;

(5) If the Na ₂ O content of the reclaimed sand after repeated washing and dehydration is higher than 0.05%, it needs to be regenerated by strong scrubbing (the mass ratio of sand to water is 1:1.2) and dehydrated;

(6) Wet reclaimed sand with Na ₂ O content less than 0.05% should be dried directly for use.

Example 5

(1) Mix the old water glass sand and water in a certain proportion (the mass ratio of sand to water is 1:0.9) and add them into the regeneration treatment tank for mechanical stirring treatment for 12 minutes;

(2) After the mechanical stirring treatment, take out the regenerated wet sand from the treatment tank for dehydration, and then perform multiple leaching and dehydration. higher than 5%;

(3) The sewage removed before the wet sand leaching and after the first leaching is filtered and directly returned to the regeneration treatment pool to make the next batch of used sand regeneration water until the alkalinity of the sewage in the regeneration treatment pool exceeds 2mol /L, pump out the sewage in the regeneration treatment pool, and make alkaline raw materials after filtration;

(4) The sewage removed after the second and third leaching of the regenerated sand is filtered and treated and then enters the low-concentration sewage reuse pool. Take the same amount of water from the pool and add it to the treatment pool to continue to regenerate the old sand;

(5) If the Na ₂ O content of reclaimed sand after repeated washing and dehydration is higher than 0.05%, it needs to be regenerated by strong scrubbing (the mass ratio of sand to water is 1:1) and dehydrated;

(6) Wet reclaimed sand with Na ₂ O content less than 0.05% should be dried directly for use.

Example 6

(1) Mix the old sodium silicate sand and water in a certain proportion (the mass ratio of sand to water is 1:1) and add them to the regeneration treatment tank for mechanical stirring for 10 minutes;

(2) After the mechanical stirring treatment, the regenerated wet sand is taken out from the treatment tank for dehydration, and then rinsed and dehydrated several times. higher than 5%;

(3) The sewage removed before the wet sand leaching and after the first leaching is filtered and directly returned to the regeneration treatment pool to make the next batch of used sand regeneration water until the alkalinity of the sewage in the regeneration treatment pool exceeds 2mol /L, pump out the sewage in the regeneration treatment pool, and make alkaline raw materials after filtration;

(4) The sewage removed after the second and third leaching of the regenerated sand is filtered and treated and then enters the low-concentration sewage reuse pool. Take the same amount of water from the pool and add it to the treatment pool to continue to regenerate the old sand;

(5) If the Na ₂ O content of reclaimed sand after repeated washing and dehydration is higher than 0.05%, it needs to be regenerated by strong scrubbing (the mass ratio of sand to water is 1:1) and dehydrated;

(6) Wet reclaimed sand with Na ₂ O content less than 0.05% should be dried directly for use.

Example 7

(1) Mix the old sodium silicate sand and water in a certain proportion (the mass ratio of sand to water is 1:0.3) and add them into the regeneration treatment pool for microwave shock treatment for 8 minutes;

(2) After microwave shock treatment, take out the regenerated wet sand from the treatment tank for dehydration, and then perform multiple leaching and dehydration. The water consumption for each leaching is 10% of the quality of the regenerated sand. higher than 4%;

(3) The sewage removed before the wet sand leaching and after the first leaching is filtered and directly returned to the regeneration treatment pool to make the next batch of used sand regeneration water until the alkalinity of the sewage in the regeneration treatment pool exceeds 2mol /L, pump out the sewage in the regeneration treatment pool, and make alkaline raw materials after filtration;

(4) The sewage removed after the second and third leaching of the regenerated sand is filtered and treated and then enters the low-concentration sewage reuse pool. Take the same amount of water from the pool and add it to the treatment pool to continue to regenerate the old sand;

(5) If the Na ₂ O content of the reclaimed sand after repeated washing and dehydration is higher than 0.05%, it needs to be regenerated by strong scrubbing (the mass ratio of sand to water is 1:2) and dehydrated;

(6) Wet reclaimed sand with Na ₂ O content less than 0.05% should be dried directly for use.

Example 8

(1) Mix the old water glass sand and water in a certain proportion (the mass ratio of sand to water is 1:0.4) and add them into the regeneration treatment pool for microwave treatment for 6 minutes;

(2) After microwave shock treatment, take out the regenerated wet sand from the treatment tank for dehydration, and then perform multiple leaching and dehydration. The water consumption for each leaching is 30% of the quality of the regenerated sand. higher than 4%;

(3) The sewage removed before the wet sand leaching and after the first leaching is filtered and directly returned to the regeneration treatment pool to make the next batch of used sand regeneration water until the alkalinity of the sewage in the regeneration treatment pool exceeds 2mol /L, pump out the sewage in the regeneration treatment pool, and make alkaline raw materials after filtration;

(4) The sewage removed after the second and third leaching of the regenerated sand is filtered and treated and then enters the low-concentration sewage reuse pool. Take the same amount of water from the pool and add it to the treatment pool to continue to regenerate the old sand;

(5) If the Na ₂ O content of the reclaimed sand after repeated washing and dehydration is higher than 0.05%, it needs to be regenerated by strong scrubbing (the mass ratio of sand to water is 1:1.5) and dehydrated;

(6) Wet reclaimed sand with Na ₂ O content less than 0.05% should be dried directly for use.

Example 9

(1) Mix the old water glass sand and water in a certain proportion (the mass ratio of sand to water is 1:0.5) and add them into the regeneration treatment pool for microwave shock treatment for 4 minutes;

(2) After microwave shock treatment, take out the regenerated wet sand from the treatment tank for dehydration, and then perform multiple leaching and dehydration. The water consumption for each leaching is 10% of the quality of the regenerated sand. higher than 4%;

(3) The sewage removed before the wet sand leaching and after the first leaching is filtered and directly returned to the regeneration treatment pool to make the next batch of used sand regeneration water until the alkalinity of the sewage in the regeneration treatment pool exceeds 2mol /L, pump out the sewage in the regeneration treatment pool, and make alkaline raw materials after filtration;

(4) The sewage removed after the second and third leaching of the regenerated sand is filtered and treated and then enters the low-concentration sewage reuse pool. Take the same amount of water from the pool and add it to the treatment pool to continue to regenerate the old sand;

(5) If the Na ₂ O content of the reclaimed sand after repeated washing and dehydration is higher than 0.05%, it needs to be regenerated by strong scrubbing (the mass ratio of sand to water is 1:0.8) and dehydrated;

(6) Wet reclaimed sand with Na ₂ O content less than 0.05% should be dried directly for use.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (7)

1. a kind of alkaline sewage recovery method of used sodium silicate sand wet reclamation, it is characterised in that this method comprises the following steps：

Used sodium silicate sand is pre-processed in processing pond, then repeatedly elution and dehydration obtain reclaimed sand and alkaline sewage, detect Na₂Whether O content is less than preset value, works as Na₂O content is less than preset value, dries the reclaimed sand, works as Na₂O content is higher than default Value, regeneration is cleaned to the reclaimed sand, is dehydrated and dries again, thus completes the regeneration treatment of the used sodium silicate sand,；

Wherein, the part alkaline sewage is recovered to the processing pond, until the basicity of solution is pre- more than basicity in the processing pond If value, then extracting the solution in the processing pond out, and alkaline sewage described in another part is added into processing pond relaying It is continuous to reuse.

A kind of 2. alkaline sewage recovery method of used sodium silicate sand wet reclamation as claimed in claim 1, it is characterised in that institute Pretreatment is stated using vibration friction, mechanical agitation or one kind in microwave oscillation or combination.

3. a kind of alkaline sewage recovery method of used sodium silicate sand wet reclamation as claimed in claim 1 or 2, its feature exist In the repeatedly elution and dehydration are at least carried out three times, and the elution is eluted using water-locator, and the dehydration is using air pressure or true Sky dehydration.

4. a kind of alkaline sewage recovery method of used sodium silicate sand wet reclamation as described in claim any one of 1-3, it is special Sign is, during the pretreatment, the ratio of used sodium silicate sand and water is 1：0.3~1.

5. a kind of alkaline sewage recovery method of used sodium silicate sand wet reclamation as described in claim any one of 1-4, it is special Sign is that the partial alkaline sewage is for the first time and is dehydrated obtained alkaline sewage for the second time, and the another part is alkaline The alkaline sewage that sewage is third time and later dehydration obtains.

6. a kind of alkaline sewage recovery method of used sodium silicate sand wet reclamation as described in claim any one of 1-5, it is special Sign is, institute's water consumption is eluted in the elution and accounts for the 5%~30% of sand weight, moisture content is not higher than 5% in the reclaimed sand.

7. a kind of alkaline sewage recovery method of used sodium silicate sand wet reclamation as described in claim any one of 1-6, it is special Sign is, when the scouring regenerates, the ratio of reclaimed sand and water is 1：0.8~2.