Treatment system and treatment method for quartz sand production wastewater

Abstract

The invention relates to the technical field of quartz sand, in particular to a quartz sand production wastewater treatment system and method.The quartz sand production wastewater treatment system comprises a pretreatment unit, and the pretreatment unit comprises a high-mud wastewater line, an acid wastewater line and an organic wastewater line and is used for conducting classified pretreatment on wastewater from different sources; the purification unit comprises an ultrafiltration device, a resin adsorption tower and a reverse osmosis device and is used for deeply desalting and purifying the comprehensive wastewater treated by the pretreatment unit, and the curing unit comprises a vibrating membrane reactor, an evaporation crystallizer and a plate-and-frame filter press and is used for curing a concentrated solution generated by the system. According to the technical scheme provided by the invention, the pretreated liquid is purified and filtered through ultrafiltration, resin adsorption and reverse osmosis in sequence, so that the high quality of reuse water is ensured, and the quality of the reuse water far exceeds that of the reuse water subjected to simple precipitation and filtration.

Description

Technical Field

[0001] This invention relates to the field of quartz sand technology, and more specifically to a treatment system and method for quartz sand production wastewater. Background Technology

[0002] Currently, the global quartz sand industry is experiencing rapid growth. Particularly in emerging market countries like China, the demand for quartz sand is constantly increasing due to accelerated industrialization and the rise of high-tech industries. Simultaneously, quartz sand purification technologies and beneficiation processes are continuously improving and being perfected.

[0003] The production of quartz sand generates wastewater, mainly from desliming wastewater from crushing and screening, flotation wastewater, and acidic wastewater from acid washing and purification. Among them, the desliming wastewater from crushing and screening has extremely poor settling properties, the flotation wastewater contains residual flotation reagents, and the acidic wastewater contains metal ions, fluorides, chlorides, etc.

[0004] Conventional treatment methods involve neutralization and precipitation, but dissolved organic matter and fluoride ions are difficult to remove through simple precipitation, which can affect the quality of reclaimed water. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of poor water quality in the recycled water of existing treatment methods, and to provide a treatment system for quartz sand production wastewater to ensure high quality of recycled water.

[0006] To achieve the above objectives, the present invention provides a treatment system for wastewater from quartz sand production, comprising: The pretreatment unit includes a high-mud wastewater line, an acidic wastewater line, and an organic wastewater line connected in parallel, for classifying and pretreating wastewater from different sources. The purification unit includes an ultrafiltration device, a resin adsorption tower, and a reverse osmosis device arranged in series, for deep desalination and purification of the integrated wastewater after the pretreatment unit. The curing unit includes a vibrating membrane reactor, an evaporator crystallizer, and a plate and frame filter press arranged in series to cure the concentrate produced by the system. The pretreatment unit, purification unit, and curing unit are connected in series.

[0007] Preferably, the high-sludge wastewater line includes a hydrocyclone and a sludge thickening tank arranged in sequence, the acidic wastewater line includes an equalization tank and a two-stage reaction sedimentation tank arranged in sequence, and the organic wastewater line includes an advanced oxidation reactor.

[0008] Preferably, it also includes a recycled water tank, with the product water pipeline of the reverse osmosis unit and the condensate pipeline of the evaporator crystallizer respectively connected to the recycled water tank.

[0009] Another aspect of the present invention provides a method for treating wastewater from quartz sand production, applicable to the aforementioned wastewater treatment system for quartz sand production, comprising pumping the supernatant after pretreatment into an ultrafiltration device, the water purified by ultrafiltration entering a resin adsorption tower and a reverse osmosis device in sequence, the water filtered by the reverse osmosis device entering a recycled water tank, and the concentrated water generated by the reverse osmosis device entering a solidification unit.

[0010] Preferably, the SDI of the water purified by the ultrafiltration device is <3.

[0011] Preferably, the conductivity of the water filtered by the reverse osmosis device is <50 μS / cm.

[0012] Preferably, when the high-sludge wastewater line of the pretreatment unit is working, the wastewater enters the hydrocyclone and overflows into the sludge thickening tank, where silica flocculant is added.

[0013] Preferably, when the acidic wastewater line of the pretreatment unit is in operation, the wastewater enters the equalization tank for homogenization, then is pumped into the primary reaction sedimentation tank, where Ca(OH)2 is added until the pH is 10-11, and the supernatant enters the secondary reaction sedimentation tank where a heavy metal scavenging agent is added.

[0014] Preferably, the concentrated water produced by reverse osmosis enters a vibrating membrane reactor for efficient reconcentration, and the concentrated liquid produced by the vibrating membrane reactor enters an evaporator crystallizer. After the water is evaporated and condensed, it enters a recycled water tank, and the mixed inorganic salts precipitated at the bottom of the evaporator crystallizer are centrifuged for dehydration.

[0015] Preferably, the silica-containing sludge collected from hydrocyclones, sludge thickening tanks, and other processes is dewatered using a plate and frame filter press.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In the technical solution provided by this invention, the pretreated liquid is purified and filtered sequentially through ultrafiltration, resin adsorption, and reverse osmosis, ensuring high quality of reclaimed water, which far exceeds the quality of reclaimed water after simple sedimentation and filtration. Attached Figure Description

[0017] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts. Wherein: Figure 1 A schematic diagram of the process for treating wastewater from quartz sand production. Detailed Implementation

[0018] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0019] This invention provides a specific implementation method for a wastewater treatment system for quartz sand production, such as... Figure 1 As shown, the system includes parallel high-sludge wastewater lines, acidic wastewater lines, and organic wastewater lines. These three lines form a pretreatment unit for classifying and pretreating wastewater from different sources based on its characteristics. This avoids damage to the equipment due to the wastewater's properties, thereby extending the equipment's lifespan. The high-sludge wastewater line includes a hydrocyclone and a sludge thickening tank arranged in sequence to treat desludge wastewater and initially separate most of the silica fume. The acidic wastewater line includes an equalization tank and a two-stage reaction sedimentation tank arranged in sequence. The organic wastewater line includes an advanced oxidation reactor (AOR) to degrade residual organic matter generated during flotation and other processes. Compared to ordinary oxidation reactors, the AOR can oxidize complex organic macromolecules step by step until they are finally converted into harmless carbon dioxide and water. The non-selectivity of the AOR can treat complex and variable mixed organic wastewater, while simultaneously decomposing non-biodegradable organic matter into easily biodegradable substances such as small-molecule carboxylic acids, creating conditions for subsequent biochemical treatment. The system includes an ultrafiltration unit, a resin adsorption tower, and a reverse osmosis unit arranged in series. The ultrafiltration unit, resin adsorption tower, and reverse osmosis unit together form a purification unit to deeply desalinate and purify the comprehensive wastewater after the pretreatment unit and reuse the produced water. The combination of ultrafiltration + resin adsorption + reverse osmosis ensures the high quality of the reused water, which is far superior to the quality of reused water after simple sedimentation and filtration, thereby improving the reuse rate. The system includes a vibrating membrane reactor, an evaporator crystallizer, and a plate and frame filter press arranged in series. The vibrating membrane reactor, evaporator crystallizer, and plate and frame filter press form a solidification unit to solidify the concentrated liquid generated by the system, achieving zero discharge. The system converts the soluble pollutants that cannot be removed into stable solid salts through evaporation and crystallization, truly achieving zero liquid discharge and reduction and resource utilization of solid waste throughout the entire process. It also includes a recycled water tank, with the product water pipeline of the reverse osmosis unit and the condensate pipeline of the evaporator crystallizer connected to the recycled water tank respectively, resulting in no wastewater discharge and significant environmental benefits.

[0020] In another aspect, the present invention provides a specific embodiment of a method for treating wastewater from quartz sand production, applicable to the aforementioned wastewater treatment system for quartz sand production, comprising: High-mud wastewater first enters the hydrocyclone of the high-mud wastewater line. The underflow, rich in coarse-grained mud and sand, is directly retained, while the overflow containing fine mud enters the sludge thickening tank. Silica mud flocculant is added to accelerate the settling of fine mud. Acidic wastewater enters the equalization tank of the acidic wastewater line for homogenization and is then pumped into the primary reaction sedimentation tank. Ca(OH)2 is added until the pH reaches 10-11, generating CaF2 precipitate to remove fluoride ions. At the same time, most of the Fe³⁺, Al³⁺ and other metal hydroxides are precipitated. The supernatant enters the secondary reaction sedimentation tank, where heavy metal scavenging agents are added to deeply remove residual Cu, Pb, Zn and other ions. Organic wastewater enters the advanced oxidation reactor of the organic wastewater line. The generated hydroxyl radicals non-selectively degrade and mineralize residual flotation reagents and other recalcitrant organic matter, eliminating their pollution and toxicity to subsequent membrane systems.

[0021] All the supernatant after pretreatment is mixed and pumped into the ultrafiltration unit to thoroughly remove the remaining suspended solids, colloids, and bacteria, ensuring that the SDI of the effluent is <3. The water purified by ultrafiltration enters the resin adsorption tower, which selectively adsorbs residual trace heavy metal ions and small organic molecules in the water. The water purified by the resin adsorption tower then enters the reverse osmosis unit to remove most of the dissolved salts in the water, producing water with a conductivity of <50μS / cm, which enters the recycled water tank. It should be noted that the recycled water in the recycled water tank can be directly reused in the production line to replace fresh water, or it can be used as a water source for other scenarios.

[0022] The concentrated water produced by reverse osmosis enters a vibrating membrane reactor for efficient re-concentration, reducing its volume. The concentrated liquid produced by the vibrating membrane reactor enters an evaporator crystallizer, where the water is evaporated and condensed, and then reused as high-quality makeup water in a reclaimed water tank. The mixed inorganic salts (mainly NaCl, Na2SO4, and a small amount of calcium salts, etc.) precipitated at the bottom of the evaporator are centrifuged and dehydrated, and then safely landfilled as industrial miscellaneous salts, achieving the final solidification of pollutants. The silica-containing sludge collected from hydrocyclones, sludge thickening tanks, and other processes is dehydrated to a moisture content of <40% by a plate and frame filter press. The dehydrated silica sludge cake can be used as a building material additive, such as in brick making, cement production, or as a soil conditioner for resource utilization, completely avoiding the generation of solid waste.

[0023] Through practice, the inventors have learned that, compared with the traditional neutralization-coagulation sedimentation-sand filtration process, the wastewater treatment using the above-described system and process of this invention increases the wastewater reuse rate by 30-40% and extends the cleaning cycle of the membrane equipment by more than 3 times. Under long-term operation, it is more economical and has significant environmental benefits than the traditional process.

[0024] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A system for treating wastewater from quartz sand production, characterized in that The application relates to a wastewater treatment system, which comprises: a pretreatment unit, which comprises a high-silt wastewater line, an acid wastewater line and an organic wastewater line arranged in parallel for classifying and pretreating wastewater from different sources; a purification unit, which comprises an ultrafiltration device, a resin adsorption tower and a reverse osmosis device arranged in series for deep desalination and purification of the comprehensive wastewater treated by the pretreatment unit; and a solidification unit, which comprises a diaphragm reactor, an evaporation crystallizer and a plate-frame filter press arranged in series for solidifying the concentrated liquid generated by the system. The pretreatment unit, the purification unit and the solidification unit are arranged in series. The high-silt wastewater line comprises a cyclone and a sludge concentration tank arranged in sequence, the acid wastewater line comprises an adjusting tank and a two-stage reaction and precipitation tank arranged in sequence, and the organic wastewater line comprises a high-level oxidation reactor.

2. The quartz sand production wastewater treatment system according to claim 1, characterized by: The system further comprises a reuse water tank, and a water production pipeline of the reverse osmosis device and a condensate pipeline of the evaporation crystallizer are connected to the reuse water tank through connecting pipes.

3. The quartz sand production wastewater treatment system according to claim 1, characterized by: The supernatant treated by the pretreatment unit is pumped into the ultrafiltration device, the water filtered and purified by the ultrafiltration device enters the resin adsorption tower and the reverse osmosis device in sequence, the water filtered by the reverse osmosis device enters the reuse water tank, and the concentrated water produced by the reverse osmosis device enters the solidification unit.

4. A method for treating quartz sand production wastewater, which is applied to the quartz sand production wastewater treatment system according to any one of claims 1 to 3, characterized by: The water filtered and purified by the ultrafiltration device has an SDI of less than 3.

5. The method for treating quartz sand production wastewater according to claim 4, characterized by: The water filtered by the reverse osmosis device has a conductivity of less than 50 muS / cm.

6. The method for treating quartz sand production wastewater according to claim 4, characterized by: When the high-silt wastewater line of the pretreatment unit is in operation, wastewater enters the cyclone, the overflow enters the sludge concentration tank, and a silicon sludge flocculant is added.

7. The method for treating quartz sand production wastewater according to claim 4, characterized by: When the acid wastewater line of the pretreatment unit is in operation, wastewater enters the adjusting tank for homogenization, is pumped into the first-stage reaction and precipitation tank, Ca(OH)2 is added to the wastewater to make the pH value of the wastewater be 10-11, the supernatant enters the second-stage reaction and precipitation tank, and a heavy metal capturing agent is added.

8. The method for treating quartz sand production wastewater according to claim 4, characterized by: The concentrated water produced by the reverse osmosis enters the diaphragm reactor for efficient re-concentration, the concentrated liquid produced by the diaphragm reactor enters the evaporation crystallizer, water is evaporated and condensed to enter the reuse water tank, and the mixed inorganic salt separated from the bottom of the evaporation crystallizer is centrifuged and dewatered.

9. The method for treating quartz sand production wastewater according to claim 4, characterized by: The silicon-containing sludge collected from the cyclone, the sludge concentration tank and other links is dewatered by the plate-frame filter press.

10. The method for treating quartz sand production wastewater according to claim 7, characterized by: ​

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