CN113105091A

CN113105091A - Low-temperature drying treatment process for electroplating sludge

Info

Publication number: CN113105091A
Application number: CN202110417944.9A
Authority: CN
Inventors: 金子杰; 朱有法; 杨长城
Original assignee: Zhejiang Norman Environmental Protection Engineering Technology Co ltd
Current assignee: Zhejiang Norman Environmental Protection Engineering Technology Co ltd
Priority date: 2021-04-19
Filing date: 2021-04-19
Publication date: 2021-07-13

Abstract

The invention relates to a drying treatment process, in particular to a low-temperature drying treatment process for electroplating sludge. After the pretreatment of a coarse grating → a centrifugal machine → crushing 1 → a beating machine → a filter press → a crushing machine 2 → a cleaner. The problem that wet sludge 5 is clamped on the cutting strips in the cutting strip forming process of the low-temperature sludge drying machine to cause the failure of the cutting strip machine is solved, and meanwhile, after the sludge-water mixture 1 is pretreated, the moisture content of the wet sludge 5 is lower, the sludge granularity is smaller, the sludge quality is more uniform, and the subsequent cutting strip forming is facilitated.

Description

Low-temperature drying treatment process for electroplating sludge

Technical Field

The invention relates to a drying treatment process, in particular to a low-temperature drying treatment process for electroplating sludge.

Background

The electroplating sludge is a precipitate which is generated in the electroplating wastewater treatment process and takes heavy metal hydroxides such as copper, chromium and the like as main components, and the components are complex, so that the electroplating industry becomes one of the heavily polluted industries. If the electroplating sludge cannot be scientifically and reasonably treated, the electroplating sludge can bring harm which is hard to imagine for people. For example, the toxic and harmful heavy metal substances in the electroplating sludge seriously affect the soil quality, and water resources are polluted and harm the health of animals and plants. A large amount of electroplating sludge is formed during the treatment of electroplating wastewater, the electroplating sludge has the characteristics of high water content, high thermal stability of heavy metal components, easy migration and the like, and secondary pollution is easily caused if the electroplating sludge is not properly treated. According to HW17 surface treatment waste in the national hazardous waste catalogue (2021 edition), the electroplating sludge belongs to hazardous waste, the hazardous waste treatment cost is high, the electroplating sludge is directly subjected to pressure filtration and then treated by qualified hazardous waste treatment units at present, the water content of the sludge is 65-80%, the treatment cost is high, in order to reduce the treatment cost of the electroplating sludge and the water content of the electroplating sludge, the electroplating sludge is subjected to reduction treatment, the subsequent treatment load of the electroplating sludge can be reduced, meanwhile, the treatment cost of the electroplating sludge of enterprises can be greatly reduced, and the drying economic benefit of the enterprises is improved, so that the low-temperature reduction treatment process of the electroplating sludge is provided.

Disclosure of Invention

The invention mainly solves the defects in the prior art, and provides the low-temperature drying treatment process for the electroplating sludge, which reduces the water content of the electroplating sludge and lightens the subsequent treatment cost of the electroplating sludge.

The technical problem of the invention is mainly solved by the following technical scheme:

a low-temperature drying treatment process for electroplating sludge comprises the following steps:

firstly, the mud-water mixture 1 in the mud mixing pool enters a pump into a centrifuge, and large-sized blocks in the mud-water mixture 1 are removed through a coarse grid to form a mud-water mixture 2;

secondly, dewatering the mud-water mixture 2 by a centrifuge to generate wet sludge 1;

thirdly, the wet sludge 1 enters a crusher 1 through a conveying system 1 to be crushed to form wet sludge 2;

the wet sludge 2 enters a pulping system through the conveying system 2 and is added with water for pulping to form a muddy water mixture 3, and the muddy water is homogenized, so that the mud quality of the following wet sludge and dry sludge is more uniform;

pumping the muddy water mixture 3 into a filter press for filter pressing to form wet sludge 3, and adding a certain amount of PAM and PAC into the muddy water mixture 3 before filter pressing;

sixthly, the wet sludge 3 enters a crusher 2 through a conveying system 3 to be crushed to form wet sludge 4;

seventhly, the wet sludge 4 enters a wet sludge bin through a conveying system 4, and the wet sludge bin is used as a turnover bin for feeding of the low-temperature sludge drying machine;

allowing wet sludge 4 to enter an impurity remover from a wet sludge bin through a conveying system 5 to further remove impurities, ensuring that large-size hard impurities in sludge entering a material inlet of a drying machine have no influence on the normal operation of a slitter, and enabling the sludge after impurity removal to be wet sludge 5;

ninthly, wet sludge 5 enters a sludge low-temperature drying machine from an outlet of the impurity removing machine through a conveying system 6, is subjected to slitting molding by a slitting machine and then enters the sludge low-temperature drying machine for low-temperature drying to obtain dried sludge, namely dry sludge for short;

and the dry mud enters a dry mud collecting system through a conveying system 7, and the dry mud is transported out for disposal after being stored to a certain amount.

Preferably, in the step I, the specification of the coarse grating is 15-40 mm, the water content of the mud-water mixture 1 is 99.3% -99.5%, and the water content of the mud-water mixture 2 is 99.3% -99.5%;

in the step I, the pump is a sludge screw pump, and the outlet pressure is 0.4-1.2 MPa.

Preferably, the operation temperature of the centrifugal machine in the step II is 0-60 ℃, and the maximum separation factor is 2350-4080G;

in the second step, the wet sludge 1 has the water content of 80-88 percent and is in a shape of a ball.

Preferably, the crushing device in the third step is one of a jaw crusher, a roller crusher, a hammer crusher, an impact crusher or a combined crusher, and can crush sundries with compressive strength not more than 350MPa, and the size of the sundries is not more than 250-900 mm;

the conveying system 1 is one or two of a screw conveyor and a scraper conveyor, the material of a blade of the screw conveyor is manganese steel, and the material of the scraper conveyor is SUS 304;

and step three, the moisture content of the wet sludge 2 is 80-88%.

Preferably, in the step (iv), the conveying system 2 is one or both of a screw conveyor and a scraper conveyor, the material of the screw conveyor blade is manganese steel, and the material of the scraper conveyor is SUS 304;

the pulping system in the fourth step is a submersible mixer made of SUS 304;

adding water into one or more of centrifuge effluent, filter press effluent or sludge low-temperature dryer condensate water, wherein the water adding amount of 3 per ton of wet sludge is 16-39 t;

in the step (iv), the water content of the mud-water mixture 3 is 99.3% -99.5%.

Preferably, in the fifth step, the pump is a sludge screw pump, and the outlet pressure is 0.4-1.2 MPa;

the filter press in the step (v) is a plate-and-frame filter press, and the operating pressure is 1.6-2.0 MPa;

in the fifth step, the water content of the wet sludge 3 is 65-70%, the wet sludge is in a cake shape, and the thickness of a filter cake is 20-30 mm;

in the fifth step, the dosage of PAM is 0.1-0.3% of the absolute dry sludge, and the dosage of PAC is 3-5% of the absolute dry sludge.

Preferably, in the step (c), the conveying 3 system is a belt conveyor which is a steel wire rope core conveying belt with the bandwidth of 1000-1400 mm;

step sixthly, the crusher 2 is a fluted disc type filter cake crusher;

sixthly, the water content of the wet sludge 4 is 65-70 percent.

Preferably, in step (c), the conveying system 4 is one or both of a screw conveyor and a scraper conveyor, the screw conveyor blade is made of manganese steel, and the scraper conveyor is made of SUS 304.

Preferably, in the step viii, the conveying system 5 is one or two of a screw conveyor and a scraper conveyor, the material of the screw conveyor blade is manganese steel, and the material of the scraper conveyor is SUS 304;

in the step eight, the shell, the shaft, the cavity and the filtering orifice plate of the impurity remover are made of SUS304 and a carbon steel bracket, so that impurities with the particle size of more than 20mm can be removed;

in the step (viii), the moisture content of the wet sludge 5 is 65-70%.

Preferably, in the step ninthly, the conveying system 6 is one or two of a screw conveyor and a scraper conveyor, the material of the blade of the screw conveyor is manganese steel, and the material of the scraper conveyor is SUS 304;

the sludge low-temperature drying machine in the step ninthly is one of a sludge low-temperature belt drying machine or a sludge low-temperature waste heat drying machine, the air supply temperature is 68-85 ℃, the return air temperature is 50-65 ℃, and the cooling form is one of air cooling or water cooling;

ninthly, the dry mud is strip-shaped, and the water content is adjustable within the range of 10-60%.

Preferably, the conveying system 7 in step r is a scraper conveyor, closed, and made of SUS 304;

step (r) the dry mud collection system is one of a dry mud bin or ton bag.

By the technical scheme, the low-temperature drying device for the electroplating sludge has at least the following advantages:

(1) according to the invention, after the mud-water mixture 1 is pretreated by the coarse grating → the centrifugal machine → the crushing 1 → the beating machine → the filter press → the crushing machine 2 → the impurity removing machine, the problem that the wet sludge 5 is clamped on the cutting strip in the cutting strip forming process of the sludge low-temperature drying machine is solved, and meanwhile, the pretreated mud-water mixture 1 has lower moisture content of the wet sludge 5, smaller sludge granularity and more uniform mud quality, and is more beneficial to subsequent cutting strip forming.

(2) The drying equipment used by the invention is a sludge low-temperature drying machine, belongs to direct low-temperature drying, directly acts on sludge by low-temperature drying hot air, has high thermal efficiency and low temperature, does not crack and volatilize organic matters in the sludge, and only takes away water from the sludge by circulating hot air, thereby solving the problems of easy cracking of organic matters in the sludge, increasing tail gas treatment and difficult heat energy recovery caused by direct high-temperature heating.

Drawings

FIG. 1 is a schematic process flow diagram of the present invention.

Detailed Description

The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings.

Example 1: as shown in the figure, the low-temperature drying treatment system for the electroplating sludge comprises a sludge pool, a coarse grid, a centrifugal machine, a crusher 1, a beater, a filter press, a crusher 2, a wet sludge bin, an impurity remover, a low-temperature sludge drying machine and a dry material collecting system which are sequentially connected. The sludge tank is used for collecting electroplating sludge generated in the electroplating wastewater treatment process; the coarse grating is used for removing large-sized object blocks in the muddy water mixture 1; the centrifuge is used for removing most of water in the muddy water mixture 2; the crusher is used for crushing the wet sludge 1 into small-particle sludge 2; the pulping system is added with water and stirred uniformly, and plays a role in homogenizing the muddy water; the filter press performs filter pressing and dewatering on the mud-water mixture 3 to form wet sludge 3 with lower water content; the crusher 2 is used for crushing the cake-shaped wet sludge 3 into wet sludge 4 with smaller size, so that the wet sludge can more easily enter a drying machine feed hopper for slitting and forming; the wet sludge bin is used for storing wet sludge 4 and has the function of transferring the bin to the sludge fed into the drier; the impurity removing machine is used for crushing residual impurities in the wet sludge 4 and removing impurities again so as to ensure that large-size hard impurities in the sludge entering a material inlet of the drying machine have no influence on the normal operation of the slitter; the sludge low-temperature drying system performs low-temperature drying after slitting and forming the wet sludge 5, and the discharged material is dry sludge; the dry sludge collection system is used for temporarily storing the dried sludge.

In this embodiment: the mud-water mixture 1 in the mud mixing tank is pumped into a feed inlet of the centrifuge through a pipeline, large-sized blocks in the mud-water mixture 1 are removed through a coarse grating, and the pipeline and the part of the pump in direct contact with mud need to have corrosion resistance.

In this embodiment: the outlet of the centrifuge is connected with the inlet of the crusher 1 through a conveying system 1, the conveying system 1 is one or two of a screw conveyor and a scraper conveyor, the blades of the screw conveyor are made of manganese steel, and the scraper conveyor is made of SUS 304.

In this embodiment: the outlet of the crusher 1 is connected with the inlet of the pulping system through a conveying system 2, the conveying system 2 is one or two of a screw conveyor and a scraper conveyor, the blades of the screw conveyor are made of manganese steel, and the scraper conveyor is made of SUS 304.

In this embodiment: the outlet of the pulping system is pumped into the inlet of the filter press through a pipeline, and the pipeline and the part of the pump in direct contact with the mud are made of materials with corrosion resistance.

In this embodiment: the wet sludge 3 produced at the discharge port of the filter press is connected with the feed port of the crusher 2 through a conveying system 3, the conveying system 3 is a belt conveyor which is a steel wire rope core conveying belt, and the belt width is 1000-1400 mm.

In this embodiment: the discharge port of the crusher 2 is connected with the feed inlet of the wet mud bin through a conveying system 4, the conveying system 4 is one or two of a screw conveyor and a scraper conveyor, the blades of the screw conveyor are made of manganese steel, and the scraper conveyor is made of SUS 304.

In this embodiment: the discharge port of the wet mud bin is connected with the feed inlet of the impurity removing machine through a conveying system 5, the conveying system 5 is one or two of a screw conveyor and a scraper conveyor, the blades of the screw conveyor are made of manganese steel, and the scraper conveyor is made of SUS 304.

In this embodiment: the discharge port of the impurity remover is directly connected with the feed port of the drier through a conveying system 6, a high-low material level indicator is arranged on the feed hopper of the drier and used for automatically controlling the sludge material level height, so that the continuous and stable operation of the low-temperature drier is ensured, the conveying system 6 is one or two of a scraper conveyor or a shaftless screw conveyor, the blades of the screw conveyor are made of manganese steel, and the scraper conveyor is made of SUS 304.

In this embodiment: the discharge hole of the sludge low-temperature drying machine is connected with the feed inlet of a dry sludge collecting system through a conveying system 7, the conveying system 7 is a scraper conveyor and is closed, the scraper conveyor is made of SUS304, and the dry sludge collecting system is a dry sludge bin or a ton bag (support).

The invention provides an electroplating sludge low-temperature drying treatment process system, which is characterized in that after pretreatment by a coarse grating, a centrifugal machine, a crushing machine 1, a beater, a filter press, a crusher 2 and an impurity removing machine, the formed wet sludge 5 has higher homogenization degree, does not contain large-size hard blocks, does not cause abnormal damage to a slitter of a sludge low-temperature drying device, can adjust the moisture content of the wet sludge 5 through a wet sludge 3 generated by a filter pressing system so as to be more beneficial to slitting forming of the sludge low-temperature drying machine, directly performs low-temperature drying on the sludge after slitting forming, and can adjust the moisture content of sludge discharged from the drying machine within the range of 10-60% according to specific needs.

It should be understood that the above description is only a preferred embodiment of the present invention, and not intended to limit the present invention, and those skilled in the art can make various changes and modifications to the above embodiments without departing from the scope of the present invention.

Claims

1. The low-temperature drying treatment process for the electroplating sludge is characterized by comprising the following steps of:

2. The low-temperature drying treatment process for the electroplating sludge according to claim 1, which is characterized in that:

the specification of the coarse grating is 15-40 mm, the water content of the mud-water mixture 1 is 99.3% -99.5%, and the water content of the mud-water mixture 2 is 99.3% -99.5%;

3. The low-temperature drying treatment process for the electroplating sludge according to claim 1, which is characterized in that:

the operation temperature of the centrifuge is 0-60 ℃, and the maximum separation factor is 2350-4080G;

4. The low-temperature drying treatment process for the electroplating sludge according to claim 1, which is characterized in that:

the crushing device is one of a jaw crusher, a roller crusher, a hammer crusher, a counterattack crusher or a composite crusher, can crush sundries with compressive strength not more than 350MPa, and the size of the sundries is not more than 250-900 mm;

and step three, the moisture content of the wet sludge 2 is 80-88%.

5. The low-temperature drying treatment process for the electroplating sludge according to claim 1, which is characterized in that:

in the fourth step, the conveying system 2 is one or two of a screw conveyor and a scraper conveyor, the material of a blade of the screw conveyor is manganese steel, and the material of the scraper conveyor is SUS 304;

the pulping system in the fourth step is a submersible mixer made of SUS 304;

in the step (iv), the water content of the mud-water mixture 3 is 99.3% -99.5%.

6. The low-temperature drying treatment process for the electroplating sludge according to claim 1, which is characterized in that:

in the fifth step, the pump is a sludge screw pump, and the outlet pressure is 0.4-1.2 MPa;

7. The low-temperature drying treatment process for the electroplating sludge according to claim 1, which is characterized in that:

sixthly, the conveying 3 system is a belt conveyor which is a steel wire rope core conveying belt with the bandwidth of 1000-1400 mm;

step sixthly, the crusher 2 is a fluted disc type filter cake crusher;

sixthly, the water content of the wet sludge 4 is 65-70 percent.

8. The low-temperature drying treatment process for the electroplating sludge according to claim 1, which is characterized in that:

in the step (c), the conveying system 4 is one or two of a screw conveyor and a scraper conveyor, the material of the blades of the screw conveyor is manganese steel, and the material of the scraper conveyor is SUS 304.

9. The low-temperature drying treatment process for the electroplating sludge according to claim 1, which is characterized in that:

in the step III, the conveying system 5 is one or two of a screw conveyor and a scraper conveyor, the material of a blade of the screw conveyor is manganese steel, and the material of the scraper conveyor is SUS 304;

in the step (viii), the moisture content of the wet sludge 5 is 65-70%.

10. The low-temperature drying treatment process for the electroplating sludge according to claim 1, which is characterized in that:

the conveying system 6 in the step ninthly is one or two of a spiral conveyor and a scraper conveyor, the blades of the spiral conveyor are made of manganese steel, and the scraper conveyor is made of SUS 304;

11. The low-temperature drying treatment process for the electroplating sludge according to claim 1, which is characterized in that:

in step (c), the conveying system 7 is a scraper conveyor, closed, and made of SUS 304;

step (r) the dry mud collection system is one of a dry mud bin or ton bag.