CN101817650B - Method for treating incinerated fly ash of domestic garbage with cooperation of cement kiln - Google Patents

Abstract

The invention discloses a method for treating incinerated fly ash of domestic garbage with cooperation of a cement kiln, which comprises the following steps of: 1) washing and pre-treating the fly ash, 2) treating sewage, and 3) calcining cement clinker, wherein the process of washing and pre-treating the fly ash in the step 1) comprises a step of washing the fly ash by using a three-stage washing treatment device consisting of a washing tank and a vacuum filter, and the water and the fly ash are mixed in a weight ratio of 2:1-3:1; the process of treating the sewage in the step 2) comprises steps of desalting supernate and returning the purified condensate water to the step 1) to perform repeated washing so as to realize water recycle; and when the cement clinker is calcined in the step 3), the calcining temperature in the cement kiln can reach 1,750 DEG C. Therefore, the method can ensure that heavy metal ions in the treated fly ash are effectively fixed in crystal lattices of the cement clinker and dioxin is totally decomposed, and realizes hazard-free and reclamation treatment of the fly ash; and the calcined cement can reach the physical and mechanical properties of P.O42.5 cement.

Description

A kind of method of treating incinerated fly ash of domestic garbage with cooperation of cement kiln

Technical field

The present invention relates to a kind of treatment process of domestic garbage incineration flyash; Particularly utilize the cement kiln synergic processing domestic garbage incineration flyash, realize the method for the innoxious completely a kind of treating incinerated fly ash of domestic garbage with cooperation of cement kiln with resource utilization of domestic garbage incineration flyash.

Background technology

Because the city is in continuous development, the domestic refuse generation is huge to be increased, and has become the important factor of restriction urban development at present.Burning disposal is one of most important means of handling at present domestic waste.But because through in the domestic refuse of burning, the chloride content of flying ash is up to more than 10%, and contains trace heavy metals such as organic pollutant such as benzopyrene, benzanthrene, Dioxins and Cr, Cd, Hg, Pb, Cu, Ni, is classified as danger wastes.

Domestic and international existing domestic garbage incineration flyash is innoxious mainly to comprise solidification and stabilization, wet chemical treatment and pyroprocessing three major types with method stabilization treatment.The fluctuation of each component and unstable make the wet chemical treatment method also be in the laboratory study stage at present in the flying dust, are difficult to reach the purpose of industrial applications.Domestic comparatively general method of disposal is that flying dust is carried out single collection, after cement solidification is handled, sends into the Hazardous wastes landfill yard and carries out landfill.But handle domestic garbage incineration flyash with the cement curing mode, be faced with the defective that the heavy metals immobilization stabilising effect is poor, the objectionable impurities leaching yield is high; And landfill takies a large amount of land resources, and landfill yard has potential environmental pollution influence to peripheral ecology, is potential source of pollution.Mainly be to utilize the cement kiln cement baking aspect pyroprocessing, because of in the flying dust because chloride ion content is high, not only cement kiln disposal amount is low, and influences the normal operation of kiln system.

Publication number is to disclose a kind of " method of domestic garbage incineration flyash cement kiln calcining resource " in the application for a patent for invention of 101182144A wherein to disclose domestic garbage incineration flyash is washed-method that drops into cement kiln calcining with other raw material as cement slurry after the carbonating pre-treatment, and this method can make the heavy metal in the flying dust under hot conditions, be fixed in the cement clinker lattice effectively; Simultaneously, the content of chlorine can reduce to 1% in the domestic garbage incineration flyash after the processing, handles domestic garbage incineration flyash for cement kiln feasible method is provided; But water consumption is big in this method; The sewage that produces in the washing preprocessing process does not carry out desalting treatment; Saltiness is high, is difficult to reach the requirement of reuse water, and the flying dust filter cake moisture content is too high when raw-meal ingredient gets into cement kiln calcining; Not only incorporation is little, and raw meal proportioning process and kiln system stability are all had detrimentally affect.

Summary of the invention

In order to solve the problem that exists in the above-mentioned prior art; The purpose of this invention is to provide a kind of water-saving; The method of a kind of treating incinerated fly ash of domestic garbage with cooperation of cement kiln that the raw material ratio that accounts for process safety, rationally, the incorporation that the flying dust after the processing is disposed at cement kiln effectively improves.

To achieve these goals, the technical scheme of the present invention's employing is following: a kind of method of treating incinerated fly ash of domestic garbage with cooperation of cement kiln comprises the steps:

1) flying dust washing pretreatment process; It comprises the step of carrying out the flying dust washing by the washing treatment unit of water washing tank and vacuum filter combination with three grades; Concrete operations are: in used flying dust, add entry, its water mixes with 2: 1～3: 1 weight ratio with flying dust, in the one-level water washing tank, feeds CO ₂Stir into the washing slip, CO ₂The feeding amount be 10.4-13.8 kilogram (CO ₂)/ton slip; Then it is sent into one-level vacuum filter filter dehydration, solid-liquid separation goes out filtrating and filter cake; Wherein, filtrating directly enters sewage lagoon, and filter cake is sent into the secondary water washing tank and carried out the washing second time; The washing slip is sent into secondary vacuum filter filter dehydration after stirring, the secondary solid-liquid separation goes out filtrating and filter cake, and the filtrating that obtains is back to the one-level water washing tank, repeats washing; The filter cake that obtains is sent into three grades of water washing tanks and is washed for the third time; This washing slip is sent into three grades of vacuum filter filter dehydrations after stirring; Three times solid-liquid separation goes out filtrating and filter cake, and the filtrating that obtains is back to secondary water washing tank, repeated washing; The filter cake that obtains is sent in the washing flying dust warehouse for use behind drying machine drying;

2) WWT operation; Concrete operations are: the filtrating that A) step 1) is entered sewage lagoon is carried out reaction precipitation through reaction settling basin, and adds chemicals simultaneously, and the heavy metal and the layering of removing in the filtrating through chemical co-precipitation method go out supernatant and throw out; Used chemical agent is sodium sulphite and ferrous sulfate; The ST of chemical co-precipitation method was at least 3 hours.

B) with steps A) in throw out send into whizzer and carry out solid-liquid separation, the filtrating that obtains is back to reaction settling basin, repeats precipitation process; The filter cake that obtains is directly sent into behind the drying machine drying for use; Steps A) supernatant in feeds CO ₂Carry out acid-base neutralisation, feed CO ₂After make the pH value in this supernatant be reduced to 9 from 10.78-11.91; Liquid after the neutralization gets into the settling tank deposition, and secondary clearing goes out supernatant and throw out again; C) with step B) in supernatant carry out desalting treatment through the triple effect evaporation mold; The salt that crystallization goes out is sent into the crystal salt warehouse, obtains water of condensation after evaporating the water vapor condensation that, and water of condensation is back to said three grades of water washing tanks after being collected to clean water basin again, reuses; Step B) throw out in goes out filtrating and filter cake through the whizzer solid-liquid separation, and said filter cake is for use behind drying machine drying; Said filtrating is back to repeating step A in the said reaction settling basin);

3) calcination of cement clinker; With filter cake and the step 2 in the said washing flying dust of the step 1) warehouse) said filter cake after the oven dry through the metering handling equipment from the kiln tail more than 1000 ℃ high temperature section get into cement kiln calcining; Wherein, the filter cake moisture content after the oven dry is 1%～3%; Calcining temperature in the said cement kiln can reach 1750 ℃.

Above-mentioned steps 1) one-level, secondary in, three grades the churning time of washing slip are 20～30 minutes; It is steam piano that washing material after the stirring gets into the used handling equipment of vacuum filter.

Owing to adopted technique scheme; Beneficial effect of the present invention is following: 1, flying dust is pressed water: flying dust=2: 1～weight ratio was mixed through three grades of washings and vacuum filtering and dewatering processing in 3: 1; The flying dust filter cake that finally obtains; The clearance of cl ions can rise to more than 95%, for the processing of incineration of refuse flyash with utilize feasible.2, the sewage of flying dust washing is after the WWT operation is handled; Again be back to the washing in the flying dust washing pretreatment process; Realized the recycle of water, made that the actual used water amount of water is 0.7～1 ton of water/ton flying dust, reduce water consumption significantly in the water washing process.3, adopt the desalination of triple effect evaporation crystallization apparatus in the WWT after the flying dust washing, sewage Zhong Shui is reached with salt separate.Reach and wash buck 100% reuse, the purpose of zero release to external world.4. flying dust is through after washing pre-treatment, and chloride ion content is not higher than 0.5%, and the ability of cement kiln safe disposal flying dust brought up to about 3% by not surpassing 0.5% of raw material amount, and the flying dust processing power strengthens, and utilization ratio improves.5. utilize method of the present invention to handle domestic garbage incineration flyash, the filter cake that obtains is sent into the cement that cement kiln calcining goes out after oven dry, can reach the performance requriements of P.O42.5 cement, has realized the flying dust comprehensive utilization of resources.Through the washing after flying dust; Because chlorine and alkali metal content are low; Solved in the prior art cement kiln and be prone to skinning and influence the difficult problem that this cement kiln system runs well, reduced the time of cement kiln shutdown maintenance, improved the production efficiency of cement kiln because of disposing flying dust.7. flying dust gets into cement kiln calcining through 1000 ℃ of high temperature section of kiln tail, and Dioxins is decomposed fully, and heavy metal effectively is fixed in the cement clinker lattice, has realized the innoxious and disposal of resources of flying dust.

Description of drawings

Fig. 1 is a process flow diagram of the present invention

Fig. 2 is the particular flow sheet of flying dust washing pretreatment process

Fig. 3 is the particular flow sheet of WWT operation

Fig. 4 is a cement burning operation particular flow sheet

Embodiment

Below in conjunction with accompanying drawing the method for treating incinerated fly ash of domestic garbage with cooperation of cement kiln of the present invention is done further to specify.

As shown in Figure 1: technical process of the present invention comprises flying dust washing pretreatment process, WWT operation and calcination of cement clinker three big steps.Wherein, handle the filter cake that obtains through flying dust washing pretreatment process 1 and after dryer 6 oven dry, send into washing flying dust warehouse 5, get into calcination of cement clinker in the cement burning operation 3 then; The filtrating that obtains gets into the WWT operation 2 in second step, after dryer 6 oven dry, sends into washing flying dust warehouse 5 through the filter cake that obtains after this step process; Evaporate and be back to after the water of condensation that purifies in the flying dust washing pretreatment process 1, be recycled and reused for the washing flying dust; Can effectively reduce the water consumption of washing flying dust.

In the 3rd step cement burning operation 3, the waste gas that cement kiln is discharged behind quench tower 8 chillings, after bag dust arrester installation 9 gathers dust processing, enters atmosphere.

As shown in Figure 2: in flying dust washing pretreatment process; Comprise the washing pretreatment unit by water washing tank and vacuum filter combination of three grades of settings, wherein, the input terminus of one-level water washing tank 11 is equipped with the supply pond 4 of an input water; Output terminal and one-level vacuum filter 12 join; On one-level vacuum filter 12, be provided with 2 output ports, a port is connected with sewage lagoon 13, and another port and secondary water washing tank 14 join; Secondary water washing tank 14 output terminals and secondary vacuum filter 15 join, and secondary vacuum filter 15 is provided with 2 output ports, and an end and one-level water washing tank 11 join, and the other end is communicated with three grades of water washing tanks 16; The output terminal of three grades of water washing tanks 16 and three grades of vacuum filters 17 join, and three grades of vacuum filters 17 are provided with 2 output ports, and an end and secondary water washing tank 14 join, and the other end is communicated with dryer 6 inlets, and dryer 6 delivery ports are connected with washing flying dust warehouse 5.

The concrete operations that this flying dust washing is handled are: domestic garbage incineration flyash is dropped in the one-level water washing tank 11; In one-level water washing tank 11, add water by supply pond 4; Water mixes the back mechanical stirring with its flying dust with 2: 1～3: 1 weight ratio and becomes the washing slip after 20～30 minutes, when stirring, in this washing slip, feeds CO ₂, CO ₂The feeding amount be 10.4-13.8 kilogram (CO ₂)/ton (slip) is used to adjust the material property of this washing slip, helps the operation of follow-up drying plant; With single screw rod steam piano it is sent into one-level vacuum filter 12 filter dehydrations then, solid-liquid separation goes out filtrating and filter cake; Wherein, filtrating directly enters sewage lagoon 13; Filter cake is sent into secondary water washing tank 14 and is carried out the washing second time; The washing slip is sent into secondary vacuum filter 15 filter dehydrations with single screw rod steam piano after stirring, the secondary solid-liquid separation goes out filtrating and filter cake, and the filtrating that obtains is back to one-level water washing tank 11, repeats washing; The filter cake that obtains is sent into three grades of water washing tanks 16 and is washed for the third time; This washing slip is sent into three grades of vacuum filter 17 filter dehydrations with single screw rod steam piano after stirring; Three times solid-liquid separation goes out filtrating and filter cake, and the filtrating that obtains is back to secondary water washing tank 14, repeats washing; The filter cake that obtains is through dryer 6 oven dry, and the cake moisture after the oven dry is 1%～3%, sends in the washing flying dust warehouse 5 it for use then.

As shown in Figure 3; Include and enter the reaction settling basin 21 that the sewage lagoon 13 of filtrating joins in the WWT operation 2; Output terminal at reaction settling basin 21 is provided with 2 output ports, wherein, 1 port is provided with whizzer 22, is connected to dryer 6 with whizzer 22; In addition 1 port is provided with neutralization tank 23, and neutralization tank 23 outlets are provided with a neutralization precipitation pond 24, and this neutralization precipitation pond 24 is provided with 2 delivery ports, and 1 delivery port and above-mentioned whizzer 22 join; 1 delivery port is equipped with a triple effect evaporation mold 25 in addition; This triple effect evaporation mold 25 is provided with 2 delivery ports, and wherein 1 delivery port is equipped with one and collects the crystal salt warehouse 26 of crystal salt; In addition 1 delivery port and clean water basin 27 join; Clean water basin 27 are communicated with three grades of water washing tanks 16 through pipeline.

The concrete operations of above-mentioned WWT operation are: the filtrating that A) step 1) is entered sewage lagoon 13 is sent into and is added chemical agents in the reaction settling basin 21; Used chemical agent adopts sodium sulphite and ferrous sulfate; Concrete adding method is: add excessive sodium sulphite medicament reaction earlier and remove heavy metal, add an amount of ferrous sulfate medicament then and remove excessive S ^2-, the heavy metal ion of filtrating and S ^2-Be able to remove through chemical co-precipitation method, reaction precipitation after 3 hours layering go out supernatant and throw out; B) with steps A) in throw out send into whizzer 22 and carry out solid-liquid separation, the filtrating that obtains is back to reaction settling basin 21, repeats precipitation process; The filter cake that obtains is sent into washing flying dust warehouse 5 after directly sending into dryer 6 oven dry; Steps A) supernatant in is sent into and is fed CO in the neutralization tank 23 ₂Carry out acid-base neutralisation, make that the pH value in this supernatant is reduced to 9 from 10.78-11.91, the liquid after the neutralization reaction gets into settling tank 24 depositions, and secondary clearing goes out supernatant and throw out to precipitate 4 hours again; C) with step B) in supernatant carry out desalting treatment through triple effect evaporation mold 25; The salt that crystallization goes out is sent into crystal salt warehouse 26, obtains water of condensation after evaporating the water vapor condensation that, and water of condensation is back to said three grades of water washing tanks 16 after being collected to clean water basin 27 again, reuses; Step B) throw out in goes out filtrating and filter cake through whizzer 22 solid-liquid separation, and said filter cake is sent into washing flying dust warehouse 5 after dryer 6 oven dry; Said filtrating is back to repeating step A in the said reaction settling basin 21).

As shown in Figure 4; The used cement kiln 31 of cement burning grog is the new dry process rotary kiln; Concrete operations are: the filter cake that will wash in the flying dust warehouse 5 is sent into the above-mentioned new dry process rotary kiln from kiln tail high temperature section and is calcined through the metering handling equipment, and calcining temperature can be up to 1750 ℃ in this kiln body, thereby can guarantee that heavy metal effectively is fixed in the cement clinker lattice; Dioxins is decomposed fully, and final calcining becomes cement clinker.The waste gas that its kiln tail is discharged is qualified discharge after quench tower 8 and bag dust arrester installation 9 are handled.

The cement that adopts the inventive method disposal flying dust to produce can reach the performance requriements that P.O42.5 cement meets GB175-2007 " general purpose portland cement ".Detected result is following:

Sequence number Test item Standard-required (P.O42.5) Detected result 1 28 days ultimate compression strength, Mpa ≥42.5 51.7 2 28 days folding strengths, Mpa ≥6.5 9.0 3 Chloride ion content, % ≤0.06 0.04

Claims (6)

1. the method for a treating incinerated fly ash of domestic garbage with cooperation of cement kiln comprises the steps:

1) flying dust washing pretreatment process; It comprises the step of carrying out the flying dust washing by the washing treatment unit of water washing tank and vacuum filter combination with three grades; Concrete operations are: in described flying dust, add entry, its water mixes with 2: 1～3: 1 weight ratio with flying dust, in the one-level water washing tank, feeds CO ₂Stir into the washing slip, then it is sent into one-level vacuum filter filter dehydration, solid-liquid separation goes out filtrating and filter cake; Wherein, filtrating directly enters sewage lagoon, and filter cake is sent into the secondary water washing tank and carried out the washing second time; The washing slip is sent into secondary vacuum filter filter dehydration after stirring, the secondary solid-liquid separation goes out filtrating and filter cake, and the filtrating that obtains is back to the one-level water washing tank, repeats washing; The filter cake that obtains is sent into three grades of water washing tanks and is washed for the third time; This washing slip is sent into three grades of vacuum filter filter dehydrations after stirring; Three times solid-liquid separation goes out filtrating and filter cake, and the filtrating that obtains is back to secondary water washing tank, repeated washing; The filter cake that obtains is sent in the washing flying dust warehouse for use behind drying machine drying;

2) WWT operation; Concrete operations are: the filtrating that A) step 1) is entered sewage lagoon is carried out reaction precipitation through reaction settling basin, and adds chemical agent simultaneously, and the heavy metal and the layering of removing in the filtrating through chemical co-precipitation method go out supernatant and throw out; Wherein, chemical agent is sodium sulphite and ferrous sulfate; B) with steps A) in throw out send into whizzer and carry out solid-liquid separation, the filtrating that obtains is back to reaction settling basin, repeats precipitation process; The filter cake that obtains is directly sent into behind the drying machine drying for use; Steps A) supernatant in feeds CO ₂Carry out acid-base neutralisation, neutral liquid gets into the settling tank deposition, and secondary clearing goes out supernatant and throw out again; C) with step B) in supernatant carry out desalting treatment through the triple effect evaporation mold; The salt that crystallization goes out is sent into the crystal salt warehouse, obtains water of condensation after evaporating the water vapor condensation that, and water of condensation is back to said three grades of water washing tanks after being collected to clean water basin again, reuses; Step B) throw out in goes out filtrating and filter cake through the whizzer solid-liquid separation, and said filter cake is for use behind drying machine drying; Said filtrating is back to repeating step A in the said reaction settling basin);

3) calcination of cement clinker; With filter cake and the step 2 in the said washing flying dust of the step 1) warehouse) said filter cake after the oven dry through the metering handling equipment from the kiln tail more than 1000 ℃ high temperature section get into cement kiln calcining; Wherein, the filter cake moisture content behind drying machine drying is 1%～3%; Calcining temperature in the said cement kiln can reach 1750 ℃.

2. the method for treating incinerated fly ash of domestic garbage with cooperation of cement kiln according to claim 1 is characterized in that: the said CO of step 1) ₂The feeding amount be 10.4-13.8 kilogram (CO ₂)/ton slip.

3. the method for treating incinerated fly ash of domestic garbage with cooperation of cement kiln according to claim 1, it is characterized in that: the churning time of the said washing slip of step 1) is 20～30 minutes.

4. the method for treating incinerated fly ash of domestic garbage with cooperation of cement kiln according to claim 1 is characterized in that: it is steam piano that the said washing slip of step 1) is sent into said one-level, secondary, three grades of used handling equipments of vacuum filter.

5. the method for treating incinerated fly ash of domestic garbage with cooperation of cement kiln according to claim 1 is characterized in that: step 2) A) described in chemical agent be sodium sulphite and ferrous sulfate; The ST of said chemical co-precipitation method was at least 3 hours.

6. the method for treating incinerated fly ash of domestic garbage with cooperation of cement kiln according to claim 1 is characterized in that: step 2) B) described in feed CO ₂Make the pH value in the said supernatant be reduced to 9 from 10.78-11.91.