JP5334312B2 - Cement manufacturing apparatus and manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently recover heavy metals such as lead from a cement production process and to increase the quantity of a recovered salt while avoiding the explosion in an electrostatic dust collector or the occurrence of harmful materials such as dioxins. <P>SOLUTION: Provided is an apparatus 1 or the like for producing cement, which includes a belt feeder 7 for supplying pellets P granulated while mixing a material containing solid carbon with a material containing chlorine, to a section between the middle of the cement kiln 2 and the lowest stage cyclone of a preheater; a bleeding probe 4 for bleeding a part of the kiln combustion gas from the inlet 2a of the kiln; a dry chlorine by-pass equipment 8 for removing chlorine from the bleed gas G1; a dehydrator 12 for dehydrating chlorine by-pass dust D2 obtained in the dry chlorine by-pass equipment 8 after a sulfiding agent is added into the chlorine by-pass dust D2; a floatation apparatus 18 for recovering the heavy metals from the cake C obtained by dehydration by the dehydrator; and a spray dryer 16 for recovering salts from a filtrate L1 obtained by dehydration by the dehydrator. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a cement manufacturing apparatus and manufacturing method, and in particular, from dust contained in gas extracted from a part of combustion gas extracted from a cement kiln exhaust gas passage from a kiln bottom of a cement kiln to a lowermost cyclone, etc. The present invention relates to an apparatus and method for recovering heavy metals and salts.

  Conventionally, since lead (Pb) in cement is immobilized, it has been considered that there is no elution into soil. However, as the amount of recycled resources used in cement production has increased in recent years, the amount of lead in cement has also increased, and its content has been greatly exceeded. Since there is a possibility that the risk of leaching into the soil increases with increasing concentration, a technique for reducing the lead concentration in the cement to the conventional content level is necessary.

  In recent years, the recycling of wastes into cement raw materials or fuels has been promoted, and as the amount of waste processed increases, the amount of volatile components such as chlorine, sulfur, and alkali brought into the cement kiln also increases. The amount of bypass dust is also increasing. Chlorine bypass dust is used in the cement crushing process, but it is expected that the generation amount will increase and the allowable cement concentration of heavy metals including lead will be exceeded. There was a need to develop a method for removing and recovering heavy metals from the cement manufacturing process.

  Therefore, for example, in Patent Document 1, in order to effectively separate and remove chlorine and lead in the waste supplied to the cement manufacturing process, the waste water washing step and the filtered solid alkali elution A step, a deleading step for precipitating and separating lead from the filtrate, a decalcifying step for precipitating and separating calcium from the deleaded filtrate, and heating the filtrate to precipitate chlorides for separation Disclosed is a waste processing method including a salinity recovery step.

  Further, in Patent Document 2, in separating and removing lead and zinc from waste such as fly ash, a solution containing calcium ions is mixed to obtain a slurry, followed by solid-liquid separation to obtain a solid containing zinc. And a step of obtaining an aqueous solution containing lead, a step of obtaining a solution containing lead sulfide and calcium ions by solid-liquid separation after adding a sulfurizing agent to the aqueous solution containing lead, etc. A processing method is described.

  Further, Patent Document 3 extracts a part of the cement kiln combustion gas from the cement manufacturing process, collects dust contained in the extracted combustion gas, and removes one or more selected from thallium, lead, and selenium. Alternatively, a method for removing and recovering heavy metals from a cement manufacturing process characterized by recovering is described.

Patent Document 4 discloses that the raw material temperature in the cement kiln is 800 to 1100 ° C. by controlling the O ₂ concentration of the combustion gas in the kiln bottom of the cement kiln to 5% or less and / or the CO concentration to 1000 ppm or more. Lead in which the area is reduced to promote volatilization of lead, and then a part of the combustion gas in the cement kiln is extracted to collect the dust contained in the combustion gas and to recover the lead from the collected dust A removal method is described.

JP 2003-1218 A JP 2003-201524 A JP 2006-347794 A International Publication 2008/050678 Pamphlet

  However, in the methods described in Patent Documents 1 to 3, heavy metals such as lead contained in the chlorine bypass dust are removed, but the ratio of heavy metals removed out of the system through the chlorine bypass dust is: Only about 30% of the total, even if 100% of the heavy metals in the chlorine bypass dust are removed, the remaining 70% is still taken up by the clinker manufactured in the cement kiln. It is not easy to reduce the content. Therefore, it is important to promote the volatilization of heavy metals in the cement kiln and increase the concentration rate of heavy metals in chlorine bypass dust.

  Here, a chlorination volatilization method and a reduction volatilization method are known as heavy metal volatilization techniques. However, if the chlorination volatilization method that is generally performed is applied to the cement firing step, it is necessary to input a much larger amount of chlorine than a common amount in cement production. On the other hand, the application of the reduction volatilization method is problematic in terms of cement quality because the color of the cement is yellow.

  Further, in the method described in Patent Document 4, in order to increase the volatilization rate of heavy metals, the oxygen concentration in the kiln bottom of the cement kiln is suppressed, and an atmosphere that generates CO gas is formed. There is a problem that there is a risk of explosion of an electrostatic precipitator for collecting dust contained in the kiln combustion gas and generation of harmful substances such as dioxins.

  Therefore, the present invention has been made in view of the above problems in the prior art, and avoids the explosion of an electrostatic precipitator and the generation of harmful substances such as dioxins, while the lead from the cement manufacturing process. The purpose is to collect heavy metals efficiently and at the same time increase the amount of recovered salts.

To achieve the above object, the present invention is to a supply device for supplying a material containing fixed carbon in the interval of up to the lowermost cyclone of the preheater which is attached to the cement kiln from an intermediate Mentokirun, kiln of the cement kiln An extraction probe for extracting a part of the combustion gas from the cement kiln exhaust gas flow path from the bottom to the lowermost cyclone, a dust collector for collecting dust contained in the combustion gas extracted by the extraction probe, A dissolution tank that dissolves the dust collected by the dust collector in water, a dehydrator that dehydrates the dust dissolved in the dissolution tank after adding a sulfiding agent, and a cake obtained by dehydration by the dehydrator. cement from including the heavy metals recovery apparatus for recovering heavy metals, and said dewatering device salts recovery apparatus for recovering the salt from the filtrate obtained by dewatering by A production apparatus comprising a mixing granulator for mixing and granulating the substance containing fixed carbon and the substance containing chlorine, and the granulated product by the mixed granulator is supplied by the supply apparatus. It supplies to the area from the middle of the said cement kiln to the lowest cyclone of the preheater attached to this cement kiln .

Further, the present invention is to a supply device for supplying a material containing fixed carbon in the interval of up to the lowermost cyclone of the preheater which is attached to the cement kiln from the middle of Mentokirun, the lowermost from kiln of the cement kiln An extraction probe for extracting a part of the combustion gas from the cement kiln exhaust gas flow path leading to the cyclone, a wet dust collector for collecting dust contained in the combustion gas extracted by the extraction probe, and the wet collection A dehydration device that adds desulfurization agent to the dust collected by the dust device and then dehydrates, a heavy metal recovery device that recovers heavy metals from the cake obtained by dehydration by the dehydration device, and a dehydration device that dehydrates the dust. a cement manufacturing apparatus and a salt recovery device for recovering salts from the resulting filtrate, and the material containing the fixed carbon, chlorine A mixing granulator that mixes and granulates the substances to be contained, and the granulated product by the mixing granulator is fed from the middle of the cement kiln to the cement kiln by the supply device. It supplies to the section to the lower cyclone .

  And according to both said invention, by supplying the substance containing fixed carbon from the middle of the cement kiln of the cement kiln to the lowermost cyclone section of the preheater attached to the cement kiln, heavy metals in the cement kiln It is possible to increase the volatilization rate of the heavy metals and to increase the concentration rate of heavy metals at a position where a part of the combustion gas of the cement kiln is extracted. As a result, when part of the combustion gas of the cement kiln is extracted, the amount of heavy metals extracted along with the combustion exhaust gas increases, so that heavy metals can be efficiently recovered with chlorine bypass dust and the like. Salts can also be recovered. Further, the amount of waste treated in the cement manufacturing process can be increased by the amount of recovered heavy metals. Furthermore, since it is not necessary to create an atmosphere that generates CO gas by suppressing the oxygen concentration at the kiln bottom of the cement kiln, the safety of the cement manufacturing equipment is also ensured and implemented without increasing the environmental load. Is possible.

In addition , by using a granulated product in which a substance containing fixed carbon and a substance containing chlorine are used, it is possible to efficiently volatilize and concentrate heavy metals in a cement kiln and the like. By supplying both fixed carbon-containing substances and chlorine to the target location, the volatilization rate of heavy metals can be further increased, and the concentration rate of heavy metals at the location where part of the combustion gas is extracted is further increased. Can do. Furthermore, since the KCl concentration in the chlorine bypass dust is increased by adding the chlorine component, the amount of recovered salts can be increased from the solution after flotation.

Furthermore, the invention provides a substance comprising fixed carbon in the interval of up to the lowermost cyclone of the preheater from the middle of the cell Mentokirun are attached to the cement kiln, leading to the lowermost cyclone from kiln of the cement kiln A part of the combustion gas is extracted from the cement kiln exhaust gas flow path, and the dust contained in the extracted combustion gas is collected, the collected dust is dissolved in water, and a sulfide is added to the dissolved dust. Dehydration after addition, recovering heavy metals from the cake obtained by the dehydration, and recovering salts from the filtrate obtained by the dehydration, the cement production method, wherein the substance containing fixed carbon and chlorine content The granulated material mixed with the contained material is supplied to the section from the middle of the cement kiln to the lowermost cyclone of the preheater attached to the cement kiln. Characterized in that it.

Further, the invention provides a substance comprising fixed carbon in the interval of up to the lowermost cyclone of the preheater from the middle of the cell Mentokirun are attached to the cement kiln, leading to the lowermost cyclone from kiln of the cement kiln A part of the combustion gas is extracted from the cement kiln exhaust gas flow path, and the dust contained in the extracted combustion gas is wet-collected, and a desulfurizing agent is added to the wet-collected dust, followed by dehydration, and the dehydration A cement manufacturing method for recovering heavy metals from a cake obtained by the above step and recovering salts from a filtrate obtained by the dehydration, wherein the substance containing fixed carbon and the substance containing chlorine are mixed. The granulated material is supplied to a section from the middle of the cement kiln to the lowermost cyclone of the preheater attached to the cement kiln .

According to both inventions related to the cement manufacturing method, as in the invention related to the cement manufacturing apparatus, the safety of the cement manufacturing apparatus is ensured, and heavy metals are efficiently recovered with chlorine bypass dust or the like without increasing the environmental load. And the salt can be recovered. Further, the amount of waste treated in the cement manufacturing process can be increased by the amount of recovered heavy metals. Furthermore, by using a granulated product that is a mixture of a substance containing fixed carbon and a substance containing chlorine, the volatilization rate of heavy metals is further increased, and the concentration of heavy metals at a position where a part of the combustion gas is extracted The rate can be further increased. Further, by adding a chlorine component, the KCl concentration in the chlorine bypass dust can be increased, and the amount of recovered salts from the solution after flotation can be increased.

  In the above cement manufacturing method, the ratio of the CaO concentration to the Cl concentration of the collected dust can be adjusted to 0.1 or more and 20 or less, and thereby, when fusing and recovering lead by dissolving chlorine bypass dust In addition, the recovery efficiency can be improved.

Further, in the above cement manufacturing method, the SO ₂ concentration in the combustion gas after dust collection the dust, as a standard oxygen concentration of 18%, can be adjusted to 1000ppm or 10000ppm or less. Thereby, the volatilization state of lead can be stabilized, and if volatilization is insufficient, a substance containing fixed carbon can be introduced and adjusted.

  As described above, according to the present invention, it is possible to efficiently recover heavy metals such as lead from the cement manufacturing process while maintaining stable operation and avoiding the generation of harmful substances, and at the same time increase the amount of recovered salts. Is possible.

It is a flowchart which shows the whole structure of 1st Embodiment of the cement manufacturing apparatus concerning this invention. It is a flowchart which shows the dry-type chlorine bypass installation of the cement manufacturing apparatus of FIG. It is a figure which shows the relationship between Cl density | concentration in chlorine bypass dust, and lead concentration. Is a diagram showing a relationship between SO ₂ concentration and lead volatilization rate of the exhaust gas in the chlorine bypass. It is a figure which shows the relationship between CaO density | concentration / Cl density | concentration in a chlorine bypass dust, and a lead recovery rate. It is a flowchart which shows the whole structure of 2nd Embodiment of the cement manufacturing apparatus concerning this invention. It is a flowchart which shows the wet chlorine bypass installation of the cement manufacturing apparatus of FIG.

  Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment of a cement manufacturing apparatus according to the present invention. This cement manufacturing apparatus 1 includes a cement kiln 2, a clinker cooler 3 and a calcining furnace 5, which constitute a cement firing facility, and a dry chlorine bypass. The facility 8 includes a waste water treatment device 13 for recovering heavy metals such as lead and salts from the chlorine bypass dust D2 generated in the dry chlorine bypass facility 8, a spray dryer 16, a flotation device 18, and the like.

The mixing granulator 6 is provided for granulating while mixing a carbon source such as heavy oil ash and a chlorine source such as CaCl _2. The mixing granulator 6 includes an Eirich mixer, Pelegaia, etc. An apparatus capable of simultaneously performing stirring, kneading and granulation can be used. In place of the mixing granulator 6, a batch type or continuous type kneading / mixing machine, an extrusion type (disc pelleter, press pelleter, etc.), a compression type (tablet machine, briquette machine, etc.), a rolling type (pan It can also be used in combination with a granulator such as a pelletizer.

The belt feeder 7 is provided to put the pellets P granulated by the mixing granulator 6 into the kiln bottom 2 a of the cement kiln 2. Instead of the belt feeder 7, an apron feeder, a vibration feeder, or the like can be used, and pellets P may be ejected from the kiln bottom 2a into the cement kiln 2 using air or the like. It can also be fed from the body part.

  The probe 4 constitutes a part of the dry chlorine bypass facility 8 and is provided for extracting a part of the combustion gas from the kiln bottom 2 a of the cement kiln 2.

  The dry chlorine bypass equipment 8 is generally used to remove chlorine from the combustion exhaust gas of the cement kiln 2, and as shown in FIG. 2, a cooling fan that cools the bleed gas G1 from the probe 4 with cold air A1. 23, a cyclone 24 that classifies the cooled extracted gas G1 into coarse powder D1, fine powder (chlorine bypass dust) D2 and gas G2, a cooler 25 that cools the fine powder D2 and gas G2, and collects the fine powder D2. And the separated coarse powder D1 having a low chlorine content is returned to the cement kiln system, and the chlorine bypass dust D2 having a high chlorine content recovered by the dust collector 27 is stored in the dust tank 9. The The exhaust gas G3 discharged from the dust collector 27 is returned to an exhaust gas flow path such as a preheater attached to the kiln 2 or an outlet of the preheater via an exhaust fan 29.

  Returning to FIG. 1, the dissolution tank 10 is provided to add water W to the chlorine bypass dust D2 supplied from the dust tank 9 to elute water-soluble chlorine contained in the chlorine bypass dust D2.

  The stirring tank 11 is provided to add a sulfiding agent to the slurry S1 discharged from the dissolving tank 10 and sulfidize lead chloride and the like contained in the slurry S1.

  The dehydrator 12 is provided for filtering the slurry S2 discharged from the agitation tank 11 for solid-liquid separation. The dehydrator 12 can be a vertical filter press having a plurality of filter plates stacked in the vertical direction, a belt filter, or the like.

  The waste water treatment device 13 is provided for recovering heavy metals contained in the filtrate L1 discharged from the dehydrator 12, and includes respective addition devices (not shown) such as hydrochloric acid, a ferrous compound, potassium carbonate, and the like.

  The filtration / separation device 14 is a solid-liquid separation device provided with an ultra-fine nonwoven fabric having a lamellar structure, and is provided for removing sediments such as salt iron from the filtrate L2 after wastewater treatment.

  The COD treatment device 15 is provided to reduce the COD of the waste water L3 from the filtration separation device 14, and although not shown, a mixing tank for mixing the waste water L3 with a flocculant such as a polymer flocculant, COD A coagulation tank for coagulating and adsorbing the components on the coagulant and a solid-liquid separator at the rear stage of the coagulation tank are provided. In addition to the above configuration, an activated carbon adsorption tower may be installed as the COD treatment device 15 to adsorb the COD component on the activated carbon. Alternatively, a catalytic oxidative decomposition method in which an oxidizing agent such as ozone, hydrogen peroxide, or hypochlorite is allowed to act in the presence of an oxidation catalyst may be applied.

  The spray dryer 16 sprays and atomizes the COD-treated waste water L4, contacts with a high-temperature air current in a drying chamber (not shown), and instantaneously granulates and drys the salt in the waste water L4 into a spherical powder. It is provided for recovery in the form of granules. For this granulation drying, the hot gas G4 discharged from the clinker cooler 3 is used. On the other hand, when the amount of heat is insufficient or when the amount of heat cannot be secured, a new heat source such as a hot stove, exhaust gas from any cement kiln system, or hot gas after dust removal may be used. Depending on the quality of the salt to be recovered, either the combination of the waste water treatment device 13 and the filtration separation device 14 or the COD treatment device 15 or both can be omitted.

  The mixing agitation tank 17 is provided to add the pH adjuster, the foaming agent or the hydrophobic agent, and the flotation water from the filter press 19 to the cake C from the dehydrator 12 for mixing and agitation.

  The flotation device 18 includes a bubbling device, and the slurry S3 from the mixing and agitation tank 17 is subjected to a flotation operation to floss F containing lead and a sink (tail slurry) SI containing chlorine, thallium, selenium, and the like. Provided to separate.

The filter press 19 solid-liquid separates the floss F from the flotation device 18, the sink SI, or the salt iron from the filtration separation device 14 and supplies lead, gypsum (CaSO ₄ .2H ₂ O) or iron raw material from each. Provided for recovery.

  Next, operation | movement of the cement manufacturing apparatus 1 which has the said structure is demonstrated, referring centering on FIG.

Heavy oil ash as a carbon source and CaCl ₂ as a chlorine source are charged into the mixing granulator 6 using a quantitative feeder, and water is added so that the granulated product has a predetermined moisture content. And mix and granulate. The details of the input amounts of heavy oil ash and CaCl ₂ will be described later. The pellet P is made into the pellet P by the mixing granulator 6 when the particle size is too small when it is introduced from the kiln bottom 2a etc., the pellet P flows to the lowermost cyclone side along with the gas flowing through the cement kiln exhaust gas flow path. As a result, the heavy oil ash to the lead volatilization region and the supply amount of CaCl ₂ to the lead concentration region are reduced, and it is avoided that efficient lead volatilization / recovery cannot be performed.

  In the mixing granulator 6, it is preferable to granulate so that the particle size of the pellet P is 5 to 50 mm, and then to dry it with a dryer (not shown). When the particle size of the dried pellet P is less than 5 mm, the pellet P thrown into the cement kiln 2 scatters and the supply amount of the pellet P to the volatilization temperature range of lead is reduced to ensure an efficient volatilization rate. It becomes impossible to concentrate and recover lead efficiently. On the other hand, when the particle size of the pellet P exceeds 50 mm, there is a concern that the color of the cement exhibits a yellow color, which causes a problem in terms of cement quality.

  Next, during the cement firing by the cement kiln 2, the pellet P is introduced from the kiln bottom 2 a of the cement kiln 2 by the belt feeder 7 to promote the volatilization of lead in the cement kiln 2. In addition to the addition of pellets P, the composition of the cement raw material to be fed into the cement kiln 2 and the amount of waste to be treated in the cement kiln 2 are adjusted to increase the chlorine concentration at or near the kiln bottom 2a. . Specifically, as shown in FIG. 3, the chlorine concentration of the dust collected from the extraction gas G1 by the probe 4 is adjusted to 5 to 40% by mass, thereby increasing the lead concentration in the dust. Can be made.

In addition, by measuring the SO ₂ concentration in the gas discharged from the dry chlorine bypass facility 8, it is possible to grasp the situation where lead is volatilized. Can be raised. Specifically, as shown in FIG. 4, by adjusting the SO ₂ concentration to 1000 ppm to 10000 ppm (the value when the O ₂ concentration in the gas is 18%), the lead volatilization rate is set to 92% or more. Can be maintained.

  Next, a part of the combustion gas is extracted from the kiln bottom 2a of the cement kiln 2 by the probe 4, and in the dry chlorine bypass facility 8, the extraction gas G1 from the probe 4 is supplied from the cooling fan 23 as shown in FIG. Cooled by the cold air A1, the extracted gas G1 is separated into coarse powder D1 and fine powder (chlorine bypass dust) D2 by the cyclone 24, and the separated coarse powder D1 having a low chlorine content is returned to the cement kiln system. In 25, the gas G2 and the fine powder D2 cooled by the cold air A2 from the cooling fan 26 are collected by the dust collector 27, and the collected chlorine bypass dust D2 having a high chlorine content is stored in the dust tank 9. Since this chlorine bypass dust D2 has a higher concentration of lead than in the past due to more volatilization of lead, by separating this lead, lead can be efficiently removed from the cement manufacturing process. The lead content of the cement clinker produced and discharged from the clinker cooler 3 can be reduced.

In the dissolution tank 10, water W is added to the chlorine bypass dust D2 supplied from the dust tank 9, and the water-soluble chlorine content contained in the chlorine bypass dust D2 is eluted. Next, after adding a sulfurizing agent such as sodium hydrosulfide (NaSH) or sodium sulfide (Na ₂ S) to the slurry S1 discharged from the dissolution tank 10 in the stirring tank 11, the slurry S2 discharged from the stirring tank 11 Is filtered with a dehydrator 12 and separated into solid and liquid. The reason for adding the sulfiding agent is to sulfidize lead chloride and the like contained in the slurry S1 and precipitate as sulfides, and lead sulfide (PbS) is generated by this sulfidation.

  The filtrate L1 separated by the dehydrator 12 is supplied to the waste water treatment device 13. In the waste water treatment device 13, hydrochloric acid, a ferrous compound, potassium carbonate, etc. are added to the filtrate L1, and lead contained in the filtrate L1. Collect heavy metals such as In the wastewater treatment device 13, using the coprecipitation effect of heavy metals with iron, first, hydrochloric acid was added to the filtrate L1 to adjust the pH to 4 or less, then the ferrous compound was added, and the pH was adjusted in the second tank. The adjusting agent is added to adjust the pH to 8.5 to 11.0, and the produced precipitate such as iron salt is collected by the filtration separation device 14.

  Next, in the COD processing device 15, the waste water L3 from the filtration separation device 14 and a flocculant such as a polymer flocculant are mixed, and the COD component is agglomerated and adsorbed on the flocculant, thereby reducing the COD of the waste water L3.

  Next, in the spray dryer 16, the COD-treated waste water L4 is sprayed and atomized, brought into contact with the hot gas G4 from the clinker cooler 3, and granulated and dried instantaneously, and salts such as KCl in the waste water L4 are removed. Collect into spherical powder. The exhaust of the spray dryer 16 is discharged to the atmosphere in its entirety, or the moisture in the gas is recovered and the recovered water is reused in the dissolution tank 10 or the like, and the gas is discharged to the atmosphere or returned to the kiln system.

  On the other hand, the cake C separated by the dehydrator 12 is supplied to the mixing and stirring tank 17 and remelted using the flotation circulating water from the filter press 19 to obtain a slurry S3. After adjusting the pH by adding sulfuric acid, the MIBC Add foaming agent or hydrophobizing agent such as (Methyl Isobutyl Carbinol).

  Next, in the flotation apparatus 18, the slurry S3 from the mixing and stirring tank 17 is separated into a floss F containing lead and a sink SI containing chlorine, thallium, selenium, and the like by a flotation operation. Here, the ratio of the CaO concentration to the Cl concentration (CaO concentration / Cl concentration) of the chlorine bypass dust D2 recovered by the dry chlorine bypass facility 8 is adjusted to 0.1 or more and 20 or less, as shown in FIG. The lead recovery rate in the flotation process can be improved. In adjusting this CaO concentration / Cl concentration, the composition of the cement raw material put into the cement kiln 2, the amount of waste processed in the cement kiln 2 are adjusted, the cyclone of the dry chlorine bypass facility 8 is adjusted. This can be dealt with by changing the classification point. Note that the lead contained in the recovered floss F is recovered after solid-liquid separation by the filter press 19 and can be reused, for example, by being reduced to the base.

On the other hand, the sink SI containing chlorine or the like is also solid-liquid separated by the filter press 19. The cake from which the chlorine content obtained here is removed includes gypsum (CaSO ₄ .2H ₂ O) produced by the reaction of sulfuric acid added in the latter stage of the dehydrator 12 with the calcium content in the dust. Therefore, the collected gypsum can be supplied to a cement mill and used for cement production.

  Moreover, the salt iron etc. from the filtration separation apparatus 14 are solid-liquid separated with the filter press 19, and the obtained cake can be utilized as an iron raw material for cement manufacture.

  On the other hand, the filtrate obtained by the filter press 19 can be returned to the flotation device 18 and reused as circulating water.

  In the above embodiment, the case where lead is separated from the chlorine bypass dust D2 has been exemplified. However, zinc, cadmium, antimony, selenium, arsenic, thallium and mercury can be separated in the same manner as described above. it can.

  In addition to chlorine bypass dust D2, a part of the combustion gas is extracted from the cement kiln exhaust gas passage from the kiln bottom 2a of the cement kiln 2 to the lowermost cyclone, and the dust contained in the extracted combustion gas may be used. For example, the heavy metals can be separated by the same method as described above.

  In the above embodiment, heavy oil ash is exemplified as a substance containing fixed carbon, but coke, coal tar pitch, tire, coal, anthracite, bituminous coal, lignite, lignite, graphite, flame retardant plastic, phenol resin, Furan resin, thermosetting resin, cellulose, charcoal, waste toner, mixed coke, fine coke, electrode scrap, activated coke, carbide, and unburned carbon contained in fly ash alone or in combination of two or more of these Can be used.

In addition, CaCl ₂ is exemplified as the substance containing chlorine, but alkali metal chlorides such as NaCl and KCl, alkaline earth metal chlorides, metal chlorides such as FeCl ₂ and CuCl ₂ , chlorine-containing waste plastics, vinyl chloride Municipal waste incineration ash, dredged soil, scrapped car shredder dust can be used alone or in combination of two or more thereof.

Next, 2nd Embodiment of the cement manufacturing apparatus concerning this invention is described, referring FIG.6 and FIG.7.

The cement manufacturing apparatus 31 according to the present embodiment is characterized by using a wet chlorine bypass facility 32 instead of the dry chlorine bypass facility 8 of the cement manufacturing apparatus 1 in the first embodiment. Since this is the same as the cement manufacturing apparatus 1, in FIG. 6, the same reference numerals and symbols are assigned to the same apparatuses, substances and the like as in FIG.

  As shown in FIG. 7, the wet chlorine bypass facility 32 includes a cooling fan 33 that cools the extraction gas G1 from the probe 4 with cold air A3, coarse cooling powder D1, and fine powder (chlorine bypass dust) D2 from the cooling extraction gas G1. And a cyclone 34 that is classified into the gas G2, a wet dust collector 35 that wet-collects exhaust gas from the cyclone 34, and the like.

  The wet dust collector 35 is composed of a scrubber 35a that cools the fine powder D2 and gas G2 in contact with moisture in the slurry S4, a circulating liquid tank 35b that circulates the dust-collected dust slurry between the scrubber 35a, and the working water. A cleaning tower 35c for spraying, a circulation pump 35d, and a discharge pump 35e are provided.

  In the wet chlorine bypass facility 32, a part of the combustion gas is extracted from the kiln bottom 2a of the cement kiln 2 by the probe 4, and the cooled extraction gas G1 is separated into coarse powder D1 and fine powder (chlorine bypass dust) D2. The separated coarse powder D1 having a low chlorine content is returned to the cement kiln system, the fine powder and gas having a high chlorine content are guided to the wet dust collector 35, and the water content of the slurry S4 supplied from the circulating liquid tank 35b, etc. Cool by. Then, the fine powder D2 in the gas G2 is collected by the wet dust collector 35, and the dust collection dust slurry S5 is filtered by the dehydrator 12 for solid-liquid separation. The exhaust gas G3 discharged from the cleaning tower 35c of the wet dust collector 35 is returned to an exhaust gas passage such as a preheater attached to the kiln 2 or an outlet of the preheater via an exhaust fan 36.

In the cement manufacturing apparatus 31 shown in FIG. 6, the pellet P obtained by mixing and granulating a carbon source such as heavy oil ash and a chlorine source such as CaCl ₂ using the mixing granulator 6 is cemented via the belt feeder 7. The process of putting in the kiln bottom 2a of the kiln 2 and the process after the dehydrator 12 after passing through the wet chlorine bypass facility 32 are the same as those of the cement manufacturing apparatus 1 shown in FIG. Salts can be recovered in the dryer 16, and lead, gypsum, and iron raw materials can be separated and recovered in the filter press 19. At this time, the chlorine concentration of the dust collected from the extraction gas G1 extracted by the probe 4 is adjusted to 5 to 40% by mass, or the SO ₂ concentration in the gas discharged from the wet chlorine bypass facility 32 is adjusted. It is also possible to improve the volatilization / recovery rate of lead by adjusting the amount of carbon to 1000 ppm to 10000 ppm or adjusting the CaO concentration / Cl concentration of the chlorine bypass dust D2 to 0.1 to 20 This is the same as in the case of the cement manufacturing apparatus 1 in FIG.

DESCRIPTION OF SYMBOLS 1 Cement manufacturing apparatus 2 Cement kiln 2a Kiln bottom 3 Clinker cooler 4 Probe 5 Calciner 6 Mixing granulator 7 Belt feeder 8 Dry chlorine bypass equipment 9 Dust tank 10 Dissolution tank 11 Stirrer tank 12 Dehydrator 13 Waste water treatment apparatus 14 Filtration Separation device 15 COD processing device 16 Spray dryer 17 Mixing and stirring tank 18 Flotation device 19 Filter press 23 Cooling fan 24 Cyclone 25 Cooler 26 Cooling fan 27 Dust collector 29 Exhaust fan 31 Cement production device 32 Wet chlorine bypass equipment 33 Cooling fan 34 Cyclone 35 Wet dust collector 35a Scrubber 35b Circulating liquid tank 35c Cleaning tower 35d Circulating pump 35e Discharge pump 36 Exhaust fan A1-A3 Cold air C Cake D1 Coarse powder D2 Fine powder (chlorine bypass dust)
F Floss G1 Extraction gas G2 Gas G3 Exhaust gas G4 Hot gas L1, L2 Filtrate L3, L4 Drainage P Pellets S1 to S4 Slurry S5 Dust collection dust slurry SI Sink W Water

Claims (6)

A supply device for supplying a substance containing fixed carbon to a section from the middle of the cement kiln to the lowermost cyclone of the preheater attached to the cement kiln;
An extraction probe for extracting a part of combustion gas from the cement kiln exhaust gas flow path from the bottom of the cement kiln to the bottom cyclone;
A dust collector that collects dust contained in the combustion gas extracted by the extraction probe; a dissolution tank that dissolves the dust collected by the dust collector in water;
A dehydrator for dehydrating after adding a sulfurizing agent to the dust dissolved in the dissolution tank;
A heavy metal recovery device for recovering heavy metals from the cake obtained by dehydration by the dehydration device;
A cement production device comprising a salt recovery device for recovering salts from the filtrate obtained by dehydration by the dehydration device ,
Comprising a mixing granulator for mixing and granulating the substance containing fixed carbon and the substance containing chlorine;
A granulated product produced by the mixing granulator is supplied to the section from the middle of the cement kiln to the lowermost cyclone of a preheater attached to the cement kiln by the supply device. A supply device for supplying a substance containing fixed carbon to a section from the middle of the cement kiln to the lowermost cyclone of the preheater attached to the cement kiln;
An extraction probe for extracting a part of combustion gas from the cement kiln exhaust gas flow path from the bottom of the cement kiln to the bottom cyclone;
A wet dust collector that wet-collects dust contained in the combustion gas extracted by the extraction probe; and
A dehydrator for dehydrating after adding a sulfurizing agent to the dust collected by the wet dust collector;
A heavy metal recovery device for recovering heavy metals from the cake obtained by dehydration by the dehydration device;
A cement production device comprising a salt recovery device for recovering salts from the filtrate obtained by dehydration by the dehydration device ,
Comprising a mixing granulator for mixing and granulating the substance containing fixed carbon and the substance containing chlorine;
A granulated product produced by the mixing granulator is supplied to the section from the middle of the cement kiln to the lowermost cyclone of a preheater attached to the cement kiln by the supply device. Supplying a substance containing fixed carbon to the section from the middle of the cement kiln to the lowermost cyclone of the preheater attached to the cement kiln;
Extracting a part of the combustion gas from the cement kiln exhaust gas passage from the bottom of the kiln to the bottom cyclone,
Collecting dust contained in the extracted combustion gas;
Dissolving the collected dust in water;
After adding a sulfurizing agent to the dissolved dust, dehydration,
Recovering heavy metals from the cake obtained by the dehydration,
A cement production method for recovering salts from the filtrate obtained by the dehydration ,
Supplying a granulated product obtained by mixing the substance containing fixed carbon and the substance containing chlorine to a section from the middle of the cement kiln to the lowermost cyclone of the preheater attached to the cement kiln. A method for manufacturing cement. Supplying a substance containing fixed carbon to the section from the middle of the cement kiln to the lowermost cyclone of the preheater attached to the cement kiln;
Extracting a part of the combustion gas from the cement kiln exhaust gas passage from the bottom of the kiln to the bottom cyclone,
Wet dust contained in the extracted combustion gas,
Dehydration after adding a sulfurizing agent to the wet dust collected,
Recovering heavy metals from the cake obtained by the dehydration,
A cement production method for recovering salts from the filtrate obtained by the dehydration ,
Supplying a granulated product obtained by mixing the substance containing fixed carbon and the substance containing chlorine to a section from the middle of the cement kiln to the lowermost cyclone of the preheater attached to the cement kiln. A method for manufacturing cement. The cement manufacturing method according to claim 3 or 4 , wherein a ratio of the CaO concentration to the Cl concentration of the collected dust is adjusted to 0.1 or more and 20 or less. The method for producing cement according to claim 3, 4 or 5 , wherein the SO ₂ concentration in the combustion gas after collecting the dust is adjusted to 1000 ppm or more and 10000 ppm or less with a standard oxygen concentration of 18%. .

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