JP5501694B2 - Fertilizer and method and apparatus for manufacturing the same - Google Patents

Description

  The present invention relates to a fertilizer and a method and apparatus for manufacturing the same, and more particularly to a method for manufacturing a fertilizer containing selenium in a cement manufacturing process.

  Selenium is harmful to the human body if taken in excess, but is also an essential element for the human body and causes deficiencies when taken in low amounts. Since selenium is contained in everyday foods such as meat and vegetables, it usually does not cause deficiency, but the selenium content of vegetables depends on the selenium content of the soil where the vegetables grow. For this reason, there are reports on deficiency in some parts of China, Hokkaido, and other areas that have low selenium content.

  On the other hand, in the cement manufacturing process, as the amount of waste processing increases, the amount of chlorine bypass dust generated also increases, so the chlorine bypass dust that has been washed with water has been desalted and effectively used as a cement raw material. doing. At that time, in order to reduce the selenium concentration in the waste water generated by the water washing process to a safe standard, for example, in the method for treating extracted dust of cement kiln combustion gas described in Patent Document 1, heavy metals are washed after the water washing of the extracted dust. By adding the solid content containing gypsum and selenium produced by the reaction of the sulfuric acid added to recover the coal and the calcium content in the chlorine bypass dust to the cement crushing process, The amount of selenium-removing agent required for wastewater treatment is reduced.

JP 2008-75139 A

  As described above, when the selenium content rate in the soil is high, the selenium content rate of the grown plant is also high and leads to prevention of deficiency. Therefore, a fertilizer having a high selenium content rate is required for soil with a low selenium content rate. . However, according to the fertilizer control law, it is not always easy to obtain fertilizers with a high selenium content rate, such as prohibiting the addition of selenium to fertilizers.

  On the other hand, as described in Patent Document 1, in the cement manufacturing process, the concentration of selenium contained in the chlorine bypass dust is reduced and the amount of the selenium-removing agent required for the wastewater treatment is reduced. There is a drug cost to remove selenium.

  Therefore, the present invention has been made in view of the above problems, and it is possible to easily obtain a fertilizer having a high selenium content rate, and to reduce the addition of a chemical for removing selenium in a cement manufacturing process. The purpose is to make it unnecessary.

  In order to achieve the above object, the present inventors have conducted intensive research, and as a result, when chlorinating dust is washed with water, the selenium contained in the chlorine bypass dust is kept on the filtrate side as much as possible. The present inventors have found that a fertilizer having a high selenium content can be obtained, and have made the present invention.

  That is, the present invention is a fertilizer, and a part of the combustion gas is extracted from the kiln exhaust gas passage from the kiln bottom of the cement kiln to the lowermost cyclone, and the dust in the extracted gas is recovered and washed with water. The dried product obtained by drying the filtrate after washing with water is characterized by containing selenium and potassium chloride.

  Since this fertilizer contains selenium, it can be used effectively for soil with a low selenium content rate, and it is manufactured using the chlorine bypass equipment normally attached to cement manufacturing equipment, so the manufacturing cost is low. Can be suppressed. In addition, in the cement manufacturing process, it is possible to reduce or eliminate the amount of chemicals that have been added to remove selenium from the filtrate after washing with water. Is also connected.

  The content of water-soluble selenium in this fertilizer can be 0.05 mg / kg or more and less than 6 mg / kg. According to this fertilizer, since it contains 0.05 mg / kg or more of water-soluble selenium that will be directly contained in the grown plant, it can be used effectively for soil with a low selenium content rate, and for removing selenium. The use amount of the added drug can be reduced, and the cement manufacturing cost can be reduced accordingly.

  The content of water-soluble selenium in the fertilizer can be 6 mg / kg or more and less than 42 mg / kg. According to this fertilizer, it can be effectively used for soil having a lower selenium content than the above fertilizer, and it is not necessary to add a selenium removal agent that has been used in the conventional cement manufacturing process. Cement production costs can be reduced.

  The content of water-soluble selenium in the fertilizer can be 42 mg / kg or more and 240 mg / kg or less. In order to produce this fertilizer, for example, when chlorine bypass dust is dissolved in water, an acid or an oxidant is added to keep more selenium on the filtrate side, so that more water-soluble selenium than the above fertilizer. A fertilizer with a high content can be obtained.

  Further, the present invention is a fertilizer manufacturing method, wherein a part of combustion gas is extracted from a kiln exhaust gas passage from a kiln bottom of a cement kiln to a lowermost cyclone, and dust in the extracted gas is recovered. The fertilizer containing selenium and potassium chloride is obtained by drying the filtrate after washing with water. According to the present invention, similar to the above-described invention, fertilizer containing selenium can be produced at low cost, and if the chlorine bypass facility is operated, it can be produced continuously, so that stable supply is possible. Is possible.

  Further, the present invention is a fertilizer manufacturing method, wherein a part of combustion gas is extracted from a kiln exhaust gas passage from a kiln bottom of a cement kiln to a lowermost cyclone, and dust in the extracted gas is recovered. The dust and water were mixed, and a chemical for dissolving selenium contained in the dust was added to the water. The slurry after the chemical addition was separated into solid and liquid, and separated by the solid and liquid separation. The liquid phase is dried to obtain a fertilizer containing selenium and potassium chloride. According to the present invention, by adding a chemical for dissolving selenium contained in dust and then solid-liquid separation, more selenium can be recovered, and a fertilizer with a higher selenium content can be obtained. Can do.

Further, the present invention is a fertilizer manufacturing apparatus, a water washing apparatus for washing dust in gas extracted from a kiln exhaust gas flow path from the kiln bottom of a cement kiln to the lowest cyclone, and washing the filtrate processing apparatus for removing undesired substances containing calcium components from the filtrate after washing by water washing device, drying undesired substances filtrate removed comprises calcium content in the aqueous wash filtrate processor, fertilizer characterized in that it comprises a dry product obtained Ru drying apparatus as. By using this apparatus, it becomes possible to keep selenium on the filtrate side, and a fertilizer having a high selenium content rate can be obtained.

  The fertilizer manufacturing apparatus can be provided with a granulating apparatus for granulating the dried product dried by the drying apparatus, whereby a granular fertilizer having a high selenium content can be obtained.

  As described above, according to the present invention, a fertilizer having a high selenium content rate can be easily obtained, and a fertilizer having a different selenium content rate can be provided according to a user's request. It is possible to reduce or eliminate the addition of a chemical for removing selenium in the process.

It is a flowchart which shows 1st Embodiment of the fertilizer manufacturing apparatus concerning this invention. It is a flowchart which shows 2nd Embodiment of the fertilizer manufacturing apparatus concerning this invention. It is a flowchart which shows 3rd Embodiment of the fertilizer manufacturing apparatus concerning this invention.

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

  FIG. 1 shows a first embodiment of a fertilizer manufacturing apparatus according to the present invention. This fertilizer manufacturing apparatus 1 is attached to a cement kiln, and includes a water washing apparatus 2 for washing chlorine bypass dust with water, and a filter after washing with water. A water washing filtrate treatment device 3 for removing unnecessary substances such as heavy metals and calcium from the liquid L1, a drying device 4 for drying the filtrate L7 treated by the water washing filtrate treatment device 3, and a drying device 4 And a granulating apparatus 5 for granulating the dried products D1 and D2.

  The water washing apparatus 2 performs solid-liquid separation into a dissolution tank 12 for dissolving chlorine in the chlorine bypass dust D stored in the tank 11 in the hot water H, and a slurry S1 discharged from the dissolution tank 12 into a cake C1 and a filtrate L1. It is comprised with the filter 13 and the storage tank 14 which stores the filtrate L1 stirring. Chlorine bypass dust D is dust collected from the combustion gas extracted from the kiln exhaust gas flow path from the bottom of the kiln of the cement kiln to the lowermost cyclone. In particular, the coarse powder contained in the extracted gas is separated. This refers to fine powder, but also includes powder that does not separate coarse powder.

The water-washing filtrate treatment apparatus 3 includes a chemical liquid reaction tank 16 (16A to 16C) for removing heavy metals in the filtrate L1 discharged from the storage tank 14, and a slurry L2 discharged from the chemical liquid reaction tank 16 from the cake C2 and the filtrate L3. A filter press 17 for solid-liquid separation, a stirring tank 18 for removing potassium by adding potassium carbonate (K ₂ CO ₃ ) to the filtrate L3 discharged from the filter press 17, and discharging from the stirring tank 18 Filter press 19 for solid-liquid separation of the filtrate L4 into cake C3 and filtrate L5, adjustment tank 20 for adjusting pH by adding hydrochloric acid (HCl) to filtrate L5, and filtrate L6 discharged from adjustment tank 20 And a sand filter 21 that adsorbs and removes heavy metals remaining on the surface.

The chemical reaction tank 16A is provided for adding sodium hydrosulfide (NaSH) to the filtrate L1 to generate lead sulfide (PbS) and thallium sulfide (Tl ₂ S). The chemical reaction tank 16B is provided for reducing the selenium by adding ferrous chloride (FeCl ₂ ) after adjusting the pH by adding hydrochloric acid to the filtrate L1 supplied from the chemical reaction tank 16A. The reason for adding hydrochloric acid is to enhance the reduction effect of ferrous chloride. The chemical reaction tank 16C is provided for adjusting the pH by adding lime milk to the filtrate L1 supplied from the chemical reaction tank 16B. The reason for adjusting the pH is to condense and precipitate the ferrous hydroxide produced by the addition of ferrous chloride.

  The drying device 4 includes a spray dryer 24 for drying the filtrate L7 supplied from the sand filter 21 by the exhaust gas G1 discharged from a clinker cooler (not shown) attached to the cement kiln, and the exhaust gas discharged from the spray dryer 24. The bag filter 25 that collects the dry matter D2 in G2 and the water heater 26 that warms the working water with the exhaust gas G3 of the bag filter 25 and uses it as the hot water H of the dissolution tank 12 are configured.

  The spray dryer 24 includes an atomization device, a hot air introduction device, a drying chamber, a dry powder separation / collection device, an exhaust treatment device, and a product cooling device, which are not shown below. The atomization device sprays the filtrate L7 with a nozzle, and the hot air introduction device is a device that introduces the exhaust gas G1 discharged from the clinker cooler into the drying chamber. In order to control the particle size of the dried products D1 and D2 with the spray dryer 24, the supply liquid amount of hot air (exhaust gas G1), supply liquid concentration, hot air temperature, hot air amount, chamber temperature, exhaust air temperature, nozzle pressure, The droplet average particle size and the like are adjusted as appropriate.

  The granulating device 5 is provided for granulating the dried material D1 discharged from the spray dryer 24 and the dried material D2 from the bag filter 25 to obtain the fertilizer M.

  Next, a method for manufacturing the fertilizer M using the fertilizer manufacturing apparatus 1 having the above configuration will be described with reference to FIG.

  While supplying the chlorine bypass dust D stored in the tank 11 to the dissolution tank 12, the warm water H is supplied to the dissolution tank 12, and the chlorine bypass dust D is dissolved in the warm water H. As a result, water-soluble chlorine contained in the chlorine bypass dust D is dissolved in the hot water H.

  Next, the slurry S1 discharged from the dissolution tank 12 is solid-liquid separated by the filter 13 into the filtrate L1 and the cake C1. The cake C1 from which the chlorine content has been removed is used as a cement raw material.

  On the other hand, the filtrate L1 containing chlorine is supplied to the chemical reaction tank 16A, and sodium hydrosulfide (NaSH) is added as a sulfiding agent to the filtrate L1 in the chemical reaction tank 16A, and lead and thallium in the filtrate L1. Is sulfided to produce lead sulfide and thallium sulfide.

  Next, after supplying the filtrate L1 from the chemical reaction tank 16A to the chemical reaction tank 16B and adjusting the pH to 4 or less by adding hydrochloric acid, ferrous chloride is added to reduce selenium.

  Next, the filtrate L1 is supplied from the chemical reaction tank 16B to the chemical reaction tank 16C, lime milk is added to the filtrate L1 to adjust the pH to 8.0 to 9.0, and then ferrous chloride is added. The ferrous hydroxide produced by is precipitated.

  The filtrate L2 discharged from the chemical solution reaction tank 16C is solid-liquid separated by the filter press 17 into the cake C2 and the filtrate L3. The cake C2 containing heavy metals such as lead sulfide, thallium sulfide and selenium is reused as a cement raw material. On the other hand, the filtrate L3 discharged from the filter press 17 is stored in the stirring tank 18.

  Potassium carbonate is added to the filtrate L3 stored in the stirring tank 18 to remove calcium, and the filtrate L4 is further solid-liquid separated into cake C3 and filtrate L5 by the filter press 19. The cake C3 containing the removed calcium content is reused as a cement raw material or the like. On the other hand, the filtrate L5 discharged from the filter press 19 is stored in the adjustment tank 20.

  In the adjustment tank 20, hydrochloric acid is added to the filtrate L5 to adjust the pH, and the sand filter 21 adsorbs and removes floating solids (SS) remaining in the filtrate L6 discharged from the adjustment tank 20.

  Next, the exhaust gas G1 of about 230 ° C. discharged from the clinker cooler is introduced into the spray dryer 24, and the chamber temperature is adjusted by the hot air temperature and the exhaust air temperature of the spray dryer 24. After each temperature is stabilized, the filtrate L7 from the sand filter 21 (selenium remains in the filtrate L7) is supplied to the spray dryer 24, and the filtrate L7 is sprayed at a predetermined nozzle pressure. And dried with exhaust gas G1.

  The exhaust gas G1 used for drying the filtrate L7 is introduced into the bag filter 25 through the exhaust treatment device of the spray dryer 24, and after solid-gas separation, the working water is heated by the water heater 26, and the obtained hot water H Is used as hot water H in the dissolution tank 12. On the other hand, the dried product D2 collected by the bag filter 25 is supplied to the granulator 5 together with the dried product D1 dried in the air stream by the spray dryer 24. Finally, in the granulating apparatus 5, the fertilizer M can be obtained by granulating the dried product D1 and the dried product D2.

  When the selenium content of the fertilizer M obtained as described above was measured, it was 0.08 to 10 mg / kg, and the content of water-soluble selenium was 0.05 to 6 mg / kg. On the other hand, as a result of measuring the selenium content of commercially available phosphate fertilizers or composite fertilizers using sulfuric acid and phosphoric acid, the total content of selenium is 0.37 mg / kg on average, Since the content rate is 0.0023 mg / kg on average, it can be seen that a fertilizer having a significantly higher selenium content than the commercially available fertilizer can be obtained by the present invention. In particular, since the water-soluble selenium content directly taken into the grown plant is high, it can be suitably used for soil with a low selenium content.

  In this embodiment, selenium is removed to some extent from the filtrate L1, but the selenium remaining in the filtrate L7 after the treatment by the water-washing filtrate treatment apparatus 3 is used, and selenium in the soil is used. Applicable when there is a request that does not become excessive from the user depending on the content.

  In addition, according to the present embodiment, since the fertilizer is manufactured using a cement manufacturing process, the manufacturing cost of the fertilizer can be kept low, and in particular, it is dried using the exhaust gas G1 from the clinker cooler, Since the warm water H for washing treatment is heated using the exhaust gas G2 used for drying, the operating cost can be further reduced. Instead of the exhaust gas G1 from the clinker cooler, the exhaust gas from the uppermost cyclone of the preheater attached to the cement kiln may be cooled and adjusted for temperature.

  Furthermore, according to the present embodiment, since the filtrate L7 is dried in the air stream using the spray dryer 24, the material to be dried is crystallized in the droplets, and the droplets after spraying are in contact with the inner wall of the chamber. There is no adhesion troubles. In addition, since everything in the droplet is crystallized, the sprayed component becomes the fertilizer as it is, and the component variation of the fertilizer is small.

  Next, 2nd Embodiment of the fertilizer manufacturing apparatus concerning this invention is described, referring FIG.

  The fertilizer manufacturing apparatus 31 includes a sedimentation separator 32 instead of the filter press 17 of the fertilizer production apparatus 1 shown in FIG. 1, and includes a filter press 33 on the downstream side of the sedimentation separator 32. About a component, it is the same as that of the fertilizer manufacturing apparatus 1. 2, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those in FIG.

  The sedimentation separator 32 is provided for sedimenting and collecting heavy metals and the like. The illustrated sedimentation separator 32 is a cylindrical type having a mud collecting rake at the bottom of the container, but in addition to this, an inclined plate sedimentation separator having a plurality of separation plates inclined at a predetermined angle can also be used. .

  The filter press 33 is provided for solid-liquid separation of the sediment discharged from the sedimentation separator 32 and using the cake C4 as a cement raw material or the like.

  Next, the method to manufacture the fertilizer M using the fertilizer manufacturing apparatus 31 which has the said structure is demonstrated. In the present embodiment, the process from the dissolution of the chlorine bypass dust D in the dissolution tank 12 to the supply of the filtrate L1 solid-liquid separated by the filter 13 to the chemical reaction tank 16A, and the filter discharged from the sand filter 21. The steps from supplying the liquid L7 to the spray dryer 24 until granulating by the granulating device 5 are the same as those in the first embodiment, but the processing method in the water washing filtrate processing device 3 is different.

  That is, in the present embodiment, hydrochloric acid is added to the chemical reaction tank 16A to adjust the pH, and NaSH or a chelating agent is added to precipitate heavy metals such as lead and thallium. At this time, selenium remains dissolved in the filtrate L1.

Next, the filtrate L1 is supplied from the chemical reaction tank 16A to the chemical reaction tank 16B, and ferric chloride (FeCl ₃ ) is added to aggregate the precipitated heavy metals.

  Further, the filtrate L1 is supplied from the chemical reaction tank 16B to the chemical reaction tank 16C, and a polymer flocculant is added to the filtrate L1 to allow sedimentation and separation of heavy metals in the next step.

  The filtrate L2 discharged from the chemical solution reaction tank 16C is supplied to the sedimentation separator 32, and heavy metals other than selenium are settled and recovered. The sediment containing heavy metals and the like is separated into solid and liquid by a filter press 33 and the cake C4 is used as a cement raw material. On the other hand, the supernatant L3 containing selenium in the sedimentation separator 32 is stored in the stirring tank 18, and the subsequent processing method after the stirring tank 18 is the same as in the first embodiment. Finally, In the granulator 5, the fertilizer M can be obtained by granulating the dried product D1 and the dried product D2.

  When the selenium content of the fertilizer M obtained as described above was measured, it was 6 to 70 mg / kg, and the content of water-soluble selenium was 3.6 to 42 mg / kg. This is because a chemical for removing selenium was not used in removing heavy metals in the water-washed filtrate treatment apparatus 3, and as a result, a fertilizer having a higher selenium content compared to the first embodiment. Can be obtained.

  Moreover, according to this Embodiment, compared with 1st Embodiment, since the chemical | medical agent for removing a selenium is not used, the chemical | medical agent cost can be reduced and it leads also to the reduction of an operating cost.

  Next, 3rd Embodiment of the fertilizer manufacturing apparatus concerning this invention is described, referring FIG.

  This fertilizer manufacturing apparatus 41 has the same apparatus configuration as that of the second embodiment except that hydrochloric acid, nitric acid, hydrogen peroxide solution, sodium hypochlorite, ozone, etc. are added to the dissolution tank 12 of the water washing apparatus 2. The acid or oxidizing agent is added, and more selenium contained in the chlorine bypass dust D is eluted in the hot water H. Thereby, the selenium which melt | dissolves in the filtrate L1 increases, and the fertilizer with a high selenium content rate is obtained by that much.

  When the selenium content of the fertilizer M obtained in this way was measured, it was 70 to 400 mg / kg, and the content of water-soluble selenium was 42 to 240 mg / kg. Thus, in this Embodiment, since more selenium contained in the chlorine bypass dust D was eluted in warm water H, compared with 2nd Embodiment, a selenium content rate can be raised further, Commercial fertilizer It can be seen that a fertilizer having a significantly higher selenium content can be obtained than

  As described above, as described in each embodiment, in the present invention, the chlorine bypass facility attached to the cement manufacturing apparatus is used, and selenium is not removed from the filtrate after washing or the selenium removal rate is suppressed. This makes it possible to provide fertilizers with different selenium contents according to the user's request, and at the same time reduce the amount of chemicals added to remove selenium in the cement manufacturing process, Since it can be made unnecessary, the cement manufacturing cost can be reduced.

DESCRIPTION OF SYMBOLS 1 Fertilizer manufacturing apparatus 2 Water washing apparatus 3 Water washing filtrate processing apparatus 4 Drying apparatus 5 Granulation apparatus 11 Tank 12 Dissolution tank 13 Filter 14 Storage tank 16 (16A-16C) Chemical reaction tank 17 Filter press 18 Stirring tank 19 Filter press 20 Adjustment Tank 21 Sand filter 24 Spray dryer 25 Bag filter 26 Water heater 31 Fertilizer production device 32 Settling separator 33 Filter press 41 Fertilizer production device

Claims (8)

  A part of the combustion gas is extracted from the kiln exhaust gas channel from the kiln bottom of the cement kiln to the bottom cyclone, and the dust in the extracted gas is collected and washed with water, and the filtrate after washing is dried. A fertilizer comprising selenium and potassium chloride.   The fertilizer according to claim 1, wherein the content of water-soluble selenium is 0.05 mg / kg or more and less than 6 mg / kg.   The fertilizer according to claim 1, wherein the content of water-soluble selenium is 6 mg / kg or more and less than 42 mg / kg.   The fertilizer according to claim 1, wherein the content of water-soluble selenium is 42 mg / kg or more and 240 mg / kg or less. A part of the combustion gas is extracted from the kiln exhaust gas flow path from the kiln bottom of the cement kiln to the bottom cyclone,
Dust in the extracted gas is collected and washed with water,
The fertilizer manufacturing method characterized by drying the filtrate after this water washing, and obtaining the fertilizer containing a selenium and potassium chloride. A part of the combustion gas is extracted from the kiln exhaust gas flow path from the kiln bottom of the cement kiln to the bottom cyclone,
Collecting dust in the extracted gas;
Mixing the dust and water, adding a chemical for dissolving selenium contained in the dust in the water,
Solid-liquid separation of the slurry after the addition of the drug,
A method for producing a fertilizer, wherein the liquid phase separated by the solid-liquid separation is dried to obtain a fertilizer containing selenium and potassium chloride. A water washing device for washing dust in the gas extracted from the kiln exhaust gas flow path from the kiln bottom of the cement kiln to the bottom cyclone,
A water washing treatment apparatus for removing unnecessary substances containing calcium from the filtrate after washing with the water washing apparatus;
Aqueous wash filtrate processor dried undesired substances filtrate removed comprises calcium components, the fertilizer production apparatus characterized in that it comprises a resulting Ru drying apparatus dry matter as a fertilizer. The fertilizer manufacturing apparatus according to claim 7 , further comprising a granulating apparatus that granulates the dried product dried by the drying apparatus.

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