JP5201454B2 - Phosphorus recovery material and phosphorus recovery method - Google Patents
Phosphorus recovery material and phosphorus recovery method Download PDFInfo
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- JP5201454B2 JP5201454B2 JP2008143895A JP2008143895A JP5201454B2 JP 5201454 B2 JP5201454 B2 JP 5201454B2 JP 2008143895 A JP2008143895 A JP 2008143895A JP 2008143895 A JP2008143895 A JP 2008143895A JP 5201454 B2 JP5201454 B2 JP 5201454B2
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- calcium silicate
- silicate hydrate
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- 239000011574 phosphorus Substances 0.000 title claims description 213
- 229910052698 phosphorus Inorganic materials 0.000 title claims description 213
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 title claims description 208
- 238000011084 recovery Methods 0.000 title claims description 110
- 239000000463 material Substances 0.000 title claims description 82
- 238000000034 method Methods 0.000 title claims description 45
- 239000000378 calcium silicate Substances 0.000 claims description 67
- 229910052918 calcium silicate Inorganic materials 0.000 claims description 67
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 claims description 62
- 239000011575 calcium Substances 0.000 claims description 47
- 239000002351 wastewater Substances 0.000 claims description 42
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 38
- 238000006243 chemical reaction Methods 0.000 claims description 32
- 239000002245 particle Substances 0.000 claims description 28
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 26
- 239000000843 powder Substances 0.000 claims description 24
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 21
- 229910052588 hydroxylapatite Inorganic materials 0.000 claims description 21
- XYJRXVWERLGGKC-UHFFFAOYSA-D pentacalcium;hydroxide;triphosphate Chemical compound [OH-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O XYJRXVWERLGGKC-UHFFFAOYSA-D 0.000 claims description 21
- 239000000047 product Substances 0.000 claims description 20
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 19
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 19
- 239000000920 calcium hydroxide Substances 0.000 claims description 19
- 235000011116 calcium hydroxide Nutrition 0.000 claims description 19
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 19
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 18
- 229910052791 calcium Inorganic materials 0.000 claims description 18
- 239000002244 precipitate Substances 0.000 claims description 16
- 239000011148 porous material Substances 0.000 claims description 15
- 229910052757 nitrogen Inorganic materials 0.000 claims description 13
- 238000001027 hydrothermal synthesis Methods 0.000 claims description 9
- 238000001556 precipitation Methods 0.000 claims description 8
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 239000004575 stone Substances 0.000 claims description 6
- 238000005054 agglomeration Methods 0.000 claims description 3
- 230000002776 aggregation Effects 0.000 claims description 3
- ABLZXFCXXLZCGV-UHFFFAOYSA-N Phosphorous acid Chemical compound OP(O)=O ABLZXFCXXLZCGV-UHFFFAOYSA-N 0.000 claims 1
- 239000011044 quartzite Substances 0.000 claims 1
- 239000007788 liquid Substances 0.000 description 32
- 230000000052 comparative effect Effects 0.000 description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 19
- 239000002253 acid Substances 0.000 description 17
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 14
- 239000002686 phosphate fertilizer Substances 0.000 description 11
- 239000002994 raw material Substances 0.000 description 11
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 11
- 235000012239 silicon dioxide Nutrition 0.000 description 11
- 239000005416 organic matter Substances 0.000 description 10
- 239000006227 byproduct Substances 0.000 description 9
- 239000010865 sewage Substances 0.000 description 9
- 239000001506 calcium phosphate Substances 0.000 description 8
- 229910000389 calcium phosphate Inorganic materials 0.000 description 8
- 235000011010 calcium phosphates Nutrition 0.000 description 8
- 239000002002 slurry Substances 0.000 description 8
- QORWJWZARLRLPR-UHFFFAOYSA-H tricalcium bis(phosphate) Chemical compound [Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O QORWJWZARLRLPR-UHFFFAOYSA-H 0.000 description 8
- 238000004062 sedimentation Methods 0.000 description 7
- 239000010802 sludge Substances 0.000 description 7
- 238000005345 coagulation Methods 0.000 description 6
- 230000015271 coagulation Effects 0.000 description 6
- 239000013078 crystal Substances 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 150000003017 phosphorus Chemical class 0.000 description 6
- 230000000704 physical effect Effects 0.000 description 6
- 230000009257 reactivity Effects 0.000 description 6
- -1 calcium silicate hydrates Chemical class 0.000 description 5
- 238000002425 crystallisation Methods 0.000 description 5
- 238000000926 separation method Methods 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 4
- 239000003337 fertilizer Substances 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000011381 foam concrete Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000010456 wollastonite Substances 0.000 description 3
- 229910052882 wollastonite Inorganic materials 0.000 description 3
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 2
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 239000003463 adsorbent Substances 0.000 description 2
- 239000001110 calcium chloride Substances 0.000 description 2
- 229910001628 calcium chloride Inorganic materials 0.000 description 2
- 229910001424 calcium ion Inorganic materials 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000000701 coagulant Substances 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000012851 eutrophication Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 2
- 238000005065 mining Methods 0.000 description 2
- MKTRXTLKNXLULX-UHFFFAOYSA-P pentacalcium;dioxido(oxo)silane;hydron;tetrahydrate Chemical compound [H+].[H+].O.O.O.O.[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O MKTRXTLKNXLULX-UHFFFAOYSA-P 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- IVORCBKUUYGUOL-UHFFFAOYSA-N 1-ethynyl-2,4-dimethoxybenzene Chemical compound COC1=CC=C(C#C)C(OC)=C1 IVORCBKUUYGUOL-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 229910014497 Ca10(PO4)6(OH)2 Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000004931 aggregating effect Effects 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- ILRRQNADMUWWFW-UHFFFAOYSA-K aluminium phosphate Chemical compound O1[Al]2OP1(=O)O2 ILRRQNADMUWWFW-UHFFFAOYSA-K 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052586 apatite Inorganic materials 0.000 description 1
- QLULGSLAHXLKSR-UHFFFAOYSA-N azane;phosphane Chemical compound N.P QLULGSLAHXLKSR-UHFFFAOYSA-N 0.000 description 1
- 229940043430 calcium compound Drugs 0.000 description 1
- 150000001674 calcium compounds Chemical class 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003093 cationic surfactant Substances 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004567 concrete Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000004889 fertilizer analysis Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910000398 iron phosphate Inorganic materials 0.000 description 1
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 244000144972 livestock Species 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- VSIIXMUUUJUKCM-UHFFFAOYSA-D pentacalcium;fluoride;triphosphate Chemical compound [F-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O VSIIXMUUUJUKCM-UHFFFAOYSA-D 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000012488 sample solution Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000009849 vacuum degassing Methods 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/10—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in agriculture
- Y02A40/20—Fertilizers of biological origin, e.g. guano or fertilizers made from animal corpses
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- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Removal Of Specific Substances (AREA)
- Silicates, Zeolites, And Molecular Sieves (AREA)
- Fertilizers (AREA)
Description
本発明は、排水等からリンを回収する際に、大型の装置を必要とせず、回収物をリン酸肥料として利用することができるリン回収資材およびリン回収方法に関する。 The present invention relates to a phosphorus recovery material and a phosphorus recovery method that do not require a large apparatus when recovering phosphorus from waste water or the like and can use the recovered material as phosphate fertilizer.
リンは生物にとって必須の元素であり、食料の生産および生命活動を営むためには、欠くことができない貴重な資源である。従来、リンはリン鉱石から得られているが、リン鉱石資源は次第に乏しくなっており、現在の採掘コストでまかなえる品質の良い鉱石の埋蔵量は世界規模で今後約４０年〜５０年に過ぎないと言われており、また採掘コストが数倍かかる地下資源を含めても１００年ほどで枯渇すると予測されている。主要なリン鉱石産出国では、リン鉱石の輸出を規制する動きも実質始まっており、リン資源を全量輸入に頼っているわが国では、リンの再資源化は国家的課題である。 Phosphorus is an essential element for living organisms, and is a valuable resource that is indispensable for food production and life activities. Traditionally, phosphorus has been derived from phosphorus ore, but the resources of phosphorus ore are becoming scarce, and the reserves of high-quality ore that can be covered by the current mining costs are only about 40 to 50 years in the world. In addition, it is predicted that it will be depleted in about 100 years even if it includes underground resources that require several times the mining cost. In major phosphorus ore producing countries, the movement to regulate the export of phosphorus ore has actually started, and in Japan, which relies on imports of all phosphorus resources, the recycling of phosphorus is a national issue.
リン資源はリン鉱石以外にもリン安等の化成品、食料、家畜飼料の形で国内に持ち込まれ、様々な形で利用されているが、リン鉱石の枯渇が懸念される中、リンを回収・再利用することは殆ど行われておらず、使用されたリンの一部は下水、工場排水を通じて排出され、内湾や湖沼など閉鎖性水域に流入して富栄養化の問題を引き起こしている。 In addition to phosphorus ore, phosphorus resources are brought into the country in the form of chemical products such as phosphorus ammonium, food, and livestock feed, and are used in various forms.・ Reuse is rarely done, and some of the phosphorus used is discharged through sewage and factory effluent and flows into closed waters such as inner bays and lakes, causing eutrophication problems.
排水からリンを回収し再利用するシステムを確立することができれば、地球的規模でのリン資源枯渇の問題解決に貢献でき、かつ内湾や湖沼などの富栄養化による環境破壊の防止にも大きな効果が期待できる。 If a system for recovering and reusing phosphorus from wastewater can be established, it can contribute to solving the problem of phosphorus resource depletion on a global scale, and also has a significant effect on preventing environmental destruction by eutrophication of inner bays and lakes. Can be expected.
従来、排水中からリンを除去する方法としては、凝集沈殿法、吸着法、晶析法等が知られている。(イ)凝集沈殿法は、カルシウム、アルミニウム、鉄など、リンと不溶性沈殿を生成する無機凝集剤を排水に添加し、沈殿を分離除去する方法である。(ロ)吸着法は、活性アルミナや水酸化ジルコニウム等のリンを吸着する充填層を設け、そこに処理水を通水してリンを除去する方法である。(ハ) 晶析法は、リン鉱石などリン酸カルシウム系の種結晶を充填させた充填層に、カルシウムイオンを添加した処理水を通水し、種晶表面にリン酸カルシウム（ヒドロキシアパタイト）を晶析させ、リンを除去する方法である。 Conventionally, coagulation precipitation methods, adsorption methods, crystallization methods, and the like are known as methods for removing phosphorus from wastewater. (A) The coagulation sedimentation method is a method in which an inorganic coagulant that forms an insoluble precipitate with phosphorus, such as calcium, aluminum, or iron, is added to waste water, and the precipitate is separated and removed. (B) The adsorption method is a method in which a packed bed for adsorbing phosphorus such as activated alumina or zirconium hydroxide is provided and treated water is passed therethrough to remove phosphorus. (C) In the crystallization method, treated water added with calcium ions is passed through a packed bed filled with calcium phosphate seed crystals such as phosphate ore to crystallize calcium phosphate (hydroxyapatite) on the seed crystal surface. This is a method for removing phosphorus.
凝集沈殿法において、凝集剤としてアルミニウム塩や鉄塩を用いる方法では、生成したリン酸アルミニウム、リン酸鉄が植物に利用されないため、肥料等に再利用するのは困難である。また、凝集剤として消石灰、塩化カルシウム等のカルシウム化合物を用いる方法では、生成するリン酸カルシウムは植物に利用されやすい形態であり、肥料等に再利用するためには好適である。しかし、生成したリン酸カルシウムは微細粒子であるため、濾過や沈降分離などの固液分離操作が面倒であり、生成したケーキの含水率が高くハンドリングが困難であるという問題がある。また、下水など有機物を多く含む排水からリンを回収する場合、有機物がリン酸カルシウムの沈殿とともに共沈するため生成物の純度が低く、回収物を肥料取締法で定められた副産りん酸肥料（ク溶性りん酸１５％以上、全窒素１％未満）として一般的な肥料の流通ルートにのせて販売することはきわめて難しい。 In the coagulation-precipitation method, in the method using an aluminum salt or iron salt as a coagulant, the produced aluminum phosphate and iron phosphate are not used in plants, and thus it is difficult to reuse them as fertilizers. Moreover, in the method using calcium compounds such as slaked lime and calcium chloride as a flocculant, the generated calcium phosphate is in a form that can be easily used by plants, and is suitable for reuse in fertilizers and the like. However, since the produced calcium phosphate is fine particles, solid-liquid separation operations such as filtration and sedimentation separation are troublesome, and there is a problem that the moisture content of the produced cake is high and handling is difficult. In addition, when recovering phosphorus from wastewater containing a large amount of organic matter such as sewage, the purity of the product is low because the organic matter co-precipitates with the precipitation of calcium phosphate. It is extremely difficult to sell it on a general fertilizer distribution route as soluble phosphoric acid (15% or more, less than 1% total nitrogen).
吸着法は、吸着剤が高価であると云う難点があるばかりでなく、リンを再利用するためには、吸着剤からリンを脱離し、それを他の手段で回収するという手間がかかるため、リンの再利用という観点からは不向きである。 The adsorption method not only has the disadvantage that the adsorbent is expensive, but in order to reuse phosphorus, it takes time and effort to desorb phosphorus from the adsorbent and recover it by other means. It is not suitable from the viewpoint of reusing phosphorus.
晶析法は、純度の高いリン酸カルシウムを得ることができるが、新たな核を発生することなく結晶成長させるための過飽和領域がヒドロキシアパタイトの場合はごく狭いため、カルシウム濃度とｐＨ条件のコントロールが非常に難しい。さらに、晶析法の場合は凝集沈殿法に比べて結晶成長速度を緩やかにする必要があるので多量の種晶を充填槽にホールドアップしなければならず、装置設備に多大なコストを要するばかりでなく、循環水量の増大によるランニングコストも高くなり、排水の処理方法としては好ましい方法とはいえない。 The crystallization method can obtain high-purity calcium phosphate, but since the supersaturated region for crystal growth without generating new nuclei is very narrow in the case of hydroxyapatite, the control of the calcium concentration and pH conditions is extremely limited. It is difficult. Furthermore, in the case of the crystallization method, it is necessary to slow the crystal growth rate compared to the coagulation sedimentation method, so a large amount of seed crystals must be held up in the filling tank, and the equipment costs much. In addition, the running cost due to an increase in the amount of circulating water also increases, and it cannot be said that it is a preferable method for treating waste water.
これら従来の方法を解決する手段として、珪酸カルシウムを主成分とする脱リン剤を使う方法が種々提案されている。例えば、特開昭６１−２６３６３６号公報（特許文献１）にはＣａＯ/ＳｉＯ2モル比が１.５〜５の範囲内にある珪酸カルシウム水和物を主成分とする水処理剤が記載されている。また、特公平２−２０３１５号公報（特許文献２）には空隙率５０〜９０％の独立気泡を有する珪酸カルシウム水和物からなる脱リン材が記載されている。特開平１０−２３５３４４号公報（特許文献３）には珪酸カルシウム水和物を主成分とした直径数ミリ程度の球状または中空状に成形した脱リン材が記載されている。さらに、特開２０００−１３５４９３号公報（特許文献４）には珪灰石を用いた脱リン方法が提案されている。
従来の珪酸カルシウムを主成分とする脱リン材を用いる処理方法は、回収物の脱水性や有機物混入の問題はある程度回避できるものの、リンとの反応速度が遅いため、回収物のリン濃度を上げるためには長い反応時間を必要とする。また、回収されるリン含有物はク溶性リン酸の含有量が１５％に満たないため、肥料取締法で定める副産りん酸肥料に該当せず、リン酸肥料として利用することができない。ク溶性リン酸の含有量を１５％以上に高めるには処理装置の容積を大きくする必要があり、コストアップを招くため実用的ではない。 The conventional treatment method using a dephosphorization material mainly composed of calcium silicate can avoid the problems of dehydration and organic matter contamination of the recovered material to some extent, but the reaction rate with phosphorus is slow, so the phosphorus concentration of the recovered material is increased. This requires a long reaction time. Moreover, since the content of phosphorus contained in the recovered phosphorus is less than 15%, it does not fall under the by-product phosphate fertilizer defined by the Fertilizer Control Law and cannot be used as phosphate fertilizer. In order to increase the content of the soluble phosphoric acid to 15% or more, it is necessary to increase the volume of the processing apparatus, which increases the cost, and is not practical.
本発明は、従来のリン回収資材およびリン回収方法における上記問題を解決したものであり、排水等からリンを回収する際に、大型の装置を必要とせず、回収物を副産りん酸肥料として利用することができるリン回収資材およびリン回収方法を提供する。 The present invention solves the above-mentioned problems in conventional phosphorus recovery materials and phosphorus recovery methods, and does not require a large apparatus when recovering phosphorus from wastewater or the like, and the recovered product is used as a by-product phosphate fertilizer. Provided are phosphorus recovery materials and phosphorus recovery methods that can be used.
本発明は、以下に示す構成によって上記課題を解決したリン回収資材とリン回収方法に関する。
〔１〕凝集沈殿用のリン回収資材であり、非晶質シリカ粉と消石灰または珪石粉末と消石灰の水熱反応によって生成した多孔質の珪酸カルシウム水和物からなり、平均粒子径(メジアン径)１０μｍ以上〜１５０μｍ以下、細孔容積０.３cm 3 /ｇ以上、嵩密度０.１ｇ/cm 3 以上〜０.７ｇ/cm 3 以下、Ｃａ/Ｓｉモル比０.４以上〜１.５以下であることによって、回収物のク溶性リン酸が１５％以上および全窒素が１％未満になることを特徴とするリン回収資材。
〔２〕非晶質シリカ粉と消石灰または珪石粉末と消石灰の水熱反応によって生成した多孔質の珪酸カルシウム水和物からなり、平均粒子径(メジアン径)１０μｍ以上〜１５０μｍ以下、細孔容積０.３cm 3 /ｇ以上、嵩密度０.１ｇ/cm 3 以上〜０.７ｇ/cm 3 以下、Ｃａ/Ｓｉモル比０.４以上〜１.５以下である請求項１に記載するリン回収資材を用い、
反応終了時の排水のｐＨが５.０以上〜９.０未満の範囲で、
排水中のリン含有量に対して、Ｃａ／Ｐモル比が１.５以上〜２.５以下になる量のリン回収資材を排水に添加し、
１０℃以上〜１００℃未満の温度にし、
排水に含まれるリン酸によって珪酸カルシウム水和物を逐次的に分解させてカルシウムを溶出させ、該排水中のリンと反応させて珪酸カルシウム水和物粒子表面にヒドロキシアパタイトを生成せしめ、凝集沈殿物を分離してリンを回収することを特徴とするリン回収方法。
The present invention relates to a phosphorus recovery material and a phosphorus recovery method that have solved the above problems with the following configurations.
[1] Phosphorus recovery material for agglomeration and precipitation, consisting of porous calcium silicate hydrate produced by hydrothermal reaction of amorphous silica powder and slaked lime or silica stone powder and slaked lime, with average particle diameter (median diameter) 10μm or ~150μm less, a pore volume of 0.3 cm 3 / g or more, a bulk density of 0.1 g / cm 3 or more ~0.7g / cm 3 or less, Ca / Si molar ratio of 0.4 or more to 1.5 or less A phosphorus recovery material characterized in that the recovered product has a soluble phosphoric acid content of 15% or more and total nitrogen content of less than 1% .
[2] A porous calcium silicate hydrate formed by hydrothermal reaction of amorphous silica powder and slaked lime or silica stone powder and slaked lime, with an average particle diameter (median diameter) of 10 μm to 150 μm and a pore volume of 0 .3cm 3 / g or more, a bulk density of 0.1 g / cm 3 or more ~0.7g / cm 3 or less, the phosphorus recovery material according to claim 1 Ca / Si molar ratio of 0.4 or more to 1.5 or less Use
The pH of the waste water at the end of the reaction is in the range of 5.0 to less than 9.0,
Add phosphorus recovery material to the wastewater in such an amount that the Ca / P molar ratio is 1.5 to 2.5 with respect to the phosphorus content in the wastewater.
The temperature is set to 10 ° C or higher and lower than 100 ° C,
The calcium silicate hydrate is sequentially decomposed by phosphoric acid contained in the waste water to elute calcium, react with the phosphorus in the waste water to generate hydroxyapatite on the surface of the calcium silicate hydrate particles, and aggregate precipitate The phosphorus collection | recovery method characterized by isolate | separating and collect | recovering phosphorus.
また、本発明は以下に示す構成からなるリン回収方法に関する。
〔６〕リン含有排水に珪酸カルシウム水和物を添加してリンを凝集沈殿させて回収する方法において、酸を添加して該排水のｐＨを酸性側にし、珪酸カルシウム水和物の逐次的な分解でカルシウムを溶出させ、該排水中のリンと反応させて珪酸カルシウム水和物粒子表面にヒドロキシアパタイトを生成せしめ、凝集沈殿物を分離してリンを回収することを特徴とするリン回収方法。
〔７〕平均粒子径(メジアン径)１５０μm以下の微粉末であり、細孔容積０.３cm3/ｇ以上である多孔質の珪酸カルシウム水和物からなるリン回収資材を用いる上記[６]に記載するリン回収方法。
〔８〕上記[６]または上記[７]のリン回収方法において、反応終了時のｐＨが５.０以上〜９.０未満になるように酸を添加するリン回収方法。
〔９〕排水中のリン含有量に対して、Ｃａ／Ｐモル比が１.５以上〜２.５以下になるようにリン回収資材を添加する上記[６]〜[８]の何れかに記載するリン回収方法。
〔１０〕処理温度が１０℃以上〜１００℃未満である上記[６]〜上記[９]の何れかに記載するリン回収方法。
Moreover, this invention relates to the phosphorus collection | recovery method which consists of a structure shown below.
[6] In a method of adding calcium silicate hydrate to phosphorus-containing wastewater and aggregating and recovering phosphorus, the acid is added to bring the pH of the wastewater to the acidic side. A phosphorus recovery method characterized in that calcium is eluted by decomposition and reacted with phosphorus in the waste water to form hydroxyapatite on the surface of calcium silicate hydrate particles, and the aggregated precipitate is separated to recover phosphorus.
[7] In the above [6], a phosphorus recovery material consisting of porous calcium silicate hydrate having an average particle diameter (median diameter) of 150 μm or less and a pore volume of 0.3 cm 3 / g or more is used. The phosphorus recovery method described.
[8] The phosphorus recovery method according to [6] or [7], wherein an acid is added so that the pH at the end of the reaction is 5.0 or more and less than 9.0.
[9] The phosphorus recovery material is added so that the Ca / P molar ratio is 1.5 or more and 2.5 or less with respect to the phosphorus content in the waste water. The phosphorus recovery method described.
[10] The phosphorus recovery method according to any one of [6] to [9] above, wherein the treatment temperature is 10 ° C. or higher and lower than 100 ° C.
本発明のリン回収資材は、従来の資材とは異なり、極めて多孔性の高い珪酸カルシウム水和物の微粉末であるため、リンとの反応性が高く、珪酸カルシウム水和物から供給されるカルシウムと反応して速やかにヒドロキシアパタイトを生成し、排水中のリン濃度を急激に低減することができる。 Unlike the conventional materials, the phosphorus recovery material of the present invention is a highly porous calcium silicate hydrate fine powder, so it has high reactivity with phosphorus and is supplied from calcium silicate hydrate. It reacts quickly with it to produce hydroxyapatite, and the phosphorus concentration in the waste water can be drastically reduced.
本発明のリン回収資材はリンとの反応性が高いので、ヒドロキシアパタイト（リン酸カルシウム）が多く、また沈殿物は排水中の有機物の巻き込み少ないため、ク溶性リン酸量１５％以上、全窒素量１％未満のリン含有沈澱物を回収することができ、これは副産りん酸肥料の条件を満たすので、有効に利用することができる。 Since the phosphorus recovery material of the present invention is highly reactive with phosphorus, it contains a large amount of hydroxyapatite (calcium phosphate), and the precipitate contains less organic matter in the wastewater, so that the amount of soluble phosphoric acid is 15% or more and the total amount of nitrogen is 1 % Phosphorus-containing precipitates can be recovered, which meets the conditions of by-product phosphate fertilizer and can be used effectively.
本発明のリン回収資材を用いて回収した沈殿物は含水率が低いので取扱性がよい。さらに、本発明のリン回収資材はリンとの反応性が高いので、短時間に処理することができ、処理槽の容量も小型化することができる。 The precipitate recovered using the phosphorus recovery material of the present invention has a low water content and thus has good handleability. Furthermore, since the phosphorus collection | recovery material of this invention has high reactivity with phosphorus, it can process in a short time and the capacity | capacitance of a processing tank can also be reduced in size.
以下、本発明を実施形態に基づいて具体的に説明する。なお、％は単位固有の場合を除き質量％である。 Hereinafter, the present invention will be specifically described based on embodiments. In addition,% is mass% except the case intrinsic | native to a unit.
〔リン回収資材〕
本発明のリン回収資材は、凝集沈殿用のリン回収資材であり、非晶質シリカ粉と消石灰または珪石粉末と消石灰の水熱反応によって生成した多孔質の珪酸カルシウム水和物からなり、平均粒子径(メジアン径)１０μｍ以上〜１５０μｍ以下、細孔容積０.３cm 3 /ｇ以上、嵩密度０.１ｇ/cm 3 以上〜０.７ｇ/cm 3 以下、Ｃａ/Ｓｉモル比０.４以上〜１.５以下であることによって、回収物のク溶性リン酸が１５％以上および全窒素が１％未満になることを特徴とするリン回収資材である。
[Phosphorus recovery materials]
The phosphorus collection material of the present invention is a phosphorus collection material for agglomeration and precipitation, and is composed of porous calcium silicate hydrate produced by a hydrothermal reaction between amorphous silica powder and slaked lime or silica stone powder and slaked lime, and has an average particle size diameter (median diameter) 10 [mu] m or more ~150μm less, a pore volume of 0.3 cm 3 / g or more, a bulk density of 0.1 g / cm 3 or more ~0.7g / cm 3 or less, Ca / Si molar ratio of 0.4 or more and By being 1.5 or less, it is a phosphorus collection | recovery material characterized by 15% or more of the soluble phosphoric acid of collection | recovery, and less than 1% of total nitrogen .
本発明のリン回収資材は、好ましくは、平均粒子径１０μｍ以上〜１５０μｍ以下、嵩密度０.１ｇ/cm3以上〜０.７ｇ/cm3以下、Ｃａ/Ｓｉモル比０.４以上〜１.５以下であり、ク溶性リン酸１５％以上および全窒素１％未満の沈殿物を回収することができるリン回収資材である。 Phosphorus recovery material of the present invention, preferably, the average particle diameter of 10μm or more ~150μm less, a bulk density of 0.1 g / cm 3 or more ~0.7g / cm 3 or less, Ca / Si molar ratio of 0.4 or more to 1. It is a phosphorus recovery material that is 5 or less, and can collect precipitates of 15% or more of soluble phosphoric acid and less than 1% of total nitrogen.
本発明において、リン回収資材の珪酸カルシウム水和物は水中のリンと反応して一般式〔Ｃａ10(ＰＯ4)6(ＯＨ)2〕によって表される難溶性のリン酸カルシウム（ヒドロキシアパタイト）を生成するので、この沈殿物を排水から分離することによってリンを排水から回収することができる。 In the present invention, calcium silicate hydrate, a phosphorus recovery material, reacts with phosphorus in water to form poorly soluble calcium phosphate (hydroxyapatite) represented by the general formula [Ca 10 (PO 4 ) 6 (OH) 2 ] Thus, phosphorus can be recovered from the wastewater by separating the precipitate from the wastewater.
本発明のリン回収資材の粒径は、リンの回収効率を高め、濾過性および沈降性の良い回収物を得るためには、平均粒径(メジアン径)が１５０μm以下の微粉末が好ましい。平均粒径が１５０μmより大きいと、液との接触面積が低下し、リンとの反応性が低下する。なお、平均粒径が１０μmより小さいと濾過性および沈降性が低下し、リン回収後の固液分離が難しくなる傾向があるので、反応性と共に濾過性のよいリン回収資材を得るには平均粒径１０μm以上が好ましい。 The particle diameter of the phosphorus recovery material of the present invention is preferably a fine powder having an average particle diameter (median diameter) of 150 μm or less in order to increase the recovery efficiency of phosphorus and obtain a recovered product with good filterability and sedimentation. When the average particle size is larger than 150 μm, the contact area with the liquid decreases and the reactivity with phosphorus decreases. Note that if the average particle size is smaller than 10 μm, the filterability and sedimentation properties tend to be reduced, and solid-liquid separation after phosphorus recovery tends to be difficult. A diameter of 10 μm or more is preferable.
さらに、本発明のリン回収資材は細孔容積０.３cm3/ｇ以上の高多孔質性の珪酸カルシウム水和物である。細孔容積が０.３cm3/ｇ未満ではリンとの反応性が十分ではない。この細孔容積に関連して、本発明のリン回収資材は、好ましくは、嵩密度０.１ｇ/cm3以上〜０.７ｇ/cm3以下のものがよい。嵩密度は多孔質度が高いほど低く、嵩密度が０.７ｇ/cm3より大きいと多孔性が不十分であり、リンとの反応性が低くなる。一方、嵩密度が０.７ｇ/cm3より小さいものはリンとの十分な反応速度を有する。ただし、嵩密度が０.１ｇ/cm3より小さいと濾過性（脱水性）が劣るので、濾過性のよいリン回収資材を得るには嵩密度は０.１ｇ/cm3以上〜０.７ｇ/cm3以下が好ましい。 Furthermore, the phosphorus recovery material of the present invention is a highly porous calcium silicate hydrate having a pore volume of 0.3 cm 3 / g or more. When the pore volume is less than 0.3 cm 3 / g, the reactivity with phosphorus is not sufficient. In connection with this pore volume, phosphorus recovery material of the present invention preferably has a bulk density of 0.1 g / cm 3 or more ~0.7g / cm 3 is good or less. The higher the degree of porosity, the lower the bulk density. When the bulk density is greater than 0.7 g / cm 3 , the porosity is insufficient and the reactivity with phosphorus is low. On the other hand, those having a bulk density of less than 0.7 g / cm 3 have a sufficient reaction rate with phosphorus. However, if the bulk density is less than 0.1 g / cm 3 , the filterability (dehydration) is inferior. Therefore, in order to obtain a phosphorus recovery material with good filterability, the bulk density is 0.1 g / cm 3 or more to 0.7 g / cm 3 or less is preferred.
本発明のリン回収資材は、平均粒子径１５０μm以下の微粉末であって、細孔容積０.３cm3/ｇ以上、好ましくは嵩密度０.１ｇ/cm3以上〜０.７ｇ/cm3以下であり、従来の軽量気泡コンクリートや造粒成形した珪酸カルシウム水和物よりも多孔質であるので、液中のリンとの反応速度が速く、珪酸カルシウム水和物から供給されたカルシウムと排水中のリンが速やかに反応してヒドロキシアパタイトが生成し、短時間で排水中のリンを沈澱化することができる。 Phosphorus recovery material of the present invention is a fine powder of less than or equal to the average particle diameter of 150 [mu] m, pore volume 0.3 cm 3 / g or more, preferably bulk density 0.1 g / cm 3 or more ~0.7g / cm 3 or less Because it is more porous than conventional lightweight cellular concrete or granulated and molded calcium silicate hydrate, the reaction rate with phosphorus in the liquid is faster, and the calcium supplied from calcium silicate hydrate and wastewater This phosphorus reacts promptly to produce hydroxyapatite, and phosphorus in the waste water can be precipitated in a short time.
また、本発明のリン回収資材は、珪酸カルシウム水和物のカルシウムとケイ素のモル比（Ｃａ/Ｓｉ）が０.４〜１.５であるものが好ましく、０.８〜１.２のモル比がより好ましい。Ｃａ/Ｓｉモル比が１.５より大きいとリンの回収率が低下する。Ｃａ/Ｓｉモル比が０.４未満では回収物のヒドロキシアパタイトの含量が低下し、ク溶性リン酸量を１５％以上に高めるのが難しくなる。 In addition, the phosphorus recovery material of the present invention preferably has a calcium / silicon molar ratio (Ca / Si) of 0.4 to 1.5, preferably 0.8 to 1.2 mol. A ratio is more preferred. If the Ca / Si molar ratio is greater than 1.5, the phosphorus recovery rate decreases. When the Ca / Si molar ratio is less than 0.4, the content of hydroxyapatite in the recovered product is lowered, making it difficult to increase the amount of soluble phosphoric acid to 15% or more.
本発明のリン回収資材によれば、リンとの反応速度が速いため、排水に投入後１〜２時間という短時間で回収物のリン酸含有量を１５％以上に高めることができる。さらに、下水など有機性排水を対象とした場合でも、回収物は有機物の巻き込みが少ないため、全窒素を１％未満とすることができ、副産りん酸肥料の条件に適する回収物を得ることができる。 According to the phosphorus collection | recovery material of this invention, since the reaction rate with phosphorus is quick, the phosphoric acid content of a collection | recovery can be raised to 15% or more in a short time of 1 to 2 hours after throwing into waste_water | drain. Furthermore, even when organic wastewater such as sewage is targeted, the collected material contains less organic matter, so the total nitrogen can be reduced to less than 1%, and a recovered material suitable for the conditions of by-product phosphate fertilizer is obtained. Can do.
本発明のリン回収資材において、ヒドロキシアパタイトの生成に必要なカルシウムは、他からカルシウムを添加することなく、珪酸カルシウム水和物のリン酸による逐次的な分解によって供給されるので、液中のカルシウムの初期濃度は低く、ヒドロキシアパタイトの過飽和度も液全体としては低い状態が維持される。 In the phosphorus recovery material of the present invention, calcium necessary for the production of hydroxyapatite is supplied by sequential decomposition of calcium silicate hydrate with phosphoric acid without adding calcium from other sources. The initial concentration of is low, and the supersaturation degree of hydroxyapatite is kept low as a whole liquid.
さらに、珪酸カルシウム水和物の分解にともなって、カルシウムイオンが多孔質の細孔を通じて粒子表面に供給されるため、ヒドロキシアパタイトの結晶化は珪酸カルシウム水和物粒子の表面のみで起こる。そのため、凝集沈殿法のカルシウム源として本発明の珪酸カルシウム水和物を用いると、該水和物表面にヒドロキシアパタイトが堆積し、微細なヒドロキシアパタイト粒子が液中に遊離することなく、従って、濾過性および沈降性の良いケーキを得ることができる。 Furthermore, as calcium silicate hydrate is decomposed, calcium ions are supplied to the particle surface through porous pores, so that crystallization of hydroxyapatite occurs only on the surface of the calcium silicate hydrate particles. Therefore, when the calcium silicate hydrate of the present invention is used as a calcium source for the coagulation precipitation method, hydroxyapatite is deposited on the surface of the hydrate, and fine hydroxyapatite particles are not released in the liquid. Cake having good property and sedimentation can be obtained.
一方、従来の凝集沈殿法において、消石灰や塩化カルシウムなどのカルシウム溶解度の高い化合物を用いた場合は、これらを投入した直後に液中のカルシウム濃度は非常に高いレベルに達するため、リン酸イオンと瞬時に反応してヒドロキシアパタイトの過飽和度は非常に高まり、液中にヒドロキシアパタイトの微細結晶が遊離して多数生成する。そのため、生成したケーキは濾過性に劣り、固液分離が困難になる。また、含水率が高いだけでなく、下水処理場の処理水のように有機物を多量に含有している場合は、有機物と共沈するため回収物の純度が低くなる。 On the other hand, when a compound with high calcium solubility such as slaked lime or calcium chloride is used in the conventional coagulation sedimentation method, the calcium concentration in the solution reaches a very high level immediately after the addition of these, so phosphate ions and It reacts instantaneously and the supersaturation degree of hydroxyapatite is greatly increased, and a large number of hydroxyapatite fine crystals are liberated in the liquid. Therefore, the produced cake is inferior in filterability, and solid-liquid separation becomes difficult. Moreover, not only has a high water content, but also contains a large amount of organic matter such as treated water in a sewage treatment plant, the purity of the recovered product is lowered because it co-precipitates with the organic matter.
また、本発明の珪酸カルシウム水和物と異なる軽量気泡コンクリート、珪灰石、造粒成形した珪酸カルシウム水和物などを用いた場合にも、排水中のリンをヒドロキシアパタイトとして回収することができるが、これらの珪酸カルシウム水和物は多孔性に劣り、排水中のリンと反応する表面積が小さいため、反応速度が遅い。 In addition, even when lightweight cellular concrete, wollastonite, granulated calcium silicate hydrate, etc., which are different from the calcium silicate hydrate of the present invention are used, phosphorus in waste water can be recovered as hydroxyapatite. These calcium silicate hydrates are inferior in porosity and have a low reaction rate because they have a small surface area that reacts with phosphorus in the waste water.
例えば、軽量気泡コンクリートはトバモライトを主体とした珪酸カルシウム化合物中に独立気泡を多く含む性状であって連続気泡を持たないため、生成した多孔質体の多孔性が劣り、全細孔容積は０.２cm3/ｇ程度である。また、造粒成形した珪酸カルシウム水和物は連続気泡を持つが、全細孔容積は０.２cm3/ｇ程度である。従って、これらの珪酸カルシウム水和物はリンとの反応速度が遅く、リンを回収するための時間が長くかかるため、これらの珪酸カルシウム水和物を用いて凝集沈殿法を行なうことは実際的ではない。 For example, lightweight aerated concrete is a property containing many closed cells in a calcium silicate compound mainly composed of tobermorite and does not have open cells, so the porosity of the produced porous body is inferior and the total pore volume is 0. It is about 2 cm 3 / g. The granulated and molded calcium silicate hydrate has open cells, but the total pore volume is about 0.2 cm 3 / g. Therefore, since these calcium silicate hydrates have a slow reaction rate with phosphorus and it takes a long time to recover phosphorus, it is not practical to perform a coagulation precipitation method using these calcium silicate hydrates. Absent.
本発明のリン回収資材として用いる珪酸カルシウム水和物は結晶質でもよく、非晶質でもよい。例えば、珪酸原料と石灰原料とを水性スラリーとしたものをオートクレーブ中において水熱反応を行なって合成した一般的によく知られている珪酸カルシウム水和物を好適に用いることができる。珪酸原料が非晶質の形態であれば、１００℃未満の温度で合成することも可能である。その種類としては、珪酸カルシウム水和物であれば特に限定されず、例えば、トバモライトなどの結晶質珪酸カルシウム、あるいは非晶質珪酸カルシウムなど何れの珪酸カルシウムを用いることができる。これらは単独で用いても良いし、２種以上を組み合わせて用いても良い。 The calcium silicate hydrate used as the phosphorus recovery material of the present invention may be crystalline or amorphous. For example, a generally well-known calcium silicate hydrate synthesized by hydrothermal reaction of an aqueous slurry of a silicic acid raw material and a lime raw material in an autoclave can be suitably used. If the silicic acid raw material is in an amorphous form, it can be synthesized at a temperature of less than 100 ° C. The type is not particularly limited as long as it is a calcium silicate hydrate. For example, any calcium silicate such as crystalline calcium silicate such as tobermorite or amorphous calcium silicate can be used. These may be used alone or in combination of two or more.
本発明のリン回収資材として用いる平均粒径１５０μm以下、および細孔容積０.３cm3/ｇ以上、好ましくは嵩密度０.１ｇ/cm3以上〜０.７ｇ/cm3以下の珪酸カルシウム水和物を得るためには、珪酸原料の性質に応じ、Ｃａ/Ｓｉモル比、反応温度、時間などの反応条件を適宜制御して製造すればよい。特に多孔質度の高い珪酸カルシウム水和物を得るためには、珪酸とカルシウムの反応を進めることが肝要で、珪酸原料の性質に応じて反応温度と時間を適宜制御する必要がある。 The average particle diameter of 150μm or less, and the pore volume 0.3 cm 3 / g or more, preferably bulk density 0.1 g / cm 3 or more ~0.7g / cm 3 or less of calcium silicate hydrate for use as phosphorus recovery material of the present invention In order to obtain a product, the reaction conditions such as the Ca / Si molar ratio, the reaction temperature, and the time may be appropriately controlled according to the properties of the silicic acid raw material. In particular, in order to obtain a calcium silicate hydrate having a high degree of porosity, it is important to advance the reaction between silicic acid and calcium, and it is necessary to appropriately control the reaction temperature and time according to the properties of the silicic acid raw material.
〔リン回収方法〕
本発明のリン回収資材を用いたリン回収方法において、リン回収資材を添加するリン含有排水のｐＨがアルカリ性であると、ヒドロキシアパタイトの生成が遅くなる。本発明のリン回収資材は、他からカルシウムを添加することなく、該排水に含まれるリン酸による珪酸カルシウム水和物の逐次的な分解によってカルシウムを溶出させ、このカルシウムと排水に含まれるリンの反応によって珪酸カルシウム水和物の表面にヒドロキシアパタイトを生成させる。従って、処理液のｐＨがアルカリ性側である場合には、他の酸、例えば塩酸、硫酸、硝酸等の無機酸、酢酸などの有機酸を添加してｐＨを酸性側にすることにより、珪酸カルシウム水和物の逐次的な分解を促進させるのが良い。
[Phosphorus recovery method]
In the phosphorus recovery method using the phosphorus recovery material of the present invention, when the pH of the phosphorus-containing wastewater to which the phosphorus recovery material is added is alkaline, the production of hydroxyapatite is delayed. The phosphorus recovery material of the present invention elutes calcium by sequential decomposition of calcium silicate hydrate with phosphoric acid contained in the waste water without adding calcium from the other, and the phosphorus contained in the calcium and waste water. Hydroxyapatite is produced on the surface of calcium silicate hydrate by the reaction. Therefore, when the pH of the treatment solution is on the alkaline side, calcium silicate can be obtained by adding another acid, for example, an inorganic acid such as hydrochloric acid, sulfuric acid or nitric acid, or an organic acid such as acetic acid to make the pH acidic. It is desirable to promote the sequential decomposition of the hydrate.
酸を添加する場合には、反応終了時のｐＨが５.０以上〜９.０以下になる添加量が好ましい。酸を過剰に添加してｐＨが５.０より低くなると、ヒドロキシアパタイトよりも溶解度の高いＣａＨＰＯ4・２Ｈ2Ｏの安定域に入るため、リンの回収率が低下する。酸の添加量が不足してｐＨが９.０を上回ると、珪酸カルシウム水和物からのカルシウムの溶出が不十分となり、この場合もリンの回収率が十分に向上しない。排水の種類によっては、含有される塩類の影響により、同量の酸を添加しても反応開始前のｐＨは大きく変動する。反応終了時のｐＨが５.０以上〜９.０以下になるように、添加する酸の量を適宜加減することが肝要である。 In the case of adding an acid, the addition amount is preferably such that the pH at the end of the reaction is 5.0 or more and 9.0 or less. If the acid is added excessively and the pH is lower than 5.0, the recovery rate of phosphorus is lowered because CaHPO 4 .2H 2 O, which has higher solubility than hydroxyapatite, enters the stable region. When the amount of acid added is insufficient and the pH exceeds 9.0, elution of calcium from the calcium silicate hydrate becomes insufficient, and in this case, the phosphorus recovery rate is not sufficiently improved. Depending on the type of wastewater, the pH before the start of the reaction varies greatly even when the same amount of acid is added due to the influence of the contained salts. It is important to appropriately adjust the amount of acid to be added so that the pH at the end of the reaction is 5.0 or more and 9.0 or less.
排水に対して添加する本発明のリン回収資材の量は、排水中に含まれるリンに対するリン回収資材中のカルシウムのモル比（添加モル比、Ｃａ/Ｐ）が１.５以上〜２.５以下の範囲に入るように定めることが望ましい。この添加モル比が２.５を上回ると未反応の珪酸カルシウム化合物が残留し、アパタイトの生成量が不十分となるため、回収物中のリン含有量が低下する。一方、添加モル比が１.５より低いとリンの溶解度が高くなり、十分な回収率が得られなくなる。 The amount of the phosphorus recovery material of the present invention added to the waste water is such that the molar ratio of calcium in the phosphorus recovery material to phosphorus contained in the waste water (addition molar ratio, Ca / P) is 1.5 or more to 2.5. It is desirable to set it within the following range. When this addition molar ratio exceeds 2.5, an unreacted calcium silicate compound remains and the amount of apatite produced becomes insufficient, so that the phosphorus content in the recovered material is lowered. On the other hand, when the addition molar ratio is lower than 1.5, the solubility of phosphorus becomes high, and a sufficient recovery rate cannot be obtained.
リン含有排水の処理において、処理温度は高いほうが効率的にリンを回収することができる。処理温度の上限は特に定めるものではないが、加熱コスト等を勘案すれば工業的にみて１０℃以上〜１００℃以下、より好ましくは２５℃以上〜７０℃以下が適当である。また、液を攪拌して反応を促進することができる。処理時間は、珪酸カルシウム水和物の種類などによって異なり、一概に定めることはできないが、通常は０.５〜４時間程度で十分である。 In the treatment of phosphorus-containing wastewater, the higher the treatment temperature, the more efficiently phosphorus can be recovered. The upper limit of the treatment temperature is not particularly defined, but considering the heating cost and the like, it is industrially suitable from 10 ° C to 100 ° C, more preferably from 25 ° C to 70 ° C. Further, the reaction can be promoted by stirring the liquid. The treatment time varies depending on the type of calcium silicate hydrate and cannot be determined in general, but usually about 0.5 to 4 hours is sufficient.
本発明のリン回収方法において、リン含有排水にあらかじめ酸を添加した後、珪酸カルシウム水和物を添加するバッチ反応方式が望ましいが、酸を添加した処理水と珪酸カルシウム水和物とを連続的に供給して反応させる連続反応方式、あるいは処理水と酸と珪酸カルシウム水和物の三者を連続的に供給して反応させる連続反応方式によっても十分なリン回収率が得られる。 In the phosphorus recovery method of the present invention, a batch reaction method in which calcium silicate hydrate is added after adding acid to phosphorus-containing wastewater in advance is desirable, but the treated water and calcium silicate hydrate added with acid are continuously added. A sufficient phosphorus recovery rate can also be obtained by a continuous reaction system in which the reaction is carried out by supplying them to the reaction, or a continuous reaction system in which the treated water, acid and calcium silicate hydrate are continuously supplied and reacted.
以下に本発明の実施例を比較例と共に示す。なお、製造したリン回収資材ならびにリン回収品の物性は下記測定方法によって求めた。 Examples of the present invention are shown below together with comparative examples. In addition, the physical property of the manufactured phosphorus collection | recovery material and phosphorus collection | recovery goods was calculated | required with the following measuring method.
〔細孔容積〕１５０℃で１時間真空脱気を行なった試料につき、日本ＢＥＬ社装置(BELSORP-mini)を用い、窒素吸着法（ＢＪＨ法）により測定した。
〔嵩密度〕タップデンサー(セイシン企業製：ＫＹＴ−2000)にて５００回タップして嵩密度を求めた。
〔平均粒子径〕レーザー回折式粒度分布測定装置(堀場製作所製品：LA-300)を用いて測定した。
[Pore volume] A sample subjected to vacuum degassing at 150 ° C. for 1 hour was measured by a nitrogen adsorption method (BJH method) using a Japan BEL apparatus (BELSORP-mini).
[Bulk Density] The bulk density was determined by tapping 500 times with a tap denser (manufactured by Seishin Corporation: KYT-2000).
[Average particle diameter] The average particle diameter was measured using a laser diffraction particle size distribution analyzer (Horiba, Ltd. product: LA-300).
〔Ｘ線回折像〕ミニフレックスＸ線回折装置(理学社製)を用い、Ｃｕ管球、管電圧３０ｋＶ、管電流１５mＡ、サンプリング幅０.０２°、スキャンスピード４°/分の条件で測定した。
〔ク溶性リン酸〕肥料分析法に基づき、１ｇのサンプルを２％クエン酸で３０℃、１時間振盪し、溶解したリン酸をバナドモリブデン酸アンモニウム法で定量した。
〔全炭素、全窒素〕JISM８８１９に準拠し元素分析計で分析を行なった。
[X-ray diffraction image] Using a mini-flex X-ray diffractometer (manufactured by Rigaku Corporation), measurement was performed under the conditions of a Cu tube,
[Cu-soluble phosphoric acid] Based on the fertilizer analysis method, a 1 g sample was shaken with 2% citric acid at 30 ° C for 1 hour, and the dissolved phosphoric acid was quantified by the ammonium vanadomolybdate method.
[Total carbon, total nitrogen] The analysis was performed with an element analyzer in accordance with JISM8819.
〔実施例１〕
珪酸原料（平均粒径２０μmの非晶質シリカ粉）と消石灰をＣａ/Ｓｉモル比１.０の設定で調合し、水−固形分比１０相当分の水を加え、オートクレーブ中で攪拌しながら１８０℃、４時間、水熱反応を行なった。生成した珪酸カルシウム水和物スラリーを濾過し、乾燥して、珪酸カルシウム水和物からなるリン回収資材を得た。この物性値を表１に示す。試薬リン酸を水に溶かしてリン濃度３００mg/lのリン含有液を調製した。このリン含有液１８００mlに対し、資材の添加モル比（Ｃａ／Ｐ）＝２.００に相当する量の上記リン回収資材を添加し、３０℃に加温した恒温槽中で一定時間攪拌した。この試料液を濾過後、モリブデンブルー法により濾液のリン濃度を求めた。リン回収試験結果を図１に示す。
[Example 1]
Silicic acid raw material (amorphous silica powder having an average particle size of 20 μm) and slaked lime are prepared at a Ca / Si molar ratio of 1.0, water corresponding to a water-solid content ratio of 10 is added, and stirred in an autoclave. Hydrothermal reaction was performed at 180 ° C. for 4 hours. The produced calcium silicate hydrate slurry was filtered and dried to obtain a phosphorus recovery material consisting of calcium silicate hydrate. The physical property values are shown in Table 1. Reagent phosphoric acid was dissolved in water to prepare a phosphorus-containing solution having a phosphorus concentration of 300 mg / l. The amount of the phosphorus recovery material corresponding to the material addition molar ratio (Ca / P) = 2.00 was added to 1800 ml of this phosphorus-containing liquid, and the mixture was stirred for a certain period of time in a constant temperature bath heated to 30 ° C. After filtering this sample solution, the phosphorus concentration of the filtrate was determined by the molybdenum blue method. The phosphorus recovery test results are shown in FIG.
〔実施例２〕
珪酸原料（平均粒径２０μmの非晶質シリカ粉）と消石灰をＣａ/Ｓｉモル比１.０の設定で調合し、水−固形分比８相当分の水を加え、温浴中で攪拌しながら９５℃、１２時間、反応を行なった。生成した珪酸カルシウム水和物スラリーを濾過し、乾燥して、珪酸カルシウム水和物からなるリン回収資材を得た。この物性値を表１に示す。実施例１と同様な条件でリン含有溶液の処理を行なった、その結果を図１に示す。
[Example 2]
Silicic acid raw material (amorphous silica powder with an average particle size of 20 μm) and slaked lime are prepared at a Ca / Si molar ratio of 1.0, water corresponding to a water-solid content ratio of 8 is added, and stirred in a warm bath. The reaction was carried out at 95 ° C. for 12 hours. The produced calcium silicate hydrate slurry was filtered and dried to obtain a phosphorus recovery material consisting of calcium silicate hydrate. The physical property values are shown in Table 1. The result of treating the phosphorus-containing solution under the same conditions as in Example 1 is shown in FIG.
〔実施例３〕
珪酸原料（平均粒径１０μmの珪石粉末）と消石灰をＣａ/Ｓｉモル比０.８の設定で調合し、水−固形分比１５相当分の水を加え、オートクレーブ中で攪拌しながら１８０℃、８時間水熱反応を行なった。生成した珪酸カルシウム水和物スラリーを濾過、乾燥して、結晶質の珪酸カルシウム水和物からなるリン回収資材を得た。この物性値を表１に示す。
Example 3
Silicic acid raw material (silica stone powder having an average particle size of 10 μm) and slaked lime were prepared at a Ca / Si molar ratio of 0.8, water corresponding to a water-solid content ratio of 15 was added, and the mixture was stirred at 180 ° C. in an autoclave. Hydrothermal reaction was performed for 8 hours. The produced calcium silicate hydrate slurry was filtered and dried to obtain a phosphorus recovery material composed of crystalline calcium silicate hydrate. The physical property values are shown in Table 1.
〔比較例１〕
珪酸原料（平均粒径１０μmの珪石粉末）４３ｇと普通セメント５７ｇを十分混合した後、水を添加して造粒し、室温で２４時間養生を行なった。その後、この造粒物をオートクレーブに入れ、水に浸した状態で１８０℃、８時間、水熱反応を行なわせ、珪酸カルシウム水和物の粒状物を得た。乾燥後、粒状物を１４９μm全通に粉砕した。この物性値を表１に示す。実施例１と同様な条件でリン含有溶液の処理を行なった。その結果を図１に示す。
[Comparative Example 1]
After thoroughly mixing 43 g of silicic acid raw material (silica stone powder having an average particle size of 10 μm) and 57 g of ordinary cement, water was added to granulate, followed by curing at room temperature for 24 hours. Thereafter, this granulated product was put in an autoclave and subjected to a hydrothermal reaction at 180 ° C. for 8 hours in a state of being immersed in water to obtain a granular product of calcium silicate hydrate. After drying, the granular material was pulverized throughout 149 μm. The physical property values are shown in Table 1. The phosphorus-containing solution was treated under the same conditions as in Example 1. The result is shown in FIG.
〔比較例２〕
軽量気泡コンクリート粉末（物性値を表１に示す）を用い、実施例１と同様な条件でリン含有溶液の処理を行なった。その結果を図１に示す。
[Comparative Example 2]
Using a lightweight cellular concrete powder (property values are shown in Table 1), the phosphorus-containing solution was treated under the same conditions as in Example 1. The result is shown in FIG.
〔比較例３〕
珪灰石粉末（物性値を表１に示す）を用い、実施例１と同様な条件でリン含有溶液の処理を行なった。その結果を図１に示す。
[Comparative Example 3]
The phosphorous-containing solution was treated under the same conditions as in Example 1 using wollastonite powder (property values shown in Table 1). The result is shown in FIG.
図１に示すように、１２０分後の処理液中のリン濃度についてみると、比較例１〜比較例３は何れもは３０mg/l以上であるが、実施例１〜２は何れも５mg/l以下であり、比較例１〜３に対して実施例１〜２のリン回収資材の優位性は明らかである。また、実施例１〜２では反応時間３０分後で処理液中のリン濃度は１１mg/l以下に低減されているが、比較例１〜３の反応３０分後における処理液中のリン濃度は１００mg/l以上であり、短時間内の処理効果が格段に異なる。 As shown in FIG. 1, regarding the phosphorous concentration in the treatment solution after 120 minutes, Comparative Examples 1 to 3 are all 30 mg / l or more, but Examples 1 to 2 are all 5 mg / l. 1 or less, and the superiority of the phosphorus recovery materials of Examples 1 and 2 over the Comparative Examples 1 to 3 is clear. In Examples 1 and 2, the phosphorus concentration in the treatment liquid was reduced to 11 mg / l or less after 30 minutes of reaction time, but the phosphorus concentration in the treatment liquid after 30 minutes of reaction in Comparative Examples 1 to 3 was It is 100 mg / l or more, and the treatment effect within a short time is significantly different.
〔実施例１１〕
珪酸原料（平均粒径２０μmの非晶質シリカ粉）と消石灰をＣａ/Ｓｉモル比１.５の設定で調合し、水−固形分比８相当分の水を加え、温浴中で攪拌しながら９５℃、１２時間反応を行なった。生成した珪酸カルシウム水和物スラリーを濾過、乾燥して、珪酸カルシウム水和物からなるリン回収資材を得た。実施例１と同様な条件でリン含有溶液の処理を行なった。その結果を表２に示す。
Example 11
Silicic acid raw material (amorphous silica powder having an average particle size of 20 μm) and slaked lime are prepared at a Ca / Si molar ratio of 1.5, water corresponding to a water-solid content ratio of 8 is added, and stirred in a warm bath. The reaction was carried out at 95 ° C. for 12 hours. The produced calcium silicate hydrate slurry was filtered and dried to obtain a phosphorus recovery material consisting of calcium silicate hydrate. The phosphorus-containing solution was treated under the same conditions as in Example 1. The results are shown in Table 2.
〔比較例５〕
珪酸原料（平均粒径２０μmの非晶質シリカ粉）と消石灰をＣａ/Ｓｉモル比２.０の設定で調合し、水−固形分比８相当分の水を加え、温浴中で攪拌しながら９５℃、１２時間反応を行なった。生成した珪酸カルシウム水和物スラリーを濾過、乾燥して、珪酸カルシウム水和物からなるリン回収資材を得た。実施例１と同様な条件でリン含有溶液の処理を行なった。その結果を表２に示す。
[Comparative Example 5]
Silicic acid raw material (amorphous silica powder with an average particle size of 20 μm) and slaked lime are prepared at a Ca / Si molar ratio of 2.0, water corresponding to a water-solid content ratio of 8 is added, and stirred in a warm bath. The reaction was carried out at 95 ° C. for 12 hours. The produced calcium silicate hydrate slurry was filtered and dried to obtain a phosphorus recovery material consisting of calcium silicate hydrate. The phosphorus-containing solution was treated under the same conditions as in Example 1. The results are shown in Table 2.
表２に示すように、リン回収資材のＣａ/Ｓｉモル比が、１.０の実施例２、０.８の実施例３、１.５の実施例１１は何れも高いリン回収率が得られる。一方、比較例５のように、Ｃａ/Ｓｉモル比が２.０と高い比較例５は大幅にリン回収率が低下する。従って、リン回収資材のＣａ/Ｓｉモル比は１.５以下が好ましい。 As shown in Table 2, Example 2 in which the Ca / Si molar ratio of the phosphorus recovery material was 1.0, Example 3 in 0.8, and Example 11 in 1.5 obtained a high phosphorus recovery rate. It is done. On the other hand, as in Comparative Example 5, Comparative Example 5 having a high Ca / Si molar ratio of 2.0 has a significantly reduced phosphorus recovery rate. Therefore, the Ca / Si molar ratio of the phosphorus recovery material is preferably 1.5 or less.
〔実施例４〕
下水処理場由来の活性汚泥を７０℃、１時間加熱し、汚泥中のリンを液中に放出させた。この汚泥を放冷後、カチオン性界面活性剤を２００mg/lの割合で添加し、３５００rpmで２０分間遠心分離して、リン含有液を得た。このリン含有液の分析値を表３に示す。このリン含有液１５００ｍｌに硫酸を添加してｐＨを２.５に下げた後、実施例１のリン回収資材を、添加モル比（Ｃａ/Ｐ）＝１.８５になる量を投入し、３０℃に加温した恒温槽中で２時間攪拌して沈澱を生成させ、リンを回収した。この結果を図２に示す。終了後スラリーを自然沈降濃縮し、沈殿を濾過・乾燥してリン回収物を得た。回収品の物性ならびに分析値を表４に示す。
Example 4
The activated sludge derived from the sewage treatment plant was heated at 70 ° C. for 1 hour to release phosphorus in the sludge into the liquid. After allowing this sludge to cool, a cationic surfactant was added at a rate of 200 mg / l, and centrifuged at 3500 rpm for 20 minutes to obtain a phosphorus-containing liquid. The analytical values of this phosphorus-containing liquid are shown in Table 3. After adding sulfuric acid to 1500 ml of this phosphorus-containing liquid and lowering the pH to 2.5, the phosphorus recovery material of Example 1 was added in an amount such that the addition molar ratio (Ca / P) = 1.85, and 30 The mixture was stirred for 2 hours in a thermostatic bath heated to 0 ° C. to form a precipitate, and phosphorus was recovered. The result is shown in FIG. After completion, the slurry was naturally precipitated and concentrated, and the precipitate was filtered and dried to obtain a phosphorus recovery product. Table 4 shows the physical properties and analytical values of the collected products.
〔実施例５〕
実施例２のリン回収資材を用い、実施例４と同様な条件でリン含有液の処理を行なった。この結果を図２および表４に示す。
Example 5
Using the phosphorus recovery material of Example 2, the phosphorus-containing liquid was treated under the same conditions as in Example 4. The results are shown in FIG.
〔実施例６〕
実施例３のリン回収資材を用い、実施例４と同様な条件でリン含有液の処理を行なった。この結果を図２および表４に示す。
Example 6
The phosphorus-containing liquid was treated under the same conditions as in Example 4 using the phosphorus recovery material of Example 3. The results are shown in FIG.
〔比較例６〕
比較例２の珪酸カルシウム水和物粉末を用い、実施例４と同様な条件でリン含有液の処理を行なった。この結果を図２および表４に示す。
[Comparative Example 6]
Using the calcium silicate hydrate powder of Comparative Example 2, the phosphorus-containing liquid was treated under the same conditions as in Example 4. The results are shown in FIG.
〔比較例７〕
比較例３の珪酸カルシウム水和物粉末を用い、実施例４と同様な条件でリン含有液の処理を行なった。この結果を図２および表４に示す。
[Comparative Example 7]
Using the calcium silicate hydrate powder of Comparative Example 3, the phosphorus-containing liquid was treated under the same conditions as in Example 4. The results are shown in FIG.
〔比較例８〕
消石灰粉末を用い、実施例４と同様な条件でリン含有排水の処理を行なった。この結果を図２および表４に示す。
[Comparative Example 8]
Phosphorus-containing wastewater was treated under the same conditions as in Example 4 using slaked lime powder. The results are shown in FIG.
図２および表４に示すように、本発明のリン回収資材を用いた実施例４、実施例５、実施例６のリン回収率は何れも９５％程度であり高い。この回収物の濾過時間は４１秒以下であり、濾過性が良好で、含水率も２００％以下であり低いレベルにある。さらに、回収物のク溶性リン酸量は２０％前後であって、窒素含有量は少なく１％以下であり、副産りん酸肥料の条件（ク溶性リン酸１５.０％以上、全窒素１.０％未満）を満足している。 As shown in FIG. 2 and Table 4, the phosphorus recovery rates of Examples 4, 5, and 6 using the phosphorus recovery material of the present invention are all about 95% and are high. The recovered material has a filtration time of 41 seconds or less, good filterability, and a moisture content of 200% or less, which is at a low level. Furthermore, the amount of soluble phosphoric acid in the recovered material is around 20%, the nitrogen content is small and less than 1%, and the conditions of by-product phosphate fertilizer (15.0% or more of soluble phosphoric acid, total nitrogen 1) (Less than 0.0%).
一方、従来の珪酸カルシウム水和物をリン回収資材として用いた比較例６、比較例７では、排水中のリンとの反応性に劣るため、回収物のリン酸濃度は１５％未満であり、副産りん酸肥料の条件を満足することができない。また、消石灰を用いた比較例８は、リンの回収率は高いものの、回収物の濾過時間は１９０秒であり、濾過性が著しく低く、さらに含水率も高い。また、有機物が共沈するため回収物中の有機物含量が高く、全窒素は１％を超えるので副産りん酸肥料の条件に適合しない。 On the other hand, in Comparative Example 6 and Comparative Example 7 using conventional calcium silicate hydrate as a phosphorus recovery material, the phosphoric acid concentration of the recovered product is less than 15% because of poor reactivity with phosphorus in the waste water, The conditions of by-product phosphate fertilizer cannot be satisfied. In Comparative Example 8 using slaked lime, although the recovery rate of phosphorus is high, the filtration time of the recovered material is 190 seconds, the filterability is remarkably low, and the moisture content is also high. In addition, since organic matter co-precipitates, the organic matter content in the recovered material is high, and the total nitrogen exceeds 1%, so it does not meet the conditions of by-product phosphate fertilizer.
〔実施例７〕
実施例４と同様な条件で下水処理場由来の活性汚泥を処理し、リン含有液を得た。このリン含有液に硫酸を添加してｐＨを３.３に下げた後、実施例１のリン回収資材を、添加モル比（Ｃａ/Ｐ）＝１.８５になる量を投入し、３０℃に加温した恒温槽中で２時間攪拌してリンの回収を行なった。その結果を表５に示す。
Example 7
An activated sludge derived from a sewage treatment plant was treated under the same conditions as in Example 4 to obtain a phosphorus-containing liquid. After adding sulfuric acid to this phosphorus-containing liquid and lowering the pH to 3.3, the phosphorus recovery material of Example 1 was added in an amount such that the addition molar ratio (Ca / P) = 1.85, and 30 ° C. Then, phosphorus was recovered by stirring for 2 hours in a constant temperature bath. The results are shown in Table 5.
〔実施例８〕
実施例７と同様に、リン含有液に硫酸を添加してｐＨを２.３に下げた後、実施例１のリン回収資材を用い、実施例７と同様な条件でリンの回収を行なった。その結果を表５に示す。
Example 8
Similarly to Example 7, after adding sulfuric acid to the phosphorus-containing liquid to lower the pH to 2.3, phosphorus was recovered under the same conditions as in Example 7 using the phosphorus recovery material of Example 1. . The results are shown in Table 5.
〔比較例９〕
実施例７と同様に、リン含有液に硫酸を添加してｐＨを１.８に下げた後、実施例１のリン回収資材を用い、実施例７と同様な条件でリンの回収を行なった。その結果を表５に示す。
[Comparative Example 9]
In the same manner as in Example 7, sulfuric acid was added to the phosphorus-containing liquid to lower the pH to 1.8, and then phosphorus was recovered under the same conditions as in Example 7 using the phosphorus recovery material of Example 1. . The results are shown in Table 5.
〔比較例１０〕
実施例４と同様な条件で下水処理場由来の活性汚泥を処理してリン含有液を得た。酸は添加せずに、実施例１のリン回収資材を用い、実施例７と同様な条件でリンの回収を行なった。その結果を表５に示す。
[Comparative Example 10]
An activated sludge derived from a sewage treatment plant was treated under the same conditions as in Example 4 to obtain a phosphorus-containing liquid. Phosphorus was recovered under the same conditions as in Example 7 using the phosphorus recovery material of Example 1 without adding an acid. The results are shown in Table 5.
実施例７、実施例８はリン回収後の濾液のｐＨが７〜９の範囲に入るように予め酸を処理液に添加してリン回収試験を行なったものである。実施例７および実施例８のリン回収率は９０％以上であり高いが、酸を過剰に添加して最終ｐＨが５未満の比較例９、酸無添加で最終ｐＨが９を上回る比較例１０ではリンの回収率は低下する。 In Examples 7 and 8, a phosphorus recovery test was performed by previously adding an acid to the treatment liquid so that the pH of the filtrate after phosphorus recovery was in the range of 7-9. The phosphorus recovery rate of Example 7 and Example 8 is as high as 90% or more, but Comparative Example 9 in which the final pH is less than 5 by adding excessive acid, and Comparative Example 10 in which the final pH is higher than 9 without addition of acid. Then, the phosphorus recovery rate decreases.
〔実施例９〕
実施例４と同様な条件で下水処理場由来の活性汚泥を処理し、リン含有液を得た。このリン含有液に硫酸を添加してｐＨを２.７に下げた後、実施例１のリン回収資材を用い、このリン回収資材と上記リン含有液を連続的に反応容器に供給し、反応温度３０℃、平均滞留時間１時間の設定でリン回収実験を行なった。反応終了後のスラリーは自然沈降して濃縮した沈殿を濾過し、乾燥してリン回収物を得た。その結果を表６に示す。
Example 9
An activated sludge derived from a sewage treatment plant was treated under the same conditions as in Example 4 to obtain a phosphorus-containing liquid. After adding sulfuric acid to the phosphorus-containing liquid to lower the pH to 2.7, the phosphorus recovery material of Example 1 was used, and the phosphorus recovery material and the phosphorus-containing liquid were continuously supplied to the reaction vessel. A phosphorus recovery experiment was conducted at a temperature of 30 ° C. and an average residence time of 1 hour. After completion of the reaction, the slurry was naturally settled and the concentrated precipitate was filtered and dried to obtain a phosphorus recovery product. The results are shown in Table 6.
リン回収を連続反応で行なった実施例９においても、表６に示すように、リンの回収率が高く、回収物は良好な濾過性を有し、含水率も低い。また副産りん酸肥料の登録要件であるク溶性リン酸１５．０％以上、全窒素１．０％未満という条件を満足できる。 Also in Example 9 in which the phosphorus recovery was performed by a continuous reaction, as shown in Table 6, the phosphorus recovery rate was high, the recovered material had good filterability, and the water content was low. Moreover, the conditions of 15.0% or more of soluble phosphoric acid and less than 1.0% of total nitrogen, which are registration requirements for by-product phosphate fertilizer, can be satisfied.
〔実施例１０〕
実施例４と同様な条件で下水処理場由来の活性汚泥を処理し、リン含有液を得た。このリン含有液に硫酸を添加してｐＨを２.５に下げた後、実施例１のリン回収資材を、添加モル比（Ｃａ/Ｐ）＝１.４０、１.６７、１.８５、２.５０の設定でそれぞれ添加し、実施例４と同様な条件でリン回収実験を行なった。この時の添加モル比（Ｃａ／Ｐ）に対するリン回収率と、回収品のリン含有率の変化を図３に示す。
Example 10
An activated sludge derived from a sewage treatment plant was treated under the same conditions as in Example 4 to obtain a phosphorus-containing liquid. After adding sulfuric acid to this phosphorus-containing liquid to lower the pH to 2.5, the phosphorus recovery material of Example 1 was added at a molar ratio (Ca / P) = 1.40, 1.67, 1.85, Phosphorus recovery experiments were conducted under the same conditions as in Example 4 with the addition of 2.50. FIG. 3 shows changes in the phosphorus recovery rate relative to the addition molar ratio (Ca / P) and the phosphorus content of the recovered product.
図３によれば、リン回収資材の添加モル比（Ｃａ／Ｐ）が低くなると回収率が急速に低下し、逆に添加モル比が高い場合は、回収率は頭打ちとなって回収品のリン酸含有量が低下する。このことから、リン回収資材の添加モル比（Ｃａ／Ｐ）は、１.５以上〜２.５以下であることが望ましい。 According to FIG. 3, the recovery rate decreases rapidly when the added molar ratio (Ca / P) of the phosphorus recovery material decreases, and conversely, when the added molar ratio is high, the recovery rate reaches a peak and the phosphorus in the recovered product is reduced. The acid content is reduced. From this, it is desirable that the addition molar ratio (Ca / P) of the phosphorus recovery material is 1.5 or more and 2.5 or less.
本発明のリン回収資材は多孔質な珪酸カルシウム水和物を用いているので、リンとの反応速度が高く、コンパクトな装置で固液分離が容易な回収品を得ることができる。また回収品の有機物含量が低いため、回収品は副産りん酸肥料の登録要件を満足することができる。また、リン回収の際に、リン含有排水に酸を添加することによって、珪酸カルシウム水和物との反応をスムーズに進めることができ、短時間でリンを回収できる。 Since the phosphorus collection | recovery material of this invention uses the porous calcium silicate hydrate, the reaction rate with phosphorus is high, and the collection | recovery goods with which a solid-liquid separation is easy can be obtained with a compact apparatus. Moreover, since the organic matter content of the recovered product is low, the recovered product can satisfy the registration requirement of by-product phosphate fertilizer. In addition, by adding an acid to the phosphorus-containing wastewater at the time of phosphorus recovery, the reaction with calcium silicate hydrate can proceed smoothly, and phosphorus can be recovered in a short time.
Claims (2)
反応終了時の排水のｐＨが５.０以上〜９.０未満の範囲で、
排水中のリン含有量に対して、Ｃａ／Ｐモル比が１.５以上〜２.５以下になる量のリン回収資材を排水に添加し、
１０℃以上〜１００℃未満の温度にし、
排水に含まれるリン酸によって珪酸カルシウム水和物を逐次的に分解させてカルシウムを溶出させ、該排水中のリンと反応させて珪酸カルシウム水和物粒子表面にヒドロキシアパタイトを生成せしめ、凝集沈殿物を分離してリンを回収することを特徴とするリン回収方法。 It consists of porous calcium silicate hydrate produced by hydrothermal reaction of amorphous silica powder and slaked lime or quartzite powder and slaked lime, with an average particle diameter (median diameter) of 10 μm to 150 μm and a pore volume of 0.3 cm 3. / g or more, a bulk density of 0.1 g / cm 3 or more ~0.7g / cm 3 or less, using a phosphorus recovery materials described Ca / Si molar ratio claim 1 is 0.4 or more to 1.5 or less,
The pH of the waste water at the end of the reaction is in the range of 5.0 to less than 9.0,
Add phosphorus recovery material to the wastewater in such an amount that the Ca / P molar ratio is 1.5 to 2.5 with respect to the phosphorus content in the wastewater.
The temperature is set to 10 ° C or higher and lower than 100 ° C,
The calcium silicate hydrate is sequentially decomposed by phosphoric acid contained in the waste water to elute calcium, react with the phosphorus in the waste water to generate hydroxyapatite on the surface of the calcium silicate hydrate particles, and aggregate precipitate The phosphorus collection | recovery method characterized by isolate | separating and collect | recovering phosphorus.
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Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP5461802B2 (en) * | 2008-08-13 | 2014-04-02 | 幸雄 柳沢 | Dephosphorization material and dephosphorization apparatus |
| JP5931369B2 (en) * | 2010-08-03 | 2016-06-08 | 小野田化学工業株式会社 | Phosphorus recovery material and method for producing the same |
| JP5864045B2 (en) * | 2011-02-28 | 2016-02-17 | 小野田化学工業株式会社 | Method for producing phosphorus recovery material |
| JP2013006733A (en) * | 2011-06-24 | 2013-01-10 | Taiheiyo Cement Corp | Method for recovery of phosphorus and using the phosphorus as fertilizer |
| WO2012176579A1 (en) | 2011-06-24 | 2012-12-27 | 太平洋セメント株式会社 | Method for recovering phosphorus and using same as fertilizer |
| JP5931534B2 (en) * | 2012-03-27 | 2016-06-08 | 国立研究開発法人農業・食品産業技術総合研究機構 | Wastewater treatment system with amorphous calcium silicate hydrate. |
| JP5925034B2 (en) * | 2012-04-20 | 2016-05-25 | 日本インシュレーション株式会社 | Composition for heat insulating material, molded body for heat insulating material, and production method thereof |
| WO2013168245A1 (en) * | 2012-05-09 | 2013-11-14 | 太平洋セメント株式会社 | Phosphorous-collecting material, method for producing phosphorous-collecting material, and phosphorous collection method |
| JP5972050B2 (en) * | 2012-05-25 | 2016-08-17 | 太平洋セメント株式会社 | Method for producing phosphorus recovery material |
| FR3011188B1 (en) | 2013-09-27 | 2020-11-27 | Brgm | ARSENIC TRAPPING DEVICE |
| JP6899650B2 (en) * | 2016-12-15 | 2021-07-07 | 小野田化学工業株式会社 | Phosphate fertilizer and its manufacturing method |
| JP7388950B2 (en) * | 2020-02-28 | 2023-11-29 | 太平洋セメント株式会社 | Waste liquid treatment method |
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| CN112408350B (en) * | 2020-11-03 | 2023-04-07 | 中国五环工程有限公司 | Process for producing feed-grade calcium hydrophosphate from phosphorus-containing wastewater |
Family Cites Families (5)
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| JPS62152588A (en) * | 1985-12-27 | 1987-07-07 | Ube Ind Ltd | Treatment of water containing phosphate |
| JPS62183898A (en) * | 1986-02-10 | 1987-08-12 | Onoda Cement Co Ltd | Method for dephosphorization of sewage containing phosphorus |
| JPS63116798A (en) * | 1986-11-06 | 1988-05-21 | Asahi Chem Ind Co Ltd | Removing method for phosphorous and nitrogen ion in water |
| JPH0342096A (en) * | 1989-04-21 | 1991-02-22 | Shigenobu Kasamatsu | Method for removing phosphate ion and sulfate ion in water |
| JP3379924B2 (en) * | 1999-10-18 | 2003-02-24 | 株式会社ホクコン | Adsorbent |
-
2008
- 2008-05-30 JP JP2008143895A patent/JP5201454B2/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20240083819A1 (en) * | 2021-03-22 | 2024-03-14 | Sublime Systems, Inc. | Decarbonized cement blends |
| US12065379B2 (en) * | 2021-03-22 | 2024-08-20 | Sublime Systems, Inc. | Decarbonized cement blends |
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