CN106744764A - A kind of method for producing potassium dihydrogen phosphate - Google Patents
A kind of method for producing potassium dihydrogen phosphate Download PDFInfo
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- CN106744764A CN106744764A CN201611004641.XA CN201611004641A CN106744764A CN 106744764 A CN106744764 A CN 106744764A CN 201611004641 A CN201611004641 A CN 201611004641A CN 106744764 A CN106744764 A CN 106744764A
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- Prior art keywords
- phosphoric acid
- dihydrogen phosphate
- potassium
- potassium dihydrogen
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- 235000019796 monopotassium phosphate Nutrition 0.000 title claims abstract description 60
- 229910000402 monopotassium phosphate Inorganic materials 0.000 title claims abstract description 60
- PJNZPQUBCPKICU-UHFFFAOYSA-N phosphoric acid;potassium Chemical compound [K].OP(O)(O)=O PJNZPQUBCPKICU-UHFFFAOYSA-N 0.000 title claims abstract description 60
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 37
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims abstract description 151
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims abstract description 75
- FUFJGUQYACFECW-UHFFFAOYSA-L calcium hydrogenphosphate Chemical compound [Ca+2].OP([O-])([O-])=O FUFJGUQYACFECW-UHFFFAOYSA-L 0.000 claims abstract description 75
- 235000019700 dicalcium phosphate Nutrition 0.000 claims abstract description 74
- 238000000034 method Methods 0.000 claims abstract description 43
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims abstract description 40
- 238000006243 chemical reaction Methods 0.000 claims abstract description 33
- 229910000343 potassium bisulfate Inorganic materials 0.000 claims abstract description 28
- 238000002425 crystallisation Methods 0.000 claims abstract description 27
- 239000000706 filtrate Substances 0.000 claims abstract description 27
- 238000005649 metathesis reaction Methods 0.000 claims abstract description 26
- CHKVPAROMQMJNQ-UHFFFAOYSA-M potassium bisulfate Chemical compound [K+].OS([O-])(=O)=O CHKVPAROMQMJNQ-UHFFFAOYSA-M 0.000 claims abstract description 24
- 230000008569 process Effects 0.000 claims abstract description 23
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 18
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 17
- 239000011574 phosphorus Substances 0.000 claims abstract description 17
- 239000000047 product Substances 0.000 claims abstract description 16
- 239000003337 fertilizer Substances 0.000 claims abstract description 10
- 238000001816 cooling Methods 0.000 claims abstract description 3
- 239000000243 solution Substances 0.000 claims description 36
- 239000011575 calcium Substances 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 238000000354 decomposition reaction Methods 0.000 claims description 20
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 19
- 229910052791 calcium Inorganic materials 0.000 claims description 19
- 239000002002 slurry Substances 0.000 claims description 16
- 238000006386 neutralization reaction Methods 0.000 claims description 10
- 230000035484 reaction time Effects 0.000 claims description 7
- 239000002131 composite material Substances 0.000 claims description 3
- 239000002253 acid Substances 0.000 claims description 2
- PZDFRGGOXGETNN-UHFFFAOYSA-N phosphane;potassium Chemical compound P.[K] PZDFRGGOXGETNN-UHFFFAOYSA-N 0.000 claims description 2
- 239000010413 mother solution Substances 0.000 claims 5
- 238000005360 mashing Methods 0.000 claims 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims 2
- 239000000460 chlorine Substances 0.000 claims 2
- 229910052801 chlorine Inorganic materials 0.000 claims 2
- MPNNOLHYOHFJKL-UHFFFAOYSA-N peroxyphosphoric acid Chemical compound OOP(O)(O)=O MPNNOLHYOHFJKL-UHFFFAOYSA-N 0.000 claims 2
- 239000012141 concentrate Substances 0.000 claims 1
- 229910052739 hydrogen Inorganic materials 0.000 claims 1
- 239000001257 hydrogen Substances 0.000 claims 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims 1
- 230000008025 crystallization Effects 0.000 abstract description 25
- 239000012452 mother liquor Substances 0.000 abstract description 20
- 229910052700 potassium Inorganic materials 0.000 abstract description 16
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 abstract description 15
- 239000011591 potassium Substances 0.000 abstract description 15
- 239000002994 raw material Substances 0.000 abstract description 13
- 238000004064 recycling Methods 0.000 abstract description 7
- 239000007788 liquid Substances 0.000 abstract description 5
- 150000001875 compounds Chemical class 0.000 abstract description 4
- 239000002699 waste material Substances 0.000 abstract description 3
- 230000002860 competitive effect Effects 0.000 abstract description 2
- 238000011084 recovery Methods 0.000 abstract description 2
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 16
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 16
- 229910000389 calcium phosphate Inorganic materials 0.000 description 11
- YYRMJZQKEFZXMX-UHFFFAOYSA-L calcium bis(dihydrogenphosphate) Chemical compound [Ca+2].OP(O)([O-])=O.OP(O)([O-])=O YYRMJZQKEFZXMX-UHFFFAOYSA-L 0.000 description 10
- 235000019691 monocalcium phosphate Nutrition 0.000 description 10
- 229940062672 calcium dihydrogen phosphate Drugs 0.000 description 9
- 238000003756 stirring Methods 0.000 description 8
- 239000012535 impurity Substances 0.000 description 7
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 238000001914 filtration Methods 0.000 description 5
- JTNCEQNHURODLX-UHFFFAOYSA-N 2-phenylethanimidamide Chemical compound NC(=N)CC1=CC=CC=C1 JTNCEQNHURODLX-UHFFFAOYSA-N 0.000 description 4
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 4
- 229910001424 calcium ion Inorganic materials 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 4
- 229910052939 potassium sulfate Inorganic materials 0.000 description 4
- 235000011151 potassium sulphates Nutrition 0.000 description 4
- 238000000746 purification Methods 0.000 description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 3
- 229910019142 PO4 Inorganic materials 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- 229960005069 calcium Drugs 0.000 description 3
- 238000010494 dissociation reaction Methods 0.000 description 3
- 230000005593 dissociations Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000010452 phosphate Substances 0.000 description 3
- 229910000027 potassium carbonate Inorganic materials 0.000 description 3
- 239000000376 reactant Substances 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- BDRTVPCFKSUHCJ-UHFFFAOYSA-N molecular hydrogen;potassium Chemical compound [K].[H][H] BDRTVPCFKSUHCJ-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 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 2
- 241000251468 Actinopterygii Species 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 241000238631 Hexapoda Species 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-L Phosphate ion(2-) Chemical compound OP([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-L 0.000 description 1
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 240000004808 Saccharomyces cerevisiae Species 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 241000607479 Yersinia pestis Species 0.000 description 1
- KYAXVUURGCWDJW-UHFFFAOYSA-N [K].P(=O)(O)(O)[O-].[NH4+] Chemical compound [K].P(=O)(O)(O)[O-].[NH4+] KYAXVUURGCWDJW-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000003973 alkyl amines Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000003674 animal food additive Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 238000010009 beating Methods 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 229960001714 calcium phosphate Drugs 0.000 description 1
- 239000001506 calcium phosphate Substances 0.000 description 1
- 235000011010 calcium phosphates Nutrition 0.000 description 1
- YYRMJZQKEFZXMX-UHFFFAOYSA-N calcium;phosphoric acid Chemical compound [Ca+2].OP(O)(O)=O.OP(O)(O)=O YYRMJZQKEFZXMX-UHFFFAOYSA-N 0.000 description 1
- 239000012295 chemical reaction liquid Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 description 1
- 229910000388 diammonium phosphate Inorganic materials 0.000 description 1
- 235000019838 diammonium phosphate Nutrition 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-M dihydrogenphosphate Chemical compound OP(O)([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-M 0.000 description 1
- ZPWVASYFFYYZEW-UHFFFAOYSA-L dipotassium hydrogen phosphate Chemical compound [K+].[K+].OP([O-])([O-])=O ZPWVASYFFYYZEW-UHFFFAOYSA-L 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 239000012527 feed solution Substances 0.000 description 1
- 238000000855 fermentation Methods 0.000 description 1
- 230000004151 fermentation Effects 0.000 description 1
- 239000000796 flavoring agent Substances 0.000 description 1
- 235000013373 food additive Nutrition 0.000 description 1
- 239000002778 food additive Substances 0.000 description 1
- 235000013355 food flavoring agent Nutrition 0.000 description 1
- 235000010855 food raising agent Nutrition 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 230000010534 mechanism of action Effects 0.000 description 1
- 239000002366 mineral element Substances 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 235000016709 nutrition Nutrition 0.000 description 1
- 230000009965 odorless effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000002367 phosphate rock Substances 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- -1 polyoxyethylene Polymers 0.000 description 1
- 150000003112 potassium compounds Chemical class 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000006228 supernatant Substances 0.000 description 1
- 239000002426 superphosphate Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 230000009967 tasteless effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/30—Alkali metal phosphates
- C01B25/301—Preparation from liquid orthophosphoric acid or from an acid solution or suspension of orthophosphates
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Fertilizers (AREA)
Abstract
本发明涉及一种生产磷酸二氢钾的方法，将饲料级磷酸氢钙先和工业级磷酸进行预分解反应，再加入硫酸氢钾进行复分解反应，过滤出硫酸钙和滤液，对滤液进行净化处理后浓缩冷却结晶，制备出磷酸二氢钾产品，结晶母液返回到饲料级磷酸氢钙中进行循环操作，或用于无氯复合肥的生产。与现有技术相比，本发明方法采取磷酸与饲料级磷酸氢钙进行预反应大幅度提高了饲料级磷酸氢钙中磷的回收率，达到95％以上，另外硫酸氢钾中钾的收率达到99.5％，同时，本发明中的磷酸实现了循环使用，无废液排放，本工艺流程简单，原料中的磷和钾收率高，可以大幅度地降低生产成本，环保可持续，具有极大的竞争优势。
The invention relates to a method for producing potassium dihydrogen phosphate. The feed-grade calcium hydrogen phosphate is pre-decomposed with industrial-grade phosphoric acid, and then potassium hydrogen sulfate is added for metathesis reaction. Calcium sulfate and filtrate are filtered out, and the filtrate is purified. After concentration, cooling and crystallization, the potassium dihydrogen phosphate product is prepared, and the crystallization mother liquor is returned to feed-grade calcium hydrogen phosphate for recycling operation, or used for the production of chlorine-free compound fertilizer. Compared with the prior art, the method of the present invention adopts phosphoric acid and feed-grade calcium hydrogen phosphate to carry out pre-reaction, greatly improves the recovery rate of phosphorus in feed-grade calcium hydrogen phosphate, reaching more than 95%, and the yield of potassium in potassium hydrogensulfate in addition 99.5%, at the same time, the phosphoric acid in the present invention can be recycled without waste liquid discharge, the process flow is simple, the yield of phosphorus and potassium in the raw material is high, the production cost can be greatly reduced, it is environmentally friendly and sustainable, and has extremely big competitive advantage.
Description
技术领域technical field
本发明涉及磷酸盐的制备，尤其是涉及一种生产磷酸二氢钾的方法。The present invention relates to the preparation of phosphate, especially relate to a kind of method of producing potassium dihydrogen phosphate.
背景技术Background technique
磷酸二氢钾，为一种无色或白色带光泽的斜方体，能溶于水，其水溶液呈酸性，微溶于醇，有吸湿潮解性。Potassium dihydrogen phosphate is a colorless or white glossy rhomboid, soluble in water, its aqueous solution is acidic, slightly soluble in alcohol, and has hygroscopicity and deliquescence.
磷酸二氢钾在工业、农业、食品行业、医药均有广泛的应用：在农业上，其作为一种高浓度的高级磷钾复肥，具有显著增产、抗旱、耐寒作用，而且对防治作物病虫害也有特殊作用，另外因其具有营养成分高(P、K有效成分>90％)，化学性质稳定，无嗅，无味，无毒，易溶于水，不结块，因而适用于各种土壤和作物；在饲料添加剂中用作补充磷和钾的矿物元素添加剂，特别是在鱼饲料中普遍应用；在工业上，常用于细菌培养剂，制作酵母培养剂；在食品添加剂中磷酸二氢钾是食品磷酸盐重要品种之一，用作品质改良剂、发酵促进剂、调味剂、缓冲剂以及与磷酸氢二钾并用作为膨松剂。磷酸二氢钾的生产方法有中和法、萃取法、离子交换法、复分解法、直接法、结晶法和电解法等，目前中国的磷酸二氢钾主要通过热法磷酸和钾碱的中和反应制备，约占全国磷酸二氢钾总生产能力的90％以上，该方法工艺技术成熟，但其生产成本高。Potassium dihydrogen phosphate is widely used in industry, agriculture, food industry, and medicine: in agriculture, as a high-grade phosphorus and potassium compound fertilizer with high concentration, it has the effects of significantly increasing production, drought resistance, and cold resistance, and it is effective in preventing and controlling crop diseases and insect pests. It also has a special effect. In addition, because of its high nutritional content (P, K active ingredients >90%), stable chemical properties, odorless, tasteless, non-toxic, soluble in water, and non-caking, it is suitable for various soils and Crops; used as a mineral element additive to supplement phosphorus and potassium in feed additives, especially commonly used in fish feed; in industry, it is often used in bacterial culture agents to make yeast culture agents; in food additives, potassium dihydrogen phosphate is One of the important varieties of food phosphate, it is used as quality improver, fermentation accelerator, flavoring agent, buffer and used together with dipotassium hydrogen phosphate as leavening agent. The production methods of potassium dihydrogen phosphate include neutralization method, extraction method, ion exchange method, double decomposition method, direct method, crystallization method and electrolysis method, etc. At present, potassium dihydrogen phosphate in China is mainly neutralized by thermal phosphoric acid and potassium alkali Reaction preparation accounts for more than 90% of the total production capacity of potassium dihydrogen phosphate in the country. This method has mature technology, but its production cost is high.
有文献报道采用饲料级磷酸氢钙和硫酸氢钾制备磷酸二氢钾的工艺，文献和专利中的制备工艺，是在复分解阶段将硫酸氢钾溶液直接加入到饲料级磷酸氢钙的料浆中进行复分解反应，反应式如下：There are reports in the literature on the process of preparing potassium dihydrogen phosphate by using feed-grade calcium hydrogen phosphate and potassium hydrogen sulfate. The preparation process in the literature and patents is to directly add potassium hydrogen sulfate solution to the slurry of feed-grade calcium hydrogen phosphate in the double decomposition stage. Carry out metathesis reaction, reaction formula is as follows:
KHSO4+CaHPO4·2H2O→KH2PO4+CaSO4·2H2O↓KHSO 4 +CaHPO 4 2H 2 O→KH 2 PO 4 +CaSO 4 2H 2 O↓
该反应中反应物磷酸氢钙难溶于水，生成的硫酸钙也难溶于水，硫酸钙容易在磷酸氢钙表面堆积，形成包裹，使得磷酸氢钙的溶解困难，导致磷酸氢钙磷的分解率降低。原料的利用率低下，使生产成本上升；同时，该种复分解工艺导致复分解反应后的过滤液中硫酸根浓度高，影响最终磷酸二氢钾产品的纯度，如果增加滤液除杂过程，将导致总体生产成本的增加。In this reaction, the reactant calcium hydrogen phosphate is insoluble in water, and the calcium sulfate generated is also insoluble in water. Calcium sulfate is easy to accumulate on the surface of calcium hydrogen phosphate to form a package, which makes the dissolution of calcium hydrogen phosphate difficult, resulting in the loss of calcium hydrogen phosphate and phosphorus. The decomposition rate is reduced. The low utilization rate of raw materials increases the production cost; at the same time, this kind of metathesis process leads to a high concentration of sulfate radicals in the filtrate after the metathesis reaction, which affects the purity of the final potassium dihydrogen phosphate product. If the process of removing impurities from the filtrate is increased, the overall Increased production costs.
中国专利CN 103879980B中公开了一种用饲料级磷酸氢钙生产磷酸二氢钾的方法，该方法以饲料级磷酸氢钙为原料，与磷酸溶液进行转化反应后再与硫酸进行萃取反应，过滤后得到的滤液用工业级磷酸调节PH为7.1～8.5，后再向滤液中加入碳酸钾和氢氧化钾溶液进行中和反应，反应完成后调节PH为8.5～9.5，过滤所得滤液通过工业级磷酸继续调节PH为4～4.5，调节反应液密度，待晶体全部析出后离心干燥得到磷酸二氢钾。该专利中磷酸以反应物的形式参与反应，同时该工艺下生产成本很高。Chinese patent CN 103879980B discloses a method for producing potassium dihydrogen phosphate with feed-grade calcium hydrogen phosphate. The method uses feed-grade calcium hydrogen phosphate as raw material, carries out conversion reaction with phosphoric acid solution, and then carries out extraction reaction with sulfuric acid. The obtained filtrate is adjusted to a pH of 7.1 to 8.5 with industrial grade phosphoric acid, and then potassium carbonate and potassium hydroxide solution are added to the filtrate for neutralization reaction. Adjust the pH to 4-4.5, adjust the density of the reaction liquid, and centrifuge and dry after all the crystals are precipitated to obtain potassium dihydrogen phosphate. In this patent, phosphoric acid participates in the reaction in the form of a reactant, and the production cost is very high under this process.
中国专利CN 103058158A直接采用肥料级的磷酸氢钙与硫酸氢钾进行复分解反应，没有磷酸参与分解磷酸氢钙的反应；同时，其结晶母液中不含有磷酸，母液循环的作用仅仅在于提高磷酸二氢钾产品的收率。Chinese patent CN 103058158A directly uses fertilizer-grade calcium hydrogen phosphate and potassium hydrogen sulfate for metathesis reaction, and no phosphoric acid participates in the reaction of decomposing calcium hydrogen phosphate; at the same time, its crystallization mother liquor does not contain phosphoric acid, and the effect of mother liquor circulation is only to increase the dihydrogen phosphate Yield of potassium product.
中国专利CN 104944397A由净化湿法磷酸与氧化钙或氢氧化钙或碳酸钙反应制备磷酸钙盐，再采用硫酸氢钾或硫酸钾溶液进行复分解反应，过程加入聚氧乙烯烷基胺和丙二醇嵌段聚醚组成的复合助剂以降低晶体表面自由能，过滤除去硫酸钙后，过滤液经浓缩、结晶、洗涤干燥后得磷酸二氢钾。Chinese patent CN 104944397A prepares calcium phosphate salt by reacting purified wet-process phosphoric acid with calcium oxide or calcium hydroxide or calcium carbonate, and then uses potassium bisulfate or potassium sulfate solution for metathesis reaction, adding polyoxyethylene alkylamine and propylene glycol blocks during the process The composite additive composed of polyether is used to reduce the free energy of the crystal surface. After filtering to remove calcium sulfate, the filtrate is concentrated, crystallized, washed and dried to obtain potassium dihydrogen phosphate.
专利CN 105819939A公布了一种水溶性肥料的生产方法，包括如下工艺过程：以含磷酸二氢钙为主要成分的重过磷酸钙、用中低品位磷矿生产饲料级磷酸氢钙的一段中和清液及农用硫酸钾为原料，进行复分解反应，生成含磷酸二氢钾的溶液；进行一次过滤后的滤渣作为生产富过磷酸钙的原料，补充磷和硫；滤液含磷酸二氢钾为主要成分的溶液，再用氢氧化钾或液氨进行中和除杂反应，进行二次过滤后，滤渣作为补充进入饲料级磷酸氢钙的原料或作为生产肥料级磷酸氢二氨的原料等。专利CN 105819939A，是采用湿法磷酸经过一段中和去除沉淀后的清液与农用硫酸钾进行复分解反应，生成含磷酸二氢钾的溶液，该溶液经除杂制备水溶性肥料(磷酸二氢钾，或磷酸二氢钾铵)。专利CN 105819939A中磷酸参与了后续与氢氧化钾或是液氨的中和反应。Patent CN 105819939A discloses a production method of water-soluble fertilizer, including the following process: heavy superphosphate with calcium dihydrogen phosphate as the main component, and a stage of neutralization of feed-grade calcium hydrogen phosphate with medium and low-grade phosphate rock. Clear liquid and agricultural potassium sulfate are used as raw materials for metathesis reaction to generate a solution containing potassium dihydrogen phosphate; the filter residue after one filtration is used as raw material for the production of calcium superphosphate rich, and phosphorus and sulfur are supplemented; the filtrate contains potassium dihydrogen phosphate as the main Then use potassium hydroxide or liquid ammonia to neutralize and remove impurities. After secondary filtration, the filter residue is used as a supplementary raw material for feed-grade calcium hydrogen phosphate or as a raw material for the production of fertilizer-grade diammonium hydrogen phosphate. Patent CN 105819939A uses wet-process phosphoric acid to undergo a period of neutralization to remove the precipitated clear liquid and agricultural potassium sulfate for metathesis reaction to generate a solution containing potassium dihydrogen phosphate, which is purified to prepare water-soluble fertilizer (potassium dihydrogen phosphate , or ammonium potassium dihydrogen phosphate). In patent CN 105819939A, phosphoric acid participates in the subsequent neutralization reaction with potassium hydroxide or liquid ammonia.
发明内容Contents of the invention
本发明提出一种新的生产磷酸二氢钾的方法，以解决磷酸氢钙和硫酸氢钾为原料制备磷酸二氢钾的工艺中面临的原料利用率低和生产成本高的问题。本发明的方法在复分解反应时的磷收率达到95％以上，硫酸氢钾中钾的收率达到99.5％；同时磷收率的提高，使得滤液中硫酸根的含量变小，降低了滤液净化时的成本；此外，本发明中母液循环利用，既实现了磷酸的循环使用，又降低了后续磷酸二氢钾溶液的浓缩蒸发量。同时本发明无污染废液排放，生产过程环保可持续值。The invention proposes a new method for producing potassium dihydrogen phosphate to solve the problems of low raw material utilization rate and high production cost faced in the process of preparing potassium dihydrogen phosphate as raw materials from calcium hydrogen phosphate and potassium hydrogen sulfate. The phosphorus yield of the method of the present invention reaches more than 95% when metathesis reaction, and the yield of potassium in potassium bisulfate reaches 99.5%; Simultaneously the raising of phosphorus yield makes the content of sulfate radical in the filtrate become smaller, reduces filtrate purification In addition, the recycling of the mother liquor in the present invention not only realizes the recycling of phosphoric acid, but also reduces the concentrated evaporation of the subsequent potassium dihydrogen phosphate solution. At the same time, the invention has no pollution waste liquid discharge, and the production process is environmentally friendly and sustainable.
本发明的目的可以通过以下技术方案来实现：The purpose of the present invention can be achieved through the following technical solutions:
本发明提供一种生产磷酸二氢钾的方法，具体方案为：将饲料级磷酸氢钙先和工业级磷酸进行预分解反应，再加入硫酸氢钾进行复分解反应，过滤出硫酸钙和滤液，对滤液进行净化处理后浓缩冷却结晶，制备出符合国家标准的工业级一等品的磷酸二氢钾产品，结晶母液返回到饲料级磷酸氢钙中进行循环操作，或用于无氯复合肥的生产。The invention provides a method for producing potassium dihydrogen phosphate. The specific scheme is: first carry out pre-decomposition reaction with feed grade calcium hydrogen phosphate and industrial grade phosphoric acid, then add potassium hydrogen sulfate to carry out metathesis reaction, filter out calcium sulfate and filtrate, and After purification, the filtrate is concentrated, cooled and crystallized to produce a first-class industrial-grade potassium dihydrogen phosphate product that meets national standards. The crystallized mother liquor is returned to feed-grade calcium hydrogen phosphate for recycling operation, or used for the production of chlorine-free compound fertilizers .
进一步地，饲料级磷酸氢钙和工业级磷酸进行预分解反应时，磷酸与磷酸氢钙的摩尔比为0.2～0.3：1。预分解反应的反应机理是将难溶于水的磷酸氢钙部分转变为微溶于水的磷酸二氢钙，预分解反应促进了磷酸氢钙的分解，可大幅度提高复分解反应阶段的磷收率。Further, when feed-grade calcium hydrogen phosphate and industrial-grade phosphoric acid are pre-decomposed, the molar ratio of phosphoric acid to calcium hydrogen phosphate is 0.2-0.3:1. The reaction mechanism of the pre-decomposition reaction is to convert the insoluble calcium hydrogen phosphate part into the slightly water-soluble calcium dihydrogen phosphate. Rate.
进一步地，饲料级磷酸氢钙和工业级磷酸进行预分解反应时，反应温度为50℃～70℃，反应时间为1h～2h。Further, when feed-grade calcium hydrogen phosphate and industrial-grade phosphoric acid are subjected to pre-decomposition reaction, the reaction temperature is 50°C-70°C, and the reaction time is 1h-2h.
进一步地，硫酸氢钾和饲料级磷酸氢钙的钾磷摩尔比为0.9～1.1：1。Further, the potassium-phosphorus molar ratio of potassium hydrogen sulfate and feed-grade calcium hydrogen phosphate is 0.9-1.1:1.
进一步地，加入硫酸氢钾进行复分解反应时，反应温度为50℃～70℃，反应时间为2～4h。Further, when adding potassium bisulfate to carry out the metathesis reaction, the reaction temperature is 50° C. to 70° C., and the reaction time is 2 to 4 hours.
本发明中饲料级磷酸氢钙与工业级磷酸预分解反应混合的方式，优选采用以下两种方式：Among the present invention, feed grade calcium hydrogen phosphate and industrial grade phosphoric acid pre-decomposition reaction mix, preferably adopt following two kinds of ways:
方式一，饲料级磷酸氢钙加水打浆后，得到饲料级磷酸氢钙料浆，加入工业级磷酸与饲料级磷酸氢钙料浆进行预分解反应；Mode 1, after feed-grade calcium hydrogen phosphate is added with water and beaten, feed-grade calcium hydrogen phosphate slurry is obtained, and industrial-grade phosphoric acid and feed-grade calcium hydrogen phosphate slurry are added for pre-decomposition reaction;
饲料级磷酸氢钙加水打浆制备得到饲料级磷酸氢钙料浆时，每千克饲料级磷酸氢钙加入水的体积为2.5～5升。When feed-grade calcium hydrogen phosphate is added with water and beaten to prepare feed-grade calcium hydrogen phosphate slurry, the volume of water added per kilogram of feed-grade calcium hydrogen phosphate is 2.5 to 5 liters.
方式二，将工业级磷酸和水混合后的磷酸溶液与饲料级磷酸氢钙混合，打浆的同时进行预分解反应。Method 2: Mix the phosphoric acid solution obtained by mixing industrial-grade phosphoric acid and water with feed-grade calcium hydrogen phosphate, and perform pre-decomposition reaction while beating.
将工业级磷酸和水混合时，配制成的磷酸溶液质量百分数优选为20％～40％。When mixing industrial-grade phosphoric acid and water, the mass percentage of the prepared phosphoric acid solution is preferably 20%-40%.
当结晶母液返回到饲料级磷酸氢钙中进行循环操作时，结晶母液可以替代工业磷酸，结晶母液返回到经过磷酸预处理后的饲料级磷酸氢钙料浆中，硫酸氢钾溶液加入到结晶母液与饲料级磷酸氢钙料浆混合液中；When the crystallization mother liquor is returned to the feed grade calcium hydrogen phosphate for recycling operation, the crystallization mother liquor can replace industrial phosphoric acid, the crystallization mother liquor is returned to the feed grade calcium hydrogen phosphate slurry after phosphoric acid pretreatment, and the potassium hydrogen sulfate solution is added to the crystallization mother liquor Mixed with feed grade calcium hydrogen phosphate slurry;
当结晶母液用于无氯复合肥的生产时，硫酸氢钾溶液直接加入到经过磷酸预处理后的饲料级磷酸氢钙料浆中。When the crystallization mother liquor is used in the production of chlorine-free compound fertilizer, the potassium hydrogen sulfate solution is directly added to the feed grade calcium hydrogen phosphate slurry after phosphoric acid pretreatment.
硫酸氢钾优选以硫酸氢钾溶液的形式加入，硫酸氢钾溶液质量百分数优选为30％～50％。Potassium hydrogen sulfate is preferably added in the form of potassium hydrogen sulfate solution, and the mass percentage of potassium hydrogen sulfate solution is preferably 30% to 50%.
本发明中，所述的饲料级磷酸氢钙是由湿法磷酸经三段中和法制备得到。In the present invention, the feed-grade calcium hydrogen phosphate is prepared from wet-process phosphoric acid through a three-stage neutralization method.
本发明中，所述的工业级磷酸可以是热法磷酸，也可以是湿法磷酸。In the present invention, said industrial-grade phosphoric acid can be hot-process phosphoric acid or wet-process phosphoric acid.
本发明中，复分解反应阶段磷的收率至95％以上，K收率为99.5％以上。也就是过滤出的硫酸钙中P损失率为≤5％，K损失率≤0.5％。In the present invention, the yield of phosphorus in the metathesis reaction stage is above 95%, and the yield of K is above 99.5%. That is, the P loss rate in the filtered calcium sulfate is ≤5%, and the K loss rate is ≤0.5%.
本发明中，对滤液进行净化处理采用常规处理方法，进一步脱除残余硫酸根和钙离子等杂质。由于复反应阶段硫酸根绝大部分形成了硫酸钙被除去，大幅度缩减了净化成本。In the present invention, conventional treatment methods are adopted for purifying the filtrate to further remove impurities such as residual sulfate radicals and calcium ions. Since most of the sulfuric acid in the multiple reaction stage forms calcium sulfate and is removed, the purification cost is greatly reduced.
本发明中，浓缩冷却结晶操作时，结晶过程搅拌速度为80rpm/min～100rpm/min，结晶温度为20～40℃，结晶时间为3h～6h，制备出符合国家标准工业级一等品的磷酸二氢钾产品。In the present invention, during the concentration cooling crystallization operation, the stirring speed of the crystallization process is 80rpm/min-100rpm/min, the crystallization temperature is 20-40°C, and the crystallization time is 3h-6h, and the phosphoric acid that meets the national standard industrial grade first-class product is prepared. Potassium dihydrogen product.
本发明通过加入磷酸进行预分解反应，使得部分磷酸氢钙溶解形成一定浓度的含有游离磷酸根和钙离子的溶液；加入硫酸氢钾后，硫酸根与溶液中的钙离子反应，形成磷酸钙沉淀；硫酸钙的形成，保证了磷酸氢钙在磷酸存在下的分解反应的继续。由于形成硫酸钙的反应发生在主体溶液中，控制了硫酸钙对磷酸氢钙颗粒的包裹作用，从而提高了磷酸氢钙的分解率。同时，由于采用了磷酸溶解部分磷酸氢钙的方法，控制了反应体系的溶液量，提高了复分解液中磷酸二氢钾的浓度，降低了浓缩成本。The present invention carries out the pre-decomposition reaction by adding phosphoric acid, so that part of calcium hydrogen phosphate dissolves to form a solution containing free phosphate and calcium ions at a certain concentration; after adding potassium hydrogen sulfate, the sulfate radical reacts with calcium ions in the solution to form calcium phosphate precipitation The formation of calcium sulfate ensures the continuation of the decomposition reaction of calcium hydrogen phosphate in the presence of phosphoric acid. Since the reaction of forming calcium sulfate occurs in the main body solution, the wrapping effect of calcium sulfate on calcium hydrogen phosphate particles is controlled, thereby improving the decomposition rate of calcium hydrogen phosphate. Simultaneously, since the method of dissolving part of calcium hydrogen phosphate with phosphoric acid is adopted, the solution amount of the reaction system is controlled, the concentration of potassium dihydrogen phosphate in the metathesis solution is increased, and the concentration cost is reduced.
加入磷酸后，反应过程为：After adding phosphoric acid, the reaction process is:
H3PO4→H2PO4 -+H+ H 3 PO 4 →H 2 PO 4 - +H +
CaHPO4·2H2O+H2PO4 -+H+→Ca2++2H2PO4 -+2H2OCaHPO 4 2H 2 O+H 2 PO 4 - +H + →Ca 2+ +2H 2 PO 4 - +2H 2 O
SO4 2-+Ca2++2H2O→CaSO4·2H2O↓SO 4 2- +Ca 2+ +2H 2 O→CaSO 4 2H 2 O↓
在不加入磷酸时，磷酸氢钙的解离主要受到磷酸氢钙溶解度的影响，加入磷酸后，磷酸氢钙的解离主要受到磷酸二氢钙溶解度的影响，磷酸二氢钙的溶解度大于磷酸氢钙的溶解度，更有利于磷酸氢钙的解离，磷收率大幅度提高。When phosphoric acid is not added, the dissociation of calcium hydrogen phosphate is mainly affected by the solubility of calcium hydrogen phosphate. After adding phosphoric acid, the dissociation of calcium hydrogen phosphate is mainly affected by the solubility of calcium dihydrogen phosphate. The solubility of calcium dihydrogen phosphate is greater than that of hydrogen phosphate The solubility of calcium is more conducive to the dissociation of calcium hydrogen phosphate, and the phosphorus yield is greatly improved.
与现有技术相比，本发明方法采取磷酸与饲料级磷酸氢钙进行预反应大幅度提高了饲料级磷酸氢钙中磷的回收率，达到95％以上，另外硫酸氢钾中钾的收率达到99.5％，极大的提高了原料的利用率，缩减了原料成本；同时，本发明中的磷酸实现了循环使用，无废液排放，对比其他的磷酸二氢钾的生产工艺，本工艺原料易得且成本低，流程简单，原料中的磷和钾收率高，可以大幅度地降低生产成本，环保可持续，具有极大的竞争优势。具体而言，Compared with the prior art, the method of the present invention adopts phosphoric acid and feed-grade calcium hydrogen phosphate to carry out pre-reaction, greatly improves the recovery rate of phosphorus in feed-grade calcium hydrogen phosphate, reaching more than 95%, and the yield of potassium in potassium hydrogensulfate in addition It reaches 99.5%, which greatly improves the utilization rate of raw materials and reduces the cost of raw materials; at the same time, the phosphoric acid in the present invention can be recycled without waste liquid discharge. Compared with other production processes of potassium dihydrogen phosphate, the raw materials of this process It is easy to obtain, low in cost, simple in process, high in the yield of phosphorus and potassium in raw materials, can greatly reduce production costs, is environmentally friendly and sustainable, and has great competitive advantages. in particular,
1、本发明技术方案与背景技术中专利CN 103879980B相比，其优缺点在于：1. Compared with the patent CN 103879980B in the background technology, the technical solution of the present invention has the following advantages and disadvantages:
专利CN 103879980B中饲料级磷酸氢钙加入到磷酸溶液中，过量的磷酸将磷酸氢钙全部转化为磷酸二氢钙，形成的复分解反应液有效成分磷酸二氢钾的浓度低，在制备磷酸二氢钾产品前，通过蒸发浓缩去除的水量大，浓缩成本高。而本发明工艺是将磷酸加入到饲料级磷酸氢钙中，磷酸与磷酸氢钙的摩尔比为0.2～0.3，只有很少部分的饲料级磷酸氢钙被转化为磷酸二氢钙，再通过硫酸钙的形成，维持磷酸氢钙的分解反应；复分解反应后的料液浓度相对更高。In the patent CN 103879980B, the feed grade calcium hydrogen phosphate is added to the phosphoric acid solution, and the excess phosphoric acid converts all the calcium hydrogen phosphate into calcium dihydrogen phosphate, and the concentration of the effective component potassium dihydrogen phosphate in the metathesis reaction solution formed is low. Before potassium products, the amount of water removed by evaporation and concentration is large, and the concentration cost is high. And the process of the present invention is that phosphoric acid is added in feed grade calcium hydrogen phosphate, and the molar ratio of phosphoric acid and calcium hydrogen phosphate is 0.2～0.3, has only a small part of feed grade calcium hydrogen phosphate to be converted into calcium dihydrogen phosphate, and then passes sulfuric acid The formation of calcium maintains the decomposition reaction of calcium hydrogen phosphate; the concentration of the feed solution after the metathesis reaction is relatively higher.
专利CN 103879980B中饲料级磷酸氢钙加入到磷酸溶液中，磷酸的作用是作为反应物，和饲料级磷酸氢钙反应制备出磷酸二氢钙溶液，而硫酸的作用是沉淀钙，并形成磷酸溶液。而本发明利用磷酸使饲料级磷酸氢钙部分分解，再通过复分解反应阶段磷酸氢钙全部分解，生产磷酸二氢钾。在磷酸二氢钾的制备过程中，磷酸不被消耗，起到了类似于复分解反应“催化剂”的作用。In patent CN 103879980B, feed-grade calcium hydrogen phosphate is added to phosphoric acid solution. Phosphoric acid is used as a reactant to react with feed-grade calcium hydrogen phosphate to prepare calcium dihydrogen phosphate solution, while sulfuric acid is used to precipitate calcium and form phosphoric acid solution. . And the present invention utilizes phosphoric acid to partially decompose the feed grade calcium hydrogen phosphate, and then fully decomposes the calcium hydrogen phosphate through the metathesis reaction stage to produce potassium dihydrogen phosphate. In the preparation process of potassium dihydrogen phosphate, phosphoric acid is not consumed, which acts as a "catalyst" similar to the metathesis reaction.
专利CN 103879980B是通过所制备的磷酸与碳酸钾和氢氧化钾的中和反应制备磷酸二氢钾，中和反应后，结晶析出磷酸二氢钾，结晶母液中的主要成分是磷酸二氢钾，循环该母液的目的是提高该工艺方法的磷酸二氢钾的收率。而本发明通过磷酸预分解磷酸氢钙，然后以复分解方式直接制备磷酸二氢钾。分析整个制备过程，磷酸不被消耗，通过该结晶母液的循环，实现了磷酸的在制备过程中的高效利用，同时本发明的工艺流程更为简洁。Patent CN 103879980B is to prepare potassium dihydrogen phosphate through the neutralization reaction of prepared phosphoric acid, potassium carbonate and potassium hydroxide. After the neutralization reaction, potassium dihydrogen phosphate is crystallized. The main component in the crystallization mother liquor is potassium dihydrogen phosphate. The purpose of circulating this mother liquor is to improve the yield of the potassium dihydrogen phosphate of this technological process. And the present invention pre-decomposes calcium hydrogen phosphate by phosphoric acid, and then directly prepares potassium dihydrogen phosphate in a metathesis mode. Analysis of the entire preparation process shows that phosphoric acid is not consumed, and the efficient utilization of phosphoric acid in the preparation process is realized through the circulation of the crystallization mother liquor, and the process flow of the present invention is more concise.
另外，专利CN 103879980B中的钾来自于碳酸钾和氢氧化钾，而本发明工艺钾来自于硫酸氢钾，成本更低。In addition, the potassium in the patent CN 103879980B comes from potassium carbonate and potassium hydroxide, while the potassium in the process of the present invention comes from potassium bisulfate, and the cost is lower.
2、本发明技术方案与背景技术中专利CN 105819939A相比，其优缺点在于：2. Compared with the patent CN 105819939A in the background technology, the technical solution of the present invention has the following advantages and disadvantages:
对比文件CN 105819939A中，一段中和后的清液主要含有溶解的磷酸氢钙与游离磷酸，在与硫酸钾复分解反应，得磷酸二氢钾。并且该专利CN 105819939A中磷酸参与了后续与氢氧化钾或是液氨的中和反应。In the comparative document CN 105819939A, a section of neutralized supernatant mainly contains dissolved calcium hydrogen phosphate and free phosphoric acid, which undergo metathesis reaction with potassium sulfate to obtain potassium dihydrogen phosphate. And in the patent CN 105819939A, phosphoric acid participates in the subsequent neutralization reaction with potassium hydroxide or liquid ammonia.
本发明是向饲料级磷酸氢钙的悬浮液中加入少量磷酸，使部分磷酸氢钙转化为磷酸二氢钙溶解，然后加入硫酸氢钾进行复分解反应，随着硫酸钙沉淀的生成，未溶解的磷酸氢钙在磷酸的作用下继续溶解并参与复分解反应。从机理看，两者的反应过程不同。The present invention is to add a small amount of phosphoric acid to the suspension of feed grade calcium hydrogen phosphate, so that part of the calcium hydrogen phosphate is converted into calcium dihydrogen phosphate for dissolution, and then potassium hydrogen sulfate is added to carry out double decomposition reaction. With the generation of calcium sulfate precipitation, the undissolved Calcium hydrogen phosphate continues to dissolve under the action of phosphoric acid and participate in the metathesis reaction. Mechanistically, the reaction processes of the two are different.
另外，对比文件CN 105819939A中使用的是混酸：磷酸和硫酸，使得磷酸氢钙完全溶解，与本发明中磷酸起类似于复分解反应“催化剂”的作用机理不同。In addition, the reference document CN 105819939A uses a mixed acid: phosphoric acid and sulfuric acid, so that calcium hydrogen phosphate is completely dissolved, which is different from the mechanism of action of phosphoric acid in the present invention, which is similar to the "catalyst" of metathesis reaction.
同时，与对比文件CN 105819939A相比，两者的起始原料是不同的，制备所得的磷酸二氢钾的产品纯度是不同的。一个是肥料级，一个是饲料级或工业级。At the same time, compared with the reference document CN 105819939A, the starting materials of the two are different, and the product purity of the prepared potassium dihydrogen phosphate is different. One is fertilizer grade, one is feed grade or industrial grade.
附图说明Description of drawings
图1为本发明生产磷酸二氢钾的工艺流程图。Fig. 1 is the process flow diagram of the present invention producing potassium dihydrogen phosphate.
具体实施方式detailed description
一种生产磷酸二氢钾的方法，参考图1所示的工艺流程图，具体工艺为：A method for producing potassium dihydrogen phosphate, with reference to the process flow diagram shown in Figure 1, the concrete process is:
1、将饲料级磷酸氢钙和水打浆，制备出料浆，加入水的体积与饲料级磷酸氢钙的质量比为2.5～5L/kg。1. Beat feed grade calcium hydrogen phosphate and water to prepare slurry, and the mass ratio of the volume of added water to feed grade calcium hydrogen phosphate is 2.5-5L/kg.
2、将工业级磷酸配制成质量百分数为20％～40％的磷酸溶液，向料浆中加入磷酸溶液进行预分解反应，反应温度为50℃～70℃，加入的磷酸摩尔量与料浆中的磷酸氢钙的摩尔比为0.2～0.3。预分解反应的反应机理是将难溶于水的磷酸氢钙部分转变为微溶于水的磷酸二氢钙，预分解反应促进了磷酸氢钙的分解，可大幅度提高复分解反应阶段的磷收率。2. Prepare industrial-grade phosphoric acid into a phosphoric acid solution with a mass percentage of 20% to 40%. Add phosphoric acid solution to the slurry for pre-decomposition reaction. The reaction temperature is 50°C to 70°C. The molar ratio of calcium hydrogen phosphate is 0.2～0.3. The reaction mechanism of the pre-decomposition reaction is to convert the part of calcium hydrogen phosphate that is insoluble in water into calcium dihydrogen phosphate that is slightly soluble in water. Rate.
3、预分解反应进行1h～2h后，将硫酸氢钾配制成质量百分数为30％～50％的硫酸氢钾溶液，再缓慢加入，进行复分解反应，加入的硫酸氢钾摩尔量与料浆中的磷酸氢钙的摩尔比为0.9～1.1。3. After the pre-decomposition reaction is carried out for 1h to 2h, potassium hydrogensulfate is prepared into a potassium hydrogensulfate solution with a mass percentage of 30% to 50%, and then slowly added to carry out the double decomposition reaction. The molar ratio of calcium hydrogen phosphate is 0.9～1.1.
4、复分解反应进行2h～4h后，过滤出硫酸钙和滤液。复分解反应阶段磷的收率至95％以上，K收率为99.5％以上。4. After the metathesis reaction is carried out for 2h to 4h, the calcium sulfate and the filtrate are filtered out. The yield of phosphorus in the metathesis reaction stage is more than 95%, and the yield of K is more than 99.5%.
5、对滤液进行净化处理，进一步脱除残余硫酸根和钙离子等杂质。由于复分解反应阶段硫酸根绝大部分形成了硫酸钙被除去，大幅度缩减了净化成本。5. Purify the filtrate to further remove impurities such as residual sulfate radicals and calcium ions. Since most of the sulfuric acid in the metathesis reaction stage forms calcium sulfate and is removed, the purification cost is greatly reduced.
6、净化后的滤液进行浓缩冷却结晶，结晶过程搅拌速度为80rpm/min～100rpm/min，结晶温度为20～40℃，结晶时间为3h～6h，制备出符合国家标准工业级一等品的磷酸二氢钾产品。6. The purified filtrate is concentrated and cooled to crystallize. During the crystallization process, the stirring speed is 80rpm/min～100rpm/min, the crystallization temperature is 20～40℃, and the crystallization time is 3h～6h. Potassium dihydrogen phosphate product.
7、结晶母液可以替代工业磷酸，返回到饲料级磷酸氢钙料浆中进行预分解反应，进行循环操作，也可以用于无氯复合肥的生产。7. The crystallization mother liquor can replace industrial phosphoric acid, return to the feed grade calcium hydrogen phosphate slurry for pre-decomposition reaction, and carry out cyclic operation, and can also be used for the production of chlorine-free compound fertilizer.
下面结合附图和具体实施例对本发明进行详细说明。The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.
实施例1：Example 1:
将315kg饲料级磷酸氢钙和787.5kg的水在反应釜中混合均匀，加入174.43kg质量百分数为20％的磷酸溶液，反应温度为50℃，反应1h后加入727.07kg质量百分数为30％的硫酸氢钾溶液，反应温度为50℃，反应时间为2h；反应结束后过滤，得到硫酸钙和含磷酸二氢钾的过滤液，硫酸钙中磷和钾的损失率分别为4.93％和0.26％；滤液经过净化后，过滤除去杂质，所得滤液进行浓缩结晶，结晶过程搅拌速度为80rpm/min，结晶温度为20℃，搅拌结晶3h后，过滤得到136.01kg磷酸二氢钾产品和494.81kg母液，母液返回到反应釜中，进行循环操作；产品中磷酸二氢钾含量为98.3％，符合磷酸二氢钾工业级一等品的要求。Mix 315kg of feed grade calcium hydrogen phosphate and 787.5kg of water in the reactor evenly, add 174.43kg of phosphoric acid solution with a mass percentage of 20%, the reaction temperature is 50°C, and add 727.07kg of 30% by mass of sulfuric acid after reacting for 1h Potassium hydrogen solution, the reaction temperature is 50°C, and the reaction time is 2h; after the reaction is completed, filter to obtain calcium sulfate and potassium dihydrogen phosphate-containing filtrate, and the loss rates of phosphorus and potassium in calcium sulfate are 4.93% and 0.26% respectively; After the filtrate was purified, it was filtered to remove impurities, and the resulting filtrate was concentrated and crystallized. During the crystallization process, the stirring speed was 80rpm/min, and the crystallization temperature was 20°C. After stirring and crystallizing for 3 hours, 136.01kg of potassium dihydrogen phosphate product and 494.81kg of mother liquor were obtained by filtration. Return to the reactor and carry out recycling operation; the content of potassium dihydrogen phosphate in the product is 98.3%, which meets the requirements of the first-class industrial grade of potassium dihydrogen phosphate.
实施例2：Example 2:
将230kg饲料级磷酸氢钙和1150kg的水在反应釜中混合均匀，加入95.52kg质量百分数为40％的磷酸溶液，反应温度为70℃，反应2h后加入由389.31kg质量百分数为50％的硫酸氢钾溶液，反应温度为70℃，反应时间为4h；反应结束后过滤，得到硫酸钙和滤液，硫酸钙中磷和钾的损失率分别为4.89％和0.34％；滤液经过净化后，过滤除去杂质，所得滤液进行浓缩结晶，结晶过程搅拌速度为100rpm/min，结晶温度为40℃，搅拌结晶6h后，过滤得到32.90kg的磷酸二氢钾产品和545.44kg母液，母液返回到反应釜中，进行循环操作；产品中磷酸二氢钾含量为98.4％，符合磷酸二氢钾工业级一等品的要求。Mix 230kg of feed grade calcium hydrogen phosphate and 1150kg of water in the reactor evenly, add 95.52kg of phosphoric acid solution with a mass percentage of 40%, the reaction temperature is 70°C, and add 389.31kg of 50% by mass of sulfuric acid after 2 hours of reaction Potassium hydrogen solution, the reaction temperature is 70°C, and the reaction time is 4h; filter after the reaction to obtain calcium sulfate and filtrate, the loss rates of phosphorus and potassium in calcium sulfate are 4.89% and 0.34% respectively; after the filtrate is purified, filter to remove Impurities, the obtained filtrate is concentrated and crystallized, the stirring speed of the crystallization process is 100rpm/min, and the crystallization temperature is 40°C. After stirring and crystallizing for 6h, filter to obtain 32.90kg of potassium dihydrogen phosphate product and 545.44kg of mother liquor, and the mother liquor is returned to the reactor. Circulation operation is carried out; the content of potassium dihydrogen phosphate in the product is 98.4%, which meets the requirements of industrial grade first-class potassium dihydrogen phosphate.
实施例3：Example 3:
将180kg饲料级磷酸氢钙和647.50kg的水在反应釜中混合均匀，加入426.87kg的母液，反应温度为70℃，反应1h后加入由304.68kg质量百分数为50％的硫酸氢钾溶液，反应温度为70℃，反应时间为4h；反应结束后过滤，得到硫酸钙和滤液，硫酸钙中磷和钾的损失率分别为4.91％和0.42％；滤液经过净化后，过滤除去杂质，所得滤液进行浓缩结晶，结晶过程搅拌速度为100rpm/min，结晶温度为40℃，搅拌结晶6h后，过滤得到114.01kg磷酸二氢钾产品和477.91kg的母液，母液返回到反应釜中，进行循环操作；产品中磷酸二氢钾含量为98.34％，符合磷酸二氢钾工业级一等品的要求。Mix 180kg of feed grade calcium hydrogen phosphate and 647.50kg of water in the reactor, add 426.87kg of mother liquor, and the reaction temperature is 70°C. After 1 hour of reaction, add 304.68kg of potassium hydrogensulfate solution with a mass percentage of 50%. The temperature is 70°C, and the reaction time is 4h; after the reaction, filter to obtain calcium sulfate and filtrate, and the loss rates of phosphorus and potassium in calcium sulfate are 4.91% and 0.42% respectively; after the filtrate is purified, filter to remove impurities, and the obtained filtrate is processed Concentrated crystallization, the stirring speed of the crystallization process is 100rpm/min, and the crystallization temperature is 40°C. After stirring and crystallizing for 6 hours, 114.01kg of potassium dihydrogen phosphate product and 477.91kg of mother liquor are obtained by filtration, and the mother liquor is returned to the reactor for recycling operation; the product The content of potassium dihydrogen phosphate in the medium is 98.34%, which meets the requirements of industrial grade first-class potassium dihydrogen phosphate.
上述的对实施例的描述是为便于该技术领域的普通技术人员能理解和使用发明。熟悉本领域技术的人员显然可以容易地对这些实施例做出各种修改，并把在此说明的一般原理应用到其他实施例中而不必经过创造性的劳动。因此，本发明不限于上述实施例，本领域技术人员根据本发明的揭示，不脱离本发明范畴所做出的改进和修改都应该在本发明的保护范围之内。The above descriptions of the embodiments are for those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative efforts. Therefore, the present invention is not limited to the above-mentioned embodiments. Improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.
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| CN107188146A (en) * | 2017-07-18 | 2017-09-22 | 禄丰天宝磷化工有限公司 | Production process of feed-grade potassium dihydrogen phosphate |
| CN110697671A (en) * | 2019-11-21 | 2020-01-17 | 江西渠成氟化学有限公司 | Process for producing potassium dihydrogen phosphate by using calcium hydrogen phosphate |
| CN113816351A (en) * | 2021-10-14 | 2021-12-21 | 太仓沪试试剂有限公司 | Preparation method of high-quality monopotassium phosphate |
| CN115092900A (en) * | 2022-06-28 | 2022-09-23 | 新希望化工投资有限公司 | Process for producing potassium dihydrogen phosphate and calcium sulfate whiskers by adopting phosphorite |
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| CN103332668A (en) * | 2013-07-11 | 2013-10-02 | 瓮福（集团）有限责任公司 | Production method of monopotassium phosphate |
| CN104445124A (en) * | 2014-10-30 | 2015-03-25 | 成都化工股份有限公司 | Method for producing monopotassium phosphate by using supergravity technology |
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| CN1212248A (en) * | 1997-09-23 | 1999-03-31 | 张智新 | Method for directly producing chlorineless compound fertilizer |
| CN103332668A (en) * | 2013-07-11 | 2013-10-02 | 瓮福（集团）有限责任公司 | Production method of monopotassium phosphate |
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| CN107188146A (en) * | 2017-07-18 | 2017-09-22 | 禄丰天宝磷化工有限公司 | Production process of feed-grade potassium dihydrogen phosphate |
| CN110697671A (en) * | 2019-11-21 | 2020-01-17 | 江西渠成氟化学有限公司 | Process for producing potassium dihydrogen phosphate by using calcium hydrogen phosphate |
| CN113816351A (en) * | 2021-10-14 | 2021-12-21 | 太仓沪试试剂有限公司 | Preparation method of high-quality monopotassium phosphate |
| CN115092900A (en) * | 2022-06-28 | 2022-09-23 | 新希望化工投资有限公司 | Process for producing potassium dihydrogen phosphate and calcium sulfate whiskers by adopting phosphorite |
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