CN108946688A

CN108946688A - A kind of method of chlorination oxygenated organophosphorus waste water preparing phosphoric acid disodium hydrogen

Info

Publication number: CN108946688A
Application number: CN201710370966.8A
Authority: CN
Inventors: 袁志文
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-05-22
Filing date: 2017-05-22
Publication date: 2018-12-07

Abstract

The invention discloses a kind of methods of chlorination oxygenated organophosphorus waste water preparing phosphoric acid disodium hydrogen: adding chlorine to organism P wastewater or liquid chlorine carries out oxidation reaction, by organic phosphorus compound and trivalent phosphorous compound oxygenolysis for after pentavalent phosphate radical, with the sodium ion in solution under the conditions of pH 6-pH 11, crystallisation by cooling generates solid disodium hydrogen phosphate dodecahydrate, separation of solid and liquid obtains solid crude product, and qualified products can be obtained after purification.It repeats the above steps after residual solution is concentrated and the gross production rate of disodium hydrogen phosphate can be improved.

Description

A kind of method of chlorination oxygenated organophosphorus waste water preparing phosphoric acid disodium hydrogen

Technical field

The invention belongs to technical field of waste water processing, it is related to a kind of chlorination (chlorine or liquid chlorine) oxygenated organophosphorus waste water and makes The method for taking disodium hydrogen phosphate dodecahydrate crystal.

Background introduction

In the production process of pesticide and other organic phosphorous chemical industries, often generates and largely contain organic phosphorus compound and trivalent The waste water of phosphorus compound, the alkaline glyphosate mother liquor waste water (glycine method) generated such as herbicide glyphosate production process and acidity Double sweet phosphorus mother liquor waste waters (iminodiacetic acid (salt) acid system), dimethoate wastewater and methamidosphos wastewater etc..These waste water have high COD, height Phosphorus content, high salinity, the feature of bio-toxicity difficult to degrade, high, processing difficulty is big, and processing cost is high.These are phosphorous toxic useless Water such as without suitable treatments, will cause Heavy environmental pollution, promote the eutrophication of water body, endanger human health and ecological ring Border.

Organic phosphorus compound has refractory organics and bio-toxicity, and C-P key is stablized in molecule, interrupts the activation energy of C-P key Very high, chemical hydrolysis, pyrolysis and photodissociation do not work under normal conditions, and conventional microbiological processes can not also be handled.It wants Processing contains organism P wastewater, first has to that suitable means is taken to be converted into pentavalent phosphate for organic phosphorus, so that its toxicity is cut down, Improve wastewater biodegradability.

Chinese granted patent " method of processing N-phosphonomethyliminaacidetic acidetic wastewater by using manganese catalytic oxidation " (publication number: CN101445292B) is open One kind high temperature and pressure, manganese salt are as catalyst under conditions of, use air by it is organic phosphorus with three valent phosphors oxygenolysis for five Valence phosphate radical, then in the method for the form recycling phosphor resource of guanite precipitating.Chinese Patent Application No. CN201310166246.1 discloses a kind of utilization wet oxidation processing glyphosate mother solution, then freezing and crystallizing preparing phosphoric acid hydrogen two The method of sodium.These are using high temperature (usually above 200 using the common technology feature of wet oxidation processing organism P wastewater Degree), the operating condition of high pressure (be usually above 4Mpa) aoxidized with oxygen-containing air, operating condition is relatively hazardous, and energy consumption is high, and corrosivity is strong, Extraordinary noble metal pressure vessel is needed, cost of investment is expensive, and operating cost is high.

The present patent application proposes a kind of new method, using chlorine or liquid chlorine is added into organism P wastewater, utilizes chlorine point Son targetedly interrupts C-P key to the specific strong oxidizing property of organic phosphorus compound, by organic phosphorus compound and trivalent phosphorous compound It is oxidized to the phosphate anion of pentavalent, in conjunction with concentration (film concentration or evaporation and concentration) and freezing and crystallizing means, by the phosphorus in waste water Hydrochlorate is recycled in the form of disodium hydrogen phosphate dodecahydrate.

Reaction condition of the present invention is mild, and without expensive high temperature high voltage resistant noble metal reactor, organic phosphorus oxidation reaction is more To be thorough, compared with wet oxidation route, investment and operating cost are greatly lowered, with higher investment cost performance and preferably Phosphate recovering effect can get good economy and environmental benefit.

Summary of the invention

The present invention provides a kind of to extract manufacture phosphoric acid from the aqueous solution containing organic phosphorus compound and trivalent phosphorous compound The new process of disodium hydrogen dodecahydrate, it is characterised in that the following steps are included:

(1) suitable chlorine or liquid chlorine are added into organism P wastewater, by organic phosphorus compound and trivalent phosphorous compound It is oxidized into the pentavalent phosphate anion of inorganic states.Organism P wastewater lower for total phosphorus concentration, it is contemplated that first using concentration Means (film concentration or be concentrated by evaporation) total phosphorus concentration is improved after again chlorination aoxidize, in order to which subsequent freezing and crystallizing recycles phosphorus Sour disodium hydrogen, while reducing reactor volume.Different waste water is contained organic phosphorus and trivalent phosphorous compound due to ingredient difference Type is different with concentration difference, required best chlorine dosage, can determine optimum dosage by testing.In organism P wastewater Organic phosphorus and three valent phosphors can react at normal temperature with the chlorine or liquid chlorine being dissolved in the water, react usually several It can be completed substantially in hour.Appropriate to increase temperature, reaction speed is accelerated, and the reaction time accelerates, and oxidation effectiveness is more preferable, but by In the solubility with temperature of chlorine in water raising and reduce, reaction temperature is also unsuitable excessively high.Preferable reaction temperature is 30- 90 degrees Celsius.Need to be considered as suitable reactor simultaneously to guarantee the abundant reaction of added chlorine and organism P wastewater (as used concatenated multistage reactor), avoids the waste and leakage of chlorine.It is organic under suitable chlorine dosage and reaction condition The conversion ratio that phosphorus and three valent phosphors are converted into pentavalent phosphate radical can reach 90% or more.

(2) if the relatively high (PO of phosphorus acid ion concentration in the obtained solution of step 1₄ ^3-P content is not preferably less than 10000ppm), the operation of step 3 can directly be carried out；Otherwise (film concentration or evaporation) is concentrated to PO₄ ^3-P content is higher than 10000ppm or more, then carry out the operation of step 3.Selectivity is through film (such as nanofiltration membrane or reverse osmosis membrane) property of can choose Phosphate is retained, compared with evaporation and concentration, energy consumption is small, and it is at low cost, it is that one kind more preferably selects.But it before film concentration, needs It takes method appropriate such as to heat plus reducing agent, placement measure removes chlorine extra in waste water, avoid damage membrane element Part.PO after film concentration₄ ^3-P content can reach 20000ppm or more.After chlorination oxidation, the pH of usual waste water can decline, terminal pH Value depends on system initial pH value, total alkalinity and chlorine dosage.If the too low influence film concentration of endpoint pH or evaporation technology, use are pure Solution ph is adjusted to suitable ph by alkali or sodium hydroxide.

(3) the organism P wastewater pH with sour (preferably hydrochloric acid) after either alkali (sodium hydroxide or soda ash) reacts chlorination Value is adjusted to pH 6-pH 11 (preferred range is pH 7-pH 9), makes the phosphate in solution mainly with phosphoric acid hydrogen radical ion shape Formula exists.Phosphoric acid is strong acid in ternary, and pKa value is 2.1,7.2 and 12.3 respectively.According to the distribution curve of phosphoric acid it is found that molten When liquid pH is less than 2.1, mainly exist in the form of phosphoric acid.In pH2.1, phosphoric acid and dihydrogen phosphate respectively account for 50% or so.? Between pH 2.1 and pH 7.2, exist mainly in the form of dihydrogen phosphate.In pH 7.2, dihydrogen phosphate and phosphoric acid hydrogen Root respectively accounts for 50% or so.Between pH 7.2 and pH 12.3, exist mainly in the form of hydrogen phosphate.

(4) many organism P wastewaters contain sodium at high concentration ion, phosphoric acid hydrogen radical ion often containing the sodium ion of high concentration Aqueous solution be cooled to 12 degrees Celsius or less (preferred temperatures be 0-5 degrees Celsius), 12 water of disodium hydrogen phosphate if more than The saturation solubility of object is closed, just crystallization generates solid disodium hydrogen phosphate dodecahydrate.If Na ion concentration is not in waste water It is enough, sodium ion (such as sodium chloride) can be supplemented suitably to guarantee crystallization effect.

(5) (such as suction filtration or centrifugation means) are separated by solid-liquid separation to the oxidation solution after crystallization, obtain disodium hydrogen phosphate The solid crude product and residual solution of dodecahydrate.

(6) step 1 to step 5 is repeated after the residual solution of step 5 being concentrated to operate, and disodium hydrogen phosphate 12 can be improved Hydrate solids total recovery.

(7) crude product of gained disodium hydrogen phosphate dodecahydrate often contains a certain amount of impurity, can be washed, again The technological means such as crystallization are purified, to obtain qualified products.

Specific embodiment

Below in conjunction with specific embodiment, the invention will be further described.

Embodiment 1

5 tons of alkalinity glyphosate mother solution caused by producing glyphosate by using glycine are taken, are passed through 320 kilograms of chlorine closed anti- Stirring in kettle is answered sufficiently to react, 60 degree of reaction temperature, the reaction time 12 hours.It is 22400mg/L that total phosphorus is detected after reaction, wherein PO₄ ^3-- P concentration is 20700mg/L.Adding sodium hydroxide is adjusted to pH 7.5 after the reaction was completed.Then knot is freezed under 3 degrees Celsius After 12 hours brilliant, suction filtration obtains 1085 kg of phosphoric acid disodium hydrogen dodecahydrate solid crude products.Residual solution is again passed by into nanofiltration Film concentration, reoxidized, adjusting pH, freezing and crystallizing, suction filtration obtain 208 kg of phosphoric acid disodium hydrogen dodecahydrate solid crude products. The above process can be repeated several times, in glyphosate mother solution the yield of total phosphorus preparing phosphoric acid disodium hydrogen can achieve theoretical yield 97% with On.After being purified to above-mentioned 12 crystalline of crude product disodium hydrogen phosphate using cold pure water, recrystallization, obtained using fluidized bed drying To the product of higher degree.Testing result shows that product quality meets country HG/T 2965-2009 industrial phosphoric acid disodium hydrogen mark It is quasi-.

Embodiment 2

Acid 5 tons of pmida mother liquor are taken, 170 kilograms of chlorine is passed through and reaction is sufficiently stirred in closed reactor, are reacted 60 degree of temperature, the reaction time 12 hours.It is 12400ppm that total phosphorus is detected after reaction, wherein PO₄ ^3-- P concentration is 10900ppm.Instead After the completion of answering, solution ph is highly acid, and adding sodium hydroxide is adjusted to pH 7.5.Then small in 3 degrees Celsius of lower freezing and crystallizings 12 Shi Hou, suction filtration obtain 458 kg of phosphoric acid disodium hydrogen dodecahydrate solid crude products.By residual solution again pass by nanofiltration membrane concentration, Reoxidized, adjusting pH, freezing and crystallizing, suction filtration obtain 197 kg of phosphoric acid disodium hydrogen dodecahydrate solid crude products.It can weigh again The above process is answered, the yield of total phosphorus preparing phosphoric acid disodium hydrogen can achieve 97% or more theoretical yield in pmida mother liquor.To upper After 12 crystalline of crude product disodium hydrogen phosphate is stated using cold pure water, recrystallization purification, obtained using fluidized bed drying higher The product of purity.Testing result shows that product quality meets the industrial phosphoric acid disodium hydrogen mark in national standard HG/T 2965-2009 It is quasi-.

The above-mentioned description to embodiment is for that can understand and apply the invention convenient for those skilled in the art. Person skilled in the art obviously easily can make various modifications to these embodiments, and described herein general Principle is applied in other embodiments without having to go through creative labor.Therefore, the present invention is not limited to embodiments here, originally Field technical staff announcement according to the present invention, the improvement made for the present invention and modification all should be in protection models of the invention Within enclosing.

Claims

1. a kind of method of chlorination oxidation processes organism P wastewater and preparing phosphoric acid disodium hydrogen, it is characterised in that including following step It is rapid: 1) that appropriate chlorine or liquid chlorine being added into organism P wastewater, organic phosphorus compound and trivalent phosphorous compound are oxidized into The pentavalent phosphate radical of inorganic states；2) as step 1 aoxidizes in resulting solution, phosphate concentration is higher, can directly carry out step 3 Operation carries out the operation of step 3 again after being otherwise concentrated；3) oxidation solution ph is adjusted to pH6-pH11 (preferred range is There is phosphate mainly in the form of hydrogen phosphate, solution is then cooled to 12 degrees Celsius or less (preferably Temperature is 0-5 degrees Celsius), phosphoric acid hydrogen radical ion and sodium ion crystallization in solution generate solid disodium hydrogen phosphate 12 and are hydrated Object；If sodium ion in liquor concentration is too low, appropriate sodium salt can be added and promote crystallization process；4) it carries out being separated by solid-liquid separation and obtains phosphoric acid hydrogen Disodium dodecahydrate solid crude product and residual solution obtain qualified product after solid crude product purification；5) after residual solution being concentrated Repeating step 1, the total recovery of disodium hydrogen phosphate dodecahydrate solid can be improved to step 4 operation.