CN101985426B - Method for treating glyphosate mother solution - Google Patents

Abstract

The invention discloses a method for treating glyphosate mother solution, which comprises the following steps of: adding aqueous solution of calcium hydroxide into the glyphosate mother solution to regulate pH until the solution is alkaline and make triethylamine hydrochloride in the mother solution generate triethylamine simultaneously; adding the treated glyphosate mother solution into a distillation tower for distillation, and collecting 40 to 100 DEG C fractions on the top of the tower; adding a dehydrating agent into the fractions on the top of the tower to obtain the triethylamine; and adding hydrochloric acid into the mother solution at the bottom of the tower to regulate the pH until the solution is neutral, performing solid-liquid separation and treating and discharging separated waste water. The process is simple and high-efficiency; the recovery rate of the triethylamine is over 98.5 percent; the chemical oxygen demand (COD) of the discharged waste water is less than 500mg/L, total phosphate (TP) is less than 1mg/L and ammonia nitrogen is less than 15mg/L; the zero emission of the waste water is basically realized; and the method has great environmental benefit and economical benefit.

Description

A kind for the treatment of process of glyphosate mother solution

Technical field

The present invention relates to a kind for the treatment of process of glyphosate mother solution, thereby particularly a kind of production from the dialkyl phosphite method reclaimed triethylamine the glyphosate crystalline mother solution that glyphosate obtains and do not had the treatment process that waste water is discharged substantially.

Technical background

Glyphosate is as the steriland herbicide of a kind of efficient, wide spectrum, low toxicity, and range of application has more and more widely become at present the weedicide of consumption maximum in the world, and current domestic preparation glyphosate adopts dialkyl phosphite method and iminodiacetic acid (salt) acid system more.

The glyphosate crystalline mother solution treatment process that produces in the glyphosate of the dialkyl phosphite method production at present process mainly is that crystalline mother solution is added the liquid caustic soda neutralization, the triethylamine layering is come out, change synthetic the use after the dehydration over to, the separation mother liquor advances rectifying tower and carries out rectifying, the triethylamine reuse utilization that steams, the mother liquor after the rectifying carries out membrane concentration and prepares 10% aqua.

But along with the progressively raising of country to environmental requirement, active constituent content is lower than 30% gyphosate solution and has not allowed to carry out production and selling.This means the incompatible requirement at present of technology that present glyphosate enterprise handles mother liquor, must have some changes or upgrade.Patent 200410099086.4 and 200610154907.9 proposes to feed ammonia and reclaims triethylamine in glyphosate mother solution, the ammonium glyphosate that ammonium chloride obtains concentrating is removed in the redistillation dehydration, but its triethylamine rate of recovery is lower, the concentrated ammonium glyphosate salts solution that obtains simultaneously is not easy to be recycled yet, and cost is higher.

Now, seeking a kind of triethylamine that can reclaim can reduce waste water again to discharge, alleviate the treatment process of the glyphosate mother solution of environmental protection pressure be the problem that the glyphosate industry needs to be resolved hurrily.

Summary of the invention

The invention provides a kind of dialkyl phosphite method and produce the treatment process of the glyphosate mother solution that obtains, this method is compared with existing technology, reduced production cost, improved the triethylamine rate of recovery, efficiently solve the handling problem of glyphosate mother solution, substantially realize the zero release of waste water, had bigger environmental protection and economic benefit.

Handle problems in order to solve glyphosate mother solution, the contriver has obtained through a large amount of creative experiments that a kind of operation is simple, the high-efficient treatment method of economical rationality, present method has replaced liquid caustic soda in the existing technology with alkaline calcium, not only reduce wastewater flow rate, reduced cost, and calcium ion makes COD and TP in the waste water reduce about 70% than existing technology also with the organophosphorus in the mother liquor and inorganic phosphorus precipitation; Present method employing distillation tower removes the triethylamine in the mother liquor, and simple to operate, the rate of recovery can reach more than 98%.This shows that present method has solved the deficiency that exists in the existing technology, realized the progress of glyphosate mother solution treatment technology.

Concrete technical scheme of the present invention is as follows:

A kind for the treatment of process of glyphosate mother solution is characterized in that may further comprise the steps at least:

(1) add calcium hydroxide aqueous solution in the glyphosphonic acid aqueous mother liquor and make mother liquor become alkalescence, the triethylamine hydrochloride reaction in the mother liquor simultaneously generates triethylamine;

(2) glyphosate mother solution after step (1) is handled flows into distillation tower and distills, and collects the cut of 40～100 ℃ of cats head;

(3) add dewatering agent in the overhead fraction and obtain triethylamine;

(4) add hydrochloric acid at the bottom of the tower in the mother liquor and regulate pH to neutral, carry out solid-liquid separation then, the waste water after the separation is discharged after treatment;

Wherein, step (3) is interchangeable with step (4) order.

When glyphosate mother solution of the present invention was equipped with glyphosate for adopting the dialkyl phosphite legal system, the remaining glyphosphonic acid aqueous mother liquor in back was separated out in the glyphosate crystallization.

In the above-mentioned steps (1), calcium hydroxide aqueous solution concentration is 10～25wt%; Add calcium hydroxide aqueous solution and be adjusted to glyphosate mother solution pH more than or equal to 10.5, preferably regulate pH to 10.5-12.0.

In the above-mentioned steps (2), the distillation tower working pressure is absolute pressure 0.1～1.0atm.

In the above-mentioned steps (3), described dewatering agent is sodium hydroxide or calcium oxide.

In the above-mentioned steps (4), adopt at least a of following method to handle before waste water is discharged:

A. waste water reclamation is used for the preparation calcium hydroxide aqueous solution;

B. waste water reclaims calcium chloride through distillation dehydration, and the waste water after the recovery is discharged, and the calcium chloride that the waste water distillation dehydration obtains is hydration calcium chloride or Calcium Chloride Powder Anhydrous.

Treatment process gained triethylamine water content of the present invention is less than 0.5%, and the triethylamine rate of recovery is more than 98.5%, and the waste water COD of discharge is less than 500mg/L, and TP is less than 1mg/L, and ammonia nitrogen is less than 15mg/L.

Adopt the present invention to handle the glyphosate crystalline mother solution and have following advantages:

(1) owing to adopt alkaline calcium to replace in the existing technology in the liquid caustic soda and reclaim triethylamine, wastewater flow rate reduces, and cost also has substantial degradation simultaneously;

(2) owing to added the calcic thing, the organophosphorus in the mother liquor and inorganic phosphorus and calcium reaction generate precipitation and remove, and have reduced COD and the TP of waste water, have alleviated the subsequent disposal load.

(3) adopt technology of the present invention simple, efficient, the triethylamine rate of recovery does not have waste water substantially and discharges more than 98.5%, and the environmental protection and economy benefit is outstanding.

Embodiment

Below by specific embodiment the present invention is further set forth, should be understood that, following explanation only is in order to explain the present invention, its particular content not to be limited.

Embodiment 1

Get the glyphosate crystalline mother solution 1000.0g that contains triethylamine 19.8%, the aqueous solution 800.0g that adds the calcium hydroxide of 10% concentration fully mixes, pH of mixed 10.5 is squeezed in normal pressure (absolute pressure the is 1.0atm) water distilling apparatus and is distilled, and collects 70～100 ℃ cut.

The cut that steams is water white triethylamine, adds to obtain 98.5% triethylamine 198.0g, water content 0.4%, the triethylamine rate of recovery 98.5% after sheet alkali dewaters.

Tower bottoms after the distillation adds hydrochloric acid and is adjusted to neutral filtering separation, obtains the calcium chloride solution of concentration about 15%.

Embodiment 2

Get the calcium chloride solution that obtains among the embodiment 1 and add calcium oxide and be made into 20% the aqueous solution, standby.

Get the glyphosate crystalline mother solution 1000.0g that contains triethylamine 19.8%, the aqueous solution 420.0g that adds the calcium hydroxide of 20% concentration fully mixes, pH of mixed 11.0 is squeezed in decompression (absolute pressure the is 0.3atm) water distilling apparatus and is distilled, and collects 45～70 ℃ cut.

The cut that steams is water white triethylamine, adds to obtain 98.5% triethylamine 199.1g, water content 0.5%, the triethylamine rate of recovery 99.0% after calcium oxide dewaters.

Tower bottoms after the distillation adds hydrochloric acid and is adjusted to neutral filtering separation, obtains the calcium chloride solution of concentration about 25%.

Embodiment 3

Get the calcium chloride solution that obtains among the embodiment 1 and add calcium oxide and be made into 25% the aqueous solution, standby.

Get the glyphosate crystalline mother solution 1000.0g that contains triethylamine 19.8%, the aqueous solution 350.0g that adds the calcium hydroxide of 25% concentration fully mixes, pH of mixed 11.8 is squeezed in decompression (absolute pressure the is 0.1atm) water distilling apparatus and is distilled, and collects 40～60 ℃ cut.

The cut that steams is water white triethylamine, adds to obtain 98.5% triethylamine 200.0g, water content 0.4%, the triethylamine rate of recovery 99.5% after calcium oxide dewaters.

Tower bottoms after the distillation adds hydrochloric acid and is adjusted to neutral filtering separation, obtains the calcium chloride solution of concentration about 30%.

Embodiment 4

Get the calcium chloride solution that obtains among the embodiment 2 and add calcium oxide and be made into 15% the aqueous solution, standby.

Get the glyphosate crystalline mother solution 1000.0g that contains triethylamine 19.8%, the aqueous solution 600g that adds the calcium hydroxide of 15% concentration fully mixes, pH of mixed 11.5 is squeezed in decompression (absolute pressure the is 0.5atm) water distilling apparatus and is distilled, and collects 45～82 ℃ cut.

The cut that steams is water white triethylamine, adds to obtain 98.5% triethylamine 199.6g, water content 0.3%, the triethylamine rate of recovery 99.3% after calcium oxide dewaters.

Tower bottoms after the distillation adds hydrochloric acid and is adjusted to neutral filtering separation, obtains the calcium chloride solution of concentration about 25%.Obtain hydration calcium chloride or Calcium Chloride Powder Anhydrous after the aqueous solution evaporate dehydration of this calcium chloride, the COD of evaporation condensate is less than 500mg/L, and TP is less than 1mg/L, and ammonia nitrogen is less than 15mg/L.

Embodiment 5

PH is 14.0 after adding calcium hydroxide aqueous solution, and other steps are with embodiment 4, and the gained triethylamine rate of recovery is 99.5%.Mother liquor adds hydrochloric acid and is adjusted to neutral filtering separation at the bottom of the tower, obtains the calcium chloride solution of concentration about 26%.This calcium chloride solution part reclaims and is used for the preparation calcium hydroxide aqueous solution, and remaining gets hydration calcium chloride or Calcium Chloride Powder Anhydrous through distillation dehydration, and COD is less than 500mg/L in the remaining phlegma in evaporation back, and TP is less than 1mg/L, and ammonia nitrogen is less than 15mg/L.

Embodiment 6

PH is 13.0 after adding calcium hydroxide aqueous solution, and other are with embodiment 3.

The used hydrochloric acid of the present invention is the pH regulator agent, and its concentration is not particularly limited, and among above-mentioned all embodiment, the processing sequence of composition is not limit at the bottom of the dehydration of cat head composition and the tower.

Claims (9)

1. the treatment process of a glyphosate mother solution is characterized in that may further comprise the steps at least:

(1) add calcium hydroxide aqueous solution in the glyphosphonic acid aqueous mother liquor and make mother liquor become alkalescence, the triethylamine hydrochloride reaction in the mother liquor simultaneously generates triethylamine;

(2) glyphosate mother solution after step (1) is handled flows into distillation tower and distills, and collects the cut of 40 ~ 100 ℃ of cats head;

(3) add dewatering agent in the overhead fraction and obtain triethylamine;

(4) add hydrochloric acid at the bottom of the tower in the mother liquor and regulate pH to neutral, carry out solid-liquid separation then, the waste water after the separation is discharged after treatment;

When described glyphosate mother solution was equipped with glyphosate for adopting the dialkyl phosphite legal system, the remaining glyphosphonic acid aqueous mother liquor in back was separated out in the glyphosate crystallization.

2. treatment process according to claim 1 is characterized in that: in the step (4), adopt at least a processing the in the following method before waste water is discharged:

A. waste water reclamation is used for the preparation calcium hydroxide aqueous solution;

B. waste water reclaims calcium chloride through distillation dehydration, and the waste water after the recovery is discharged.

3. treatment process according to claim 1 and 2 is characterized in that: calcium hydroxide aqueous solution concentration is 10 ~ 25wt% in the step (1).

4. treatment process according to claim 1 and 2 is characterized in that: in the step (1), add calcium hydroxide aqueous solution and be adjusted to glyphosate mother solution pH more than or equal to 10.5.

5. treatment process according to claim 4 is characterized in that: in the step (1), adding calcium hydroxide aqueous solution, to be adjusted to glyphosate mother solution pH be 10.5-12.0.

6. treatment process according to claim 1 and 2 is characterized in that: the distillation tower working pressure is absolute pressure 0.1 ~ 1.0atm in the step (2).

7. treatment process according to claim 1 and 2, it is characterized in that: dewatering agent is sodium hydroxide or calcium oxide described in the step (3).

8. treatment process according to claim 1 and 2 is characterized in that: dehydration back triethylamine water content is less than 0.5%, and the triethylamine rate of recovery is more than 98.5%; The waste water COD of discharging is less than 500mg/L, and TP is less than 1mg/L, and ammonia nitrogen is less than 15mg/L.

9. treatment process according to claim 1 and 2 is characterized in that: step (3) is interchangeable with step (4) order.