CN1388065A

CN1388065A - Three-step circular metathesis process of producing potassium nitrate

Info

Publication number: CN1388065A
Application number: CN 01114497
Authority: CN
Inventors: 张罡; 徐典章; 张一甫; 沈晃宏
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-05-29
Filing date: 2001-05-29
Publication date: 2003-01-01
Anticipated expiration: 2021-05-29
Also published as: CN1194893C

Abstract

The three-step circular metathesis process of producing potassium nitrate includes: compounding 34-37 baume solution with potassium chloride, ammonium nitrate and assistant sodium nitrate in the weight ratio of 75 to 100-125 to 15-35 at 70-100 deg.c; filtering, cooling and separation to obtain potassium nitrate and mother liquor I; evaporation and concentration of mother liquor I to 37-40 baume, cooling to 50-70 deg.c and separation to obtain by-product farm ammonium chloride and mother liquor II, with the assistant sodium nitrate being always maintained in the solution for circular use. The present invention can realize the large-scale production of potassium nitrate.

Description

Three-step circular metathesis process of producing potassium nitrate

The present invention relates to a kind of double decomposition circulation process and produce saltpetre, particularly use the technical field of ammonium nitrate and Repone K preparing potassium nitrate by means of double decomposition.

At present, domestic production saltpetre mainly is to adopt metathesis four one-step circulation methods, and main flow process is: 1. add Repone K in circulating mother liquor; 2. behind the solution crystallisation by cooling again centrifugation get saltpetre; 3. add ammonium nitrate in the crystalline mother solution; 4. solution gets ammonium chloride through evaporation concentration, crystallisation by cooling, centrifugation, separates Recycling Mother Solution and uses.This production technique has the following disadvantages:

If when 1. using ammonium nitrate production producer work in-process ammonium nitrate solution to produce saltpetre, contained moisture content in the work in-process ammonium nitrate solution must evaporate in process of production, thereby makes that energy consumption increases in the production process, and the production time prolongs.

2. this production technique mainly is made up of four steps, and technology controlling and process is too much relatively, and particularly Repone K and ammonium nitrate segmentation intermittently add, and are unfavorable for realizing large-scale continuous operation.

The object of the present invention is to provide a kind of can further saving energy and reduce the cost, reduce operation steps, realize the method that the large-scale continuous industrial double decomposition circulation process of saltpetre is produced saltpetre.

Main contents of the present invention and technical characterictic are: with Repone K, ammonium nitrate, auxiliary agent SODIUMNITRATE by weight 75: (100～125): (15～35) are made into the solution of 34～37 degree Beaume under 70～100 ℃ of temperature, filter the back cooling and be cooled to 15～30 ℃, centrifugation gets saltpetre and mother liquor I, with mother liquor I evaporation concentration to 37～40 degree Beaume, be cooled to 50～70 ℃ again, then the feed liquid centrifugation got byproduct ammonium chloride and mother liquor II.

The auxiliary agent SODIUMNITRATE is only adding for the first time, after be retained in the solution all the time and circulate, SODIUMNITRATE content is 4.5～11% in the mother liquor.

Describe in detail below:

1. with Repone K, ammonium nitrate, SODIUMNITRATE by weight 75: (100～125): (15～35) are soluble in water, are deployed into the solution of 34～37 degree Beaume under 70～100 ℃ of temperature.SODIUMNITRATE is to add in the reaction soln its main effect as auxiliary agent: the one, improve the product crystalline quality, and the 2nd, help improving product yield.Because SODIUMNITRATE solubleness is big, and SODIUMNITRATE content is less relatively in the solution, SODIUMNITRATE content is 4.5～11% in the mother liquor, and therefore, the auxiliary agent SODIUMNITRATE is retained in the solution all the time and circulates.

2. after solution being filtered, cool again.Along with the reduction of temperature, saltpetre solubleness reduces in the solution.Therefore, solution temperature descends low more (as 0 ℃), and saltpetre solubleness is also low, and the potassium nitrate crystal amount of separating out is many more.But, in the temperature range that the present invention selects solution is cooled to be easy to realize, promptly be cooled to 15～30 ℃ from the consideration that cuts down the consumption of energy.

3. cooled feed liquid is sent from scheming and carries out centrifugation, and in sepn process, use a small amount of cold water washing, separate obtaining agricultural saltpetre of major product of the present invention and mother liquor I.Agricultural saltpetre contains k ₂O 〉=44.3%, N 〉=13.2%, CL≤0.8%, H ₂O≤3.0%.

4. with mother liquor I evaporation concentration to 37～40 degree Beaume, be cooled to 50～70 ℃ again, then feed liquid be sent from scheming and carry out centrifugation, separate byproduct agricultural ammonium chloride of the present invention and mother liquor II.The gained agricultural ammonium chloride contains N 〉=23.6%, K ₂O≤7%, H ₂O≤3.0%

5. by weight 75: (78～81) add Repone K and ammonium nitrate in mother liquor II, add entry again, wherein the Repone K add-on be in first wife's solution the Repone K add-on 40～55%, under 70～100 ℃ of temperature, be deployed into the solution of 34～37 degree Beaume.

Press later the said sequence cyclical operation.

The present invention has following advantage:

1, being fit to ammonium nitrate production producer directly uses the work in-process ammonium nitrate solution to produce saltpetre.Compare with using solid ammonium nitrate, can save operations such as evaporation necessary in the orthonitric acid ammonium production process, centrifugal, packing carrying and dissolving, reduced production cost significantly.

2 and domestic present metathesis four one-step circulation methods produce saltpetre and compare, reduced by an addition step, make technology controlling and process more simple and convenient, help realizing the production equipment continuous operation.

3, add the auxiliary agent SODIUMNITRATE in the reaction soln, make the product crystalline quality be improved, improved product yield simultaneously, make the K in the solution ⁺Be converted into the K of saltpetre ⁺Can reach 50%.

4, complete closed cyclic production, the output product population equates substantially that with input raw material total amount generally speaking, 1 ton of saltpetre of every production consumes 0.81 ton in Repone K, 0.86 ton in ammonium nitrate, 0.67 ton of byproduct agricultural ammonium chloride, raw material availability height.

5, metathesis four one-step circulation methods of domestic present employing are produced the saltpetre device as using present method instead, and equipment is not done change substantially, and comprehensive cost has bigger decline.

6, product saltpetre quality meets and exceeds external agricultural saltpetre.

7, no any " three wastes " produce, and environment is not had any pollution.

Description of drawings:

Fig. 1 is a technological process block-diagram of the present invention.

Embodiment of the present invention as shown in Figure 1, with Repone K, ammonium nitrate, auxiliary agent SODIUMNITRATE by weight 75: (100～125): (15～35) are made into the solution of 34～37 degree Beaume under 70～100 ℃ of temperature, filter the back cooling and be cooled to 15～30 ℃, centrifugation gets saltpetre and mother liquor I, with mother liquor I evaporation concentration to 37～40 degree Beaume, be cooled to 50～70 ℃ again, then feed liquid is sent from scheming and carries out centrifugation, separate byproduct agricultural ammonium chloride and mother liquor II, mother liquor II recycles.

Embodiment 1: with Repone K (K ₂O 〉=60%, NaCl≤2%), ammonium nitrate (N 〉=34.6%), auxiliary agent SODIUMNITRATE (NaNO ₃〉=98%), dissolved in the water by weight 75: 125: 15, under 70 ℃ of temperature, be made into the solution of 36 degree Beaume, after the solution filtration, under constantly stirring, solution is forced to be cooled to 30 ℃, being sent from scheming then separates, and add a small amount of cold water washing, get rid of, get agricultural saltpetre and (contain K up to no obvious drop ₂O 44.6%, and N 13.68%, and Cl 0.69%, H ₂O 2.76%) and mother liquor I;

With mother liquor I evaporation concentration to 37～40 degree Beaume, be cooled to 50～70 ℃ again, then feed liquid is sent from scheming and carries out centrifugation, separate to such an extent that the byproduct agricultural ammonium chloride (contains N 23.84%, K ₂O 6.81%, H ₂O2.76%) with mother liquor II;

Add entry among the mother liquor II, added Repone K and ammonium nitrate by weight 75: 80, its Repone K add-on be in first wife's solution the Repone K add-on 48%, under 70 ℃ of temperature, be deployed into the solution of 36 degree Beaume, after the solution filtration, be cooled to 30 ℃, centrifugation gets agricultural saltpetre and (contains K ₂O 44.6%, and N 13.41%, and Cl 0.76%, H ₂O 3.0%) and mother liquor I.

Embodiment 2: with Repone K, ammonium nitrate, auxiliary agent SODIUMNITRATE, dissolved in the water by weight 75: 100: 35, be made into the solution of 34 degree Beaume under 100 ℃ of temperature, after the solution filtration, under constantly stirring, solution is forced to be cooled to 15 ℃, be sent from scheming and separate, get agricultural saltpetre and (contain K ₂O 44.32%, N13.3%, and Cl 0.67%, H ₂O 2.90%) and mother liquor I;

Mother liquor I evaporation concentration to 37 degree Beaume, is cooled to 50 ℃ again, then feed liquid is sent from scheming and carries out centrifugation, get the byproduct agricultural ammonium chloride and (contain N 24.84%, K ₂O 4.98%, H ₂O 2.53%) and mother liquor II;

Add entry among the mother liquor II, added Repone K and ammonium nitrate by weight 75: 79, its Repone K add-on be in first wife's solution the Repone K add-on 51%, under 100 ℃ of temperature, be deployed into the solution of 34 degree Beaume, after the solution filtration, be cooled to 15 ℃, centrifugation gets agricultural saltpetre and (contains K ₂O 44.41%, and N 13.34%, and Cl 0.58%, H ₂O 2.8%) and mother liquor I.

Claims

1, a kind of three-step circular metathesis process of producing potassium nitrate is characterized in that may further comprise the steps:

1. with Repone K, ammonium nitrate, auxiliary agent SODIUMNITRATE by weight 75: (100～125): (15～35) are deployed into the solution of 34～37 degree Beaume under 70～100 ℃ of temperature;

2. solution filtration, cooling are cooled to 15～30 ℃, centrifugation mother liquor I and saltpetre;

3. with mother liquor I evaporation concentration to 37～40 degree Beaume, be cooled to 50～70 ℃ again, centrifugation gets ammonium chloride and mother liquor II.

2, method according to claim 1 is characterized in that the auxiliary agent SODIUMNITRATE is only adding for the first time, after be retained in the solution all the time and circulate, SODIUMNITRATE content is 4.5～11% in the mother liquor.