CN104445293A

CN104445293A - Method for recycling waste potassium nitrate generated in glass toughening into potassium nitrate reagent

Info

Publication number: CN104445293A
Application number: CN201410808898.5A
Authority: CN
Inventors: 刘建; 曹灵峰
Original assignee: CHANGSHA XINBEN CHEMICAL CO LTD
Current assignee: CHANGSHA XINBEN CHEMICAL CO LTD
Priority date: 2014-12-22
Filing date: 2014-12-22
Publication date: 2015-03-25

Abstract

The invention discloses a method for recycling waste potassium nitrate generated in glass toughening into a potassium nitrate reagent. The method comprises the following steps: (1) crushing waste potassium nitrate generated in chemical toughening of glass into small pieces, adding into a solvent, and heating to 80-100 DEG C to completely dissolve the waste potassium nitrate to obtain a waste potassium nitrate solution; (2) adding ammonium salt into the waste potassium nitrate solution to ensure that the mole ratio of NH<4+> to NO<2-> in the waste potassium nitrate solution is (1-1.05):1, reacting for 1-2 hours, detecting the concentration of NH<4+> ions in the solution, and regulating the pH value to be 5-7 by adding a nitric acid reagent when the concentration of the NH<4+> ions is smaller than 10ppm so as to transform potassium hydroxide and potassium carbonate in the solution into potassium nitrate; keeping the temperature for 0.5-1 hour; filtering, cooling and crystalizing to obtain a crystal product; and (3) centrifuging, washing and drying the crystal product to obtain the potassium nitrate reagent, retaining and storing a centrifuged mother liquid obtained after centrifugation and a washing liquid obtained after washing.

Description

A kind of method glass tempering waste nitric acid potassium being recovered as reagent saltpetre

Technical field

The invention belongs to technical field of chemistry and chemical engineering, be specifically related to a kind of method glass tempering waste nitric acid potassium being recovered as reagent saltpetre.

Technical background

Glass chemistry toughening saltpetre purity is the saltpetre of more than 99.6%, requires that Na ion concentration is less than 200ppm, and calcium ion, magnesium ion, iron concentration are less than 10ppm, adds a small amount of catalyzer during use.Existing market price is 10000 ~ 18000 yuan/ton, reaches more than 20000 yuan/ton from the saltpetre of Israel's import.Along with electron trade development, toughened glass screen consumption constantly increases.Chemical tempering is the process of sodium ion in the potassium ion displacement glass in fused potassium nitrate, and constantly carrying out therefore with tempering, in fused salt, sodium ion constantly increases, and when sodium ion reaches certain concentration, just can not be used for tempering, stove water can only work as scrap handling.Containing mechanical impurity, NO2 in waste nitric acid potassium ^-, CO3 ^2-, OH ^-and a small amount of organic impurity.The current annual consumption of China and generation waste nitric acid potassium amount reach more than 30,000 tons, and general producer only does Agricultural Potassium Nitrate sale by after the fragmentation of waste nitric acid potassium, recrystallization removing mechanical impurity at present, and added value is low.Simultaneously because the foreign ion in waste nitric acid potassium and organic impurity do not process, be directly brought in product, both affected product purity, in product use procedure, secondary pollution may be caused to environment again.Therefore, remove the foreign ion in waste nitric acid potassium and organic impurity, improve product purity, and then it is imperative to improve value-added content of product.

Summary of the invention

The present invention is only overcoming the deficiencies in the prior art, provides mechanical impurity, organic impurity and foreign ion in a kind of waste nitric acid potassium produced by glass chemistry toughening to remove, is recovered as the method for reagent saltpetre.

In order to achieve the above object, technical scheme provided by the invention is:

Described method glass tempering waste nitric acid potassium being recovered as reagent saltpetre comprises the steps:

(1) add in solvent after the broken frustillatum of waste nitric acid potassium glass chemistry toughening produced, be heated to 80 ~ 100 DEG C and waste nitric acid potassium is dissolved completely, obtain waste nitric acid potassium solution;

(2) in waste nitric acid potassium solution, add ammonium salt, make NH in waste nitric acid potassium solution ₄ ⁺with NO ₂ ^-mol ratio be 1 ~ 1.05:1, reaction 1 ~ 2 as a child detects NH in solution ₄ ⁺ionic concn, works as NH ₄ ⁺ionic concn adds reagent nitric acid adjust ph when being less than 10ppm be 5 ~ 7, its objective is and the potassium hydroxide in solution, salt of wormwood are converted into saltpetre, is incubated 0.5 ~ 1 hour, more after filtration, crystallisation by cooling, obtain crystallisate;

(3) crystallisate is centrifugal, washing, dry, obtain reagent saltpetre; The washings of the centrifuge mother liquor of centrifugal rear gained and the rear gained of washing retains standby depositing.

Preferably, step (1) described solvent is water.

Preferably, step (2) described ammonium salt is NH ₄cl, (NH ₄) ₂sO ₄or NH ₄nO ₃at least one in (SILVER REAGENT); Preferred NH ₄nO ₃, its objective is the Nitrite transformation in solution to be nitrate.

Preferably, for improving yield, step (3) described centrifuge mother liquor and washings are used as the solvent cycle described in step (1) after the resin absorption of wide aperture; Or detect Na in centrifuge mother liquor and washings ⁺concentration, works as Na ⁺when concentration is greater than 25000ppm, centrifuge mother liquor and washings being evaporated to hot solution proportion is 50 ~ 60, preferably 55 degree Beaume, so both ensure that the yield of saltpetre, guarantee that again in product, SODIUMNITRATE does not exceed standard, then after crystallisation by cooling, centrifugal, drying industrial potassium nitrate.

Preferably, described wide aperture resin is at least one in DXA-1, DXA-1B or DXA-7, its objective is the special catalyst component contained in absorption waste nitric acid potassium.

Compared with prior art, beneficial effect of the present invention is:

The removal of impurity technique that the present invention adopts physics removal of impurities, chemical subtraction and wide aperture resin absorption to combine, waste nitric acid potassium is purified for reagent saltpetre, yield is not less than 90%, and product indices meets reagent saltpetre standard, can be used for glass chemistry toughening, saltpetre reagent.Remaining saltpetre is recovered as industrial potassium nitrate, can be used for fireworks, glass production, and total recovery can reach 95%.

Embodiment

Embodiment 1

1) broken for 1500Kg good waste nitric acid potassium is put into be equipped with in the enamel dissolution kettle of 1000Kg deionized water, stir, be warmed up to 80 ~ 100 DEG C, dissolve completely to saltpetre;

2) NO2 in detecting step 1 solution ^-concentration be 0.03%, add 0.9Kg reagent N H ₄nO ₃, react 1 hour, detect NH in solution ₄ ⁺for 8ppm.Add reagent nitric acid again, regulator solution pH value is 6.2, is incubated 1 hour;

3) open dissolution kettle bottom valve, step 2 solution membrane filter is filtered, removing mechanical impurity;

4) step 3 solution is put into enamel crystallization kettle, crystallisation by cooling to 25 ~ 30 DEG C;

5) step 4 solution is put into centrifuge, and with a small amount of deionized water wash 2 times, obtain crude product saltpetre; Obtain simultaneously centrifugal after centrifuge mother liquor and washings after washing, standby to deposit;

6) by the ebullated dryer drying 5 hours of the crude product saltpetre of step 5, potassium nitrate product 1150Kg is obtained.

Product meets GB/T647-2011 analytical pure standard (see table 1) through inspection.

Table 1

Title	Index	Detected result
			Content (KNO ₃),w/％	》99.0	99.2

PH value	5.0～8.0	6.8
			Clarity experiment/number	《3	3
Nitrite (NO ₂),w/％	《0.001	0.0006
			Ammonium (NH ₄),w/％	《0.001	0.0005
Sodium (Na), w/%	《0.02	0.008

Embodiment 2:

1) after the adsorption tower of DXA-1 resin is housed, dissolution kettle is sent into for the mother liquor deposited and washing water by embodiment 1;

2) broken for 1200Kg good waste nitric acid potassium is put into be equipped with in the enamel dissolution kettle of 1000Kg mother liquor and washing water, stir, be warmed up to 80 ~ 100 DEG C, dissolve completely to saltpetre;

3) NO2 in detecting step 1 solution ^-concentration be 0.05%, add 2.3Kg reagent N H ₄nO ₃, react 1.5 hours, detect NH in solution ₄ ⁺for 6ppm.Add reagent nitric acid again, regulator solution pH value is 6.5, is incubated 0.5 hour;

4) open dissolution kettle bottom valve, step 2 solution membrane filter is filtered, removing mechanical impurity;

5) step 3 solution is put into enamel crystallization kettle, crystallisation by cooling to 25 ~ 30 DEG C;

6) step 4 solution is put into centrifuge, and with a small amount of deionized water wash 2 times, obtain crude product saltpetre;

7) by the ebullated dryer drying 5 hours of the crude product saltpetre of step 5, potassium nitrate product 1128Kg is obtained.

8) above-mentioned steps 1 is repeated) ~ 7) 4 times, obtain potassium nitrate product 1120Kg, 1137Kg, 1109Kg, 1140Kg successively.In conjunction with the embodiments 1, yield 90.45%.Product meets GB/T647-2011 analytical pure standard (see table 2) through inspection.

Or Na ion concentration is 26700ppm in direct-detection mother liquor and washing water, mother liquor and washing water being evaporated to hot solution proportion is 55 degree Beaume, crystallisation by cooling, centrifugal, dry, obtains 357Kg industrial potassium nitrate, total recovery 95.21%.

Table 2

Title	Index	Detected result
			Content (KNO ₃),w/％	》99.0	99.1
PH value	5.0～8.0	7.0
			Clarity experiment/number	《3	3
Nitrite (NO ₂),w/％	《0.001	0.0008
			Ammonium (NH ₄),w/％	《0.001	0.0004
Sodium (Na), w/%	《0.02	0.01

Claims

1. glass tempering waste nitric acid potassium is recovered as a method for reagent saltpetre, it is characterized in that, described method comprises the steps:

(1) add in solvent after waste nitric acid potassium fragmentation glass chemistry toughening produced, be heated to 80 ~ 100 DEG C and waste nitric acid potassium is dissolved completely, obtain waste nitric acid potassium solution;

(2) in waste nitric acid potassium solution, add ammonium salt, make NH in waste nitric acid potassium solution ₄ ⁺with NO ₂ ^-mol ratio be 1 ~ 1.05:1, reaction 1 ~ 2 as a child detects NH in solution ₄ ⁺ionic concn, works as NH ₄ ⁺ionic concn adds reagent nitric acid adjust ph when being less than 10ppm be 5 ~ 7, is incubated 0.5 ~ 1 hour, more after filtration, crystallisation by cooling, obtain crystallisate;

2. the method for claim 1, is characterized in that, step (1) described solvent is water.

3. the method for claim 1, is characterized in that, step (2) described ammonium salt is NH ₄cl, (NH ₄) ₂sO ₄or NH ₄nO ₃in at least one.

4. the method for claim 1, is characterized in that, step (3) described centrifuge mother liquor and washings is used as the solvent cycle described in step (1) after the resin absorption of wide aperture; Or detect Na in centrifuge mother liquor and washings ⁺concentration, works as Na ⁺when concentration is greater than 25000ppm, centrifuge mother liquor and washings being evaporated to hot solution proportion is 50 ~ 60 degree Beaume, after crystallisation by cooling, centrifugal, drying industrial potassium nitrate.

5. method as claimed in claim 4, it is characterized in that, described wide aperture resin is at least one in DXA-1, DXA-1B or DXA-7.