CN101734690A - Method for preparing potassium nitrate by solvent extraction method - Google Patents

Abstract

The invention discloses a method for preparing potassium nitrate by a solvent extraction method, belonging to the technical field of fertilizer. The method comprises the following steps: adding KCl and cooled 10-30%(wt) of HNO3 according to stoichiometric ratio into a first reactor operated under 10 DEG C for reaction, selecting olefine aldehyde as solvent, extracting solvent containing HNO3 and HCl in a second reactor, and finally obtaining HCl dilute aqueous solution, and washing HNO3 in ethanol containing HNO3 by water for cycle use. The method has the advantages as follows: (1) the concentration of HNO3 is reduced to 10-30%(wt), the reaction temperature of HNO3 is low, the energy consumption is little, and the method has no side effect; (2) the corrodibility is less, and the problem of device corrosion can be solved easily; and (3) the side product is pure HCl, and can be directly used as products for sale or developed into other downstream products.

Description

A kind of method of preparing potassium nitrate by solvent extraction method

Technical field: the invention belongs to technical field of fertilizers, be specifically related to a kind of preparation method of preparing potassium nitrate by solvent extraction method.

Background technology: saltpetre is widely used in fields such as military and fireworks as a kind of important oxygenant.In addition, it still is a kind of nutritive ingredient up to 60% high-quality chemical fertilizer.But, restricted it as the application of chemical fertilizer on China's agricultural because its production cost is higher.In recent years, Israel and Chilean Production of Potassium Nitrate company open and seize the huge agricultural saltpetre market of China in order to be eager, adopted well below the mode of international market price and sold agricultural saltpetre, had a strong impact on the development of China's Production of Potassium Nitrate to China.Especially over past 2 years, the influence that rapidly gone up by coal, oil equal energy source price, domestic saltpetre industry is faced with great challenge, therefore have now on the basis of Production of Potassium Nitrate technology at home and abroad, develop the Production of Potassium Nitrate novel process that raw material is cheap and easy to get, the production process energy consumption is low, reduce production costs and product price to promoting that China's saltpetre industrial expansion is very necessary.

Produce in the method for saltpetre at present, potassium element all comes from Repone K.According to NO ₃ ^-The difference in source, the method for domestic production saltpetre mainly contains 2 kinds: 1. ammonium nitrate-Repone K conversion method.System makes saltpetre with ammonium nitrate and Repone K metathesis, and side product sodium chloride.Because there are a series of problems such as equipment corrosion is serious, running is difficult to control, products obtained therefrom purity is low in this method, and the ammonium chloride of by-product is on the low side, energy consumption is more, causes saltpetre products production cost than higher.2. ion exchange method.System makes product with ammonium nitrate and Repone K by ion exchange reaction, and side product sodium chloride.This method major defect is that energy consumption is very high, equipment is huge and complex structure, because coal and other energy prices continuous rises cause saltpetre products production cost to increase always, economic benefit continues to descend.

Summary of the invention: the present invention is directed to existing production saltpetre method defect of insufficient, and the production saltpetre method of exploitation.

The present invention is achieved in that

KCl and chilled 10-30% (wt) HNO ₃Join below 10 ℃ with stoichiometric ratio in first reactor of operation and react, circulating mother liquor and recovery contain small amount of H NO ₃Solvent also join in this reactor, solvent is preferably octenal.HCl and the unreacted HNO of part that reaction process generates ₃Be extracted and enter organic phase and be removed KNO ₃Crystallization obtains KNO through sedimentation and centrifugation ₃Filter cake promptly gets KNO after the oven dry ₃Product contains K ⁺, HNO ₃Mother liquor turn back in first reactor.Contain HNO ₃With the solvent phase of HCl through the extraction of second reactor after, use H again ₂O washs it, and what obtain at last contains HNO ₃Solvent return first reactor and neutralize in second reactor, contain HNO ₃With the extracting phase of HCl with selectivity preferably extraction agent ethanol with aqueous phase HNO ₃Extract, obtain the HCl dilute aqueous soln at last, contain HNO ₃Ethanol H ₂O is with HNO ₃Recycle after washing.

The advantage that this technology is outstanding is: 1. the HCl liquid quality fraction as by product is 1%-5%, and the heat of consumption still less; 2. the contained HNO of HCl solution ₃Mass concentration only be about 0.02-1g/L, do not have HNO ₃The loss problem, do not need its processing yet; 3. the H in the system ₂The O balance is by extracting the crystalline mother solution recovery HNO wherein of second reactor ₃, H ₂O leaves system with rare HCl solution form, does not need through the solvent dehydration operation.

The following advantage of this method is more favored: 1. HNO ₃Concentration reduce to 10-30% (wt), HNO ₃Temperature of reaction is low, and less energy consumption does not have side reaction; 2. corrodibility is smaller, and the equipment corrosion problem solves easily; 3. by product is purified hydrochloric acid, can directly sell or develop into other derived product as product.

Embodiment: the present invention is described in detail below in conjunction with embodiment.

Embodiment 1

With KCl and chilled 20% (wt) HNO ₃Join in 0 ℃ of first reactor with stoichiometric ratio and to react, circulating mother liquor and recovery contain small amount of H NO ₃The solvent octenal also join in this reactor HCl and the unreacted HNO of part that reaction process generates ₃Be extracted and enter organic phase and be removed KNO ₃Crystallization obtains KNO through sedimentation and centrifugation ₃Filter cake promptly gets KNO after the oven dry ₃Product.Contain K ⁺, HNO ₃Mother liquor turn back in first reactor.Contain HNO ₃With the solvent phase of HCl through the extraction of second reactor after, use H again ₂O washs it, and what obtain at last contains HNO ₃Solvent return first reactor and neutralize in second reactor, contain HNO ₃With the extracting phase of HCl with selectivity preferably extraction agent ethanol with aqueous phase HNO ₃Extract, obtain the HCl dilute aqueous soln at last, contain HNO ₃Ethanol H ₂O is with HNO ₃Recycle after washing.

Claims (2)

1. the method for a preparing potassium nitrate by solvent extraction method, it is characterized in that KCl and chilled 10-30% (wt) HNO3 join below 10 ℃ with stoichiometric ratio in first reactor of operation reacts, the octenal solvent that contains small amount of H NO3 of circulating mother liquor and recovery also joins in this reactor, HCl that reaction process generates and the unreacted HNO3 of part are extracted and enter organic phase and be removed, the KNO3 crystallization obtains the KNO3 filter cake through sedimentation and centrifugation, promptly gets the KNO3 product after the oven dry.

2. the method for claim 1, the solvent phase that it is characterized in that containing HNO3 and HCl through the extraction of second reactor after, with H2O it is washed again, the solvent that contains HNO3 that obtains at last returns first reactor and neutralizes in second reactor, the extracting phase that contains HNO3 and HCl with selectivity preferably extraction agent ethanol aqueous phase HNO3 is extracted, obtain the HCl dilute aqueous soln at last, recycle after the ethanol that contains HNO3 washs HNO3 get off with H2O.