CN105552421A - Method for preparing high purity vanadyl sulfate electrolyte by secondary reduction - Google Patents

Abstract

The invention relates to a method for preparing high purity vanadyl sulfate electrolyte by secondary reduction. According to the method for preparing high purity vanadyl sulfate electrolyte by secondary reduction, the high purity vanadyl sulfate electrolyte is prepared through steps such as extracting vanadyl sulfate solution, inorganically reducing the vanadyl sulfate solution, preparing mixed extractant, carrying out back extraction on vanadyl sulfate, organically reducing vanadyl sulfate back extraction liquor and concentrating vanadyl sulfate electrolyte precursor. The method for preparing high purity vanadyl sulfate electrolyte by secondary reduction disclosed by the invention is simple in technology and low in cost and can be widely applied in mass production of the vanadyl sulfate electrolyte for all vanadium batteries.

Description

A kind of secondary reduction prepares the method for high-purity sulfuric acid vanadyl electrolyte

Technical field

The present invention relates to a kind of method that secondary reduction prepares high-purity sulfuric acid vanadyl electrolyte.

Background technology

Vanadium redox battery (VRB) is a kind of outstanding energy storage device.This battery capacity depends on amount and the vanadium ion concentration of electrolyte, and electrolyte can be separated with battery, and battery life is long, and reliability is high, can fast charging and discharging.Have great prospects for development in photovoltaic generation, wind power generation, peak load shifting etc.VRB battery does not have solid-state reaction, not the change of generating electrodes structure of matter form, and low price, safety and environmental protection, operation and maintenance expense is low.VRB battery is made up of two electrolysis liquid pools and battery unit from level to level.Electrolysis liquid pool is for holding two kinds of different electrolyte, and each electrolysis liquid pool is furnished with a pump, for being battery unit conveying electrolyte in the pipeline closed.Battery unit is made up of two " half-cells ", holds the electrolyte of the vanadium of different ions form in two " half-cell " respectively, and there are barrier film and the electrode for collected current in centre.Vanadic sulfate electrolyte is the active material of vanadium cell electrochemical reaction and the carrier of electric energy, is the critical material of all-vanadium flow battery, has a direct impact battery performance.At present, the research of vanadium cell enters practical stage, and its development still restricts by some key factors, and the low cost preparation of the vanadic sulfate electrolyte of high concentration and good stability is one of main restricting factor.Under existing all-vanadium flow battery technical conditions, in order to ensure the combination property of battery, require vanadium concentration > 2mol/L in vanadic sulfate electrolyte, require sodium, potassium or magnesium < 40ppm respectively in vanadic sulfate, calcium < 25ppm, iron, manganese, aluminium, copper, nickel, zinc, titanium, chromium, molybdenum, cobalt, silicon or arsenic etc. are < 10ppm respectively, and vanadic sulfate purity answers more than 99.98%.China has abundant steel-making vanadium slag and Rock coal containing alum resource, the vanadium concentration < 0.8mol/L of leaching in vanadium extracting process, reextraction, resin parsing gained vanadic sulfate solution, containing ferric iron and vanadic sulfate mass ratio in 0.008 ~ 0.05 scope, vanadic sulfate and metal total impurities quality (VOSO ₄/ Σ Me < 80, pH < 1.0, this vanadic sulfate solution can not meet electrolyte of vanadium redox battery technical requirement.Current, the preparation method of the vanadic sulfate solution of all-vanadium flow battery is V ₂o ₅powder directly adds H ₂sO ₄solution, heating for dissolving, then add reducing agent the valence state of vanadium is reduced to tetravalence.Vanadic sulfate solution concentration prepared by the method is low, and commercially available V ₂o ₅powder, before acid dissolve, will be purified through further removal of impurities, its energy consumption and cost high.Direct dissolving vanadic sulfate be prepare vanadic sulfate electrolyte the most directly, the easiest method.But vanadic sulfate is expensive, adopt that to prepare electrolyte of vanadium redox battery in this way infeasible economically.Electrolysis barium oxide is also used to prepare vanadic sulfate electrolyte.Method adopts H ₂sO ₄for anode chamber's electrolyte, V ₂o ₅and H ₂sO ₄for cathode chamber electrolyte, use graphite electrode constant-current electrolysis.The vanadium utilance of the method is low, and electrolyte purity depends on raw material V equally ₂o ₅purity.

Summary of the invention

The technical problem to be solved in the present invention is the above-mentioned defect how overcoming prior art, provides a kind of secondary reduction to prepare the method for high-purity sulfuric acid vanadyl electrolyte.

For solving the problems of the technologies described above, the method that this secondary reduction prepares high-purity sulfuric acid vanadyl electrolyte comprises the following steps,

Step (1): calcium hydroxide vanadium slag and bone coal are extracted, obtains the vanadic sulfate solution that pH is 3.0 ~ 4.0; By pH be 3.0 ~ 4.0 vanadic sulfate solution use ethylene glycol ether and the triethanolamine mixed liquor second extraction of new vanadium slag and mixed in equal amounts again, obtain stand-by vanadic sulfate solution;

Step (2): add step (1) and extract by reducing the sodium borohydride of dosage 7 ~ 9 times needed for oxides, divalent the vanadic sulfate solution obtained;

Step (3): according to weight ratio meter, by HDEHP: tributyl phosphate: sulfonated kerosene is 5 ~ 15: 3 ~ 5: 20 ~ 30 be mixed and made into extractant, comparing O/A=4:1, extraction time 30min, vanadic sulfate solution obtained to step (2) under the condition of settling time 10min carries out multi-stage counter current extraction, and progression is 3 ~ 6 grades;

Step (4): the extract that step (3) obtains is carried out two-phase laminated flow, spends deionized water and carries vanadium organic phase, comparing O/A=10:1, under the condition of washing time 5min; Use the sulfuric acid solution of 100g/L to carry out 3 ~ 6 grades of multi-stage countercurrents reextraction and carry a vanadium organic phase, compare O/A=10 ~ 5: 1, extraction time 10min, settling time 5min, after two-phase laminated flow, namely obtain vanadic sulfate anti-stripping agent;

Step (5): add ammoniacal liquor in the vanadic sulfate anti-stripping agent that step (4) is obtained, be 2 to vanadic sulfate anti-stripping agent pH, add vitamin C adjustment solution potential value < 100mV, with the extractant extraction that step (3) is obtained, progression is 3 ~ 6 grades, compare O/A=5 ~ 1:1, extraction time is 20min, after two-phase laminated flow, carries vanadium organic phase with the sulfuric acid solution washing of 3g/L, compare O/A=3:1, washing time 5min; Strip with the sulfuric acid solution multi-stage countercurrent of 50g/L, progression is 3 ~ 6 grades, compares O/A=10 ~ 5:1, back-extraction time 20min, namely obtains vanadic sulfate electrolyte precursor;

Step (6): by vanadic sulfate electrolyte precursor obtained for step (5) by 70% of distillation concentration its quality extremely complete, obtain this vanadic sulfate electrolyte.

The method technique that a kind of secondary reduction of the present invention prepares high-purity sulfuric acid vanadyl electrolyte is simple, with low cost, is widely used in the large-scale production of full vanadium cell vanadic sulfate electrolyte.

Embodiment

The method that this secondary reduction prepares high-purity sulfuric acid vanadyl electrolyte comprises the following steps,

Step (1): calcium hydroxide vanadium slag and bone coal are extracted, obtains the vanadic sulfate solution that pH is 3.0 ~ 4.0; By pH be 3.0 ~ 4.0 vanadic sulfate solution use styrene, perchloroethylene, the trichloroethylene mixed liquor second extraction of new vanadium slag and mixed in equal amounts again, obtain stand-by vanadic sulfate solution;

Step (2): add step (1) and extract by reducing the sodium borohydride of dosage 7 ~ 9 times needed for oxides, divalent the vanadic sulfate solution obtained;

Step (3): according to weight ratio meter, by HDEHP: tributyl phosphate: sulfonated kerosene is 5 ~ 15: 3 ~ 5: 20 ~ 30 be mixed and made into extractant, comparing O/A=4:1, extraction time 30min, vanadic sulfate solution obtained to step (2) under the condition of settling time 10min carries out multi-stage counter current extraction, and progression is 3 ~ 6 grades;

Step (4): the extract that step (3) obtains is carried out two-phase laminated flow, spends deionized water and carries vanadium organic phase, comparing O/A=10:1, under the condition of washing time 5min; Use the sulfuric acid solution of 100g/L to carry out 3 ~ 6 grades of multi-stage countercurrents reextraction and carry a vanadium organic phase, compare O/A=10 ~ 5: 1, extraction time 10min, settling time 5min, after two-phase laminated flow, namely obtain vanadic sulfate anti-stripping agent;

Step (5): add ammoniacal liquor in the vanadic sulfate anti-stripping agent that step (4) is obtained, be 2 to vanadic sulfate anti-stripping agent pH, add vitamin C adjustment solution potential value < 100mV, with the extractant extraction that step (3) is obtained, progression is 3 ~ 6 grades, compare O/A=5 ~ 1:1, extraction time is 20min, after two-phase laminated flow, carries vanadium organic phase with the sulfuric acid solution washing of 3g/L, compare O/A=3:1, washing time 5min; Strip with the sulfuric acid solution multi-stage countercurrent of 50g/L, progression is 3 ~ 6 grades, compares O/A=10 ~ 5:1, back-extraction time 20min, namely obtains vanadic sulfate electrolyte precursor;

Step (6): by vanadic sulfate electrolyte precursor obtained for step (5) by 70% of distillation concentration its quality extremely complete, obtain this vanadic sulfate electrolyte.

Above-mentioned execution mode is intended to illustrate that the present invention can be professional and technical personnel in the field and realizes or use; modifying to above-mentioned execution mode will be apparent for those skilled in the art; therefore the present invention includes but be not limited to above-mentioned execution mode; any these claims or specification of meeting describes; meet and principle disclosed herein and novelty, the method for inventive features, technique, product, all fall within protection scope of the present invention.

Claims (1)

1. secondary reduction prepares a method for high-purity sulfuric acid vanadyl electrolyte, it is characterized in that: described preparation method comprises the following steps,

Step (1): calcium hydroxide vanadium slag and bone coal are extracted, obtains the vanadic sulfate solution that pH is 3.0 ~ 4.0; By pH be 3.0 ~ 4.0 vanadic sulfate solution use ethylene glycol ether and the triethanolamine mixed liquor second extraction of new vanadium slag and mixed in equal amounts again, obtain stand-by vanadic sulfate solution;

Step (2): add step (1) and extract by reducing the sodium borohydride of dosage 7 ~ 9 times needed for oxides, divalent the vanadic sulfate solution obtained;

Step (3): according to weight ratio meter, by HDEHP: tributyl phosphate: sulfonated kerosene is 5 ~ 15: 3 ~ 5: 20 ~ 30 be mixed and made into extractant, comparing O/A=4:1, extraction time 30min, vanadic sulfate solution obtained to step (2) under the condition of settling time 10min carries out multi-stage counter current extraction, and progression is 3 ~ 6 grades;

Step (4): the extract that step (3) obtains is carried out two-phase laminated flow, spends deionized water and carries vanadium organic phase, comparing O/A=10:1, under the condition of washing time 5min; Use the sulfuric acid solution of 100g/L to carry out 3 ~ 6 grades of multi-stage countercurrents reextraction and carry a vanadium organic phase, compare O/A=10 ~ 5: 1, extraction time 10min, settling time 5min, after two-phase laminated flow, namely obtain vanadic sulfate anti-stripping agent;

Step (5): add ammoniacal liquor in the vanadic sulfate anti-stripping agent that step (4) is obtained, be 2 to vanadic sulfate anti-stripping agent pH, add vitamin C adjustment solution potential value < 100mV, with the extractant extraction that step (3) is obtained, progression is 3 ~ 6 grades, compare O/A=5 ~ 1:1, extraction time is 20min, after two-phase laminated flow, carries vanadium organic phase with the sulfuric acid solution washing of 3g/L, compare O/A=3:1, washing time 5min; Strip with the sulfuric acid solution multi-stage countercurrent of 50g/L, progression is 3 ~ 6 grades, compares O/A=10 ~ 5:1, back-extraction time 20min, namely obtains vanadic sulfate electrolyte precursor;

Step (6): by vanadic sulfate electrolyte precursor obtained for step (5) by 70% of distillation concentration its quality extremely complete, obtain this vanadic sulfate electrolyte.