CN102353574A

CN102353574A - Analysis method of iron content in cationic exchange resin

Info

Publication number: CN102353574A
Application number: CN2011101978520A
Authority: CN
Inventors: 张达光; 李建华; 郑敏聪; 赵炜
Original assignee: ANHUI ACADEMY OF ELECTRIC POWER SCIENCES
Current assignee: ANHUI ACADEMY OF ELECTRIC POWER SCIENCES
Priority date: 2011-07-14
Filing date: 2011-07-14
Publication date: 2012-02-15
Anticipated expiration: 2031-07-14
Also published as: CN102353574B

Abstract

An analysis method of the iron content in cationic exchange resin comprises the following steps of: firstly preparing a sample, weighing 0.1-1.0 g of the cationic exchange resin and putting it into a microwave digestion tank, adding 1-3mL of nitric acid at the concentration of 60-65% and 1-3mL of sulfuric acid at the concentration of 98%, placing the microwave digestion tank into a microwave digestion instrument, successively processing at the pressure of 0.15-0.25MPa and at the temperature of 110-125 DEG C for 2-4 min; processing at the pressure of 0.45-0.55MPa and at the temperature of 145-155 DEG C for 4-6 min; processing at the pressure of 0.75-0.85MPa and at the temperature of 165-175 DEG C for 4-6 min; processing at the pressure of 1.1-1.3 MPa and at the temperature of 180-190 DEG C for 4-6 min; and processing at the pressure of 1.4-1.6 MPa and at the temperature of 195-205 DEG C for 4-6 min so as to obtain a digestion solution, transferring the digestion solution and a washing liquid into a volumetlric flask for constant volume so as to obtain the sample, and determining the iron content by a titration method or an atomic absorption spectrometry method. The method provided by the invention is simple to operate, is clean and safe, and can be used to obtain an accurate result.

Description

Analysis of iron content method in a kind of Zeo-karb

One, technical field

The present invention relates to a kind of quantitative elementary analysis method, exactly is analysis of iron content method in a kind of Zeo-karb.

Two, background technology

Condensate is the chief component of boiler feed water, and condensate clean-up has become very important link in the modern water treatment of power plant, and subcritical and above boiler must dispose the condensate precision processing and mix bed.Condensate clean-up be for remove that whole water, vapour system produces in startup, operation and stoppage in transit process mechanical impurity; Removal is revealed the dissolved salts of bringing into from make-up water, condensate and condenser, thereby guarantees the high-purity of feedwater; Guarantee that unit when condenser generation small leakage, can normally move, when having, can give the apply for suspension required time than gross leak.It is to dose anion and cation exchange resin therein that the condensate precision processing mixes bed; To remove the dissolubility salt of bringing in the condensate; Because the regenerant of long-time running or use is of poor quality; Resin can receive iron pollution, and the water production in periodic mode that will cause the condensate precision processing to mix bed reduces, regeneration is frequent, the phenomenons such as consumption increase of regenerant.For judging whether positive resin receives iron pollution, just need to measure the iron in the resin.

Coagulate mixing bed does not also have national standard and industry standard with the mensuration of iron content in the Zeo-karb, and analysis to measure is the assay method of iron-holder in the appendix intermediate ion exchange resin of " DL/T 673-1999 fuel-burning power plant water treatment is with 001 * 7 storng-acid cation exchange resin " with reference to use.Do a simple narration in the face of this method down:

Take by weighing ion exchange resin that 1.0g removes outside moisture in crucible, add the 1ml concentrated sulphuric acid, put into muffle furnace and progressively be warming up to 850 ℃; Constant temperature calcining 2h under this temperature takes out crucible and is chilled to room temperature, adds (1+1) hydrochloric acid 10ml; Boiling 10min under little the boiling on the electric hot plate, liquid is transferred to Erlenmeyer flask, repeat to add acid and little boiling 3～4 times again; Cleansing solution is collected in the same triangular flask, and little then boiling is concentrated into about 20ml, adds about 80ml pure water.The sulfosalicylic acid indicator 1ml of adding 10% in triangular flask drips (1+1) Ammonia slowly, fully shakes; Excessive acid to the solution that neutralizes is become orange by purple; Add 2mol/L hydrochloric acid (the pH value is 1.8～2.0), add 0.1% quinoline phenanthroline 5ml, be heated to 70 ℃; Become light yellow (iron content is low for colourless) with 0.01mol/LEDTA standard solution titration to solution by aubergine while hot and be terminal point; Titration finishes temperature should be about 60 ℃, and record consumes the volume of EDTA, can calculate the content that taps a blast furnace.

There is following shortcoming in this method:

1, in the process of preparation analytical sample, to add a large amount of hydrochloric acid, experimenter's healthy meeting is caused injury to a certain degree and can produce environmental pollution.

2, this method need be dissolved appearance in high-temperature electric resistance furnace, because heating rate is wayward, often has the situation that sample spatters mistake to take place, and causes the analysis result deviation ratio bigger.

3, need at least two workaday times from preparing to prepare a complete analytical sample solution, satisfied not modern analysis requirement fast and accurately.

4, the crucible bottom at dissolving resin has a large amount of black attachments, dissolves with acid through calcination repeatedly all can not wash, and causes analysis result low.

Three, summary of the invention

The present invention is directed to the existing existing defective of method, aim to provide a kind of new analytical approach, technical matters to be solved is to improve the preparation method of analytical sample.

This analysis method comprises the preparation of sample and the mensuration of iron content, and difference with the prior art is to adopt the method for Microwave Digestion sample dissolution to prepare sample, and specific operation process is following:

Take by weighing 0.1-1.0g Zeo-karb sample and put into the micro-wave digestion jar; Add 1～3mL concentration 60-65% (mass percentage concentration again; Down with) nitric acid and 1～3mL concentration, 98% sulfuric acid is in airtight environment, successively in 0.15-0.25MPa, temperature 110-125 ℃, 2-4min; 0.45-0.55MPa, temperature 145-155 ℃, 4-6min; 0.75-0.85MPa, temperature 165-175 ℃, 4-6min; 11-1.3MPa, temperature 180-190 ℃, 4-6min; 1.4-1.6MPa, handle under the condition of temperature 195-205 ℃, 4-6min; The release of lowering the temperature at last; Be transferred to the digestion solution in the counteracting tank in the volumetric flask, jar inwall in clearing up with the distilled water cleaning of heat, cleansing solution also is transferred in the volumetric flask together and constant volume obtains sample solution.

Prepared sample solution perhaps uses the aas determination iron content perhaps with aforesaid EDTA titration measuring iron content.

Micro-wave digestion legal system sample has the following advantages and effect:

1, this new method is simple to operate, and employed sample size is fewer.

2, the amount of adding chemicals is fewer, cost-saved in the molten appearance process, reduces the pollution to environment.

3, whole molten appearance process is in airtight environment, to carry out, and can not introduce new impurity, can fully guarantee the representativeness of sample, and can not work the mischief to human body.

4, the time ratio of the molten appearance of this method is shorter, and general 1.5h～2h just can prepare a duplicate samples.

5, use this method, guarantee that sample can clear up fully, it is accurate to measure the result.The applicant uses traditional fusion method and Microwave Digestion to prepare sample solution respectively to same Zeo-karb sample, and it is following to measure the result:

The sample that traditional fusion method makes use the EDTA titration measuring as a result iron content be 43.04mg/L.

The sample that Microwave Digestion makes use the EDTA titration measuring as a result iron content be 222.10mg/L, iron content is 222.20mg/L to use the atomic absorption spectrophotometer (AAS) calibration curve method to measure as a result.Explain that the iron result who uses fusion method to survey in the Zeo-karb is on the low side, can not truly reflect the contaminated degree of resin.

The result shows that the sample solution of this method preparation can guarantee the representativeness of sample and result's accuracy.

Four, embodiment

Taking by weighing the model that 0.5g takes from the coagulation bed is D001MBP macropore strong acid cation exchange resin sample, drops in the micro-wave digestion jar, adds concentration 63% nitric acid 2mL and concentration 98% sulfuric acid 2mL.The micro-wave digestion jar is placed microwave dissolver, successively in 0.2MPa, 120 ℃ of temperature, 3min; 0.5MPa, 151 ℃ of temperature, 5min; 0.8MPa, 170 ℃ of temperature, 5min; 1.2MPa, 188 ℃ of temperature, 5min; 1.5MPa, handle under the condition of 198 ℃ of temperature, 5min, processing finishes back release, cooling, takes out counteracting tank, digestion solution clear in jar is cleared up end.

Digestion solution is transferred in the volumetric flask, and with 80 ℃ of hot distilled waters washing counteracting tanks, cleansing solution also is transferred in the volumetric flask together and constant volume obtains the analytical sample of certain volume.

Estimate the scope of iron content in the sample,, press the absorbance A of the running program difference bioassay standard liquid of atomic absorption spectrophotometer (AAS) regulation, draw concentration-absorbance (c-A) typical curve with the series standard liquid of pure iron ion reagent preparation variable concentrations; Measure the absorbance A x of sample again with same running program, then on curve in slotting Ax value try to achieve concentration of iron in the sample, and then try to achieve iron content in the sample.

Claims

1. analysis of iron content method in the Zeo-karb; Comprise the preparation of sample and the mensuration of iron content; It is characterized in that: the preparation of described sample is to take by weighing the 0.1-1.0g Zeo-karb to drop in the micro-wave digestion jar; Add 1～3mL concentration 60-65% nitric acid and 1～3mL concentration, 98% sulfuric acid again, the micro-wave digestion jar is placed microwave dissolver, successively in 0.15-0.25MPa, temperature 110-125 ℃, 2-4min; 0.45-0.55MPa, temperature 145-155 ℃, 4-6min; 0.75-0.85MPa, temperature 165-175 ℃, 4-6min; 11-1.3MPa, temperature 180-190 ℃, 4-6min; 1.4-1.6MPa, handle under the condition of temperature 195-205 ℃, 4-6min and obtain digestion solution, be transferred in volumetric flask and constant volume with cleansing solution digestion solution.