CN104502346A - Method for detecting content of total iron in desulphurization residue - Google Patents

Abstract

The invention belongs to the field of analytical chemistry, particularly belongs to the field of desulphurization residue analysis, and more particularly relates to a novel method for detecting the content of total iron in desulphurization residue, aiming to solve the problems in the prior art that the detection data on the content of total iron in desulphurization residue is inaccurate and no reliable data can be provided for the recycling of desulphurization residue. By adopting the method provided by the invention, accurate data on the content of total iron in desulphurization residue can be obtained, and reliable data can be provided for the recycling of desulphurization residue.

Description

The detection method of all iron content in desulfurization slag

Technical field

The invention belongs to analytical chemistry field, particularly relate to the analysis field of desulfurization slag, more specifically relate to the detection method of desulfurization slag all iron content.

Background technology

Along with the fast development of steel and iron industry, produce a large amount of steel slag in steelmaking process, general whole process iron and steel enterprise steel per ton produces solid waste about 0.6 ton.Steel slag be produce in ironmaking and steelmaking process and discharge with oxides such as calcium, silicon, aluminium, iron, magnesium, manganese for leading the slag of the crystallization that is combined into or amorphous state.Mainly be divided into blast furnace slag, vessel slag, electroslag, casting residue, three de-slags.Slag involved in the present invention is a kind of desulfurization slag.More and more extensive along with resource recycling, this desulfurization slag is through magnetic separation and screening, most of iron wherein can be returned certain link in iron and steel and again be come into operation as auxiliary material, for example desulfurization slag magnetic separation particle is less than 5mm, the fine powder that Iron grade is greater than 53% returns production and application again as sinter additives, and the key index of this product is exactly all iron content in sample.

At present, the Comparison between detecting methods of all iron content is ripe, mainly contains strong base EDTA titrimetry, dichromate method, sulfosalicylic acid photometry and X-ray fluorescence spectrometry etc.Dichromate method, complicated operation, finally relates to noxious material potassium dichromate, if Long-Time Service, not only have influence on the environment that operator ' s health also pollutes surrounding, do not meet modern business development requirement, and x-ray fluorescence spectrometry method, although easy and simple to handle, detect data accurately and reliably, but first need to buy expensive X-fluorescence spectrophotometer, X-ray has certain radiation, and it is healthy that long period of operation also can affect operating personnel simultaneously.It is involved in the present invention that desulfurization slag spin-off---the detection method of-slag iron powder is different from said method.

In industry standard YB/T 148-2009 slag, all iron content assay method defines the assay method of all iron content in slag, but in use, we find that its guidance method has problems, the full Iron grade of magnetic separation screen overflow, operation as occurred in correct evaluating and measuring process are extremely complicated, these problems directly may affect the real content measuring full iron in slag, and even giving in slag recycle provides misdata.

Summary of the invention

The present invention is directed to current desulfurization slag all iron content prohibited data detection true, the problem of authentic data can not be provided for the recycling of desulfurization slag, disclose the detection method of all iron content in a kind of brand-new desulfurization slag, thus accurately can provide all iron content data in desulfurization slag, for the recycling of desulfurization slag provides authentic data.

Particularly, the detection method of all iron content provided by the invention is as follows:

(1) spot sampling, and pulverized, screening particle diameter is in the desulfurization slag of below 8mm, desulfurization slag is carried out drying at the temperature of 105 DEG C ± 2 DEG C, mix, then adopt reduction device repeatedly division, to raw sample weight less than 1/10, by sample comminution extremely all by 0.075mm international standard sieves

(2) lower 0.5000 gram, the sample of sieve is got,

(3) sample is added water moistening after, add 30mL concentrated hydrochloric acid and 2mL nitric acid successively, high-temperature heating all dissolves to sample, naturally cools to room temperature, filter, be settled to 2.0000g/L,

(4) by solution dilution after constant volume 4 times, with ammoniacal liquor and hydrochloric acid conditioning solution pH to 1.8 ~ 2.0,

(5) solution is heated to 70 DEG C, and adds 10 10% sulfosalicylic acid sodium salts as instruction solution, be titrated to solution with the EDTA standard titration solution of 0.015mol/L and become glassy yellow,

(6) all iron content is calculated,

In formula: W _fethe massfraction of-full iron;

T _fe2O3-EDTA standard titration solution is to the titer of di-iron trioxide, and unit is mg/ml;

V _eDTAconsume the volume of EDTA standard titration solution during consumption-titration, unit is ml;

Take the quality of test portion during M test portion-analysis, unit is g;

1.43-di-iron trioxide and iron reduction coefficient.

Preferably, if sample dissolution weak effect in step (3), then consider and add sodium fluoride.In general 1g sodium fluoride is added.

Beneficial effect of the present invention is as follows: first the present invention does not need the dissolving method adopting high temperature alkali fuse, thus mixed solvent melting and cleaning crucible problem for up to 2 hours used and the systematic error problem brought thus under avoiding melting, only use hydrochloric acid-nitric acid+sodium fluoride for sample dissolution, solute effect is good, dissolution velocity is fast, only needs within 20 minutes, can complete sample dissolution work.

Meanwhile, adopt detection method disclosed in this invention effectively to get rid of the impact of the interference elements such as calcium in slag, magnesium, aluminium, detect data more accurately, reliably.

Compared to existing detection method, due to without the need to x-ray fluorescence analyzer, decrease the use of chemical reagent, therefore correspondingly reduce the harm to human body and environment of chemical blowdown and X ray.

Meanwhile, utilize titration detection mode disclosed in this invention, computation process is easier, avoids the problem because the upper all iron content of sieve in classic method cannot accurately draw simultaneously.By directly carrying out measuring all iron content in whole desulfurization slag, measured value is more accurate, and analysis result is more reliable.

Embodiment

In order to understand the present invention better, below in conjunction with embodiment, illustrate the present invention further.

Embodiment 1

The present invention relates to chemical reagent and checkout equipment comprises: commercially available prod and the instruments such as nitric acid (ρ 1.40g/cm3), hydrochloric acid (ρ 1.18g/cm3), calcium carbonate standard solution [C (caco3)=0.024mol/l], EDTA standard titration solution (C=0.015mol/l), sodium fluoride, ammoniacal liquor, sulfosalicylic acid sodium salt (10%), baking oven, pulverizing sampling machine, filter paper, funnel, electronic analytical balance, electric furnace, thermometer (100 DEG C).

Spot sampling, and pulverized, screening particle diameter is in the desulfurization slag of below 8mm, desulfurization slag is carried out drying at the temperature of 105 DEG C ± 2 DEG C, after being dried to constant weight, dried sample is fully mixed, adopt reduction device to carry out repeatedly division, most retrude gets two parts, every part of about 100g.Two parts of samples are pulverized sampling machine through 2MZ-200 pulverize, pulverize three times, each 1 minute, sample after pulverizing is crossed 0.075mm standard sieve, and screen overflow proceeds to pulverize, and pulverizes once, each 1 minute, until sample is all by 0.075mm standard sieve, pack was continued to employ.

Take two parts, 0.5g sample with analytical balance, be accurate to 0.0001g.Two parts of test portions are placed in 400ml beaker respectively, add little water moistening, 2ml nitric acid is dripped again after slowly adding 30ml concentrated hydrochloric acid, cover surface plate, high-temperature heating all dissolves to test portion, if any a little not molten test portion, 1g sodium fluoride can be added, take off flowing water and be cooled to room temperature, filter, be settled in 250ml volumetric flask.Draw 25ml solution respectively and put into 300ml beaker, be diluted with water to about 100ml, regulate solution pH value between 1.8 ~ 2.0 with ammoniacal liquor (1+1) and hydrochloric acid (1+1).Solution is heated to 70 DEG C, adds 10 sulfosalicylic acid sodium salt (10%) instruction solution, be slowly titrated to glassy yellow (during terminal, solution temperature is not less than 60 DEG C) with EDTA standard titration solution (C=0.015mol/l).Get the slag iron powder that on May 7th, 2014, production line afterbody produced, aforesaid operations is carried out to it.After first part of sample accurately takes, M ₁sample 0.4998g, adopts the EDTA standard titration solution titration of 0.0149mol/L, and recording its consumption volume V (EDTA) is 38.40mL; After second part of sample accurately takes, M ₂test portion 0.4989g, adopts the EDTA standard titration solution titration of 0.0149mol/L, and recording its consumption volume V (EDTA) is 38.30mL.

According to formula:

$W_1\mathrm{Fe}\%=\frac{55.84*0.0149*38.40}{0.4998}\%=63.92\%$

$W_2\mathrm{Fe}\%=\frac{55.84*0.0149*38.30}{0.4989}\%=63.87\%$

Two times result error is no more than 0.31%, and result is effective.

Get twice test result value that is averaged to calculate, obtain thus know that in the desulfurization slag that on May 7th, 2014, production line produced, all iron content is 63.9%.

Embodiment 2

Equally with the desulfurization slag that on May 7th, 2014, production line produced for testing sample, after its division, get about 1.5kg, 1.25mm standard sieve is crossed after the whole fragmentation of twin rollers, the heavy 0.512kg of Armco magnetic iron on sieve that particle diameter is greater than 1.25mm is drawn with magnetic patch, conventionally, calculating Armco magnetic iron accounting is 34.13%.

The titrimetry be less than by particle diameter in 1.25mm screen underflow embodiment 1 carries out titration, takes sample M3 test portion 0.5015g, adopts the EDTA standard titration solution titration of 0.0149mol/L, and recording its consumption volume V (EDTA) is 28.05ml; Obtain according to formulae discovery

$W_3\mathrm{Fe}\%=34.13\%+65.87\%*\frac{55.84*0.0149*28.05}{0.5015}\%=64.78\%.$

W ₃fe%>W _{on average}fe%.

The visible data carrying out detecting according to standard are bigger than normal, and reliability is reliable not as the method disclosed in the present.

Claims (3)

1. the detection method of all iron content in desulfurization slag, is characterized in that, comprise the following steps:

(1) spot sampling, and pulverized, screening particle diameter is in the desulfurization slag of below 8mm, desulfurization slag is carried out drying at the temperature of 105 DEG C ± 2 DEG C, mix, then adopt reduction device repeatedly division, to raw sample weight less than 1/10, by sample comminution extremely all by 0.075mm international standard sieves

(2) lower 0.5000 gram, the sample of sieve is got,

(3) sample is added water moistening after, add 30mL concentrated hydrochloric acid and 2mL nitric acid successively, high-temperature heating all dissolves to sample, naturally cools to room temperature, filter, be settled to 2.0000g/L,

(4) by solution dilution after constant volume 4 times, with ammoniacal liquor and hydrochloric acid conditioning solution pH to 1.8 ~ 2.0,

(5) solution is heated to 70 DEG C, and adds 10 10% sulfosalicylic acid sodium salts as instruction solution, be titrated to solution with the EDTA standard titration solution of 0.015mol/L and become glassy yellow,

(6) all iron content is calculated,

In formula: W _fethe massfraction of-full iron;

T _fe2O3-EDTA standard titration solution is to the titer of di-iron trioxide, and unit is mg/ml;

V _eDTAconsume the volume of EDTA standard titration solution during consumption-titration, unit is ml;

Take the quality of test portion during M test portion-analysis, unit is g;

1.43-di-iron trioxide and iron reduction coefficient.

2. detection method according to claim 1, is characterized in that, in described step (3) after adding nitric acid, continues to add sodium fluoride.

3. detection method according to claim 2, is characterized in that, described sodium fluoride addition is 1g.