CN104515699A - Magnesite standard sample for chemical analysis and preparation method thereof - Google Patents

Abstract

The invention discloses a magnesite standard sample for chemical analysis and a preparation method thereof, and belongs to the technical field of metallurgical analysis. The magnesite standard sample contains the following chemical elements in percentages by weight: 4-5% of SiO2, 1-2% of CaO, 40-45% of MgO, 1-2% of Fe2O3, 1-2% of Al2O3, 0.05-0.5% of MnO, 0.005-0.05% of P, 0.01-0.1% of TiO2, 0.0005-0.005% of SrO, 0.005-0.05% of K2O, 0.005-0.05% of Na2O, 0.005-0.05% of S and 45-50% of LOI; the magnesite standard sample for chemical analysis is a powder solid matter with the granularity of smaller than or equal to 98 [mu]m. The preparation method comprises the following steps: firstly, sorting with hands, washing and airing, then crushing by using a hammer and a jaw crusher respectively, then grinding by using a ball grinding mill, and finally sieving; putting oversize materials in the ball grinding mill again for repeated grinding, so that the sample completely passes through a sieve of 98 [mu]m, finally sufficiently mixing the oversize materials in a mixing machine, and packaging to obtain the magnesite standard sample. The standard sample disclosed by the invention is simple in preparation method, good in uniformity, accurate in quantity value and convenient to use, and solves the problem that the enterprise measurement of magnesite is free of standardized criteria.

Description

A kind of chemical analysis magnesite standard model and preparation method thereof

Technical field

The present invention relates to a kind of chemical analysis magnesite standard model and preparation method thereof, belong to metallurgical analysis technical field.

Background technology

Magnesite is a kind of magnesium carbonate mineral, and it is the main source of magnesium.Solution effects containing magnesium is after kalzit, and kalzit can be made to become magnesite, and therefore magnesite also belongs to kalzit race.The rock being rich in magnesium also can be changing into magnesite.Usually containing iron in magnesite, this is the result that iron or manganese replace to fall magnesium.Magnesite white or canescence, have vitreous luster, and the magnesite of iron content can present yellow to brown.If it is exactly granular for presenting crystal, if do not show crystal, be block.Magnesite can be used as fire resistive material, building materials raw material, industrial chemicals and extracting metals magnesium and magnesium compound etc.

Different industries is different to the requirement of magnesite raw material, and the fluctuation of the component content of raw material directly affects product quality, and therefore, in Accurate Determining magnesite, the content of each composition is most important.The inspection of the product of magnesite is also more and more come into one's own, the analytical approach of magnesite does not have national standard, very large difficulty is brought to testing, analyst cannot judge precision of analysis, therefore we consider the standard model developing a kind of magnesite, its composition is relatively stable over a period to come, determines the characteristic magnitude of each composition of sample, for detecting magnesite product.

Summary of the invention

The object of the invention is for the detection of magnesite sample provides a kind of standard items, for evaluating the analytical approach of magnesite product, correction analysis instrument and the detectability to analyst are evaluated.

Technical scheme of the present invention is:

A kind of chemical analysis magnesite standard model, is characterized in that,

This standard model is the powdered solid substance of granularity≤98 μm;

The chemical element of this standard model evenly containing following weight number percent: SiO ₂: 4 ~ 5, CaO:1 ~ 2, MgO:40 ~ 45, Fe ₂o ₃: 1 ~ 2, Al ₂o ₃: 1 ~ 2, MnO:0.05 ~ 0.5, P:0.005 ~ 0.05, TiO ₂: 0.01 ~ 0.1, SrO:0.0005 ~ 0.005, K ₂o:0.005 ~ 0.05, Na ₂o:0.005 ~ 0.005, S:0.005 ~ 0.05, LOI:45 ~ 50.

Further, this standard model evenly contains the chemical element of percentage by weight as in the table below:

Element	SiO 2	CaO	MgO	Fe 2O 3	Al 2O 3	MnO	P
								Standard value	4.12	1.50	43.39	1.74	1.16	0.096	0.016
Standard deviation	0.07	0.03	0.12	0.03	0.03	0.002	0.001
								Uncertainty	0.06	0.02	0.10	0.02	0.02	0.002	0.001
Element	TiO 2	SrO	K 2O	Na 2O	S	LOI
								Standard value	0.040	0.0014	0.032	0.019	0.016	47.34	/
Standard deviation	0.002	0.0001	0.002	0.001	0.002	0.14	/

Uncertainty

0.002

0.0001

0.002

0.001

0.002

0.12

/

A preparation method for chemical analysis magnesite standard model, is characterized in that, comprise the following steps:

1. take and prepare the magnesite stone meeting above-mentioned requirements;

2. first select by hand, rinse, dry, with the broken bulk sample of iron hammer, then jaw crusher is put into, be crushed to 3mm, then grinding in ball grinder 20 minutes, the screen cloth of 98 μm is crossed in discharging, screen overflow is put into bowl mill again and repeat grinding, make sample all by the screen cloth of 98 μm, screen underflow is fully mixed 120 minutes with the speed of 18r/min in mixed model machine, be packaged into the minimum package unit of 50g.

The invention has the beneficial effects as follows:

Preparation of standard sample method of the present invention is simple, homogeneity good, value is accurate, easy to use, solve enterprise and measure the problem that can comply with without standard of magnesite.

Embodiment

In order to understand the present invention better, illustrate content of the present invention further below in conjunction with embodiment, but content of the present invention is not only confined to the following examples, embodiment should not regard as limiting the scope of the present invention.

1, Composition Design: chemical element composition and content thereof are in table 1.

Its even chemical element containing following weight number percent of these standard items:

The chemical element of table 1 standard items and content (wt%)

Element

SiO 2

CaO

MgO

Fe 2O 3

Al 2O 3

MnO

P

Content

4～5

1～2

40～45

1～2

1～2

0.05～0.5

0.005～0.05

Element

TiO 2

SrO

K 2O

Na 2O

S

LOI

Content

0.01～0.1

0.0005～0.005

0.005～0.05

0.005～0.05

0.005～0.05

45～50

2, preparation method:

Get magnesite fast, detect each component content, if meet table 1 requirement, then can, according to following steps preparation standard sample, if undesirable, readopt or take the product of several content to carry out mixture by component requirements, until meet table 1 requirement.

The satisfactory sample chosen first is selected by hand, rinse, dry, with the broken bulk sample of iron hammer, then jaw crusher is put into, be crushed to 3mm, then grinding in ball grinder 20 minutes, the screen cloth of 98 μm is crossed in discharging, screen overflow is put into bowl mill again and repeat grinding, make sample all by the screen cloth of 98 μm, screen underflow is fully mixed 120 minutes with the speed of 18r/min in mixed model machine, be packaged into the minimum package unit of 50g, bottleneck compressing tablet seals, label on vial, overcoat plastic casing is packed, standard model certificate is placed with in box, the outer label of box.

3, the uniformity testing of standard items

Packaged standard model randomly draws 20 bottles, numbers in order, by the good analytical approach of precision to SiO ₂, CaO, MgO, Fe ₂o ₃, Al ₂o ₃, MnO, P, TiO ₂, K ₂o, Na ₂o, SrO, S, LOI analyze under identical analysis condition, do uniformity testing, measure three times for every bottle, and first time, sequentially second time inverted order, for the third time by 1,3,5 ..., 19,2,4,6 ..., 20, measure, uniformity testing analytical approach and sample weighting amount are in table 2.

Table 2 uniformity testing analytical approach, sample weighting amount and statistic F value

To assay, adopt method of analysis of variance to add up 20 group analysis data, the statistic result according to variance analysis is evaluated homogeneity, comprehensively analyzes the homogeneity of this standard model according to the standard deviation value of uniformity testing raw data simultaneously.

To assay, adopt method of analysis of variance to add up 20 group analysis data, judge the homogeneity of this standard model according to the statistic of variance analysis and the relative standard deviation value (RSD) of uniformity testing raw data.

As statistic F < F α, then in group and between group, data are without significant difference, and uniformity testing is qualified.

As statistic F >=F α, then there were significant differences to organize data between interior and group, and uniformity testing is defective.

The variance analysis statistic F value of each test element is all less than to the critical value F α (F0.05=1.84) of variance analysis, shows that this standard model uniformity testing is qualified.

4, standard model carries out definite value

Because magnesite detection difficulty is larger, there is no national standard method, can only detect with reference to the method for other materials, very important to the judgement of measurement result reliability, we take the mode of the how parallel result in many laboratories to carry out definite value, and each element determination fruiting quantities is no less than 50.

Table 3 magnesite standard model definite value employing method

Project	The method of inspection
		SiO 2	Perchloric acid determination, silicon molybdenum blues photometry, ICP-AES
CaO	EDTA titrimetry, ICP-AES method
		MgO	EDTA titrimetry, EGTA-CyDTA titrimetry
Fe 2O 3	Phenanthrolene photometry, ICP-AES method
		Al 2O 3	Chrome azurol S photometry, EDTA titrimetry, ICP-AES
MnO	Potassium metaperiodate photometry, ICP-AES method
		P	Molybdenum blue spectrophotometry, ICP-AES method
TiO 2	Two antipyrine methane photometries, ICP-AES method
		SrO	ICP-AES method, AAS method
K 2O	AAS method, ICP-AES method
		Na 2O	AAS method, ICP-AES method
S	Barium sulfategravimetry, infrared absorption, ICP-AES method,
		LOI	Gravimetric method

Data processing method: the Elemental analysis data that each cooperating analysis unit offers, follow procedure carries out the determination work of data processing and standard value.Its extreme difference checks in its group whether have exceptional value by method tolerance, then calculates the mean value of these data.

Result whether equally accurate is respectively organized with Cochran criteria tests, all qualified.

Check whether each mean value exists exceptional value with spatial pattern and process, all qualified.

The definite value of whole component is analyzed to mean value Xia Piluo-Weir gram (shapiro-wilk) method inspection normality of data and each group number.

After the exceptional value that is disposed, calculate arithmetic mean and the standard deviation of each group of data.The significant digit of standard value, the revision of the convention is carried out according to GB/T 8170-2008 " rules of rounding off for numerical values & expression and judgement of limiting values " according to method precision, standard deviation aligns with the figure place of standard value, general reservation 1 ~ 2 position effective digital, the standard value finally determined, standard deviation, expanded uncertainty are in table 4.

Table 4 magnesite standard model standard value, standard deviation and expanded uncertainty gather (k=2) (%)

Element	SiO 2	CaO	MgO	Fe 2O 3	Al 2O 3	MnO	P
								Standard value	4.12	1.50	43.39	1.74	1.16	0.096	0.016
Standard deviation	0.07	0.03	0.12	0.03	0.03	0.002	0.001
								Uncertainty	0.06	0.02	0.10	0.02	0.02	0.002	0.001
Element	TiO 2	SrO	K 2O	Na 2O	S	LOI

Standard value	0.040	0.0014	0.032	0.019	0.016	47.34
								Standard deviation	0.002	0.0001	0.002	0.001	0.002	0.14
Uncertainty	0.002	0.0001	0.002	0.001	0.002	0.12

Note: expanded uncertainty (k=2) in table

5, study on the stability

Carried out stability test by the requirement of standard to this standard model, the difference of all stability test projects twice measurement does not all exceed the uncertainty of definite value.According to GB/T 15000.3, if condition meets:

$|x_{\mathrm{CRM}}-x_{\mathrm{meas}}|\&le;k\sqrt{u_{\mathrm{CRM}}^2+u_{\mathrm{meas}}^2}$

X in formula _cRMrepresent the characteristic value of CRM, x _measfor the observed reading measured, k is Coverage factor, k=2 during confidence level 95%, and so can think that material is enough stable, stability is proven, and the results are shown in Table 5.

Table 5 magnesite standard model study on the stability table (%)

6, user's operation report

Beneficial effect: the economic steel of this standard sample and Laigang Deng Duojia unit use, unanimously thinks that this standard sample homogeneity is good, value is accurate, easy to use, solves enterprise and measures the problem that magnesite can comply with without standard.

User's operation report is as shown in table 6 below.

Table 6 user operation report

Element

SiO 2

CaO

MgO

Fe 2O 3

Al 2O 3

MnO

P

Content	4.13	1.50	43.35	1.72	1.13	0.095	0.016
								Element	TiO 2	SrO	K 2O	Na 2O	S	LOI
Content	0.041	0.0014	0.030	0.020	0.018	47.38

Should be understood that, for those of ordinary skills, can be improved according to the above description or convert, and all these improve and convert the protection domain that all should belong to claims of the present invention.

Claims (3)

1. a chemical analysis magnesite standard model, is characterized in that,

This standard model is the powdered solid substance of granularity≤98 μm;

The chemical element of this standard model evenly containing following weight number percent: SiO ₂: 4 ~ 5, CaO:1 ~ 2, MgO:40 ~ 45, Fe ₂o ₃: 1 ~ 2, Al ₂o ₃: 1 ~ 2, MnO:0.05 ~ 0.5, P:0.005 ~ 0.05, TiO ₂: 0.01 ~ 0.1, SrO:0.0005 ~ 0.005, K ₂o:0.005 ~ 0.05, Na ₂o:0.005 ~ 0.005, S:0.005 ~ 0.05, LOI:45 ~ 50.

2. chemical analysis magnesite standard model according to claim 1, is characterized in that,

This standard model evenly contains the chemical element of percentage by weight as in the table below:

Element SiO ₂ CaO MgO Fe ₂O ₃ Al ₂O ₃ MnO P Standard value 4.12 1.50 43.39 1.74 1.16 0.096 0.016 Standard deviation 0.07 0.03 0.12 0.03 0.03 0.002 0.001 Uncertainty 0.06 0.02 0.10 0.02 0.02 0.002 0.001 Element TiO ₂ SrO K ₂O Na ₂O S LOI Standard value 0.040 0.0014 0.032 0.019 0.016 47.34 / Standard deviation 0.002 0.0001 0.002 0.001 0.002 0.14 / Uncertainty 0.002 0.0001 0.002 0.001 0.002 0.12 /

3. the preparation method of chemical analysis magnesite standard model according to claim 1 and 2, is characterized in that, comprise the following steps:

1. take and prepare the magnesite stone meeting claim 1 or 2 and require;

2. first select by hand, rinse, dry, with the broken bulk sample of iron hammer, then jaw crusher is put into, be crushed to 3mm, then grinding in ball grinder 20 minutes, the screen cloth of 98 μm is crossed in discharging, screen overflow is put into bowl mill again and repeat grinding, make sample all by the screen cloth of 98 μm, screen underflow is fully mixed 120 minutes with the speed of 18r/min in mixed model machine, be packaged into the minimum package unit of 50g.