CN105468830A - Method for calculating iron ore powder mixing working performance by actually measured standard deviation of mixing material pile - Google Patents

Abstract

The invention discloses a method for calculating mixing efficiency in iron ore powder mixing work by actually measured standard deviation of mixing material pile, comprising: (1), carrying mathematical simulation to in iron ore powder mixing work procedure, solving the content P(A) of the iron ore in the mixing material; (2), determining the distribution of the iron ore powder discrete type random variable X, and the expectation and variance of the X; (3), solving the standard deviation rhoa of the mixing material pile after iron ore powder mixing work; (4), solving the standard deviation of the random variable X; (5), obtaining the calculation formula for using the actually measured standard deviation of mixing material pile to calculate the iron ore powder mixing work efficiency. The iron ore powder mixing work efficiency calculated by the invention can reflect the production actuality of the mixing work procedure and simultaneously is convenient in production management of the mixing work.

Description

By the method for mixing stockpile actual measurement standard deviation calculation Iron Ore Powder mixing operating efficiency

Technical field

The present invention relates to the computing method of a kind of Iron Ore Powder mixing flow chart effect, a kind of mixing stockpile actual measurement standard deviation that utilizes is to calculate the method for blending efficiency in Iron Ore Powder mixing operation specifically.

Background technology

Domestic and international iron and steel enterprise, no matter be new spectra or long-established enterprise, almost generally establish large-scale modernization Iron Ore Powder mixing operation stock ground, Iron Ore Powder mixing had become one important procedure of modern steel enterprise production technology already, therefore, while current Iron Ore Powder mixing operation stock ground technological equipment is constantly perfect, the problem how calculating blending efficiency becomes the most noticeable focus of iron and steel enterprise.

The calculating of blending efficiency is the quantitative description to Iron Ore Powder mixing operation importance, also be the estimation to a guardian technique economic target in the production management of mixing material, therefore, people did not stop the discussion to blending efficiency computing method in Iron Ore Powder mixing operation always for a long time, and in prior art, existing research mainly contains following several:

(1) traditional standard deviation: the standard deviation calculation formula that before Iron Ore Powder mixing operation, various raw material is total is:

<maths TranNum="52" num="0001"><![CDATA [<math><mrow><mi>&sigma;</mi><mi>E</mi><mo>=</mo><mfrac><mn>1</mn><mi>Z</mi></mfrac><msqrt><mrow><munderover><mo>&Sigma;</mo><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mi>k</mi></munderover><msup><mrow><mo>(</mo><mi>Z</mi><mi>i</mi><mi></mi><mi>&sigma;</mi><mi>i</mi><mo>)</mo></mrow><mn>2</mn></msup></mrow></msqrt></mrow></math>]]></maths>(i)

Wherein Zi: the cloth number of plies of certain material;

Z: the total number of plies of stockpile cloth;

σ i: corresponding to the standard deviation of Zi layer;

K: variety classes material number;

Iron Ore Powder mixes post-job standard deviation estimation formula:

<maths TranNum="59" num="0002"><![CDATA [<math><mrow><mi>&sigma;</mi><mi>A</mi><mo>=</mo><mi>&sigma;</mi><mi>E</mi><mo>/</mo><msqrt><mi>Z</mi></msqrt></mrow></math>]]></maths>(ii)

Blending efficiency calculating formula is: η=σ E/ σ Α (iii)

Wherein: η is Blending Efficiency of Blending (%);

Traditional standard deviation, in actual computation process, (i) and (ii) will substitute into (iii) formula, obtains:

<maths TranNum="64" num="0003"><![CDATA [<math><mrow><mi>&eta;</mi><mo>=</mo><msqrt><mi>Z</mi></msqrt></mrow></math>]]></maths>(iv)

Utilize the blending efficiency in (iv) formula calculating Iron Ore Powder mixing operation, only need know the total number of plies Z of stockpile cloth, can blending efficiency be drawn.But this method establishment is on the basis of simple process, too brief to the description of producing, the derivation of its mathematical theory also has the place of many worth queries, and therefore, result of calculation and the fact of formula greatly differ from each other.

(2) British VanderMoorenA.L is based upon autocorrelation function φ _dblending efficiency computing method on (K Δ t) basis: the method does not also directly calculate σ _Α, but by deriving, utilize computing formula:

<maths TranNum="70" num="0004"><![CDATA [<math><mrow><mi>&eta;</mi><mo>=</mo><msub><mi>&sigma;</mi><mi>E</mi></msub><mo>/</mo><msub><mi>&sigma;</mi><mi>A</mi></msub><mo>=</mo><msup><mrow><mo>&lsqb;</mo><mn>1</mn><mo>/</mo><mi>N</mi><mo>+</mo><mn>1</mn><mo>/</mo><msup><mi>N</mi><mn>2</mn></msup><munderover><mo>&Sigma;</mo><mrow><mi>K</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>N</mi><mo>-</mo><mn>1</mn></mrow></munderover><mrow><mo>(</mo><mi>N</mi><mo>-</mo><mi>K</mi><mo>)</mo></mrow><msub><mi>&phi;</mi><mi>a</mi></msub><mrow><mo>(</mo><mi>K</mi><mi>&Delta;</mi><mi>t</mi><mo>)</mo></mrow><mo>&rsqb;</mo></mrow><mrow><mo>-</mo><mfrac><mn>1</mn><mn>2</mn></mfrac></mrow></msup></mrow></math>]]></maths>(v)

Calculate blending efficiency,

In formula: N is the number of plies;

K＝1,2,3,……,N；

φ _a(K Δ t) is autocorrelation function;

Δ t is thickness of feed layer;

The shortcoming of this computing method is: when each layer is correlated with, along with the increase of correlativity, φ _athe value of (K Δ t) increases, make formula (v) in square bracket the numerical value of Section 2 enlarge markedly, bring favorable factor to be counteracted by this correlativity increase, in practical application owing to increasing the number of plies like this, obtain raw material autocorrelation function more difficult, thus method does not use usually.

(3) She Xi side's blending efficiency computing method: this method divides two situations, one is without accurate dosing situation, and another kind has accurate dosing situation.Step without the blending efficiency computing method in accurate dosing situation is: 1. calculate the total standard deviation E of various raw material before Iron Ore Powder mixing operation, and computing formula is (i) formula; 2. computing formula is utilized:

η=K (σ _Ε+ 1) (vi)

Calculate blending efficiency, wherein K is experience factor.Nearly all have accurate dosing owing to mixing operation at present, therefore this method does not use substantially.The blending efficiency computing method in accurate dosing situation are had to be: to utilize formula

<maths TranNum="84" num="0005"><![CDATA [<math><mrow><mi>&eta;</mi><mo>=</mo><mi>a</mi><msqrt><mi>N</mi></msqrt><msub><mi>&sigma;</mi><mi>E</mi></msub><mo>+</mo><mi>b</mi></mrow></math>]]></maths>(vii)

Calculate blending efficiency,

In formula: N is the windrow number of plies;

A, b are empirical regression coefficient, and a is slope, and b is intercept;

This formula is with herein other is enumerated blending efficiency computing formula and does not have essential distinction.

(4) the efficiency calculation method of Wang Su, Liu Jiangning: computing formula is:

<maths TranNum="91" num="0006"><![CDATA [<math><mrow><mi>&eta;</mi><mo>=</mo><mi>a</mi><msqrt><mi>N</mi></msqrt><mo>+</mo><mi>b</mi></mrow></math>]]></maths>(viii)

Blending efficiency is only relevant with the windrow number of plies, and a, b are empirical regression coefficient, and a is slope, and b is intercept, and it is not very accurate that the method is used for actual production.

(5) optimum combination Three factors computing method: utilize formula

η=K ₁η ₁+ K ₂η ₂+ K ₃η ₃(ix)

Calculate blending efficiency,

Wherein

A, a ₁, a ₂, b is experience factor, a is slope, and b is intercept, K ₁, K ₂, K ₃for the involved weight allocation value of each predictor formula; This method is actually admits that all amendment types are true with weight refinement under all accurately can not reflecting objective fact situation, the great achievement of collection repairing.

In the practice process that the production Technology development of Iron Ore Powder mixing flow chart is perfect, all be found to there is factor affect blending efficiency rule that is single and description when producing actual use correct not for these methods above, do not catch principal element, result of calculation and actual conditions gap shortcoming very far away.

Summary of the invention

Technical matters to be solved by this invention is, for the shortcoming that above prior art exists, a kind of mixing stockpile actual measurement standard deviation that utilizes is proposed to calculate the method for Iron Ore Powder mixing operating efficiency, can not only reflect that the production of mixing flow chart is actual, also be convenient to the production management mixing operation simultaneously.

The technical scheme that the present invention solves above technical matters is:

Utilize mixing stockpile actual measurement standard deviation to calculate a method for blending efficiency in Iron Ore Powder mixing operation, comprise the following steps:

(i) the content P (A) that mathematical simulation obtains iron ore in mixing material is carried out to Iron Ore Powder mixing flow chart:

If each raw material participating in mixing all only has iron ore and gangue composition, the blending operation process of mixing flow chart is regarded as n the independent Bernoulli trial repeated, " iron ore appearance " this event is represented with A, 1-A represents " gangue appearance " i.e. " A does not occur " event, the number of times occurred by A is compared with total degree, be the probability that A occurs, namely mix percentage composition P (A) (%) of iron ore in material, the total probability formula that iron ore in mixing material occurs be expressed as:

P(A)＝P(B1)P(A/B1)+P(B2)P(A/B2)+……+P(Bk)P(A/Bk)(1)

In formula: B1, B2 ..., Bk is the K kind raw material participating in mixing; A represents iron ore; P (B1), P (B2) ..., P (Bk), (%) is the charge ratio of various raw material; P (A) is the content of iron ore in mixing material; P (A/B1), P (A/B2) ..., P (A/Bk), (%) is the content of iron ore in various raw material;

In the production of reality mixing operation, P (A/B1), P (A/B2) ..., P (A/Bk) is obtained by the data of collection in worksite, collection in worksite data are the Tfe content chemically examined various raw material, Tfe content is transformed to P (A/B1), P (A/B2) ... P (A/Bk), the method for conversion is:

P(A/B1)＝(Tfe1)/70％＝10/7(Tfe1)

……

P(A/Bk)＝(Tfek)/70％＝10/7(Tfek)

Wherein (Tfe1) chemical examination Tfe that is the first raw material; (Tfek) be the chemical examination Tfe of kth kind raw material;

(ii) the distribution of Iron Ore Powder discrete random variable X is determined, the expectation and variance of X:

N the independent Bei Nuli machinery mixing test repeated is carried out to Iron Ore Powder compound, stochastic variable kind according to the heap feature of material extracting operation and the mathematical feature deterministic process of research object iron ore is discrete random variable, stochastic variable X is distributed as obedience binomial distribution, therefore, the expectation and variance of X is respectively:

E(X)＝nP(A)(2)

D(X)＝nP(A)[1-P(A)](3)

(iii) the standard deviation sigma a of stockpile is mixed after obtaining Iron Ore Powder mixing operation:

I obtains σ a by mixing stockpile qualification rate P:

1) the standard deviation sigma a of stockpile and the Process Control Theory mathematic(al) representation of mixing stockpile chemical composition Tfe qualification rate P is mixed:

I is by Tu-T ^l=2t, draws P=P (T ^l≤ X≤Tu), wherein, Tu: the quality control upper limit in the production of mixing material; T ^l: quality control lower limit in the production of mixing material;

Ii, according to P (TL≤X≤Tu)=2 Ф (3Cp)-1, obtains:

P＝2Ф(3Cp)–1

Namely Ф (3Cp)=(1+P)/2 (4)

In formula, P: the mixing stockpile qualification rate that mixing flow chart is produced; Cp: an index of engineering capacity of mixing flow chart;

2) expression formula of the standard deviation sigma a of stockpile is mixed after obtaining asking Iron Ore Powder to mix operation:

Due to Cp=(Tu-T ^l)/6 σ a,

Namely: Cp=t/3 σ a

Therefore, above-mentioned formula (4) also can be expressed as:

Ф(t/σa)＝(1+P)/2(5)

In formula, σ a is the standard deviation mixing stockpile after Iron Ore Powder mixing operation; T: the monolateral specification limit that mixing material is produced; P: the mixing stockpile qualification rate that mixing flow chart is produced;

3) according to formula (5), σ a is obtained by looking into Standard Normal Distribution value table;

The method of II statistical computation directly calculates actual measurement σ a with scientific calculator: in mixing work production, double bucket wheel reclaimer is used to carry out mixing material extracting operation to the mixing stockpile piled, when mixing material product conveying belt downward road sintering circuit feed, on product conveying belt, pick test is carried out to mixing stockpile by sampleman, then statistical computation is carried out to the Tfe compositional data that sample examination obtains, directly calculate required actual measurement σ a with scientific calculator;

(iv) the standard deviation of stochastic variable X is obtained:

Central limit theorem in probability statistics is thought: establish X1, X2 ..., Xn is n the separate stochastic variable with distribution, and its co-localization is not normal state or the unknown, but its average μ and variances sigma ²all exist, then when n is quite large, sample average approximate Normal Distribution N (μ, σ ²/ n);

N the independent Bei Nuli machinery mixing test repeated is carried out to Iron Ore Powder compound, the stochastic variable kind of its process is discrete random variable, obey binomial distribution, meet X1, X2 ..., Xn is the condition of n the separate stochastic variable with distribution, and its co-localization is not normal state, (ii) obtain average μ and variances sigma by step ²all exist, therefore, calculate the standard deviation of Iron Ore Powder mixing operation stockpile with formula below:

σΑ ²＝σE ²╱n(6)

Or

Wherein, σ E: the standard deviation that before Iron Ore Powder mixing operation, various raw material binomial distribution is overall; N: the total number of plies of cloth intending stone heap; σ Α: the standard deviation (discrete random variable) intending stone heap;

According to step (ii), σ E here ²=D (X), therefore, obtains (3) formula for people (6) formula:

σΑ ²＝P(A)[1-P(A)](8)

Or

(v) obtain and utilize mixing stockpile actual measurement standard deviation to calculate the computing formula of Iron Ore Powder mixing operating efficiency:

1) computing formula defining blending efficiency is:

η＝σe/σa(10)

Wherein, σ e: the standard deviation (random variable of continuous type) that before Iron Ore Powder mixing operation, various raw material is total; σ a: the standard deviation of the Tfe that sample examination obtains on mixing material product conveying belt;

The standard deviation that before this formula represents mixing operation, various raw material is total is through how many times of the standard deviation of mixing material or the compound obtained after mixing flow chart is produced, the Blending Efficiency of Blending of mixing flow chart is represented with this, multiple is more, and blending efficiency is higher;

2) obtain utilizing mixing stockpile actual measurement standard deviation to calculate the computing formula of Iron Ore Powder mixing operating efficiency:

According to central limit theorem, when n is sizable, have:

$\mathrm{\&sigma;}e\&ap;\mathrm{\&sigma;}A=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}---\left(11\right)$

Formula (11) is substituted into blending efficiency defined formula (10) obtain:

$\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a---\left(12\right)$

In formula: η is the blending efficiency of mixing operation; P (A) is the content of iron ore in mixing material, is determined by formula (1);

σ a: the standard deviation of Tfe that on mixing material product conveying belt, sample examination obtains, is obtained by two kinds of methods below:

(1) on mixing material product conveying belt, sample examination obtains the standard deviation of Tfe;

By formula (5) i.e. Ф (t/ σ a)=(1+P)/2 are obtained.

The invention has the beneficial effects as follows:

(1) the present invention is the calculating formula of directly producing the mixing flow chart Blending Efficiency of Blending obtained with the method simulated field of mathematics mixing material, and in " background technology " the separate equations in the prior art that describes, or use the computing method being used for estimating stock ground design effect in blending-field design; Or with above-mentioned computing method of using for the correction formula that core carries out repairing and obtain; Or obtain the very difficult mathematical formulae not meeting on-the-spot mixing work production reality of raw material autocorrelation function.Therefore, this is one of calculated value reason actual with meeting production more more accurate than the separate equations in prior art of Blending Efficiency of Blending of the present invention.

With in " background technology " compared with the Mathematical Modelling Method that the separate equations adopts in the prior art that describes, the Mathematical Modelling Method that the present invention uses meets the actual conditions of modernization stock yard mixing flow chart Blending Efficiency of Blending more.Therefore, this is calculated value with the meet production actual reason two more more accurate than the separate equations in prior art of Blending Efficiency of Blending of the present invention.

(3) present invention contemplates many factors affecting Iron Ore Powder Blending Efficiency of Blending, the influence factor of producing the mixing stockpile in stock ground in invention formula has and comparatively comprehensively describes, that is, the computing formula of Iron Ore Powder Blending Efficiency of Blending of the present invention is expressed as the multifactorial function of mixing stockpile production, meets the reality that mixing stockpile is produced.Therefore, this is calculated value with the meet production actual reason three more more accurate than the separate equations in prior art of Blending Efficiency of Blending of the present invention.

(4) present invention employs during mixing material is produced the numerous operating parameter occurred, these operational parameter data accurately, be easy to get, Tfe content, mixing material as chemically examined various raw material mix the data such as the standard deviation a of the Tfe that sample examination obtains on stone number of plies n, the qualification rate P of stockpile, mixing material product conveying belt in producing be all the data that production scene needs to measure statistics; The parameter such as P (A), σ a, Cp, only need slightly do to calculate just can obtain, and t is then the monolateral specification limit that mixing material is produced.Therefore, the application of the data obtained in these production managements in formula absolutely proves that the present invention can not only reflect that the production of mixing flow chart is actual, is also convenient to the production management mixing operation simultaneously.

(5) the meaning of formula of the present invention is: the standard deviation that before mixing operation, various raw material is total is through the multiple of the standard deviation of mixing material or the compound obtained after mixing flow chart is produced, the Blending Efficiency of Blending of mixing flow chart is represented with this, multiple is more, and blending efficiency is higher.

(6) can see from table one, " calculate η and actual measurement η " in other words between " calculating σ a and actual measurement σ a " and there is a certain distance, illustrate when ensureing proper data statistic, using the σ a of actual measurement to calculate the Blending Efficiency of Blending of mixing flow chart, more pressing close to produce actual than adopting the σ a calculated.Because it is the same with " utilize and mix stockpile qualification rate to calculate the method that Iron Ore Powder mixes the blending efficiency of operation process " to adopt calculating σ a to calculate the Blending Efficiency of Blending mixing flow chart, all calculate to mix based on stockpile qualification rate, although and the statistical computation mixing stockpile qualification rate to have simple maneuverable advantage more coarse.

(7) mix stockpile actual measurement standard deviation a the same with mixing stockpile qualification rate P, it is all quality index important in the daily production of mixing flow chart, mixing stockpile actual measurement standard deviation a compares the technical indicator being partial to mix flow chart, and mix stockpile qualification rate P and compare and be partial to mix the production target of flow chart, therefore, the Blending Efficiency of Blending of the mixing flow chart that the present invention expresses, has caught emphasis, has caught essence.

Embodiment

The raw material of the mixing operation that the present embodiment uses is that South Africa powder, Australian powder, Brazilian powder, Iranian powder, Brazil concentrate, Russian fine powder, Peru's fine powder, plum mountain fine powder, smelting mountain are from molten powder, New Zealand's fine powder, Yang Di fine powder, boron fine powder, iron scale, gas ash, slag, sinter return fine, dolomite dust.

Tfe can chemically examine gained by scene, now lists in data summary table, in table one by the chemical examination of each embodiment and calculating acquired results.

σ a can by the mixing stockpile qualification rate P measured in production, carry out looking into Standard Normal Distribution value table according to formula (5) and obtain, also can expect sample examination on product conveying belt in mixing, the Tfe compositional data then obtained sample examination carries out statistical computation and obtains.Now the Tfe compositional data that the sample examination of each embodiment obtains is carried out statistical computation and the actual measurement σ a that obtains and look into Standard Normal Distribution value table and calculate the calculating σ a two kinds of results obtained and all list in data summary table, in table one.

T in table one represents the technical requirement to mixing operation, and the present embodiment is t=0.008.

Here is the detailed process that each embodiment carries out according to the formula that the application proposes calculating:

Embodiment 1

1) formula (5) is utilized to obtain σ a:

σ a can by the mixing stockpile qualification rate P data measured in producing, utilize formula (5) i.e. Ф (t/ σ a)=(1+P)/2 obtain;

Look into Standard Normal Distribution value table, obtain t/ σ a=1.81,

σa＝t/1.81＝0.008/1.81＝0.0044。

2) utilize theory calculate σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.867\&times;0.133}/0.0044=\mathrm{77.176.}$

3) utilize practical measurement σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.867\&times;0.133}/0.0042=\mathrm{80.851.}$

Embodiment 2

1) formula (5) is utilized to obtain σ a:

σ a can by the data of mixing stockpile qualification rate P measured in producing, utilize formula (5) i.e. Ф (t/ σ a)=(1+P)/2 obtain;

Look into Standard Normal Distribution value table, obtain t/ σ a=1.15,

σa＝t/1.15＝0.008/1.15＝0.007。

2) utilize theory calculate σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.863\&times;0.137}/0.007=\mathrm{49.114.}$

3) utilize practical measurement σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.863\&times;0.137}/0.0079=\mathrm{43.525.}$

Embodiment 3

1) formula (5) is utilized to obtain σ a:

σ a can by the mixing stockpile qualification rate P data measured in producing, utilize formula (5) i.e. Ф (t/ σ a)=(1+P)/2 obtain;

Look into Standard Normal Distribution value table, obtain t/ σ a=1.75,

σa＝t/1.75＝0.008/1.75＝0.0046。

2) utilize theory calculate σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\begin{array}{c}\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.859\&times;0.141}/0.0046=\sqrt{0.1211}/0.0046=0.348/0.0046\\ =\mathrm{75.652.}\end{array}$

3) utilize practical measurement σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\begin{array}{c}\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.859\&times;0.141}/0.0053=\sqrt{0.1211}/0.0053=0.348/0.0053\\ =\mathrm{65.66.}\end{array}$

Embodiment 4

1) formula (5) is utilized to obtain σ a:

σ a can by the mixing stockpile qualification rate P data measured in producing, utilize formula (5) i.e. Ф (t/ σ a)=(1+P)/2 obtain;

Look into Standard Normal Distribution value table, obtain t/ σ a=1.20,

σa＝t/1.20＝0.008/1.20＝0.0067。

2) utilize theory calculate σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\begin{array}{c}\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.853\&times;0.147}/0.0067=\sqrt{0.1254}/0.0067=0.3541/0.0067\\ =\mathrm{52.851.}\end{array}$

3) utilize practical measurement σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\begin{array}{c}\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.853\&times;0.147}/0.0071=\sqrt{0.1254}/0.0071=\\ 0.3541/0.0071=\mathrm{49.873.}\end{array}$

Embodiment 5

1) formula (5) is utilized to obtain σ a:

σ a can by the mixing stockpile qualification rate P data measured in producing, utilize formula (5) i.e. Ф (t/ σ a)=(1+P)/2 obtain;

Look into Standard Normal Distribution value table, obtain t/ σ a=1.88,

σa＝t/1.88＝0.008/1.88＝0.0043。

2) utilize theory calculate σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\begin{array}{c}\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.859\&times;0.141}/0.0043=\sqrt{0.1211}/0.0043=0.348/0.0043\\ =\mathrm{80.93.}\end{array}$

3) utilize practical measurement σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\begin{array}{c}\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.859\&times;0.141}/0.0047=\sqrt{0.1211}/0.0047=0.348/0.0047\\ =\mathrm{74.043.}\end{array}$

Embodiment 6

1) formula (5) is utilized to obtain σ a:

σ a can by the mixing stockpile qualification rate P data measured in producing, utilize formula (5) i.e. Ф (t/ σ a)=(1+P)/2 obtain;

Look into Standard Normal Distribution value table, obtain t/ σ a=1.75,

σa＝t/1.75＝0.008/1.75＝0.0046。

2) utilize theory calculate σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\begin{array}{c}\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.881\&times;0.119}/0.0046=\sqrt{0.1048}/0.0046=0.3237/0.0046\\ =70.37\end{array}$

3) utilize practical measurement σ a to calculate the blending efficiency of Iron Ore Powder mixing operation process:

$\begin{array}{c}\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a=\sqrt{0.881\&times;0.119}/0.0040=\sqrt{0.1048}/0.0040=0.3237/0.0040\\ =\mathrm{80.925.}\end{array}$

What finally above-mentioned calculating obtained the results are shown in data summary table, and detailed data situation as shown in Table 1.

Table one Iron Ore Powder Blending Efficiency of Blending calculated with mathematical model result summary table

	Tfe	P(A)	P	t(％)	Calculate σ a (%)	Calculate η	Actual measurement σ a (%)	Actual measurement η
									Embodiment one	60.7	86.71	0.93	0.8	0.44	77.176	0.42	80.851
Embodiment two	60.4	86.29	0.75	0.8	0.7	49.114	0.79	43.525
									Embodiment three	60.1	85.86	0.92	0.8	0.46	75.652	0.53	65.66
Embodiment four	59.7	85.29	0.77	0.8	0.67	52.851	0.71	49.873
									Embodiment five	60.1	85.86	0.94	0.8	0.43	80.93	0.47	74.043
Embodiment six	61.7	88.14	0.92	0.8	0.46	70.37	0.4	80.925

In addition to the implementation, the present invention can also have other embodiments.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of application claims.

Claims (3)

1. utilize mixing stockpile actual measurement standard deviation to calculate a method for blending efficiency in Iron Ore Powder mixing operation, it is characterized in that: comprise the following steps:

(i) the content P (A) that mathematical simulation obtains iron ore in mixing material is carried out to Iron Ore Powder mixing flow chart:

If each raw material participating in mixing all only has iron ore and gangue composition, the blending operation process of mixing flow chart is regarded as n the independent Bernoulli trial repeated, " iron ore appearance " this event is represented with A, 1-A represents " gangue appearance " i.e. " A does not occur " event, the number of times occurred by A is compared with total degree, be the probability that A occurs, namely mix percentage composition P (A) (%) of iron ore in material, the total probability formula that iron ore in mixing material occurs be expressed as:

P(A)＝P(B1)P(A/B1)+P(B2)P(A/B2)+……+P(Bk)P(A/Bk)(1)

In formula: B1, B2 ..., Bk is the K kind raw material participating in mixing; A represents iron ore; P (B1), P (B2) ..., P (Bk), (%) is the charge ratio of various raw material; P (A) is the content of iron ore in mixing material; P (A/B1), P (A/B2) ..., P (A/Bk), (%) is the content of iron ore in various raw material;

In the production of reality mixing operation, P (A/B1), P (A/B2) ..., P (A/Bk) is obtained by the data of collection in worksite, collection in worksite data are the Tfe content chemically examined various raw material, Tfe content is transformed to P (A/B1), P (A/B2) ... P (A/Bk), the method for conversion is:

P(A/B1)＝(Tfe1)/70％＝10/7(Tfe1)

……

P(A/Bk)＝(Tfek)/70％＝10/7(Tfek)

Wherein (Tfe1) chemical examination Tfe that is the first raw material; (Tfek) be the chemical examination Tfe of kth kind raw material;

(ii) the distribution of Iron Ore Powder discrete random variable X is determined, the expectation and variance of X:

N the independent Bei Nuli machinery mixing test repeated is carried out to Iron Ore Powder compound, stochastic variable kind according to the heap feature of material extracting operation and the mathematical feature deterministic process of research object iron ore is discrete random variable, stochastic variable X is distributed as obedience binomial distribution, therefore, the expectation and variance of X is respectively:

E(X)＝nP(A)(2)

D(X)＝nP(A)[1-P(A)](3)

(iii) the standard deviation sigma a of stockpile is mixed after obtaining Iron Ore Powder mixing operation:

I obtains σ a by mixing stockpile qualification rate P:

1) the standard deviation sigma a of stockpile and the Process Control Theory mathematic(al) representation of mixing stockpile chemical composition Tfe qualification rate P is mixed:

I is by Tu-T ^l=2t, draws P=P (T ^l≤ X≤Tu), wherein, Tu: the quality control upper limit in the production of mixing material; T _l: quality control lower limit in the production of mixing material;

II, according to P (TL≤X≤Tu)=2 Ф (3Cp)-1, obtains:

P＝2Ф(3Cp)–1

Namely Ф (3Cp)=(1+P)/2 (4)

In formula, P: the mixing stockpile qualification rate that mixing flow chart is produced; Cp: an index of engineering capacity of mixing flow chart;

2) expression formula of the standard deviation sigma a of stockpile is mixed after obtaining asking Iron Ore Powder to mix operation:

Due to Cp=(Tu-T ^l)/6 σ a,

Namely: Cp=t/3 σ a

Therefore, above-mentioned formula (4) also can be expressed as:

Ф(t/σa)＝(1+P)/2(5)

In formula, σ a is the standard deviation mixing stockpile after Iron Ore Powder mixing operation; T: the monolateral specification limit that mixing material is produced; P: the mixing stockpile qualification rate that mixing flow chart is produced;

3) according to formula (5), σ a is obtained by looking into Standard Normal Distribution value table;

The method of II statistical computation directly calculates actual measurement σ a with scientific calculator: in mixing work production, double bucket wheel reclaimer is used to carry out mixing material extracting operation to the mixing stockpile piled, when mixing material product conveying belt downward road sintering circuit feed, on product conveying belt, pick test is carried out to mixing stockpile by sampleman, then statistical computation is carried out to the Tfe compositional data that sample examination obtains, directly calculate required actual measurement σ a with scientific calculator;

(iv) the standard deviation of stochastic variable X is obtained:

Central limit theorem in probability statistics is thought: establish X1, X2 ..., Xn is n the separate stochastic variable with distribution, and its co-localization is not normal state or the unknown, but its average μ and variances sigma ²all exist, then, when n is quite large, sample average X is similar to Normal Distribution N (μ, σ ²/ n);

N the independent Bei Nuli machinery mixing test repeated is carried out to Iron Ore Powder compound, the stochastic variable kind of its process is discrete random variable, obey binomial distribution, meet X1, X2 ..., Xn is the condition of n the separate stochastic variable with distribution, and its co-localization is not normal state, (ii) obtain average μ and variances sigma by step ²all exist, therefore, calculate the standard deviation of Iron Ore Powder mixing operation stockpile with formula below:

σΑ ²＝σE ²╱n(6)

Or $\mathrm{\&sigma;}A=\mathrm{\&sigma;}E/\sqrt{n}---\left(7\right)$

Wherein, σ E: the standard deviation that before Iron Ore Powder mixing operation, various raw material binomial distribution is overall; N: the total number of plies of cloth intending stone heap; σ Α: the standard deviation intending stone heap;

According to step (ii), σ E here ²=D (X), therefore, obtains (3) formula for people (6) formula:

σΑ ²＝P(A)[1-P(A)](8)

Or $\mathrm{\&sigma;}A=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}---\left(9\right)$

(v) obtain and utilize mixing stockpile actual measurement standard deviation to calculate the computing formula of Iron Ore Powder mixing operating efficiency:

1) computing formula defining blending efficiency is:

η＝σe/σa(10)

Wherein, σ e: the standard deviation that before Iron Ore Powder mixing operation, various raw material is total; σ a: the standard deviation of the Tfe that sample examination obtains on mixing material product conveying belt;

The standard deviation that before this formula represents mixing operation, various raw material is total is through how many times of the standard deviation of mixing material or the compound obtained after mixing flow chart is produced, the Blending Efficiency of Blending of mixing flow chart is represented with this, multiple is more, and blending efficiency is higher;

2) obtain utilizing mixing stockpile actual measurement standard deviation to calculate the computing formula of Iron Ore Powder mixing operating efficiency:

According to central limit theorem, when n is sizable, have:

$\mathrm{\&sigma;}e\&ap;\mathrm{\&sigma;}A=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}---\left(11\right)$

Formula (11) is substituted into blending efficiency defined formula (10) obtain:

$\mathrm{\&eta;}=\sqrt{P\left(A\right)\&lsqb;1-P\left(A\right)\&rsqb;}/\mathrm{\&sigma;}a---\left(12\right)$

In formula: η is the blending efficiency of mixing operation; P (A) is the content of iron ore in mixing material, is determined by formula (1);

σ a: the standard deviation of Tfe that on mixing material product conveying belt, sample examination obtains, is obtained by two kinds of methods below:

(1) on mixing material product conveying belt, sample examination obtains the standard deviation of Tfe;

By formula (5) i.e. Ф (t/ σ a)=(1+P)/2 are obtained.

2. the as claimed in claim 1 method utilizing mixing stockpile actual measurement standard deviation to calculate blending efficiency in Iron Ore Powder mixing operation, is characterized in that: step (iv) in, the standard deviation that σ Α intends stone heap is discrete random variable.

3. the as claimed in claim 1 method utilizing mixing stockpile actual measurement standard deviation to calculate blending efficiency in Iron Ore Powder mixing operation, is characterized in that: step (v) in, the standard deviation that before σ e Iron Ore Powder mixing operation, various raw material is total is random variable of continuous type.