JP2011005350A - Talc dressing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a talc dressing method in a dry state capable of enhancing the quality of a talc component by removing impurity components such as an unnecessary carbonate ore from a raw material ore of talc.SOLUTION: The raw material ore is passed through a plurality of stages of crushing processes to be forwarded as talc powder reduced in the content of impurities. First, the raw material ore is screened to remove a part of a large particle component containing many impurities and the screened ore is subjected to grinding treatment by a roller mill and a micron mill. Coarse particles, in a state that the impurities are concentrated, are screened in respective grinding processes to be discarded and the impurities are prevented from being finely ground to an excessive degree in the next grinding process.

Description

  The present invention relates to a sorting and beneficiation method that is applied to remove unnecessary impurity components such as carbonate mineral from talc raw material ore and to improve the quality of talc component, and in particular, a step of pulverizing raw material ore Thus, the present invention relates to a beneficiation method that makes it possible to obtain a high-quality talc raw material while sequentially removing impurities by a dry pulverization / sorting method by sequentially providing steps for removing impurities.

Talc, which has characteristics such as chemical stability, high whiteness, low wear, and flatness of finely divided particles, can be processed into fine powders to make many paper, synthetic resins, cosmetics, paints, etc. It is used as a filler in the field.
However, these filler materials are limited to powders that contain little impurities and that can easily use the characteristics of talc, and talc that contains a large amount of impurities should be used. There is nothing.

JP2007-106658

(Use of fine talc powder)
As technical means disclosed in the above-mentioned publicly known document, a resin product is obtained by performing processing such as mixing a raw material processed into fine particles having a particle diameter of about 0.05 to 1 μm into a synthetic resin raw material. The case where it is used as a material for increasing the amount and strength is described.
In addition, the conventional example is intended to utilize a fine powder of talc, and a method for producing ultrafine talc powder using either wet or dry pulverization means Are described in several examples.
However, the above-mentioned documents, which are publicly known in the method for producing finely divided talc, are intended for talc raw materials with a low content of impurities, and relate to a technique for finely pulverizing talc raw material with high purity. is there.

The demand for fine powders of talc, which are low in impurities, such as carbonate minerals as described above (average particle size is around 5μ) has increased rapidly with the development of the automobile industry. More than 10,000 tons are used.
However, in regions where raw materials are supplied to Japan, ore with quality and characteristics that can meet the demand is only about 15% of the total amount of mining, making it difficult to meet Japanese demand. It was. On the other hand, small grains that account for about 30% of the total mining amount in the specific supply area and talc raw material ore that has been pulverized during mining are carbonate minerals despite their high whiteness. Therefore, there is a big problem that needs to be solved that the demand for the automobile industry cannot be met. Therefore, as for the talc raw material, the current situation is that the production and demand are not balanced.

The present invention is intended to perform separation and selection of impurity components contained in talc ore regardless of the pulverization and pulverization techniques, and various apparatuses were used in the following description. The pulverizing means is used as one means for sorting.
In addition, a method of separating impurities such as talc (talc) component and carbonate mineral using a wet flotation means in order to sort out and remove impurities such as carbonate mineral contained in the raw material ore is a known example. Although disclosed, this method is currently unsuccessful in operations directed at specific feedstocks. Moreover, even if the wet sorting method can be carried out, it is possible to prevent freezing of water in winter in a cold region or to remove the moisture of the collected talc (dry until the adhering moisture is 0 or 2% or less. There is still a factor that causes the manufacturing cost to rise. Therefore, the present situation is exploring a beneficiation method that can easily perform beneficiation and obtain a low-cost talc product for the talc ore as described above.

The present invention uses a dry beneficiation method to separate impurities such as carbonate minerals contained in talc ore, and has used small ores that have not been used to date as resin paint fillers for the automotive industry. It is intended to be used as a raw material for talc fine powder.
In addition, regarding the ore used as a raw material for preparing the talc fine powder, with respect to the examples of the present invention described below, useful or unnecessary contained mineral components contained in the ore, and physical properties of those components are as follows: As shown in FIG.

As can be seen from FIG. 1, in the present invention, the talc that is removed from the ore and shipped to the market has its components represented by the chemical formula (3MgO · 4SiO 2 · H 2 O) High talc powder is white and pearly.
The impurity component contained in the ore with respect to the talc component is mainly carbonate minerals (rhombolithia, dolomite, calcite), but in addition there are chlorite and quartz. Of these components, the only component that is actually required by customers is talc, and the proportion of impurity components such as other carbonate minerals can be set as much as possible by using a dry beneficiation technique. It is an object of the present invention to separate to a small value.

In the talc raw ore described in FIG. 1 above, the terms relating to the talc component and other components contained in the ore, and the chemical formula, The actual names and the Mohs hardness are as follows.
Talc
Hydrous magnesium silicate 3MgO ・ 4SiO2 ・ H2O Mohs hardness 1
Carbonate mineral Magniteite MgCO3 Mohs hardness 4
Dolomite MgCO3 · CaCO3 Mohs hardness 4
Calcite CaCO3 Mohs hardness 3
Quartz SiO2 Mohs hardness 7
Chlorite (Mg, Fe, Al) 3,
[(OH) 8 | (Si, Al) 4, O10] Mohs hardness 2, 5
In the following description, rhyme, dolomite and calcite are collectively referred to as carbonate minerals.

As described above, in each component included in the raw ore of talc, the talc component shipped as a product is a very soft component having a Mohs hardness of 1. On the other hand, each component of impurities has a high Mohs hardness of 4 or more except that calcite has a hardness of 3.
Therefore, it was determined that each component of impurities contained in the talc ore was coarse and non-uniformly dispersed, and the separation method of the present invention described below was easily applicable. For ores, the crushing action is exerted on the talc component by utilizing the hardness difference of the impurities, but the impure element having a high hardness is processed without imparting the crushing action.
In addition, the component that becomes an impurity is in a state of coarse particles as much as possible, and is supplied for sieving as a separation step, and a method of separating and removing as large particles is used, so that the cost is relatively low. We are trying to provide a separation method.

  In order to explain the present invention, a hard component having a hardness of 3 or more, such as carbonate mineral and quartz, with respect to a talc component having a hardness of 1 will be collectively referred to as a hard component. Moreover, in this invention, it is not concerned about isolation | separation and discharge | release of chlorite, and the raw material which contains 1.5% or more of chlorite is not made into object. Furthermore, in the following description of the present invention, asbestos minerals such as warm asbestos and peridotite, and talc ore containing graphite are not considered as targets.

In the first sample used as an object of the beneficiation in the present invention, the raw material A produced in the specific area and the small raw material (-2 mm) B obtained by sieving the raw material A are pulverized. HM1 obtained by pulverizing A and HM2 obtained by pulverizing a +2 mm raw material obtained by sieving the raw material A.
In the raw material A, the particle size composition is about 50% with a particle size of 2 mm as a boundary. In addition, it can be seen that in the raw material B (raw material A having a particle size of 2 mm or less under the sieve), the particle size constitution of 500 μm or less is 50% or more.
In addition, in the pulverized HM1 and HM2, the particle size constitution of 2 mm or less shows that each particle size is almost uniform in FIG.

In the example shown in FIG. 2, the relationship between the particle size configuration (distribution) and ignition loss is considered. In the raw material A, the value of ignition loss decreases at a particle size of 2 mm, and greatly decreases at 150 μm or less. It has been made clear. The decrease in the ignition loss value indicates that the hard component content is low. As can be seen from FIG. 2, in the raw material A, the hard component contained in the ore is coarse granular. It can be estimated that it is.
Therefore, as described below, if a method is adopted in which the hard component is separated when it is in the state of large grains, the hard component is prevented from being pulverized, and the pulverization of only the talc component is promoted. It is considered that the hard component can be separated by the particle size.
In addition, in the example shown in FIG. 2, the raw material A is subjected to a sieving treatment, and the hard component is excessively pulverized by further sieving by separately pulverizing the material divided into constant particle sizes. That can be suppressed, and fine powder of the talc component can be easily obtained.

By the way, when pulverizing the small raw materials A and C (components on the sieve having a particle diameter of 2 mm or more of the raw material A), the results of pulverization using a hammer mill as a pulverizer are shown in pulverized products HM1 and HM2. However, this was pulverized using a hammer mill R-102 and a hammer mill R-105 (2 mm or more). However, when the sample pulverized by the two hammer mills was tested in the same manner as the raw material B, a preferable result could not be obtained.
In other words, from the above data, it was estimated that the use of hammer mill pulverization means that the hard component was finely pulverized together with the talc component and diffused and mixed almost uniformly from coarse to fine particles. It was. Therefore, in order to crush the raw ore of talc, it is not necessary to use a method of crushing with a strong impact such as a hammer mill, but to use a grinding and grinding method such as a roller mill. It is considered suitable for the purpose.

(Description of this application)
In the present invention, the raw ore of talc used as an object of selection is intended for ore of a specific production area that produces a large amount of it, but it is an ore having properties similar to this raw material. If there is, it does not ask the place of production. Then, by applying the screening means described below, it is possible to obtain a high-quality talc raw material that can be used as a raw material for producing a talc product.
The ore of the talc is a small-sized granule that accounts for about 30% of its output (a granular particle having a particle size of 25 mm or less is 95% or more). , Mainly containing dolomite, calcite, etc.) and quartz, which cannot be sorted out, so its use has been limited.

According to the present invention, components such as carbonate minerals and quartz (hereinafter referred to as hard components including other mineral raw materials having a Mohs hardness of 3 or more) are contained in the small raw material using a dry mechanical processing means. Then, the hard component is selected and removed, and the component that becomes a talc raw material with a loss on ignition of 7.5% or less is collected to expand the use of the small-grain raw material, which has been limited to conventional applications.
The present invention consists of the constituent elements as described below.

The present invention clearly has a difference in Mohs hardness between a component to be recovered as a product and a component to be discarded, and utilizes the difference in Mohs hardness with respect to a raw ore that recovers a product having a small Mohs hardness as a product. The present invention relates to a pulverizing / selecting method using a pulverizing method that exhibits a crushing action for components having low hardness but does not crush impurity components having high hardness.
The invention of claim 1 arranges the step of crushing and sieving in a plurality of stages so that the raw ore is pulverized and sorted in a dry manner, and gradually becomes small particles,
In the sieving process that follows each pulverization process, a process of separating large coarse particles and discarding them as impurities,
The sieving component in the sieving step is supplied for the next pulverization step to make smaller particles, and the load in the pulverization step to be gradually made smaller particles can be reduced,
A component having a small Mohs hardness is obtained as a fine powder product by a dry sorting method in which the crushing and sieving steps are sequentially repeated for sorting.

In the invention of claim 2, the raw material ore is talc ore, and the component discarded as an impurity is a component mainly composed of carbonate mineral,
In order to realize the beneficiation method, a pulverizer that preferentially crushes components with low hardness is selected and used,
Using the difference in hardness of mineral components contained in the ore, sieving is performed before the hard components are finely pulverized to remove the hard components remaining in a large grain state, and the load on the subsequent process is reduced. Process to reduce,
The pulverization and sieving process are sequentially repeated while suppressing the hard component from being finely pulverized and being diffused into the fine particles of the talc component.

The invention of claim 3 does not excessively crush the impurities that are hard components contained in the raw ore,
Hard components are discharged to the outside at the earliest possible stage of the grinding process,
It is characterized in that the impurity component of the hard component that remains in a large state in the last step and the talc component that tends to become fine powder are screened, and the sieving component is separated to obtain a talc product.

The invention of claim 4 is a pulverizer to be used in the sorting method, wherein the theory of priority pulverization according to the hardness difference of the mineral contained in the raw material ore between the component to be recovered and the impurity component to be discarded is more efficient. Select and use a model that can be realized automatically,
By minimizing the hard component of the impurity component to be discarded, it is possible to prevent the hard component from being mixed into the fine particles of the talc component,
Coarse grains containing a large amount of hard components of impurities are sequentially discharged out of the grinding system in each grinding process to prevent the hard components from being mixed into the ground talc components,
The sieving machine arranged in the final process separates and removes the hard component concentrated in the coarse particle portion.

Further, in the present invention, utilizing the property that the finely pulverized grains are thin and flat, and the characteristics of talc that is a soft property of Mohs hardness 1,
Among the impurities contained in the raw material ore, in order to separate and process carbonate minerals with a Mohs hardness of 4 in particular, the pulverization separation process is set in a plurality of stages,
Impurities are removed from the large pulverized product among the pulverized products, and the sieving component is supplied to the next pulverization step to make the next smaller particles and pulverized.
Classifying the pulverized product to remove large particles, reducing the content of impurities in the resulting sieving component, so as to obtain a talc component that improves the quality,
In the crushing process that performs the crushing and sieving treatment, the quality of the talc component after the hard component is separated in the treatment step is repeatedly performed by repeating the process of sieving the pulverized products in multiple stages. It is also possible to carry out the pulverization / separation process until it reaches the point, and ship the sieving component obtained in the final stage as a talc product.

  Using the apparatus configured as described above, the raw ore is subjected to a combination of sieving, coarse pulverization, fine pulverization, and classification. In the process of combining these steps, the coarse components enriched with hard components are separated and discharged from the pulverized product, and the pulverized pulverized product has a certain particle size as the classification point. By deciding and separating the coarse powder, it is possible to supply to the market what has reached the final goal of a loss on ignition value of 7.5% or less.

Further, in the pulverization step, for the hard component, selecting a pulverization method that does not give an extra crushing action, and sequentially discharging the coarse particles concentrated with the hard component to the outside of the pulverizer, The action of selecting hard impurity components can be performed efficiently.
The talc component to be collected as a product in the present invention is a mineral having a softness of 1, and the talc is pulverized before the hard component contained in the raw material is crushed, and the pulverized particle size It becomes a thing which can isolate | separate a hard component on the basis of. Therefore, every time the ore is pulverized, it is possible to efficiently separate and collect fine powder in which the talc component is concentrated by performing a separation process using a fixed particle size as a classification point.

It is a table | surface which shows the chemical composition and physical property of talc of an ore, and a containing mineral. It is a table | surface which shows the particle size structure and ignition loss of a small raw material and a pulverized product. It is a flowchart explaining the process process of this invention. It is a table | surface which shows the result of the small particle | grain talc coarse particle discharge | emission grinding | pulverization test by a roller mill. It is a table | surface which shows the result of the supermicron mill coarse particle discharge | emission grinding | pulverization test of a talc raw material. It is a table | surface which shows the test result of the coarse powder classification of a micron mill grinding | pulverization fine powder. It is a table | surface which shows the classification fine powder of a micron mill pulverized product, and a coarse particle size structure.

(Properties of raw ore)
In the examples described below, the raw ore of talc used as a raw material is the following or an ore having equivalent properties, and among the talc of the specific production area, removal of hard components by manual selection is possible. It is intended for a granular raw material having a small particle diameter of 30 mm or less (hereinafter referred to as a small raw material).
In addition, a raw material having a hard component content of 8% or more and less than 30% is used. However, a raw material in which the hard component is finely dispersed in a uniform manner is not an object of the present invention. That is, even if it tries to pulverize the raw material which has such a property, and it is going to isolate | separate, an impurity remains with the state of a small particle | grain with a high concentration with a useful talc component. Therefore, it is not possible to supply talc powder to a customer who is the object of the present invention and use it as a raw material for products at that customer.
In addition, as described above, ores having a chlorite content of 1.5% or more, Chrysotite, Tremolite, and talc containing oresite containing graphite cannot be treated in the present invention. So do not target as a raw material.

(Method for sorting and removing hard components)
In the present invention, the theory of preferential pulverization based on the hardness difference of minerals can be realized more efficiently, and the hard component may be pulverized by selecting a pulverizer that performs pulverization by grinding. As much as possible, the hard component can be prevented from being diffused into the fine particles of the talc component as much as possible.
And, in the pulverization process, the coarse particles having a high content of hard component are discharged out of the pulverizer, and the hard component contained in the raw material is excessively pulverized. Prevents hard components from being mixed into finely ground talc.
The pulverized product obtained as described above is passed through a classifier to classify (separate) and remove coarse particles contained in a state where the hard component is concentrated, and the fine powder of the talc component is recovered as a product.

  In the present invention, the raw ore of talc, with a particle size of 2 to 3 mm, focusing on the fact that there is a large difference in the content of hard components, sieving based on the size set as the classification point The processing steps are provided. And before the pulverization process, the process of removing the hard component with large grains is performed so as not to send the whole toward the pulverization process, the hard component is pulverized by excessively pulverizing the hard component, The device has been devised to prevent it from diffusing into the fine powder used as the product. In other words, in the processing steps described below, the hard component is included in the raw ore processing process, such as omitting the pulverization process and installing the sieving process in consideration of the content of the hard component contained in the raw ore. In order to prevent it from diffusing into the fine powder, it was possible to cope with it by changing the treatment process as needed.

Figure 3 shows a talc product that uses talc raw ore and repeats the crushing and sieving operations on the raw ore in order to remove impurities such as hard components from the talc raw ore and improve the quality. The process of obtaining (hereinafter referred to as “talc product”) is described.
As the raw ore of talc, the one from the specific production area is used. For example, it has been found that when the raw ore has a particle size of 90% or more when the particle size is 25 mm or less, the content of the hard component varies when the content is 30% or less. Then, depending on the raw material ore to be selected, the treatment process is changed to correspond.
Hereinafter, each processing step will be described in the order of the steps, and each processing step will be referred to as step A to step E.

In the flowchart of FIG. 3, the first “vibrating sieve” of Step A is provided as a pre-processing step of the crushing step of Step C following Step B.
That is, from the flow of the processing process, it flows from Step A to Step B to Step C, but in order to prevent the hard component from being excessively crushed and diffused into the powder, Depending on the “size” of the particle size, processing is not performed in step B, but is directly sent to step C, and one process (step) is skipped to enable processing. Therefore, in Step A, the raw material ore is first sieved, and the particles that can be processed in Step C are directly sieved.
In this example, the vibration sieve used in step A is a two-stage sieve considering the processing efficiency. For example, the first stage is 4 mm and the second stage is 2 mm. Then, 4 mm or more, 2 mm or more and 4 mm or less are combined and sent to Step B (roller mill), and 2 mm or less is directly used as the raw material of Step C (supermicron mill).
In addition, since the content of the hard component is increased in Step B and decreased in Step C along with the size classification, depending on the type of ore, the processing in Step B is omitted, and in Step C, It is possible to configure a processing system that only processes.

The roller mill used in Step B is an apparatus having a function equivalent to that of a so-called Raymond mill, and has a particle diameter of 2 mm or more and a hard component of 35 to 40% (in the case of a standard raw material ore) from Step A. The raw material is processed in Step B (roller mill).
The roller mill of Step B is a device that modifies a commercially available machine to match the characteristics of the raw material, and discharges coarse particles with a large content of hard components to the outside during the pulverization. It is assumed that functions are incorporated. And in the process of pulverizing the raw material, coarse particles with a high content of hard components are discharged and discarded. (Discharge can be controlled up to 20%.)
In addition, the pulverized product from which the coarse particles have been separated in Step B is used as a raw material to be processed in the supermicron mill in Step C together with the sieving material of 2 mm or less under the sieve in Step A.

Step A to step B are standard processes, but if the content of the hard component in the raw ore is low, the steps from step A to step are performed to avoid excessive grinding of the hard component. It can transfer to B1 and can change to the process by the roll crusher of step B1. In this step B1, the raw material of 2 mm or more obtained by sieving in step A is crushed so that the material of 3 mm or less is 90% or more and supplied to step C. In Step B1, only the crushing of the raw material particle size to a small particle size is performed, and the hard component contained does not change.
When this process is carried out with a hammer crusher, the hard component becomes fine powder and is diffused, and it is feared that it becomes difficult to select the hard component based on the particle diameter.

The sieving component in Step A has a particle size of −2 mm, and the hard component is reduced. Further, although the hard component increases in the component of +2 mm, since the hard component is discharged at the time of pulverization by the roller mill in Step B, the hard component of the pulverized product that has passed Step B is decreased.
The sieving component having a particle diameter of −2 mm in Step A and the pulverized product processed in Step B are combined and supplied to the supermicron mill in Step C. In the supermicron mill, grinding and pulverization are efficiently performed, the soft talc is pulverized, and the pulverizing action of the hard component remains coarse. The coarse granular hard component is transferred from the nozzle of the pulverizer. Discharged outside. The content of coarse hard components to be discharged reaches a maximum of 80% (ignition loss is 43%), and the hard components are separated and discharged extremely efficiently.
On the other hand, pulverization of the talc component is also efficiently promoted for the pulverized product which is pulverized in Step C and sent to the classification step of the next Step D. In Step C, the hard component can be discharged to the outside of the machine through the nozzle of the pulverizer within a range of up to 20% of the charged raw material. Up to 60% of this can be discharged out of the machine through the nozzle.

The raw material that was finely pulverized and separated into Step D while separating and discharging a considerable amount of the hard component in the supermicron mill of Step C had an average particle size of ± 10μ and a particle size of 35% with a cumulative rate of 95%. It is a powder.
In the step D, the target is to obtain fine powder having an average particle size of 9.0 μm or less and a cumulative particle size of 95% as particle classification from a classifier. The recovered fine powder is supplied as a resin talc raw material with a loss on ignition of 7.5% or less, and the coarse particles separated and sorted by classification are supplied to Step E.

In order to perform sorting by the classifier, a classifier having a particle size of 6 to 30 μm and a processing amount of 300 to 1500 kg / hour is selected and used as a model capable of sharp classification.
When selecting the classifier, the priority is to be able to set the classification particle size to be small, and the processing capacity and the like may be considered secondarily. In other words, rather than fearing that the classification throughput will be reduced, hard components will be sufficiently separated and sorted without considering classification performance so as to reliably achieve the target branch point. There is no fear. It should be noted that it is difficult to collect all the fine particles that are desired to be classified and collected, and it is better to plan reclassification of coarse-grained parts, assuming that a considerable amount cannot be captured.

(Reclassification)
The coarse powder part selected by classification in Step D contains fine powder rich in a considerable amount of talc components, and therefore, a classifier having better classification performance than the classifier used in Step D. Reclassification is performed in step E to recover a large amount of talc components.
In particular, in the classification of Step E, when the particle size with a cumulative rate of 95% is 20 μ or less and the hard component is not sufficiently separated with this classified particle size, the particle size with a cumulative rate of 95% May be considered to be reduced to 15-18μ.

The description of the steps in the flowchart is summarized as follows.
1) Minimize the opportunity to add pulverizing action and suppress the diffusion of hard components.
2) Hard components are discharged from the grinding process before being ground.
3) In the final step, the talc component and the hard component are separated by classification.
4) Considering the classification accuracy as the first, the recovery yield is improved by reclassification.
5) Depending on the state of the raw material ore (particle size, content of hard component), the treatment process is efficiently changed and dealt with.

In the talc product (talc powder supplied to customers) that can be collected in the final stage of the beneficiation through the above steps in sequence, the properties can be obtained as follows.
・ The loss on ignition of talc to be collected should be 7.5% or less.
-The recovery yield of talc should be 50% or more. That is, the recovery yield of the talc product varies up to 90% in a manner that is inversely proportional to the content of the hard substance, that is, the hard component contained in the raw ore of the talc to be processed.

  The talc data obtained from the pulverizer used in the process of finely pulverizing the raw ore will be described with reference to FIG. The data shown in FIG. 4 relates to the roller mill (Raymond mill) used in Step B in the process described with reference to FIG. A mechanism is provided. In this apparatus, a commercially available apparatus is modified to have a mechanism adapted to the object of the present invention.

In the example shown in FIG. 4, from the viewpoint of the loss on ignition data, in the coarse particle discharge (discard) for the processing raw material, the loss on ignition value is very large, It turns out that the hard component of a talc raw material is reduced efficiently and it transfers to the following step C. (In other words, the greater the loss on ignition, the greater the hard component content.)
In addition, about the talc raw material grind | pulverized with a roller mill (Raymond mill) and sent to Step C, it has confirmed that there is little diffusion to the fine powder of a hard component.

  The data shown in FIG. 5 relates to the supermicron mill described in Step C in FIG. 3, and by grinding and grinding a coarse granular talc raw material of 3 mm or less, the discharge of hard components to the outside, The fine pulverization of the talc component and the rough pulverization of the hard component in the raw material are efficiently performed.

As illustrated in FIG. 5, the hard component is concentrated in the coarse particles, and the hard component content of 80% can be discharged to the outside. Moreover, the content of the hard component can be discharged without changing the content up to a maximum discharge amount of 20% from the structure of this machine.
The powder pulverized in Step C is in a state in which hard and talc components of coarse particles and fine powder are efficiently concentrated, and the process proceeds to the processing step by the classifier in Step D.

  FIGS. 6 and 7 to be described next relate to data when classifying / separating coarse powder (hard component) and fine powder (talc component) with a classifier in Step D in FIG. 3. As shown in FIGS. 6 and 7, the talc raw material pulverized by the supermicron mill in Step C has a hard component concentrated in the coarse particle portion and a talc component concentrated in the fine powder portion. These are shown from the numerical values of the discharged coarse powder of the classifier and the ignition loss of the recovered fine powder.

  From FIG. 6 and FIG. 7, it can be estimated from the analysis results that the ignition loss of the recovered talc raw material is determined not by the classification recovery rate but by the particle size of the recovered fine powder. That is, the talc product has a particle size constitution of the recovered fine powder and a particle size of 20 μm with a cumulative rate of 95%.

In the classification process of Step D, the hard component can be separated from the talc raw material and supplied to the market as a product, as shown in FIGS. 6 and 7, the recovered product with a loss on ignition of 7% or less. It is. If an example meeting the above-mentioned conditions is selected from Table 5-2, Sample R-8 is applicable. That is, it is considered that fine powder having a 95% cumulative particle size of 20 μ ± 1 μ or less and an average particle size of 9.0 μ or less passes the standard of [product of talc], which is regarded as the final recovered product. .
When the classification situation for obtaining the fine powder is examined, it can be seen that the coarse powder separated as containing a large amount of hard components contains ± 20% of fine powder of 20 μ ± 1 μ or less.
In Step E shown in FIG. 3, the fine powder of coarse powder waste containing a large amount of the talc component is classified and collected again to improve the recovery rate of the talc raw material.

The process chart described with reference to FIG. 3 will be further described. First, regarding the raw material, the hard component contained in the raw ore of talc is contained in a state where relatively coarse particles are dispersed unevenly. Is done. In general, small talc raw materials differ in the content of hard components with a particle of ± 3 mm as a distinction point, and coarse particles contain a large amount of hard components.
Therefore, the present invention is not applied to ores in which the hard component is fine and uniformly dispersed. In addition, since the present invention cannot be applied to minerals such as chlorite, asbestos mineral, and graphite, other mineral processing methods are considered for talc ore having such properties, or This can be dealt with by developing other uses other than resin additives.

・ Vibrating sieve:
In order to avoid the diffusion of hard components in the raw ore, a process is selected that minimizes the chance of grinding. When the content of hard components is small and grinding in the primary process is omitted and the grinding in the secondary process is performed directly, the raw material receiving size in the secondary process is limited, or in the primary process, the small particle size raw material When there is no need for this treatment, a sieving step is provided so that only those having the required particle size are treated by sieving.
The mesh of the sieve may be changed depending on the content of the hard component and the diameter of the particles received in the process. In order to increase the throughput of the sieve, the sieve is a two-stage sieve to reduce the burden of small meshes.

-Roller mill (Raymond mill); The roller mill or Raymond mill uses a self-modified one so that coarse particles can be discharged to the outside at any time during the pulverization process.
This discharge device is a device that collects the concentrated coarse particles of hard components that are refluxed for pulverization inside the Raymond mill and discharges them to the outside.
In the present embodiment, a rotary valve is installed at the discharge port so that the inside of the Raymond mill is maintained and the discharge amount can be controlled.

Roll crusher: Should be processed by the Raymond mill, when raw ore is directly processed by a supermicron mill,
About 50% of the raw ore particle size is too large to be put into a supermicron mill. Therefore, the powder is pulverized to a particle size of 3 mm or less by compression pulverization using a roll crusher while avoiding diffusion of hard components into fine powder.
In addition, since the crusher by impact force, such as a hammer crusher, is concerned about the spreading | diffusion of the hard component to a fine powder, it is better to avoid as above-mentioned.

・ Supermicron mill: In the grinding process using Raymond mill and Supermicron mill, hard components are separated and discharged to concentrate the talc components, but there is a limit to discharging them outside the machine while crushing. Uses a method of separating the coarse particles with concentrated hard components from the pulverized raw ore powder by classification.
As described above, in order to separate by classification, when considering the conditions such as the state in which the hard component is concentrated to coarse particles and the increase in the amount of fine powder in which the talc component is concentrated, the characteristics of the supermicron mill are as follows: It serves this purpose.
A roller mill (Raymond mill) can be used to achieve the object of the present invention, like the supermicron mill, but does not reach the supermicron mill in terms of the particle size constitution of the pulverized product. Therefore, in order to recover the maximum talc component, it is desirable to use a supermicron mill.

・ Classifier: In order to reliably achieve that the talc component recovered by classification in the process of selecting and separating hard components from the raw ore has a value of ignition loss of 7.5% or less. The average particle size of the fine powder recovered by classification is 9.0 μm or less, the accumulation rate is 95%, and the particle size is 20 μm or less. This is a necessary condition.
For the classifier, it is preferable to use an apparatus that achieves this classification standard, and has a throughput of 500 kg / hour or more and a throughput as large as possible. However, since the classification accuracy decreases as the processing amount is increased, classification point setting, classification accuracy, collection rate, and the like are important items in designing the apparatus.
Note that fine powder that could not be collected by the primary classification is considered to be recovered by the secondary classification. In this case, in the secondary classification, it is required to consider that the “classification accuracy” is higher.

(Quantity limit of beneficiation in each beneficiation process)
The limits (standards) of the amount of hard component that can be sorted out in each process are as follows. (When the hard component content of the raw ore of talc is ± 30%)
1) Roll crusher grinding
Emissions with hard component content of 40-45% ± 5% emission 2) Roller mill pulverization (coarse particle emission)
Hard component content ± 50% discharge 15% maximum 3) Micron mill grinding (nozzle discharge)
Hard component content ± 80% discharge Maximum 20% discharge 4) Coarse powder cut by classifier
Hard component content ± 50% coarse powder Up to 35% discharge

  The limit value determines the discharge amount in the operation process in the range of the maximum discharge amount according to the hard component content of the processing raw material. The talc raw ore (powder with an average particle size of ± 10 μm) collected in the final process has a recovery rate of at least 55% and a loss on ignition of 7.5%. For example, when the hard component content of the raw ore of talc to be processed is small, the recovery rate is high.

Claims (4)

There is a clear difference in the Mohs hardness between the component recovered as a product and the component to be discarded, and the raw ore that recovers a product with a low Mohs hardness as a product makes use of the difference in the Mohs hardness to reduce the hardness. A crushing / selecting method that uses a crushing method that does not crush the impurity components with high hardness, while exerting crushing action on the components,
When pulverizing and selecting the raw material ore by a dry method, the steps of pulverizing and sieving are arranged in a plurality of stages so as to gradually become small particles,
In the sieving process that follows each pulverization process, a process of separating large coarse particles and discarding them as impurities,
The sieving component in the sieving step is supplied for the next pulverization step to make smaller particles, and the load in the pulverization step to be gradually made smaller particles can be reduced,
A talc beneficiation method characterized in that a component having a low Mohs hardness is obtained as a fine powder product by a dry sorting method in which the crushing and sieving steps are sequentially repeated for sorting. The raw material ore is talc ore, and the component discarded as an impurity is a component mainly composed of carbonate mineral,
In order to realize the beneficiation method, a pulverizer that preferentially crushes components with low hardness is selected and used,
Using the difference in hardness of mineral components contained in the ore, sieving is performed before the hard components are finely pulverized to remove the hard components remaining in a large grain state, and the load on the subsequent process is reduced. Process to reduce,
2. The talc beneficiation method according to claim 1, wherein the pulverization and sieving treatment are sequentially repeated while suppressing the hard component from being finely pulverized and diffused into the fine particles of the talc component. For impurities that are hard components contained in the raw ore, no extra pulverization is performed.
Hard components are discharged to the outside at the earliest possible stage of the grinding process,
2. A talc component obtained by sieving an impurity component of a hard component remaining in a large state in a final step and a talc component that tends to become fine powder, and separating an under-sieving component. Or the method of beneficiation of talc as described in 2. Select a machine that can more efficiently realize the theory of preferential crushing according to the hardness difference of the minerals contained in the raw material ore between the component to be recovered and the component of the impurity to be discarded as the crusher used in the sorting method. Used as
By minimizing the hard component of the impurity component to be discarded, it is possible to prevent the hard component from being mixed into the fine particles of the talc component,
Coarse grains containing a large amount of hard components of impurities are sequentially discharged out of the grinding system in each grinding process to prevent the hard components from being mixed into the ground talc components,
4. The talc beneficiation method according to claim 3, wherein the hard component concentrated in the coarse grain portion is separated and removed by a sieving machine arranged in the final step.

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