KR100857725B1 - Purification method for limestone - Google Patents

Abstract

A limestone purification method is provided to execute a sorting process of impure minerals by using a collector such as thiophosphate, xanthate, dithiophosphate, or the mixture of dithiophosphate and thiocarbamate and to obtain limestone of high whiteness by removing color impure minerals from raw limestone of low whiteness. A limestone purification method comprises the steps of: making crushed materials by firstly breaking raw limestone; making powdered samples by secondly breaking the crushed materials; making an ore-bearing solution by suspending the powdered samples in a solution and grinding the powdered samples; and injecting a frothing agent and a collector using one of thiophosphate, xanthate, dithiophosphate, and the mixture of dithiophosphate and thiocarbamate, into the ore-bearing solution and then, floating and sorting the powdered samples to remove color impurities including at least one of quartz, pyrite, oxide, and muscovite contained in limestone.

Description

Purification method for limestone

The present invention relates to flotation for removing the colored impurity minerals contained in limestone. The present invention relates to a method for purifying limestone, which can remove colored impurity minerals contained in limestone to reduce whiteness.

 Limestone is Korea's largest non-metallic mineral resource and is mainly used for cement, steelmaking, and steelmaking, but recently, demand for limestone is rapidly increasing throughout industries such as agriculture, pollution prevention, papermaking, paint, rubber, plastic, glass, food and medicine. High quality products are required in various fields, and high performance products have tens or hundreds of times higher value than conventional lime products.

In view of the necessity of high value-added technology of limestone from the industrial side, the economic, technical and social ripple effect is increased after the development of high value-added technology, and the value added by the high value-added value of domestic resources is created due to the high competitiveness of domestic natural mineral resources. The import substitution effect is expected. In terms of economics, it is expected to diversify the use of products related to limestone and to improve economic efficiency by recovering high white limestone from low-grade limestone.The systematic research on limestone enhances the utilization of domestic abundant resources and creates high value-added products. And import substitution effect is expected.

Limestone is not only used as such but also calcined by calcining quicklime (CaO), hydrated lime ((Ca (OH) ₂ ), precipitated calcium carbonate (CaCO ₃ ) synthesized by blowing CO ₂ into it, or various kinds of calcium compounds. And other chemical products, etc. In addition, limestone is relatively easy to pulverize, and the finely divided calcium carbonate has the characteristics as a fine powder together with the synthesized calcium carbonate.

Heavy calcium carbonate is produced by physically grinding and classifying high purity crystalline limestone with high whiteness, commonly referred to as heavy calcium carbonate or "heavy charcoal," as opposed to chemically produced hard calcium carbonate or "hard coal". It is called.

"Bulk charcoal" is simply mechanically pulverized, ranging from large grains to products with an average particle size of 1 μm or less, with recent advances in grinding classification techniques.

As such, limestone fine powder is widely used as a raw material in various industrial fields, and its application fields and usage are gradually increasing according to the development and high functionalization trend of related industries. The existing limestone fine powder was mainly for the purpose of increasing the weight, but in recent years, its importance is increasing as a raw material that plays an important role in improving the function of the product. Therefore, the processing technology for the production of materials that meet the needs of consumers by use is also rapidly developing.

However, the depletion of high-grade limestone ores and the excess of specified components of other impurities such as MgO, Al ₂ O _{3 ,} SiO ₂ and Fe ₂ O ₃ are expected to cause difficulties in the supply of raw limestone. In order to utilize limestone as a raw material for various industrial raw materials, it is also essential to improve the whiteness by adjusting the particle size to a size suitable for various uses as well as removing impurities by crushing.

An object of the present invention is to provide a limestone with improved whiteness by a method using a collecting agent such as thiophosphate, xanthate, dithiophosphate or dithiophosphate and chinocarbamate through crushing.

An object of the present invention is to primary crushed limestone ore to form a crushed material; Crushing the crushed matter to form a powder sample; Suspending the powder sample in a solution to form and polish a mineral solution; And a quartz containing a limestone after injecting a collecting agent using any one of a foaming agent, a thiophosphate, a xate, a dithiophosphate, and a mixture of dithiophosphate and chinocarbamate to the mineral solution. It is achieved by a method of purifying limestone comprising the step of floating screening to remove colored impurities containing any one or more of pyrite, oxide and mica.

By using a collecting agent such as thiophosphates, xanthates, dithiophosphates, dithiophosphates and chinocarbamate mixtures of the present invention, it is possible to select impurities from impurities and color them from low limestone ore with low whiteness. There is a remarkable and advantageous effect of removing the impurity minerals to obtain a high white limestone.

The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Limestone is a limestone ore having the characteristics as shown in Table 1 below to contain a float and sort according to the present invention contains a significant amount of water and other minerals.

Table 1 shows the results of chemical analysis of ore. SiO ₂ 0.23%, Al ₂ O ₃ 0.13%, Fe ₂ O ₃ 0.02%, CaO 55.02%, Ig. loss is 43.39%. As a result of chemical analysis, CaO showed a good quality of 55 wt.% Or more. However, limestone ore contains colored minerals pyrite and its mica containing iron oxides and iron-containing minerals. Therefore, when the limestone ore is crushed to form a powder, the whiteness of the limestone fine powder is reduced.

 Limestone ore Composition ratio (%)  Whiteness SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO Ig.loss 0.13 0.11 0.04 55.09 0.37 43.56 90.3

1 is XRD measurement data of ore.

Since the main factor affecting the grinding characteristics is the coarse mineral, X-ray diffraction analysis was used to identify the types of the coarse mineral. X-ray diffraction analysis of limestone ore showed the largest peak at 2θ = 30 °. The peaks were read using a data file of a standard material of JCPDS cardiology. The peaks were Calsite (CaCO ₃ ), and other impurities were not detected in the results of X-ray diffraction analysis.

2 and 3 are optical micrographs of the raw light. It can be seen that impurities such as quartz, pyrite, and muscovite, which were not seen in X-ray diffraction analysis, exist. In particular, pyrite and mica in impurities, even when present in a small amount, are finely ground together in the case of paper milling and are stained with limestone fine powder, thereby reducing the whiteness of the final limestone fine powder. Quartz is also a hard mineral, a material that causes the wear of papermaking equipment.

4 is a flow chart of the floating screen of limestone.

First, the limestone ore is sufficiently dried in a natural state, and then first crushed using a jaw crusher to form a crush having a particle size of 20 mm to 40 mm.

Next, the cone crusher (Cone crusher) to the primary crushed crushed secondary to 5mm ~ 15mm or less to form a powder sample. Powder samples contain significant amounts of impurities such as pyrite, quartz, and mica.

Therefore, the prepared powder sample is placed in a jar mill and liberated from impurity minerals. Charge the ball into the mill about 40 to 60% and grind the mill speed at a speed of 60 to 80% of the critical speed. At this time, the mineral liquid concentration (pulp density) is adjusted to 40 ~ 60%.

The grinding time according to the present invention preferably minimizes the particle size to 65 mesh ~ 150 mesh or less for the efficiency of the treatment process, such as minimizing the generation of particulates that adversely affect the floating screen.

When the grinding is completed, the mineral liquid is flocculated to remove pyrite, iron oxide, and dolomite, which lower the whiteness of the limestone powder during atomization.

In order to remove pyrite, the flotation according to the present invention adds a foaming agent and a collecting agent to the mineral liquid.

The scavenger according to the present invention may be any of thiophosphates, xanthates, dithiophosphates, and mixtures of dithiophosphates and chinocarbamates.

The foaming agent is added with a constant amount of fine oil, methyl isobutyl carbinol or OTX-140 at 40 g / ton to give a condition time for 5 to 15 minutes and suspended pyrite and its oxide for 2 to 4 minutes.

Floating screening according to the present invention is intended to remove pyrite and its oxide contained in limestone ore. Factors affecting the flotation experiments for removing pyrite and its oxides are known as the type and amount of trapping agent, the amount of foaming agent, hydrogen ion concentration, mineral solution concentration and particle size of raw materials.

[Table 2] below shows the limestones purified by XRF using the flotation method according to the collecting agent such as thiophosphates, xanthates, dithiophosphates, dithiophosphates and chinocarbamate mixtures. By analyzing the quantitation of the compositions.

As shown, it was found that the quality of Fe ₂ O ₃ was lowered from 0.04% to 0.01% or less in all four collecting agents, and whiteness was also improved. Even when 100 g / ton of the xanthate trapping agent was used, the whiteness of 93.4% of the concentrate could be produced.

Scavenger Composition (%)  Whiteness SiO2 Al2O3 Fe2O3 CaO MgO Ig.loss Xantes 0.15 0.12 <0.01 55.08 0.39 43.24 93.4 Thiophosphates 0.15 0.11 <0.01 55.08 0.38 43.46 93.4 Dithiophosphate 0.14 0.11 <0.01 55.14 0.38 43.40 94.1 Mixture of dithiophosphates and chinocarbamates 0.16 0.12 <0.01 55.17 0.38 43.24 94.6

 The products of flotation were quantitatively analyzed according to the type of trapping agent used during flotation. In addition, a whiteness meter was used to measure the whiteness of each product, an important factor in the physical properties of limestone powder.

5 to 7 shows the whiteness and production rate while increasing the amount of the thiophosphate, dithiophosphate or dithiophosphate and chinocarbamate mixtures listed in Table 2 from 528 g / ton to 672 g / ton. It is a change.

First, as the amount of the thiophosphate collecting agent increases, the whiteness increases from 90.3 to 94.4. In addition, the use of dithiophosphate as a collecting agent increased the whiteness to 94.9, and the use of dithiophosphate and chinocarbamate mixtures as a collecting agent increased the whiteness to 94.7. However, using 672 g / ton of the mixture of dithiophosphate and chinocarbamate showed a decrease in production rate.

8 is an X-ray diffraction diagram of impurities removed by floating separation of limestone. It can be seen that pyrite, quartz and clay components are mainly removed. Therefore, the whiteness of the maximum particle size 65 mesh limestone purified according to the removal of impurity minerals is 93.4 ~ 94.9 which is much higher than that of limestone ore (90.3). In addition, it was found that the limestone concentrate was refined using an ultra fine grinding device such as an attrition mill to make the fine powder having a maximum particle size of 10 μm or less to improve the whiteness to 98.

Although the present invention has been shown and described with reference to the preferred embodiments as described above, it is not limited to the above embodiments and those skilled in the art without departing from the spirit of the present invention. Various changes and modifications will be possible.

1 is an XRD graph of limestone ore according to the present invention,

2 and 3 are optical micrographs of impurities present in limestone ore

4 is a process flow diagram of limestone flotation according to the present invention;

Figure 5 is a graph showing the change in whiteness and yield of suspended-selected limestone according to the thiophosphate collector.

Figure 6 is a graph showing the change in whiteness and yield of suspended-selected limestone according to the dithiophosphate collector.

Figure 7 is a graph showing the change in whiteness and yield of suspended-selected limestone according to the trapping agent consisting of dithiophosphate and chinocarbamate mixture.

Claims (11)

Primary crushing limestone ore to form a crushed material; Crushing the crushed matter to form a powder sample; Suspending the powder sample in a solution to form and polish a mineral solution; And After injecting a collecting agent using any one of a foaming agent, a thiophosphate, a xanthate, a dithiophosphate, and a mixture of dithiophosphate and chinocarbamate to the mineral liquid, quartz, pyrite contained in the limestone Screening to remove colored impurities containing any one or more of metals, oxides and micas Purification method of limestone comprising a. The method of claim 1, The secondary crushing is limestone purification method using a ball mill (rod mill) or a rod mill (rod mill). The method of claim 1, The maximum particle size of the fine particles in the mineral liquid formed by the grinding is 65-150 mesh purification method of limestone. The method of claim 1, The grinding is a method for purifying limestone that proceeds at a rotational speed of 60% to 80% of the critical speed using a jar mill. The method of claim 4, wherein The method of refining limestone is the magnetic loading of the ball is 40% to 60%. The method of claim 1, The concentration of the mineral liquid is 40% to 60% purification method of limestone. delete The method of claim 1, The foaming agent is a method for purifying limestone using fine oil or methyl isobutyl carbinol. The method of claim 1, The ore is a method for purifying limestone containing at least 45% CaCO ₃ component. delete The method of claim 1, The method of purifying limestone further comprising the step of finely pulverizing the limestone purified through the step of flotation to a maximum particle size of 10 μm or less using an ultrafine grinding device.

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