KR930011267B1 - Eliminating iron and refining process of clay used with bacteria leaching process - Google Patents

Abstract

This relates to removing iron content in clay and purifying with bacteria or mould. The method comprises the steps of: cultivating clay at 30 deg.C for 3 days by dilution plate method; separating the microbial cells which produce fluorescence and viscose material; mixing microbial cell and clay and cultivating; isolating the cell which can reduce the iron content most; cultivating mould cells (50 types) and ca. 30 types of microbial cells which is cultivated at 28 deg.C for 5 days in Czapek culture; isolating the mould cells; cultivation clay, isolated microbial and mould cells; and leaching and separating the iron content.

Description

Iron removal and purification of clay by BACTERIA LEACHING

The present invention is to provide a method for removing and purifying iron contained in clay using bacteria or fungi that are microorganisms.

Clay is generally a collection of extremely fine particles and has a very characteristic surface and is widely used in many fields such as chemical engineering, papermaking and paint ceramics.

Clay is mainly called sedimentary clay, which is a secondary clay, and contains quartz, sericite, montmorillonite, and feldspar as secondary components in addition to Kaolinite and Halloysite as main constituent minerals. Titanium compounds, Illiter, muscovite, and organics are mixed, and the kinds and contents of these contaminants have a significant influence on the physical properties.

Most of the clays in Korea are mixed with impurity minerals and salts, and because of their low plasticity, low plasticity and low moldability, they cannot be used for high-quality ceramics. The present invention provides a method for overcoming this limitation.

Known methods for refining clays include a charity method to remove iron minerals and titanium compounds with high sensitivity using magnetic force of high gradient, and to dissolve impurities such as silica sand and feldspar in clay by dispersing clay in water. There are defensive methods to remove by specific gravity, and methods of eluting molten iron by chemical treatment, such as pottery, but it has not been applied to plastic clay.

Because the above-mentioned method of refining clays is generally low in effectiveness, the plasticity is rather low, and thus there is a disintegration which inhibits physical properties. The present invention is to study the method of decontamination by microorganisms, which includes culturing iron microorganisms, which are soil microorganisms, in the soil. This is because the eluted iron powder is eluted and separated by the metabolic function of microorganisms, thereby improving plasticity.

Iron is easily converted by microorganisms in most microorganisms, although it is only one of the trace elements required for growth.

However, iron in the soil may be present in a form that is not suitable for the direct use of microorganisms and plants, which can often indicate serious deficiencies.

Therefore, microorganisms are involved in the conversion of iron in different forms, and the form of the elements is known to be affected by various biological methods.

One example in the literature as known so far is that a) certain bacteria oxidize ferric iron to trivalent iron to precipitate into iron hydroxides, and b) soluble organometallic salts are degraded by many heterotrophic bacteria to precipitate into poorly soluble inorganic iron. c) Microorganisms can change insoluble trivalent iron into soluble bivalent iron due to changes in the redox potential of the environment.

D) It has been reported that poorly soluble iron is formed by the metabolism of organic acids and other carbon substances secreted by microorganisms to form organic iron complexes, and other examples provide sufficient evidence for the microbiological oxidation of ferric salts in soil. The major microorganism capable of biologically releasing iron from sulfide or iron ore is known as Thiobacillus ferrooxidans, which grows independently by oxidizing iron salts from ordinary ores in mineral soils without organic matter. It can be said that the deironing of clay by Thiobacillus ferrooxidans showed about 20% of the iron removal rate at 25 ° C. for 20 days, but the plasticity of clay was lowered by the culture at low pH.

Bacteria that can convert poorly soluble iron into two reduced irons in solution are Bacillus, Clostridium, Klebsiella, Pseudomonas sp. And Serratia sp. Bacteria have been known, and studies have shown that the results of iron removal from three minerals such as quartz sand, kolins and clay using heterotrophic microorganisms grown with organic matter as nutrients showed quite good results. Gave.

In another study, Azomonas sp. Bacteria reported the ability to separate iron compounds by chelating iron compounds by secreting 3.4 dihydroxybenzoic acid.

One scholar said Gram-negative bacteria, Alteromonas sp., Had high bacterial tolerability and the ability of proteins in the body to bind iron.

Other scientists have also suggested that Azomonas and Azotobacter sp. Can bind to iron by secreting the cellular protein sidrophore.

In the present invention, the following experiments were carried out to study the degassing method and the plastic neutralization method that can improve the clay quality based on various research reports.

(1) bacterial separation

① Isolation of bacteria

To separate microorganisms that can dissolve the solid glass iron in solution, soil samples were collected from clay and iron mines in Jeonnam, Gyeongsang, and Chungcheong provinces as shown in Table 1, and diluted with nutrient agar medium at 30 ° C for 3 days. Over 250 strains of bacteria were isolated by culturing.

[Table 1]

Sampling for bacterial isolation

② Separation of mold

The fungus was used for experiments with over 30 species isolated from 50 kinds of laboratory storage strains and soil samples by incubation for 5 days at 28 ° C. using Czapek medium. The composition of each medium is shown in Table 2.

[Table 2]

Separation medium composition

(2) Strain Selection and Storage

① bacteria

Among the isolates, strains producing fluorescent pigments and viscous substances were first isolated from the nutrient agar medium at 30 ° C. for 3 days. Among the primary isolates, one strain of bacteria with the lowest iron content in clay due to mixed culture with clay was selected and stored at 4 ℃ and used as the test strain of this experiment.

② mold

For 80 species of stored and isolated molds, 1 week of mold with the lowest iron content was selected through mixed culture with selected bacteria and stored in the same way and used as test bacteria.

③ Cultivation of bacteria

The isolated strain was nutrient broth and incubated at 100 ° C. in a 100 ml erlenmeyer flask at 20 ° C. for 2-3 days for preliminary culture for mixing with clay.

The fungus was cultured in Czapek agar medium for 6-7 days to form spores sufficiently and then used as a strain for mixed culture.

④ Cell count measurement

Cell counts were measured by viable cell count using dilution plate method and compared before and after culture.

⑤ Mixed culture with clay

Clay and the disclosure of bacteria and to examine the solubilization degree of a mold when the mixed culture of the iron the culture medium in 50ml erlenmeyer flask 100ml, into the clay 30g 121 ℃, 15 bungan sterilized after disclosure bacteria 3ml (concentration 6 × 10 ⁹ cell / ml) 1 ml (10 ⁸ spores / ml) of fungal spores were simultaneously inoculated to analyze the treated clays while incubating.

⑥ Analysis of Bacteria leaching sample

Chemical composition, plasticity, dry strength, calcined whiteness, and particle size analysis of Bacteria leaching samples were performed.

(3) Experiment result

① Cell count measurement

The number of cells in the culture was performed by viable cell count and compared before and after culture (Table 3). After dispensing nutrient agar medium in petridish and sterilizing the medium at 121 ° C. for 15 minutes in autoclave, the culture solution was diluted and smeared, and then colonized at 30 ° C. for 2-3 days. The concentration of the cultured bacteria was 5 × 10 ⁶ cfu (colony forming unit), and after incubation, the bacterial concentration increased to 6 × 10 ⁹ cfu.

[Table 3]

Cell number comparison before and after culture

* Cfu: Colony forming unit

② Bacteria leaching of clay

Table 4 shows the comparison of control and bacterial inoculation to examine the solubilization effect of iron when iron bacteria were added to GA, CH, and YC clays. First, the solubilization viscosity of iron by constant temperature days showed the highest concentration from 7 to 14 days. In addition, in the bacterial inoculation, the addition of 0.5% of the organic powder showed several times the concentration increase than that without the addition.

On the other hand, the effects of bacterial inoculation of various raw materials on the iron form showed a particularly significant effect in increasing the concentration of free iron in the solution, followed by substitutional iron and activated iron.

In the above experiment, there was a problem that the incubation period is somewhat the same.

[Table 4]

Changes in Concentrations of Each Iron by Mixed Culture of Clay

③ Chemical Composition of Bacteria leaching Clay

Table 5 compares the effects of Bacteria leaching on the chemical composition of clay.

[Table 5]

Chemical Composition of Bacteria leaching Clay

As seen above, it showed a 21.15% iron removal effect of Fe ₂ O _{3 in} the GA sample, and TiO ₂ was significantly lowered from 0.52% to 0.2%. CH sample with high iron content of ore showed 17.98% de-ironing effect, and TiO ₂ was significantly lowered from 1.4% to 0.28%, and YC sample showed that Fe ₂ O ₃ was 19.65% and TiO ₂ was 1.62% It can be seen that the trend is lowered to 0.31%.

Regardless of the region, iron bacteria are believed to work with iron minerals to remove iron and TiO ₂ components with excellent effects.

④ plasticity characteristics

Plasticity is expressed by a close relationship with the contact surface between grain boundaries, which is governed by particle size, water hydration, toroidal properties, and many factors in water. Table 6 shows the plasticity test results for the bacterial treatment samples.

[Table 6]

Efficacy of Bacteria leaching Samples

Regardless of the sample, the plasticization rate increased from 3% to 7% compared to the ore, and the plasticization property (CV) was increased by 2 to 3 times higher. Therefore, Bacteria leaching greatly improved the plasticity of clay. It shows that you have contributed. This may be due to the increase in specific surface area due to micronization of bacterial mucus secretions and silicate mineral particles.

⑤ dry strength

Table 7 shows the effects of Bacteria leaching on the dry strength of clay.

[Table 7]

Drying Strength of Bacteria leaching Clay

As seen above, the GA showed 37.12% increase in dry strength, and the CH and YC samples showed 47.6% and 53.10%, respectively, with an average of more than 40%, indicating that the Bacteria leaching effect was remarkable.

⑥ Plasticity Whiteness

The calcined whiteness of the sample treated with bacteria is shown in Table 8.

[Table 8]

Plastic Whiteness by Temperature for Clay Samples

In the above results, the firing whiteness of GA samples increased from 5.17 to 7.14%, and CH and YC samples from 5.6 to 6.7% and 13.8 to 18%, respectively. Although the sample shows a good whiteness increase, it is judged that it is not suitable for use as a high-grade clay even though its refining effect is good due to its high iron and organic content.

⑦ Particle size analysis

Table 9 shows the particle size distribution of Bacteria leaching clay.

[Table 9]

Particle Size Distribution of Bacteria leaching Clay

As shown in the table above, GA and CH samples had a particle size of less than 4μ, about 39% in defensive clay, but bacterial treatments increased to 50%. It tended to be lowered.

⑧ Result

An experiment was conducted on microorganisms that inhabit the soil of Korea and solubilize trivalent insoluble iron or absorb it into the body to reduce the iron content in clay.

The isolated microorganism is a strain of Pseudomonas sp. That secretes mucus, and the fungus is Aspergillus sp., Which is considered to cause synergy in the activity of bacteria when mixed with bacteria.

When inoculating bacteria and fungi on porcelain raw materials, it has higher ability to solubilize iron than uninoculated, and is likely to be highly useful for clay tablets by increasing plasticity and whiteness.

As a result of chemical analysis, Fe ₂ O ₃ content showed high removal effect of 17.98% ~ 21.15%. The plasticity of plastics increased by 20% and plasticity by 2 ~ 3.5 times compared with ore. Increased from 37.21% to 53%.

The particle size of the GA and CH samples increased from 39% to 50%, and the average particle size decreased to 3.66μ and 3.96μ, respectively.

Claims (1)

Bacterial species obtained by cultivating soil at 30 ° C for 3 days by dilution plate method were isolated and strains producing fluorescent pigments and viscous substances were selected and selected for bacterial strains with the lowest iron content in clay by mixing culture with clay. Over 30 strains obtained by cultivating 5 strains at 28 ° C for 5 days using Czapek medium from soils (about 50 species) and soil were selected from molds with the lowest iron content through mixed culture with clay. A method of removing and purifying iron from clay by the Bacteria leaching method which mixes strains to cultivate microorganisms to elute and separate the iron contained in the clay, and to enhance the plasticity of the clay by the mucus material of microbial secretion.