KR100196500B1 - The refrash method of fluoride acid for panel cleaning of braun tube and its apparatus - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for recycling hydrofluoric acid for use in a cathode ray tube panel, . In this case, a precipitant such as sodium hypochlorite or caustic soda is added to the reusing tank (1) containing the pulverized acid without discarding the used pulmonic acid to cause a chemical reaction to precipitate down the precipitate, The hydrofluoric acid regenerated by the fluorocarbon tank 2 is moved to the hydrofluoric acid tank 2 to clean the tube panel glass so that the spent hydrofluoric acid after the cleaning treatment can be repeatedly recycled without being discarded to drastically reduce the amount of hydrofluoric acid used for cleaning the tube panel glass As a result, it is possible not only to significantly reduce the cost of hydrofluoric acid, The processing cost to minimize the amount of wasted disposal hameuroseo hydrofluoric acid flowing into the can reduce taepok.

Description

Method and apparatus for recycling the pyrogenic acid for cleaning the cathode ray tube panel

The present invention relates to a method and an apparatus for recycling a hydrofluoric acid for cleaning a cathode ray tube panel. In order to dissolve a rough surface of a glass before attaching a fluorescent material or the like to the inner surface of a cathode ray tube panel glass, The present invention also relates to a method and apparatus for recycling a hydrofluoric acid for cleaning a cathode ray tube panel in which a precipitant suspended in pulmonary hydrofluoric acid can be removed by adding a precipitant and then recycled without disposing spent lung hydrofluoric acid.

The composition of the cathode-ray tube panel glass is mainly composed of Sio2, A1O _3, MgO, CaO, SrO, BaO, Na ₂ O, K ₂ O, etc., hydrofluoric acid (HF) before attaching the fluorescent material, such as the inner surface of the CRT panel glass (HF) reacts with these components to generate compounds such as Na ₂ SiF ₆ , BaSiF ₆ , CaSiF ₆ , NaF, NaSO ₃ F, BaCO ₃ , CaF ₂ and Ba (OH) ₂ do.

In particular, barium Ba, sodium Na and silicon Si react with hydrofluoric acid (HF) to form Na ₂ SiF ₆ and BaSiF ₆ , which are poorly soluble in hydrofluoric acid (HF) And the amount of the remaining precipitate increases as the cleaning operation is continued several times. As a result, the precipitate obstructs the cleaning nozzle by blocking the hole of the cleaning nozzle, and therefore, .

Also, when the brown and the panel glass are cleaned using the hydrofluoric acid containing precipitate through the nozzle, the fine sediment adheres to the panel glass, thereby deteriorating the performance of the CRT.

In order to solve this problem, in the related art, when the amount of the precipitate is increased and it is difficult to disperse through the nozzle, the hydrofluoric acid is disposed of and sent to the wastewater treatment plant.

However, since the concentration of hydrofluoric acid in the disposing hydrofluoric acid wastewater is about 10-30%, it is very inefficient in terms of economy, and the load of the wastewater treatment plant is increased by the hydrofluoric acid introduced into the wastewater treatment plant. The cost of wastewater treatment is increased, and there is a problem in that it is economically disadvantageous.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a barium fluoride composition capable of forming a precipitate by adding a precipitant to precipitate a precipitate contained in pulmonary hydrofluoric acid, It is an object of the present invention to provide a method and apparatus for recycling fluorocarbons for brown and panel cleaning which can maximize economic utility value by minimizing waste of fluorine by removing Ba, Si and Na ions. .

FIG. 1 is an X-ray diffraction pattern of a precipitate formed after washing a cathode ray tube glass.

FIG. 2 is an X-ray diffraction diagram of the precipitate produced after addition of sodium carbonate (Na ₂ CO ₃ ) and caustic soda (NaOH).

FIG. 3 is a configuration diagram of the apparatus of the present invention. FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

1: Reuse tank 2: Foshan tank

3: Pump 4: Conduit

5: Precipitation tank

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the advantages thereof,

The composition of the cathode-ray tube panel glass is composed of mostly SiO _2, AlO _3, MgO, CaO, SrO, BaO, Na ₂ O, K ₂ O, etc., prior to attaching a fluorescent material such as the inner surface of the CRT panel glass hydrofluoric acid (HF) (HF) reacts to form precipitates such as Na ₂ SiF ₆ , BaSiF ₆ , CaSiF ₆ , NaF, NaSO ₃ F, BaCO ₃ , CaF ₂ , and Ba (OH) ₂ Has already been described.

Figure 1 shows the X-ray diffraction pattern of the precipitate produced after washing the cathode ray tube glass. This data is comparable to BaSiF _{6 as} compared with the JCPDS card, which is the reference data book, so that most of the precipitate is BaSif ₆ .

At this time, the chemical reaction formula of BaSiF ₆ production is as follows.

Table 2 is a quantitative analysis of the ion concentration of the element contained in the hydrofluoric acid tank during the inactivation of the process. Sample No. 1 is a sample which is disturbed in the dispersion operation due to a large amount of sediment, Sample No. 2 is a sample The number 3 indicates the ion concentration at the time of washing the defective panel glass containing carbon when the defective ratio is large.

When sodium carbonate (NaCO ₃ ) and caustic soda (NaOH) are added with reference to the solubility of the fluorine ion compounds in Table 1 to remove dissolved elements and sediments. From the reaction formula (1), the following reaction formula is obtained.

First, in the case of sodium carbonate (NaCO ₃ )

For caustic soda (NaOH)

Figure 2 shows the results of X-ray diffraction of precipitates formed after the addition of sodium carbonate (Na ₂ CO ₃ ) and caustic soda (NaOH). This data is similar to that of Na ₂ SiF ₆ as compared with the JCPDS card, It can be seen that most of the precipitate is Na ₂ SiF ₆ .

At this time, it is possible to determine the most suitable addition amount from the analysis results of the coagulation speed of the precipitate when the sodium monoxide (Na ₂ CO ₃ ) and the caustic soda (NaOH) are added in the equivalent ratio, and the analysis result between the elements remaining in the hydrofluoric acid solution, Na ₂ CO ₃ ) and caustic soda (NaOH), the concentration of the remaining elements is similar but the concentration of barium ions is smaller when sodium carbonate is added and the rate of dissolution in the hydrofluoric acid solution is faster great.

In other words, caustic soda (NaOH), which is sold in granular form, is disadvantageous from the economical viewpoint because it is slower in dissolving rate and more expensive than sodium carbonate (Na ₂ CO ₃ ).

Briefly, in order to remove precipitated suspended solids from pulmonary hydrofluoric acid generated by flushing a glass tube panel with hydrofluoric acid (HF), sodium carbonate (Na ₂ CO ₃ ) or caustic soda (NaOH) (Na), silicon (Si), and barium (Ba), which are precipitate-generating elements, and at the same time produce Na ₂ SiF ₆ and BaCO ₃ , If a small amount of hydrofluoric acid at a suitable concentration (usually about 60%) is adjusted to a proper concentration for the remaining residual fluoric acid, it is possible to reuse the waste fluoric acid to be discarded after cleaning the glass tube panel glass.

FIG. 3 is a diagram showing the construction of the apparatus of the present invention. FIG. 3 is a schematic view showing the structure of the apparatus of the present invention. A pump 3 for forcibly introducing pulmonary hydrofluoric acid generated from the hydrofluoric acid tank 2 into the reusing tank 1, and a reboiler 3 for reusing the hydrofluoric acid generated from the hydrofluoric acid tank 2, And a precipitant feed-in tank 5 into which a precipitant to be introduced into the tank 1 is fed.

It is most preferable that the reusable tank 1, the hydrofluoric acid tank 2 and the conduit 4 are made of a plastic material which can withstand hydrofluoric acid. The pump 3 uses an acid-resistant pump capable of withstanding acid, The bottom surface of the utilization tank 1 is inclined for effective removal of the settled sludge, and the upper surface thereof is made of transparent plastic so that the settling state can be confirmed.

In addition, the precipitant input tank 5 can be configured not only manually but also a special control circuit to automatically adjust its dosage and administration interval.

When 1% of a precipitant such as sodium carbonate or caustic soda is added to the reusing tank 1 having the above-described waste acid and the mixture is allowed to stand for 30 minutes without stirring, the same chemical reaction as in Knowledge (6) Is complete and the precipitate is settled down and the remaining hydrofluoric acid (HF), which is not used for the chemical reaction in the pulp fluoric acid, is regenerated for recycling.

Thus, after the chemical reaction is completed, the hydrofluoric acid regenerated by the action of the pump 3 is moved to the hydrofluoric acid tank 2 to clean the cathode-ray tube panel glass. To repeat.

Specific examples will be described below by taking sample solutions of sample Nos. (1) to (4) in Table 2 below.

[Example 1]

(Na ₂ CO ₃ ) and caustic soda were added to the sample in order to recycle the sample of the sample number (1), which causes the obstruction of the nozzle hole due to the high concentration of hydrofluoric acid, (NaOH) were added at an equivalence ratio, and the results of Table 3 and Table 4 were obtained after chemical reaction.

As shown in Table 3, the fluorine concentration was slightly decreased with addition of sodium (Na ₂ CO ₃ ) at 304,000 ppM (30.4%), the silicon (Si) concentration showed a sharp decrease at 116,000 ppm, Showed a gradual decline at 19,200 ppm. As the amount of sodium carbonate (Na ₂ CO ₃ ) is increased, the amount of sodium (Na) is increased but the concentration of fluorine (F) and silicon (Si) ions is also decreased.

It can be seen that these ions form a Na ₂ SiF ₆ compound and precipitate. When the barium (Ba) concentration in the sample is 300.4 ppm as shown in Table 2, but ₂ g of sodium carbonate (Na ₂ CO ₃ ) is added, it is not shown in Table 3, but it decreases to 70.14 ppm.

On the other hand, Table 4 of the fluorine (F), silicon (Si), sodium (Na), reduction phenomenon of the ion is sodium carbonate (Na ₂ CO ₃₎ illustrates a closed HF in the element concentration in accordance with the addition amount of caustic soda (NaOH) It can be seen that the same phenomenon as the case is shown.

Table 5 shows the results of the actual application of 2 g, 4 g, and 6 g of sodium carbonate (Na ₂ CO ₃ ) to BaSiF ₆ , which is considered to be an optimal condition, to the spent hydrofluoric acid containing precipitates. There is almost no difference.

Table 6 sodium carbonate (Na ₂ CO ₃₎ to know the different settling velocity of the amount of sodium carbonate as a result of measuring the different sedimentation height in the supernatant from the actual pulmonary hydrofluoric time is BaSiF ₆ precipitate include applying (Na ₂ CO ₃₎ 2g, 4g, and 6g were added, and after stirring for 20 seconds, different settling heights were measured during the standing time.

In the case of L-fluorocarbamate supernatant containing no BaSiF ₆ , almost all precipitated within 5 minutes. In practical application, it was almost settled within 5 minutes at 4g and 10g at 6g.

These results indicate that the addition of 2, 4, and 6 g of sodium carbonate significantly reduces impurities, does not significantly reduce the concentration of fluorine, and is almost complete in less than 10 minutes.

As a result, when 2 g of sodium carbonate (Na ₂ CO ₃ ) is added, the ion concentration of fluorine is 232,000 ppm (23.2%), which is the final amount of fluorine that can be recycled. Therefore, when the proper concentration is adjusted to 60% hydrofluoric acid through the apparatus of the present invention, it can be recycled.

[Example 2]

The sample of sample No. (2) was used to recycle the pulmonary hydrofluoric acid at the time of regular replacement of the CRT panel glass for 24 hours, and it was found that the addition of sodium carbonate (Na ₂ CO ₃ ) The concentrations of the elements are shown in Table 7.

When 2 g of sodium carbonate was added, the fluorine (F) concentration was changed from 213,000 ppm (21.3%) to 183,000 ppm (18.3%), the silicon (Si) concentration from 12,065 ppm to 6,860 ppm, ppm.

In addition, 1.0 g, 3.0 g and 4.0 g showed similar trends. Silicon (Si), which causes precipitation, tends to decrease as the amount of sodium carbonate (Na ₂ CO ₃ ) is increased And the amount of sodium (Na) does not show a significant change.

Table 8 shows the settling rate of the precipitate according to the addition amount of sodium carbonate (Na ₂ CO ₃ ). The settling height was also measured by the settling time as in Example 1.

The precipitation of the precipitate is almost completed within 10 min. The amount of precipitate increases as the amount of sodium carbonate (Na ₂ CO ₃ ) increases and the decrease of silicon (Si) Reacted to form Na ₂ SiF ₆ .

As a result, when 2 g of sodium carbonate (Na ₂ CO ₃ ) is added, the fluorine ion concentration is 183,000 ppm (18.3%), which is the final amount of fluorine that can be recycled. Accordingly, if the concentration is adjusted to 60% by hydrofluoric acid through the apparatus of the present invention, there is no problem in washing the panel glass for 24 hours, and even after the use for 24 hours, it can be reproduced and used continuously.

[Example 3]

A sample of the sample No. 4 in Table 2 shows that a large amount of solids and impurities are not settled in the floating tank and the flocculant tank is used to clean the brown tube panel and to clean the defective glass after the phosphor and graphite are coated. have. Since a large amount of impurities such as a carbon component, a phosphor component, Ba ₂ SiF ₆ , Si, Na, and Ba are contained in the hydrofluoric acid after removing adhering substances adhering to the panel glass, sodium carbonate (Na ₂ CO ₃ ) was added and the result of the analysis was as shown in Table 9. The change in the concentration of fluorine (F), silicon (Si) and sodium (Na) when 1.0-3.0 g of sodium carbonate (Na ₂ CO ₃ ) is added to pulmonary hydrofluoric acid is almost the same as that in Examples 1 and 2 .

When 2 g of sodium carbonate is added, the concentration of fluorine (F) does not change much and the concentration of silicon (Si) decreases to more than half but the concentration of sodium (Na) increases.

The sedimentation rate of the precipitate was measured while increasing the addition amount of sodium carbonate (Na ₂ CO ₃ ) in the same manner as in Example 1 and Example 2, and the results are shown in Table 10.

However, unlike Examples 1 and 2, pulmonary hydrofluoric acid containing carbon particles was turbid to such an extent that the turbidity before sedimentation could not be measured due to the influence of carbon particles and phosphors, but after 10 minutes, minute carbon components were floating , And after 20 minutes the suspended solids also completely settled. And the amount of sediment is more than that of Example 1 and Example 2. [

The fluorine ion concentration is 161,000 ppm (16.1%) under the condition that 2 g of sodium carbonate (Na ₂ CO ₃ ) is added to the pulmonary hydrofluoric acid and it is stopped for 20 minutes. Therefore, this is the concentration of fluorine which can be recycled. Even when recycled, no defects were found in the products of the cathode-ray tube, and the amount of fluorine used was drastically reduced.

The effect obtained by the present invention having the above-described embodiments and actions can be achieved by using the precipitant to remove the precipitated substance effectively by using the precipitant, As a result, it is possible to greatly reduce the cost of the hydrofluoric acid, as well as to minimize the disposal amount of hydrofluoric acid introduced into the wastewater treatment facility, thereby greatly reducing the disposal cost for disposal. .

Claims (2)

In order to remove suspended sediment of pulmonary phos- phoric acid which is generated when the cathode-ray tube glass is washed with hydrofluoric acid (HF), a chemical reaction is induced by using sodium carbonate (Na ₂ CO ₃ ) or caustic soda (NaOH) (Na), silicon (Si), and barium (Ba), which are elements that are generated at the same time, and at the same time generate Na ₂ SOF ₆ and BaCO ₃ , Wherein the amount of hydrofluoric acid to be used is reduced by adjusting the concentration of the fluoric acid at a proper concentration to adjust the concentration of the fluoric acid. A refueling tank for refilling with a sedimenting agent so as to reuse the pneumatic acid introduced from the pump, a plurality of hydrofluoric acid tanks for communicating with the reusing tank and the conduit to clean the glass tube panel glass, A pump for forcibly introducing pulmonary hydrofluoric acid into the re-use tank, and a precipitant input tank for storing a precipitant to be introduced into the re-use tank.