JPH07163985A - Treatment of tool washing liquid for working aluminum material - Google Patents

Abstract

PURPOSE:To provide a treatment method capable of recovering sodium hydroxide and aluminum components which are valuable in a useful form at the time of effectively separating away useless impurities from the inside of a tool washing liquid for working aluminum materials, which liquid is aged by use. CONSTITUTION:This treatment method for the tool washing liquid for working aluminum materials comprises adding a silicic acid and/or silicic acid compd. which reacts by easily dissolving in the aged washing liquid contg. aluminum into the aged washing liquid in such a manner that the weight ratio of SiO2/ NaOH of the silicic acid and/or silicic acid compd. together with the silicic acid components intrinsically exist in the aged washing liquid attains a range of 0.05 to 0.05 and separating away the solid impurities in the aged washing liquid together with the reaction products formed after the end of the reaction of the added silicic acid and/or silicic acid compd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aging cleaning liquid generated when a tool used for processing such as plastic working and cutting of an aluminum material made of aluminum or aluminum alloy is washed with a tool cleaning liquid made of sodium hydroxide solution. Regarding processing method.

[0002]

2. Description of the Related Art For example, as a method for producing an aluminum mold, an extrusion process of an aluminum material is widely adopted. However, when an aluminum mold is produced by this extrusion process, each of them is processed according to the shape of the product. A die is prepared, and an aluminum material as a material passes through the die and is molded into a predetermined shape. Then, when this extrusion operation is completed, the aluminum material is mechanically cut along the die surface, and a part thereof remains inside the hole of the die, but subsequently, an aluminum die material of the same material with the same cross section is manufactured, etc. Except for special cases, the die is made of aluminum material inside the hole for the purpose of repairing and repairing the die having the normal cross-section, and for reuse of the die having the complex cross-section. Is removed while remaining, and the aluminum material remaining inside the hole is removed until the next use.

The removal of the aluminum material remaining inside the holes of the die is usually carried out by using an aluminum hydroxide solution having a concentration of about 200 to 450 g / liter as a cleaning liquid in the range of 80 to 1
It is carried out by dissolving an aluminum material under heating at about 00 ° C. When this cleaning solution is repeatedly used, aluminum gradually accumulates as sodium aluminate in the aluminum hydroxide of the cleaning solution, and the cleaning solution is accompanied by this. The rate of dissolution of aluminum in aluminum materials decreases, and the workability gradually decreases. If the solubility exceeds that of crystalline aluminum hydroxide (gibbsite), this dibsite precipitates and becomes cloudy, and there is a risk of adhering to vessel walls, etc. Therefore, it is necessary to march this aged cleaning liquid into a new aluminum hydroxide solution after a predetermined amount of cleaning treatment or after a predetermined time of cleaning treatment. Therefore, the aged cleaning liquid after a predetermined amount or a predetermined time of cleaning process is treated as a waste liquid.

However, the aging cleaning liquid thus discharged during the tool cleaning process is usually 200 to 45.
In addition to containing 0 g / liter of sodium hydroxide, the aluminum content is equal to 0.2 in Al / NaOH equivalent ratio.
Dissolved at a concentration of about 0.5 to 0.5, and fine particles of carbon and boron nitride derived from the solid lubricant used during extrusion processing, lubricant base oil, and further surfactants, Zn, Cr It also contains heavy metals such as etc. in a suspended state or a dissolved state, and in addition, in order to suppress the precipitation of aluminum hydroxide during the tool washing process such as dies, a hydrolysis inhibitor such as sodium gluconate is also included. Contains.

Therefore, although this aging cleaning liquid contains a large amount of useful sodium hydroxide and aluminum, it contains carbon fine particles, boron nitride fine particles, base oil, surfactants, heavy metals, and hydrolysis inhibition. It contains various inorganic or organic useless impurities (including solid content impurities) such as agents in a suspended or dissolved state, and there is no method for efficiently separating and removing these useless impurities. The current situation is that they are processed in Japanese and disposed of. And, this neutralization treatment alone wastes expensive sodium hydroxide and aluminum components, and the use of a large amount of acid is essential for this neutralization treatment. The addition of hydrous gel-like aluminum hydroxide sludge containing a large amount of water generated by
The waste liquid treatment of the aging cleaning liquid has become one of the great economic burdens.

[0006]

Therefore, as a result of intensive studies on the method for treating a tool cleaning liquid for processing aluminum materials, the inventors of the present invention have found that a predetermined amount or a predetermined time of cleaning treatment has passed. By adding a specific silicic acid and / or a silicic acid compound in a specific ratio to the aged cleaning liquid, and separating and removing the solid impurities in the aged cleaning liquid together with the reaction product produced, the unnecessary impurities can be easily separated and removed. The inventors have found that it is possible and completed the method of the present invention.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for treating a tool cleaning liquid for machining aluminum material, which effectively separates and removes unnecessary impurities from the aging cleaning liquid. Another object of the present invention is to treat an aluminum material processing tool cleaning liquid capable of separating and removing unnecessary impurities from the aging cleaning liquid and recovering valuable sodium hydroxide and aluminum components in a useful form. To provide a method.

[0008]

That is, according to the present invention, aluminum adhering to a tool used for processing an aluminum material made of aluminum or an aluminum alloy is dissolved and removed by a tool cleaning liquid made of a sodium hydroxide solution. When treating the generated aluminum-containing aging cleaning liquid, the aging cleaning liquid contains a silicic acid and / or a silicic acid compound which easily dissolves in the aging cleaning liquid and reacts with the silicic acid component originally present in the aging cleaning liquid. SiO ₂
/ NaOH weight ratio is in the range of 0.005 to 0.05, and after the reaction of the added silicic acid and / or silicic acid compound is completed, solid impurities in the aging cleaning liquid are separated together with the generated reaction product. It is a method for treating a tool cleaning liquid for processing an aluminum material to be removed.

In the method of the present invention, the tool cleaning liquid for processing an aluminum material is a tool used during processing such as plastic working or cutting of an aluminum material, especially a die used in extrusion processing or the like. When the tool is repeatedly washed with a tool washing liquid composed of a sodium hydroxide solution, it is an aging washing liquid that has undergone a predetermined washing treatment, and although not particularly limited, sodium hydroxide
In addition to containing 0 to 450 g / liter, aluminum content is dissolved at a concentration of about 0.2 to 0.5 in terms of Al / NaOH equivalent ratio, and moreover, solid lubrication used when processing aluminum materials. Carbon fine particles such as graphite and carbon black mixed from agents and lubricants, boron nitride fine particles, base oil, surfactants, heavy metals and the like are contained in a suspended or dissolved state.

In the method of the present invention, when treating the recovered aging cleaning liquid, silicic acid and / or a silicic acid compound which is easily dissolved and reacts in the aging cleaning liquid is added at a predetermined ratio.

The silicic acid and / or silicic acid compound added here is easily dissolved in the aging cleaning liquid and reacts with sodium hydroxide or sodium aluminate in the aging cleaning liquid to give the following chemical formula or composition (110). It is sufficient to produce a reaction product (hereinafter referred to as “sodalite”) represented by (° C. dried product), 1 to 1.1 Na ₂ O.1.0 to 1.3Al ₂ O ₃ .2S
iO ₂ · 3H ₂ O composition _{(Na 2 O: 18~20%,} Al 2 O 3: 34~3
5%, SiO _2: 33~34%, and H ₂ O: 13 to 15
%) Specifically, silicic acid (SiO ₂ · nH ₂ O), water glass (Na ₂ O · nSiO ₂ ), aluminum silicate (Al ₂
O ₃ · SiO ₂ · nH ₂ O), clay [(R ₂ O) · Al
₂ O ₃ .2SiO ₂ .nH ₂ O, R = Na, K] and the like. Among these silicic acid and / or silicic acid compounds, a preferable one is that it dissolves within 30 minutes when heated to 90 ° C. or higher, and after about 15 to 180 minutes, although it varies depending on the aging cleaning liquid to be treated. It should preferably generate sodalite, and silicic acid, water glass, aluminum silicate and the like are particularly preferable.

The amount of the silicic acid and / or silicic acid compound added to the aging cleaning liquid is such that the weight ratio of SiO ₂ / NaOH is 0.00 in combination with the silicic acid component originally present in the aging cleaning liquid.
The range is 5 to 0.05, preferably 0.01 to 0.03. This addition amount is SiO ₂ / NaOH weight ratio of 0.
If it is less than 005, the amount of sodalite produced is small, and it becomes difficult to efficiently separate and remove the unnecessary impurities in the aging cleaning liquid. On the contrary, the amount added is SiO ₂ / Na.
If the OH weight ratio is more than 0.05, the production amount of sodalite becomes too large, and a large amount of sodium hydroxide and aluminum components which are useful components in the aging cleaning liquid are consumed, which is not preferable.

In the method of the present invention, the silicic acid and / or the silicic acid compound is added to the aging cleaning liquid as described above, and the solid product impurities in the aging cleaning liquid are separated and removed together with the reaction product sodalite produced by the reaction. When sodalite as a reaction product is formed or when this sodalite is separated and removed, carbon fine particles or boron nitride fine particles, base oil, surfactants, heavy metals, hydrolysis inhibitors, etc. contained in the aging cleaning liquid Various inorganic or organic unnecessary impurities are simultaneously precipitated or separated and removed, and the aging cleaning liquid becomes a clean purified cleaning liquid containing sodium hydroxide and sodium aluminate as main components.

When the aging cleaning liquid contains a large amount of heavy metals as useless impurities, sodium sulfide is preferably added together with addition of silicic acid and / or a silicic acid compound, and the heavy metals are sulfurized. It is better to precipitate it as a substance, and separate and remove it together with the purified sodalite. The amount of sodium sulfide added should be adjusted not only to remove these heavy metals as much as possible, but also to consider the amount of heavy metals contained in the aging cleaning liquid, the concentration of NaOH, and the allowable concentration of residual heavy metals. It is preferable to make the amount so that it can be made small, and it can be easily determined by measuring the content of heavy metals and the NaOH concentration in the aging cleaning liquid. Then, in the case of treating the aging cleaning liquid by adding this sodium sulfide, in order to smoothly generate the sulfide of heavy metals,
The total NaOH concentration is preferably 200 g / liter or less, more preferably 150 g / liter or less.

In the method of the present invention, silicic acid and / or a silicic acid compound is added to the aging cleaning liquid, and if necessary, sodium sulfide is added, and the reaction product sodalite and solid impurities in the aging cleaning liquid are added. It is possible to obtain a clean purified cleaning liquid by removing unnecessary impurities as much as possible by separating and removing, but if necessary, for example, a polyacrylate salt-based coagulant is added to further improve the separation. It can be made even easier. The purified cleaning liquid thus obtained can be made into a useful resource as a raw material of an aluminum compound, or for ceramics, papermaking, water purification and the like.

Further, in the method of the present invention, crystalline aluminum hydroxide (dibsite) is added to the purified cleaning solution obtained as described above, if necessary, and sodium aluminate is added in the presence of the dibsite. Decomposes and precipitates the aluminum content in the purified cleaning solution as crystalline aluminum hydroxide, separates and collects this as valuable material, and uses the filtrate with less aluminum content as a reclaimed cleaning solution for tools or etching aluminum materials. It can be recycled and used effectively as a supplemental alkali source.

Regarding the reaction conditions of the hydrolysis reaction when dibsite is added to this purified washing solution and sodium aluminate is hydrolyzed in the presence of this dibsite to precipitate an aluminum content as crystalline aluminum hydroxide,
Although not particularly limited, NaOH:
After adjusting to 90-180g / liter, 40-60
It is preferable to add crystalline aluminum hydroxide seeds at 100 ° C. at a ratio of 100 to 300% of the aluminum content and stir for 12 to 48 hours.

[0018]

According to the method of the present invention, a specific silicic acid and / or a silicic acid compound is added to an aged cleaning liquid in a specific ratio, and solid reaction impurities in the aged cleaning liquid are separated and removed together with the generated reaction product (sodalite). By doing so, unnecessary impurities are separated and removed, so the generated sodalite acts as a kind of coagulant, and the unnecessary impurities present in the aging cleaning liquid are taken into this sodalite when it is generated. Alternatively, when the solid impurities are separated and removed, they are adsorbed by this sodalite and separated and removed together with this sodalite.

Further, at this time, by adding sodium sulfide, the heavy metals in the aging cleaning liquid become their sulfides and are more reliably separated and removed. Further, with respect to the clean purified cleaning liquid thus obtained, the aluminum content can be recovered as a valuable crystalline aluminum hydroxide by hydrolyzing in the presence of crystalline aluminum hydroxide. And a sodium hydroxide solution useful for other purposes can be recovered.

[0020]

EXAMPLES The method of the present invention will be specifically described below based on Examples and Comparative Examples. In the following examples and comparative examples, "%" means "% by weight".

Example 1 NaOH: 300 g / liter, Al: 87 g / liter, SiO ₂ : 1.0 g / liter, Zn: 50 mg / liter
Liter, surfactant: spectroscopic ++, suspension derived from solid lubricant: 20 mg / liter, and suspension of other colloidal metal oxides: 80 mg / liter, die for extrusion of aluminum material Aging bath solution (9
4 ° C.) was used as the aging cleaning liquid for the test.

Aging cleaning liquid (94 ° C.) 100 for this test
Sodium silicate in 0 liter (JIS No. 1 equivalent)
Was added at a weight ratio of SiO ₂ / NaOH of 0.01 to 6 kg, and the mixture was stirred at 94 ° C. for 2 hours, then pressure-filtered with a filter press using an alkali-resistant filter cloth and washed to obtain a filtrate. A total of 1050 liters of purified cleaning liquid was obtained by combining with the filter cleaning liquid.

The purified cleaning liquid obtained was clear and had a composition of NaOH: 286 g / liter (loss rate: 0.03).
%), Al: 85.8 g / liter (loss rate: 1.4
%), Zn: 40 mg / liter (residual rate: 80%),
Suspension concentration: 2 mg / liter or less (residual rate: 2.5
%) And the surfactant: minus (-) by the spectroscopic method, and the amount of filter residue was 13 kg (water content 50%).

Example 2 In the same manner as in Example 1 above, 1050 liters of the purified cleaning liquid was diluted to 3000 liters with hot water, and the diluted purified cleaning liquid was added with crystalline aluminum hydroxide (gibsite) 3
00 kg was added, and the mixture was hydrolyzed under stirring at 50 ° C. for 36 hours and filtered to obtain 108 kg of crystalline aluminum hydroxide (water content 8%).

The hydrolysis rate at this time was 40%,
After filtering off the precipitated crystalline aluminum hydroxide, the sodium aluminate solution was subjected to multiple-effect evaporation method to obtain NaOH.
By concentrating to a concentration of 300 g / liter and reusing it, 96% of the dissolved aluminum content could be finally recovered. The final NaOH loss rate is 0.1%
And the Al loss rate is 4% and the amount of filter residue is 37 kg.
The water content was 50%.

Example 3 3000 liters of the diluted purified cleaning solution obtained in the same manner as in Example 2 was used as an etching aging bath solution (NaOH concentration: 87 g / liter, Al in an aluminum surface treatment factory).
(Concentration: 25 g / liter) 33,000 liters were combined to obtain crystalline aluminum hydroxide (gibbsite) 2800
Crystallized aluminum hydroxide 860k which was precipitated by hydrolysis in the presence of kg under the conditions of 50 ° C and 24 hours for hydrolysis.
g (water content 8%) is collected as a valuable resource,
The filtrate was circulated and used as an etching treatment liquid after adjusting the NaOH concentration as necessary. At this time, the aging bath liquid side of the die cleaning liquid, that is, the diluted purified cleaning liquid 300
The aluminum content on the 0 liter side was recovered at a rate of 95%. The final NaOH loss rate was 0.05%, the Al loss rate was 5%, and the amount of filter residue was 13 kg (water content rate 50%).

Comparative Example 1 Using 1000 liters of the same aging cleaning liquid as the test aging cleaning liquid used in Example 1, the same treatment as in Example 1 was carried out without adding the sodium silicate used in Example 1. Pressure filtered. The removal rate of suspended matter at this time is 20
% Or less, and substantially 0 for dissolved components
%Met. Further, when the obtained filtered and washed liquid was neutralized by a conventional method, 36% sulfuric acid of 98% concentration was used as a neutralizing agent.
5 kg was required, and 1100 kg of a troublesome hydrous gel-like aluminum hydroxide sludge (Al content 8% by weight) was produced.

Example 4 NaOH: 305 g / liter, Al: 89 g / liter, SiO ₂ : 1.3 g / liter, Zn: 420 mg
/ Liter, surfactant: spectroscopic ++, suspension of solid lubricant derived: 18 mg / liter, and suspension of other colloidal metal oxides: 110 mg / liter, heated 1000 liters of die cleaning solution 32 diluted with water
It was set to 00 liters and used as an aging cleaning liquid for testing.

In the aging cleaning liquid for this test, SiO ₂ /
Add 16 kg of sodium silicate (JIS 1 equivalent) so that the weight ratio of NaOH becomes 0.023, and add 95 ° C.
After stirring for 3 hours, add 2 liters of 18% Na ₂ S solution, stir and mix, and press-filter and wash with a filter press using an alkali-resistant filter cloth, and combine the filtrate and the filter wash solution. A total of 3300 liters of purified cleaning liquid was obtained.

The purified cleaning liquid obtained was clear and had a composition of NaOH: 92.5 g / liter (loss rate: 0.1
%), Al: 26 g / liter (loss rate: 3.5%),
Zn: 20 mg / liter (residual rate: 15%), Na ₂
S: 30 mg / liter, suspension concentration: 2 mg / liter or less (residual rate: 2% or less), and surfactant: negative (-) by spectroscopic method, the amount of filter cake was 36 kg (water content rate 52%).

This purified cleaning solution was combined with 33000 liters of an etching aging bath solution (NaOH concentration: 87 g / liter, Al concentration: 25 g / liter) of an aluminum surface treatment factory, and in the presence of 2800 kg of crystalline aluminum hydroxide (gibbsite). The mixture was stirred and hydrolyzed at 50 ° C. for 36 hours to hydrolyze, and 992 kg of precipitated crystalline aluminum hydroxide (water content 8%) was recovered as a valuable resource, and the filtrate was adjusted for NaOH concentration if necessary. It was circulated and used as an etching treatment liquid.

The hydrolysis rate in this hydrolysis is 35%.
However, by recycling the sodium aluminate solution after filtering off the precipitated crystalline aluminum hydroxide, 94% of the dissolved aluminum content was finally converted into crystalline aluminum hydroxide (water content of 8%). 263 kg).

Comparative Example 2 1000 L of the same aging cleaning liquid as the test aging cleaning liquid used in Example 4 was used, and the same procedure as in Example 4 was performed without adding the sodium silicate and sodium sulfide used in Example 4. Treated and pressure filtered. As a result, the removal rate of the suspension was 20% or less, the obtained filtrate was not clarified, and dissolved components other than NaOH and Al could not be removed. Al could not be effectively recovered.

Comparative Example 3 Using 1000 liters of the same aging cleaning liquid as the test aging cleaning liquid used in Example 4, the sodium silicate used in Example 4 was added, and sodium sulfide was not added. In the same manner as in Example 4, pressure filtration was carried out to obtain 1050 liters of purified cleaning liquid. The purified cleaning liquid obtained was clear and had a composition of NaOH: 290 g / liter (loss rate:
0.1% or less), Al: 82 g / liter (loss rate:
3.3%, Zn: 399 mg / liter (remaining rate 95
%), Suspension concentration: 2 mg / liter or less (residual rate: 2
% Or less) and surfactant: minus (-) by spectroscopy
The filter cake amount was 36 kg (water content rate 52%).

This purified cleaning solution could be reused as a die cleaning solution, but the residual rate of Zn was high, so that the purified cleaning solution was merged with the etching aging bath solution of the aluminum surface treatment factory, regenerated, and circulated as an etching treatment solution. It could not be used.

Comparative Example 4 Example 4 except that the test aging cleaning solution used in Example 4 was diluted with 1000 liters of the same aging cleaning solution.
It was treated in the same manner as in 1. and filtered under pressure. In the case of this comparative example 4, only a small amount of ZnS was produced, and the amount of Zn in the purified liquid was 22.
The removal rate was 0 mg / liter (residual rate: 55%), and the Zn removal rate was only 10%. For this reason, as in the case of Comparative Example 3 above, it was possible to reuse as a die cleaning liquid, but the residual rate of Zn was high, and it was regenerated by merging with an etching aging bath liquid of an aluminum surface treatment factory, It could not be circulated as an etching treatment liquid.

Example 5 The same test aging cleaning liquid as in Example 4 was used, and the SiO ₂ / NaOH weight ratio was 0.02 in this aging cleaning liquid.
16 kg of sodium silicate (JIS No. 1 equivalent) was added so as to be 3, and the mixture was stirred at 95 ° C. for 3 hours, and then 1
2 liters of 8% Na ₂ S solution was added, and polyacrylic acid type flocculant [LTX-2000 manufactured by Konan Chemical Industry Co., Ltd.]
After adding 15 ppm and stirring, the resulting treatment liquid was introduced into a sedimentation tank and allowed to stand for 10 hours, the upper clear liquid was separated from the lower concentrated liquid, and 500 liter of the lower concentrated liquid thus obtained was treated with an alkali-resistant filter. A filter press using a cloth was used for pressure filtration and washing, and the above upper clarified liquid and the resulting filtrate of the lower concentrated liquid and the filter washing liquid were combined to obtain a total of 3300 liters of purified washing liquid.

The purified cleaning liquid obtained was clear and had a composition of NaOH: 92.5 g / liter (loss rate: 0.1
%), Al: 26 g / liter (loss rate: 3.5%),
Zn: 20 mg / liter (residual rate 15%), Na
₂ S: 30 mg / liter, suspension concentration: 2 mg / liter or less (residual rate: 2% or less), and surfactant: negative (-) by spectroscopic method, and the amount of filter cake is 36 kg (containing water). The rate was 52%).

This purified cleaning solution is also used in Example 4 above.
In the same manner as above, the solution was joined to the etching aging bath solution of an aluminum surface treatment plant, hydrolyzed in the presence of crystalline aluminum hydroxide (gibsite), and the precipitated crystalline aluminum hydroxide 992 kg (water content 8%) was valuable. And collect the filtrate as necessary with NaOH.
The concentration was adjusted and the solution was circulated as an etching treatment solution.
Further, finally 94% of the dissolved aluminum content could be recovered as crystalline aluminum hydroxide (263 kg with a water content of 8%).

[0040]

According to the method of the present invention, unnecessary impurities can be easily and effectively separated and removed from the aged cleaning liquid that has aged after a predetermined amount of cleaning treatment or a predetermined time of cleaning treatment. It is possible to recover the sodium hydroxide and aluminum components as the product in a useful form.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noboru Sugiyama 1-34-1 Kambara, Kambara-cho, Anbara-gun, Shizuoka Nipparu Giken Co., Ltd. (72) Yoshiro Tanaka 3-13-12 Mita, Minato-ku, Tokyo No. Nippon Light Metal Co., Ltd.

Claims (4)

[Claims] 1. Aluminium, which adheres to a tool used for processing an aluminum material made of aluminum or an aluminum alloy, is dissolved and removed by a tool cleaning liquid made of a sodium hydroxide solution, and an aged cleaning liquid containing aluminum generated at this time is treated. At this time, in this aging cleaning liquid, a silicic acid and / or a silicic acid compound which is easily dissolved and reacts in this aging cleaning liquid are combined with a silicic acid component originally present in the aging cleaning liquid to obtain a SiO ₂ / NaOH weight ratio of 0.005. ~ 0.
The added silicic acid and //
Alternatively, after the completion of the reaction of the silicic acid compound, a solid content impurity in the aged cleaning liquid is separated and removed together with the generated reaction product, and a method for treating a tool cleaning liquid for aluminum material processing. 2. The method for treating a tool cleaning liquid for machining aluminum materials according to claim 1, wherein sodium sulfide is added together with silicic acid and / or a silicic acid compound. 3. The method for treating a tool cleaning liquid for processing an aluminum material according to claim 2, wherein the treatment performed by adding sodium sulfide is performed under the condition of a total NaOH concentration of 200 g / liter or less. For cleaning tool cleaning liquid. 4. The purified cleaning liquid treated by the method according to claim 1 is hydrolyzed in the presence of crystalline aluminum hydroxide, and the aluminum content in the purified cleaning liquid is converted to crystalline aluminum hydroxide. A method for treating a tool cleaning liquid for processing aluminum materials, which comprises recovering a regenerated sodium hydroxide solution while precipitating.