CN100526221C - Aqueous solution of chromium salt and method for producing same - Google Patents
Aqueous solution of chromium salt and method for producing same Download PDFInfo
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- CN100526221C CN100526221C CNB2004800352984A CN200480035298A CN100526221C CN 100526221 C CN100526221 C CN 100526221C CN B2004800352984 A CNB2004800352984 A CN B2004800352984A CN 200480035298 A CN200480035298 A CN 200480035298A CN 100526221 C CN100526221 C CN 100526221C
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Abstract
Disclosed is an aqueous solution of a chromium salt which is characterized in that the oxalic acid content is not more than 8 weight% relative to chromium. In this aqueous solution of a chromium salt, the total organic carbon is not more than 4 weight% relative to chromium. The chromium salt may preferably be a chromium chloride, a chromium phosphate or a chromium nitrate. The chromium chloride may preferably contain a basic chromium chloride represented by the following composition formula: Cr(OH)xCly (wherein 0 < x <= 2, 1 <= y < 3, and x + y = 3). The chromium phosphate may preferably be one represented by the following composition formula: Cr(H3-3/nPO4)n (wherein n is a number satisfying 2 <= n <= 3). The chromium nitrate may preferably be a basic chromium nitrate represented by the following composition formula: Cr(OH)x(NO3)y (wherein 0 < x <= 2, 1 <= y < 3, and x + y = 3).
Description
Technical field
The present invention relates to aqueous solution of chromium salt and manufacture method thereof.
Background technology
Among the various aqueous solution of chromium salt, known chromium nitrate aqueous solution can be used as the metallic surface treatment agent and uses.The Plessy's green aqueous solution is implemented on the galvanized surface at for example various metals such as iron, nickel, copper, can be used as the treatment solution that is used to form the chemoproection film and uses (with reference to patent documentation 1).
At present, manufacture method as chromic salts such as chromium nitrate, Plessy's green, chromium chlorides, known method is, add sulfuric acid in the sodium dichromate solution that obtains in that ore is carried out alkali oxidizing roasting, reduce with organism and become chromium sulfate solution, add sodium hydroxide or anhydrous sodium carbonate therein, produce the precipitation of chromium hydroxide or chromium carbonate, after filtering, washing, add nitric acid, phosphoric acid or hydrochloric acid and dissolve.Perhaps, known in addition method is, uses carbonaceous reducing agent, the high carbon ferro-chrome that utilizes the sulfuric acid extraction treatment to obtain with electric furnace reducing chrome ore stone, and this solution of electrolysis becomes chromium metal, thereby adds nitric acid or hydrochloric acid manufacturing chromium nitrate or chromium chloride in chromium metal.
Moreover about chromium nitrate, known in addition method is in turn to carry out following step: thus in chromium trioxide, cooperate nitric acid, the amount that makes nitric acid is for preparing the step of chromium trioxide-nitric acid mixing solutions more than the equivalent that can generate chromium nitrate; In the chromium trioxide that obtains by above-mentioned steps-nitric acid mixing solutions, excessively sneak into the organic reducing agent that constitutes by the carbohydrate-derived alcohol, aldehyde, carboxylic acid or their mixture that are selected from monose, disaccharides or the starch based, the reduction chromium trioxide makes it to generate the step (for example with reference to patent documentation 2) of chromium nitrate.
About chromium chloride, thereby the applicant proposed to add hydrochloric acid in chromic acid aqueous solution and make them react the method (for example with reference to patent documentation 3) of making the high purity chlorination chromium aqueous solution with organic reducing agent that the chromic acid reaction can almost be decomposed into the carbonic acid gas G﹠W.
Among the present method, with the method for nitric acid dissolve chromium hydroxide, add sodium hydroxide or anhydrous sodium carbonate and the washing of the chromium hydroxide precipitation that obtains is very difficult in chromium sulphate, existence can not be removed the problem of impurity such as sodium in the chromium hydroxide or vitriol.
In patent documentation 2 disclosed methods, mixed nitrate in chromium trioxide for example, the amount that makes nitric acid is more than the chromium nitrate equivalent, this is effective to reducing sexavalent chrome.But, according to the condition difference, the reductive agent of interpolation be not with chromium trioxide but and nitric acid reaction, its result produces NOx sometimes.Therefore, not only need the device that takes off NOx, and become the state of danger sometimes because of the reaction of fierceness.
Patent documentation 1: the spy opens communique 2003-No. 268562
Patent documentation 2: the spy opens communique 2002-No. 339082
Patent documentation 3: the spy opens flat 1-No. 176227 communiques
Summary of the invention
Therefore, the object of the present invention is to provide a kind of aqueous solution of chromium salt and the manufacture method thereof that can eliminate the various shortcomings of above-mentioned existing in prior technology.
The present invention is to be that the aqueous solution of chromium salt of feature achieves the above object below the 8 weight % by providing with oxalic acid content with respect to chromium.
Embodiment
Below, based on the present invention preferred embodiment is described.Aqueous solution of chromium salt of the present invention is the low-level feature that is by the oxalic acid content as one of organism.In detail, if oxalic acid content is low-level, when then using aqueous solution of chromium salt of the present invention in metallic surface is handled, just can obtain the extremely excellent goods of gloss, this is distinguished.Formerly in Shuo Ming the patent documentation 2 disclosed technology, in order to make hexavalent chrome reduction, use the many organic reducing agents of carbonatomss such as starch and glucose, result from this, existing oxalic acid amount becomes and is higher than level of the present invention in the aqueous solution.
Oxalic acid amount in the aqueous solution of chromium salt of the present invention, with respect to chromium be below the 8 weight %, below the preferred 6 weight %, more preferably below the 4 weight %, to be more preferably be do not contain in fact low-level.The oxalic acid amount can be measured by for example ion chromatography.Oxalic acid content lower value in the aqueous solution of chromium salt of the present invention has no particular limits, if use manufacture method described later, just can become and does not contain such extremely low-level of oxalic acid in fact.
Aqueous solution of chromium salt of the present invention, also having whole organic carbons (below be also referred to as TOC) is low-level feature.The result of inventor's research is, is on the low-level basis, if TOC is low-level in above-mentioned oxalic acid content, then when aqueous solution of chromium salt of the present invention is used as the metallic surface treatment agent, just can obtain the excellent more goods of gloss, and this is distinguished.
So-called TOC is the total amount as organism residual C in solution.Aqueous solution of chromium salt of the present invention, with respect to chromium, preferably 4 weight % are following, preferably 2 weight % are following so low-level for TOC.Formerly in Xu Shu the patent documentation 2, disclosing in order to make sexivalent chromium positively be reduced to tervalent chromium, in chromium nitrate aqueous solution, need be the above TOC of 0.3 weight %.But the inventor at length studies for TOC, consequently, if increase the amount of TOC, then just can not obtain sufficient gloss when using aqueous solution of chromium salt as the metallic surface treatment agent, and this is distinguished.If make aqueous solution of chromium salt of the present invention with manufacture method described later, then TOC is low-level, and sexavalent chrome is positively disappeared.Lower value to the TOC in the aqueous solution of chromium salt of the present invention is not particularly limited, if use manufacture method described later, just can become when being 0.5 weight %, chromium nitrate when being 0.5 weight %, Plessy's green when chromium chloride for example is such extremely low-level of 0.1 weight %.
TOC in the aqueous solution of chromium salt of the present invention can be measured by the full organic carbon meter of TOC500 type that for example Shimadzu Seisakusho Ltd. produces.
Aqueous solution of chromium salt of the present invention, although oxalic acid content is few and preferred TOC is low-level, sexavalent chrome does not exist in fact in the aqueous solution.Therefore, in aqueous solution of chromium salt of the present invention, the little such advantage of carrying capacity of environment is arranged.Such aqueous solution is compatibly made by manufacture method described later.
As chromic salts of the present invention,, can enumerate chromium chloride, chromium nitrate, Plessy's green etc. as representational salt.But, be not restricted to these.
At chromic salts of the present invention is under the situation of chromium chloride, and chromium chloride solution is to contain useful composition formula Cr (OH)
xCl
yThe compound water solution of (in the formula) expression with 0 ≦ x ≦ 2,1 ≦ y ≦ 3, x+y=3.Chromium chloride solution of the present invention is in most cases with CrCl
3Converting, is the above aqueous solution of 25 weight %, preferably the above aqueous solution of 35 weight %.If surpass 41 weight %, then according to the difference of condition, the crystallization meeting is separated out.In the compound of representing with above-mentioned composition formula, except using CrCl
3Beyond the chromium chloride of expression, also contain with hydroxyl and replace the compound-basic chromic chloride of this chlorine of part, the compound of promptly in above-mentioned composition formula, representing with 0＜x ≦ 2,1 ≦ y＜3, x+y=3.As the example of basic chromic chloride, can enumerate Cr (OH)
0.5Cl
2.5, Cr (OH) Cl
2, Cr (OH)
2Cl etc.In addition, in the following description, when being called chromium chloride,, refer to CrCl sometimes according to article content
3The expression chromium chloride refers to basic chromic chloride sometimes.In addition, both are carried out general name and the situation that abbreviates chromium chloride as also has.
Compound with above-mentioned composition formula is represented in chromium chloride solution of the present invention, can exist respectively or also can exist with the arbitrary combination more than 2 kinds individually.By making up more than 2 kinds, can modulate the solution that is suitable for concrete purposes.
Chromium chloride solution of the present invention, in the above-mentioned composition formula when x=0, y=3, the proportion of this aqueous solution in the time of 20 ℃, preferably 1.25～1.46.
On the other hand, be under the situation of the basic chromic chloride aqueous solution at chromium chloride solution of the present invention, the proportion of this aqueous solution in the time of 20 ℃, preferably 1.35～1.44, be more preferably 1.40～1.44.If the proportion of the aqueous solution is in this scope, even prolonged preservation, liquid can not laid particular stress on yet, and the crystallization of chromium chloride is difficult to separate out and preferred.For proportion is become in the above-mentioned scope, the chlorine in the basic chromic chloride and the mol ratio (Cl/Cr) of chromium are become more than 1 and less than 3.
In the basic chromic chloride aqueous solution, chlorine in the basic chromic chloride and the mol ratio of chromium (Cl/Cr) are preferably more than 1 and less than 3.If this mol ratio is in this scope, then the crystallization of chromium chloride just is difficult to take place.In the present invention, the mol ratio of above-mentioned proportion and chlorine and chromium becomes the important factor that prevents the chromium chloride crystallization more effectively.
For the mol ratio that makes chlorine in the basic chromic chloride and chromium in above-mentioned scope, can use manufacture method for example described later.
The concentration of the basic chromic chloride in the basic chromic chloride aqueous solution can suitably be adjusted according to concrete purposes.Usually, converting with Cr, is more than the 8.2 weight %, especially preferably more than the 11.4 weight %.The upper limit of concentration is not particularly limited, but 14 weight %, particularly is suitable about 13.5 weight %.The concentration of basic chromic chloride by adding dilution waters such as ion exchanged water or pure water, can easily be adjusted.Therefore, in the basic chromic chloride aqueous solution of the present invention, with good grounds application target and can freely adjust the advantage of chromium chloride concentration.
At chromic salts of the present invention is under the situation of chromium nitrate, and chromium nitrate aqueous solution is to contain useful composition formula Cr (OH) x (NO
3) compound water solution of y (in the formula, with 0 ≦ x ≦ 2,1 ≦ y ≦ 3, x+y=3) expression.Chromium nitrate aqueous solution of the present invention is in most cases with Cr (NO
3)
3Converting, is the above aqueous solution of 25 weight %, preferably the above aqueous solution of 35 weight %.If surpass 41 weight %, then according to the condition difference, the crystallization meeting is separated out.In the compound of representing with above-mentioned composition formula, except using Cr (NO
3)
3Beyond the chromium nitrate of expression, also contain the compound-alkali formula chromium nitrate Cr (OH) for example that replaces this nitrate radical of part with hydroxyl
0.5(NO
3)
2.5, Cr (OH) (NO
3)
2, Cr (OH)
2(NO
3) etc.
With the compound that above-mentioned composition formula is represented, in chromium nitrate aqueous solution of the present invention, can distinguish existence individually, perhaps also can exist with the arbitrary combination more than 2 kinds.By making up more than 2 kinds, can modulate the solution that is suitable for concrete purposes.
At chromic salts of the present invention is under the situation of Plessy's green, and the Plessy's green aqueous solution is to contain useful composition formula Cr (H
3-3/nPO
4)
nThe aqueous solution of the Plessy's green of (in the formula, n represents the number of 2 ≦ n ≦ 3) expression (for example heavy Plessy's green).In the Plessy's green of representing with above-mentioned composition formula, except Cr (H
2PO
4)
3In addition, also contain Cr (H
1.5PO
4)
2, Cr (H
1.8PO
4)
2.5Deng.
With the compound that above-mentioned composition formula is represented, in the Plessy's green aqueous solution of the present invention, can distinguish existence individually, perhaps also can exist with the arbitrary combination more than 2 kinds.By making up more than 2 kinds, can modulate the solution that is suitable for concrete purposes.
The sexivalent chromium cpd is because have aggressiveness and oxidisability, so with in its aqueous solution of chromium salt that obtains as raw material, sneak into foreign metal ion, particularly a large amount of Na and Fe ion inevitably.To this, aqueous solution of chromium salt of the present invention seldom is a feature with these ionic content.Such high-purity chromium salt brine solution, if it is be used for particularly manufacturing, preferred because can bring into play the favourable effect that obtains highly purified chromium hydroxide with its chromium hydroxide that uses as the raw material of chromium catalyst.In the concentration determination of foreign metal ionic, can use for example ICP-AES.
Foreign metal ion in the aqueous solution of chromium salt, become Na preferably 30ppm following, be more preferably following low-level of 20ppm.About Fe, preferably 20ppm following, be more preferably below the 10ppm.In addition, with regard to this concentration, when chromic salts is chromium chloride, be as CrCl
3Be scaled the concentration of 40 weight %.When chromic salts is chromium nitrate, be as Cr (NO
3)
3Be scaled the concentration of 40 weight %.When chromic salts is Plessy's green, be as Cr (H
2PO
4)
3Be scaled the concentration of 40 weight %.
Except above-mentioned foreign metal ionic content was few, aqueous solution of chromium salt of the present invention seldom was a feature with the content of impurity negatively charged ion, particularly chloride ion and sulfate ion also.Particularly about the Plessy's green aqueous solution, the impurity negatively charged ion in this aqueous solution, Cl become preferably that 10ppm is following, more preferably to become 5ppm following so low-level.About SO
4, preferably become below the 100ppm, more preferably become below the 50ppm.
Aqueous solution of chromium salt of the present invention is not a feature with Cr bonded free counterion, for example chlorion and nitrate ion not contain in fact.Do not contain the free counterion in fact, under situation, preferred because can bring into play the inhibition crystallization to separate out such advantageous effects with high density prolonged preservation aqueous solution of chromium salt of the present invention.So-called high density is meant, when for example chromic salts is chromium nitrate, and Cr (NO
3)
3Be 40% concentration.
Aqueous solution of chromium salt of the present invention is handled usefulness, catalyst usefulness as for example metallic surface, can use well.Particularly when being used for the metallic surface processing, the advantage of the goods that can access the gloss excellence is arranged.
Then, the preferred manufacture method to aqueous solution of chromium salt of the present invention is illustrated.At first, as an example of aqueous solution of chromium salt of the present invention, the preferred manufacture method of chromium chloride solution is illustrated.The feature that this manufacture method has is that in chromic acid aqueous solution, as the fs of reaction, the interpolation organic reducing agent with the reduction in advance of a part of chromic acid, then, mixes interpolation hydrochloric acid and organic reducing agent, and reaction is finished.
At first, as the chromic acid aqueous solution of raw material, for example the Sodium chromate that obtains so that chrome ore is carried out alkali oxidizing roasting is as starting raw material, the chromium trioxide of implementing various refinement treatment and obtaining is dissolved in the water and obtains.The chromic acid aqueous solution of operating like this and obtaining, the chromium hydroxide that obtains with in chromium sulphate, adding sodium hydroxide or anhydrous sodium carbonate, with chromium carbonate as raw material and synthetic chromic acid aqueous solution is compared with the chromic acid aqueous solution that obtains with sulfuric acid or dissolving with hydrochloric acid high carbon ferro-chrome, impurity such as Fe, Na, Mg, Al, Ca, Ni, Mo, W are few.
In addition, chromic acid aqueous solution can be a solution in reaction system, also can use chromium trioxide when reaction originally.But, as a rule, use to add therein that entry is dissolved and the aqueous solution that is modulated into.Concentration to chromic acid aqueous solution is not particularly limited, but as common scope, preferably 20～60 weight %.
As the organic reducing agent that in chromic acid aqueous solution, adds, if in reduction reaction described later, almost be decomposed into carbonic acid gas and water, not residual organic decomposition thing just is not particularly limited in fact.For example, preferably use the dibasic alcohol of the monohydroxy-alcohol of methyl alcohol etc. and ethylene glycol, propylene glycol etc.As other organic reducing agent, can use the polyose of the disaccharides, starch etc. of the monose, maltose etc. of glucose etc., but if use the many carbohydrates of carbonatoms, with regard to easy residual organic decomposition thing, it is low-level to be not easy to make oxalic acid content to become.In addition, it is low-level to be not easy to make the TOC that comprises oxalic acid to become.Therefore, in this manufacture method, the preferred use is difficult to generate oxalic acid and makes TOC become low-level reductive agent-monohydroxy-alcohol or dibasic alcohol easily.In addition, if use monohydroxy-alcohol or dibasic alcohol, the advantage that obtains easily near the reduction reaction of chemical theory amount is arranged also.From these viewpoints, preferably use lower alcohol (for example carbonatoms is the alcohol below 4), particularly methyl alcohol, ethylene glycol or propylene glycol especially preferably use methyl alcohol.
Organic reducing agent can not dilute and directly adds in chromic acid aqueous solution, perhaps, can add with the state that dilutes in water yet.When in water, diluting, the concentration of organic reducing agent is become about 10～30 weight %, from the management of operability and reaction, for preferably.
As the hydrochloric acid that in chromic acid aqueous solution, is added with organic reducing agent, can use industrial hydrochloric acid, also can use synthetic hydrochloric acid or by-product hydrochloric acid.Usually, can working concentration 35 weight %, the hydrochloric acid of proportion 1.15.But, be not limited to these.These all raw materials wish to use the high density raw material that can reach purpose of the present invention.
At first,, in chromic acid aqueous solution, add organic reducing agent, after a part of chromic acid is reduced, mix hydrochloric acid and organic reducing agent in advance, be added in the chromic acid aqueous solution as the fs of reaction.Separately interpolation speed is not particularly limited.As patent documentation 2 disclosed methods, being pre-mixed acid and chromic acid aqueous solution, adding in the method for organic reducing agent, in the manufacturing of chromium chloride, along with the temperature that is produced by the reaction heat of redox reaction rises, because the generation of chromyl chloride, so be dangerous.
The reaction formula of this manufacture method when using methyl alcohol for example as organic reducing agent is (x represents the number below 3 more than 0 in the formula) as shown below.
2H
2CrO
4+2xHCl
3+CH
3OH→2Cr(OH)
3-xCl
x+CO
2+(2x+1)H
2O
Shown in above-mentioned reaction formula, chromic acid is converted to the needed hydrochloric acid theoretical amount of chromium chloride (chemical theory amount) to be made as a, chromic acid is reduced the theoretical amount (chemical theory amount) of needed organic reducing agent when being made as b, add during the reductive agent, preferably always keep the relation of a＜b.Addition means as the fs of reaction, adds organic reducing agent, reduces a part of chromic acid in advance as mentioned above, then, adds the mixing solutions of hydrochloric acid and reductive agent.This addition means needn't height management, can always keep the relation of a＜b, be good method from operability.Thus, react with uncombined hydrochloric acid of trivalent chromium and chromic acid, performance suppresses the effect of the advantageous effects of generation chromyl chloride.
Begin redox reaction by in chromic acid aqueous solution, adding organic reducing agent.Follow a large amount of heatings, be swift in response and carry out.Normally 90～110 ℃ of temperature of reaction.The water vapour that produces is cooled off by condenser, makes it at the reaction system internal reflux.
When obtaining the basic chromic chloride aqueous solution, with respect to chromic acid, can be to add hydrochloric acid more than 1 molar equivalent and less than 3 molar equivalent ground.
Reaction makes it temporary transient slaking after finishing, and can intactly become goods.Slaking is preferably carried out more than 30 minutes with 90～110 ℃.Such slaking, its main purpose are to make the Cr that exists in the solution
6+Become 0 and oxalic acid content is become below the 8 weight % with respect to chromium in fact.As required, also add organic reducing agent, with residual Cr
6+Reduction fully.In addition, as required, add hydrochloric acid, also can the inching chromium ion and the mol ratio of chlorion.
Then, as other example of aqueous solution of chromium salt of the present invention, the preferred manufacture method of the Plessy's green aqueous solution is described.In addition, in this manufacture method, for the point that does not have to specify, the explanation about the chromium chloride manufacture method of previous narration can be suitable for aptly.This manufacture method has the feature of adding phosphoric acid and being selected from least a organic reducing agent in monohydroxy-alcohol and the dibasic alcohol in chromic acid aqueous solution.
The order of adding phosphoric acid (ortho-phosphoric acid) and organic reducing agent in chromic acid aqueous solution has no particular limits.For example, phosphoric acid and organic reducing agent can add simultaneously and respectively.Perhaps, also can mixed phosphate and organic reducing agent, in chromic acid aqueous solution, add mixed solution.Preferably in chromic acid aqueous solution, be pre-mixed phosphoric acid, improve the acidity in the reaction system, then, add organic reducing agent.Thus, can suppress the generation of oxalic acid more.As phosphoric acid (ortho-phosphoric acid), can use industrial phosphoric acid.Usually, can working concentration be the above phosphoric acid of 75 weight %.But, be not limited to this.These all raw materials wish to use the high density raw material that can reach purpose of the present invention.
The reaction formula (in the formula, x represents the number of 2 ≦ x ≦ 3) as follows of this manufacture method when using ethylene glycol for example as organic reducing agent.
10H
2CrO
4+10xH
3PO
4+3(CH
2OH)
2→10Cr(H
3-3/XPO
4)
x+6CO
2+34H
2O
Begin redox reaction by in chromic acid and phosphoric acid mixed aqueous solution, adding organic reducing agent.Be accompanied by a large amount of heatings, carry out with being swift in response.Normally 90～110 ℃ of temperature of reaction.The water vapour that produces is cooled off by condenser, makes it at the reaction system internal reflux.
Reaction makes it temporary transient slaking after finishing, and can intactly become goods.Slaking is preferably carried out more than 30 minutes with 90～110 ℃.Such slaking, its main purpose are to make the Cr that exists in the solution
6+Become 0 and oxalic acid content is become below the 8 weight % with respect to chromium in fact.As required, also add organic reducing agent, with residual Cr
6+Reduction fully.In addition, as required, add phosphoric acid, also can the inching chromium ion and the mol ratio of chlorion.
Then, as other example of aqueous solution of chromium salt of the present invention, put off until some time later the preferred manufacture method of bright chromium nitrate aqueous solution.In addition, in this manufacture method, for the point that does not have to specify, the explanation about the manufacture method of chromium chloride and Plessy's green of previous narration can be suitable for aptly.This manufacture method has the feature of adding nitric acid and organic reducing agent in chromic acid aqueous solution respectively and side by side.
As the nitric acid that in chromic acid aqueous solution, is added with organic reducing agent, can use industrial nitric acid, also can use nitric acid synthesis or by-product nitric acid.Usually, can working concentration be that 67.5 weight %, proportion are 1.4 nitric acid.But, be not limited to these.These all raw materials wish to use the high density raw material that can reach the object of the invention.
Nitric acid and organic reducing agent are by simultaneously and be added in the chromic acid aqueous solution respectively.Interpolation speed to nitric acid and organic reducing agent has no particular limits.So-called " difference " refers to the state that is not with mixed nitrate and organic reducing agent and adds.If mixed nitrate and organic reducing agent, both just react, because produce NOx but dangerous.In addition, as patent documentation 2 disclosed methods, if use the method for adding reductive agent in the mixed solution of nitric acid and chromic acid, according to the condition difference, the reductive agent of interpolation is not to produce NOx with chromic acid but with nitric acid reaction sometimes.Therefore, not only need to take off the device of NOx, and can become dangerous state owing to fierce reaction.
The reaction formula (in the formula, x represents the number below 3 more than 0) as follows of this manufacture method when using methyl alcohol for example as organic reducing agent.
2H
2CrO
4+2xHNO
3+CH
3OH→2Cr(OH)
3-x(NO
3)
x+CO
2+(2x+1)H
2O
Shown in above-mentioned reaction formula, chromic acid is converted to the needed nitric acid theoretical amount of chromium nitrate (chemical theory amount) to be made as a, chromic acid is reduced the theoretical amount (chemical theory amount) of needed organic reducing agent when being made as b, simultaneously and add respectively nitric acid and organic reducing agent during, the relation ground that preferably always becomes a＜b adds both.Thus, do not react with trivalent chromium bonded nitric acid and reductive agent, performance suppresses to produce the effect of the such advantageous effects of NOx.The relation of a and b, preferred a/b is less than 1, particularly more preferably below 0.9.
Begin redox reaction by interpolation nitric acid and organic reducing agent in chromic acid aqueous solution.Be accompanied by a large amount of heatings, carry out with being swift in response.Normally 90～110 ℃ of temperature of reaction.The water vapour that produces is cooled off by condenser, makes it at the reaction system internal reflux.
In this manufacture method, add at the same time and respectively before nitric acid and the organic reducing agent, preferably in chromic acid aqueous solution, only add organic reducing agent.Its reason is that because make organic reducing agent in advance, after organic reducing agent added end, nitric acid was added in end, can always make the a/b in the reaction system become the following cause of above-mentioned value.
In chromic acid aqueous solution, add earlier under the state of organic reducing agent, add nitric acid simultaneously.Thus, both are simultaneously and be added respectively.
Reaction makes it temporary transient slaking after finishing, and can intactly become goods.Slaking is preferably carried out more than 30 minutes with 90～110 ℃.Such slaking, its main purpose are to make the Cr that exists in the solution
6+Become 0 and oxalic acid content is become below the 8 weight % with respect to chromium in fact.As required, also add organic reducing agent, with residual Cr
6+Reduction fully.In addition, as required, add nitric acid, also can the inching chromium ion and the mol ratio of nitrate ion.
By the various aqueous solution of chromium salt that each above manufacture method obtains, oxalic acid content is low-level and sexavalent chrome does not exist in fact.The various aqueous solution of chromium salt that obtain if necessary, are heated concentratedly, make it to cool off the crystallization that can obtain chromic salts.The chromic salts crystallization that obtains, oxalic acid content becomes below the 2 weight %, preferably becomes do not contain in fact low-level with respect to chromium.And, do not contain sexavalent chrome in fact.
In above-mentioned heating concentrates, can remove the moisture in the aqueous solution of chromium salt.Heating concentrates and can carry out after reaction finishes, and also can carry out in reaction.Heat in reaction when concentrating, the water vapour of generation makes it aggegation by condenser, and it is outer and concentrate that this water is discharged reaction system, and efficient height then is industrial favourable.
Embodiment
Below enumerate embodiment and specifically describe the present invention.Short of special restriction, " % " refers to " weight % ".
(embodiment 1-1)
In the glass reaction vessel of condenser is housed, add 251.6g water, drop into the 253.1g chromium trioxide again, fully stirring and dissolving becomes 50% chromic acid aqueous solution.As reductive agent, use methyl alcohol.As the fs of reaction, with 1.0g/ minute speed, use pump of constant delivery type in chromic acid aqueous solution, to be added on to add in 99.5% methyl alcohol of 12.2g 20% methanol aqueous solution of 48.4g water.This interpolation speed is to add the speed of 20% methanol aqueous solution of 60.6g in about 1 hour.In addition, 99.5% methyl alcohol of 12.2g is to be equivalent to reduce the amount of 30% chromic acid.
The reductive agent of fs add finish after, add the mixing solutions 817.9g of 35% hydrochloric acid of 99.5% methyl alcohol of 28.4g and 789.5g with 6.8g/ minute speed.This interpolation speed is the speed with the mixing solutions of methyl alcohol that added 817.9g in 2 hours and hydrochloric acid.In reaction, outside system, discharge the water of condensation of 327.7g, concentrate.The mixing solutions of reductive agent and hydrochloric acid continues 30 minutes slaking after adding end.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add methanol aqueous solution, continue slaking again.Confirm not have Cr with following described diphenylcarbazone method
6+Colour developing after, finish as reaction.In reaction, can't see the generation of chromyl chloride.Shown in the chromium chloride solution that obtains composed as follows.
＜utilize the diphenylcarbazone method to detect chromic detection method 〉
Take a morsel reaction solution in watch-glass, drip 3～5 (1+5) sulfuric acid, drip diphenylcarbazone therein, not become mauve terminal point as reduction reaction.
Table 1
| CrCl 3 | 40.5％ |
| Cr | 13.3％ |
| Cl | 27.2％ |
| The Cl/Cr mol ratio | 3.00 |
| Proportion | 1.44 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | Do not detect |
| TOC (to Cr) | 0.5％ |
| Fe | 6ppm |
| Na | 20ppm |
| Cu | Do not detect |
(embodiment 1-2)
In the glass reaction vessel of condenser is housed, add 60% chromic acid aqueous solution and the 84.1g water of 420.6g, fully stir, become 50% chromic acid aqueous solution.As reductive agent, make spent glycol.As the fs of reaction, with 1.2g/ minute speed, use pump of constant delivery type in chromic acid aqueous solution, to be added on to add in 98.5% ethylene glycol of 14.3g 20% aqueous glycol solution of 56.2g water.This interpolation speed is to add the speed of 20% aqueous glycol solution of 70.5g in about 1 hour.In addition, 98.5% ethylene glycol of 14.3g is to be equivalent to reduce the amount of 30% chromic acid.
The reductive agent of fs add finish after, add the mixing solutions 822.9g of 35% hydrochloric acid of 98.5% ethylene glycol of 33.4g and 789.5g with 6.9g/ minute speed.This interpolation speed is the speed with the mixing solutions of ethylene glycol that added 822.9g in 2 hours and hydrochloric acid.In reaction, outside system, discharge the water of condensation of 331.5g, concentrate.The mixing solutions of reductive agent and hydrochloric acid continues 30 minutes slaking after adding end.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add aqueous glycol solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.In reaction, can't see the generation of chromyl chloride.Shown in the chromium chloride solution that obtains composed as follows.
Table 2
| CrCl 3 | 40.5％ |
| Cr | 13.3％ |
| Cl | 27.4％ |
| The Cl/Cr mol ratio | 3.02 |
| Proportion | 1.44 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | 1.5％ |
| TOC (to Cr) | 0.8％ |
| Fe | 5ppm |
| Na | 18ppm |
| Cu | Do not detect |
(embodiment 1-3)
In the glass reaction vessel of condenser is housed, add 60% liquid chromic acid, the 151.1g water of 420.6g, fully stir, become 44% chromic acid aqueous solution.As reductive agent, use 99.5% methyl alcohol.As the fs of reaction, with 1.0g/ minute speed, use pump of constant delivery type in chromic acid aqueous solution, to be added on to add in 99.5% methyl alcohol of 12.2g 20% methanol aqueous solution of 48.4g water.This interpolation speed is to add the speed of 20% methanol aqueous solution of 60.6g in about 1 hour.In addition, 99.5% methyl alcohol of 12.2g is to be equivalent to reduce the amount of 30% chromic acid.
The reductive agent of fs add finish after, add the mixing solutions 423.2g of 35% hydrochloric acid of 99.5% methyl alcohol of 28.4g and 394.8g with 3.5g/ minute speed.This interpolation speed is with the methyl alcohol that added 423.2g in 2 hours and the speed of hydrochloric acid mixed solution.The mixing solutions of reductive agent and hydrochloric acid continues 30 minutes slaking after adding end.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add methanol aqueous solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.In reaction, can't see the generation of chromyl chloride.Shown in the chromium chloride solution that obtains composed as follows.
Table 3
| Cr(OH) 1.5Cl 1.5 | 33.3％ |
| Cr | 13.2％ |
| Cl | 13.6％ |
| The Cl/Cr mol ratio | 1.51 |
| Proportion | 1.36 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | Do not detect |
| TOC (to Cr) | 1.7％ |
| Fe | 6ppm |
| Na | 20ppm |
| Cu | Do not detect |
(embodiment 1-4)
In the glass reaction vessel of condenser is housed, add 256.0g water, drop into the 256.0g chromium trioxide again, fully stirring and dissolving becomes 50% chromic acid aqueous solution.Ethylene glycol as reductive agent, use 98.5%.As the fs of reaction, with 0.9g/ minute speed, use pump of constant delivery type in chromic acid aqueous solution, to be added on to add in 98.5% ethylene glycol of 15.0g 27% aqueous glycol solution of 38.9g water.This interpolation speed is to add the speed of 27% aqueous glycol solution of 53.9g in about 1 hour.In addition, 98.5% ethylene glycol of 15.0g is to be equivalent to reduce the amount of 31% chromic acid.
The reductive agent of fs add finish after, add the mixing solutions 433.0g of 35% hydrochloric acid of 98.5% ethylene glycol of 33.3g and 399.7g with 3.6g/ minute speed.This interpolation speed is with the ethylene glycol that added 433.0g in 2 hours and the speed of hydrochloric acid mixed solution.The mixing solutions of reductive agent and hydrochloric acid continues 30 minutes slaking after adding end.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add aqueous glycol solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.In reaction, can't see the generation of chromyl chloride.Shown in the chromium chloride solution that obtains composed as follows.
Table 4
| Cr(OH) 1.5Cl 1.5 | 35.2％ |
| Cr | 14.0％ |
| Cl | 16.0％ |
| The Cl/Cr mol ratio | 1.68 |
| Proportion | 1.39 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | 2.9％ |
| TOC (to Cr) | 2.9％ |
| Fe | 8ppm |
| Na | 22ppm |
| Cu | Do not detect |
(embodiment 1-5)
In the glass reaction vessel of condenser is housed, add 60% liquid chromic acid, the 84.1g water of 420.6g, fully stir, become 50% chromic acid aqueous solution.As reductive agent, use 99.5% methyl alcohol.As the fs of reaction, with 1.0g/ minute speed, use pump of constant delivery type in chromic acid aqueous solution, to be added on to add in 99.5% methyl alcohol of 12.2g 20% methanol aqueous solution of 48.4g water.This interpolation speed is to add the speed of 20% methanol aqueous solution of 60.6g in about 1 hour.In addition, 99.5% methyl alcohol of 12.2g is to be equivalent to reduce the amount of 30% chromic acid.
The reductive agent of fs add finish after, add the mixing solutions 554.8g of 35% hydrochloric acid of 99.5% methyl alcohol of 28.4g and 526.4g with 4.6g/ minute speed.This interpolation speed is with the methyl alcohol that added 554.8g in 2 hours and the speed of hydrochloric acid mixed solution.In reaction, outside system, discharge the water of condensation of 64.6g, concentrate.The mixing solutions of reductive agent and hydrochloric acid continues 30 minutes slaking after adding end.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add methanol aqueous solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.In reaction, can't see the generation of chromyl chloride.Shown in the chromium chloride solution that obtains composed as follows.
Table 5
| Cr(OH)Cl 2 | 36.0％ |
| Cr | 13.4％ |
| Cl | 18.2％ |
| The Cl/Cr mol ratio | 1.99 |
| Proportion | 1.43 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | Do not detect |
| TOC (to Cr) | 1.2％ |
| Fe | 6ppm |
| Na | 21ppm |
| Cu | Do not detect |
(embodiment 1-6)
In the glass reaction vessel of condenser is housed, add 60% liquid chromic acid, the 84.1g water of 420.6g, fully stir, become 50% chromic acid aqueous solution.As reductive agent, use 99.5% methyl alcohol.As the fs of reaction, with 1.0g/ minute speed, use pump of constant delivery type in chromic acid aqueous solution, to be added on to add in 99.5% methyl alcohol of 12.2g 20% methanol aqueous solution of 48.4g water.This interpolation speed is to add the speed of 20% methanol aqueous solution of 60.6g in about 1 hour.In addition, 99.5% methyl alcohol of 12.2g is to be equivalent to reduce the amount of 30% chromic acid.
The reductive agent of fs add finish after, add the mixing solutions 686.4g of 35% hydrochloric acid of 99.5% methyl alcohol of 28.4g and 658.0g with 5.7g/ minute speed.This interpolation speed is with the methyl alcohol that added 686.4g in 2 hours and the speed of hydrochloric acid mixed solution.In reaction, outside system, discharge the water of condensation of 196.2g, concentrate.The mixing solutions of reductive agent and hydrochloric acid continues 30 minutes slaking after adding end.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add aqueous glycol solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.In reaction, can't see the generation of chromyl chloride.Shown in the chromium chloride solution that obtains composed as follows.
Table 6
| Cr(OH) 0.5Cl 2.5 | 38.3％ |
| Cr | 13.4％ |
| Cl | 22.5％ |
| The Cl/Cr mol ratio | 2.47 |
| Proportion | 1.43 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | Do not detect |
| T0C (to Cr) | 0.9％ |
| Fe | 4ppm |
| Na | 23ppm |
| Cu | Do not detect |
(embodiment 1-7)
In the glass reactive tank of condenser is housed, add 60% chromic acid aqueous solution and the 21.0kg water of 105.2kg, fully stir, become 50% chromic acid aqueous solution.As reductive agent, use methyl alcohol.As the fs of reaction, with 0.25kg/ minute speed, use pump of constant delivery type in chromic acid aqueous solution, to be added on to add in 99.5% methyl alcohol of 3.0kg 20% methanol aqueous solution of 12.0kg water.This interpolation speed is to add the speed of 20% methanol aqueous solution of 15.0kg in about 1 hour.In addition, 99.5% methyl alcohol of 3.0kg is to be equivalent to reduce the amount of 30% chromic acid.
The reductive agent of fs add finish after, add the mixing solutions 204.5kg of 35% hydrochloric acid of 99.5% methyl alcohol of 7.1kg and 197.4kg with 1.70kg/ minute speed.This interpolation speed is with the methyl alcohol that added 204.5kg in 2 hours and the speed of hydrochloric acid mixed solution.In reaction, outside system, discharge the water of condensation of 114.4kg, concentrate.The mixing solutions of reductive agent and hydrochloric acid continues 30 minutes slaking after adding end.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add aqueous glycol solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.In reaction, can't see the generation of chromyl chloride.Reaction is cooled to normal temperature after finishing, and continues to stir diel.Separate the crystallization of separating out with separating centrifuge, reclaim the chromium chloride crystallization of 61kg.The crystallization that obtains is confirmed to be CrCl in X-ray diffraction
36H
2O.Shown in the chromium chloride crystalline that obtains is composed as follows.
Table 7
| CrCl 3·6H 2O | 97.8％ |
| Cr | 19.1％ |
| Cl | 39.0％ |
| The Cl/Cr mol ratio | 3.00 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | Do not detect |
| TOC (to Cr) | 0.1％ |
| Fe | 15ppm |
| Cu | Do not detect |
(comparative example 1-1)
In the glass reaction vessel of condenser is housed, add 251.6g water, drop into the 253.1g chromium trioxide again, fully stirring and dissolving becomes 50% chromic acid aqueous solution.As reductive agent, use glucose.As the fs of reaction, with 1.4g/ minute speed, use pump of constant delivery type in chromic acid aqueous solution, to be added on to add in 97% glucose of 17.6g 20% D/W of 67.6g water.This interpolation speed is to add the speed of 20% D/W of 85.2g in about 1 hour.In addition, 97% glucose of 17.6g is to be equivalent to reduce the amount of 30% chromic acid.
The reductive agent of fs add finish after, add the mixing solutions 830.5g of 35% hydrochloric acid of 97% glucose of 41.0g and 789.5g with 6.9g/ minute speed.This interpolation speed is with the glucose that added 830.5g in 2 hours and the speed of hydrochloric acid mixed solution.In reaction, outside system, discharge the water of condensation of 337.0g, concentrate.The mixing solutions of reductive agent and hydrochloric acid continues 30 minutes slaking after adding end.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add D/W, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.In reaction, can't see the generation of chromyl chloride.Shown in the chromium chloride solution that obtains composed as follows.
Table 8
| CrCl 3 | 40.4％ |
| Cr | 13.3％ |
| Cl | 27.0％ |
| The Cl/Cr mol ratio | 2.99 |
| Proportion | 1.45 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | 8.3％ |
| TOC (to Cr) | 4.5％ |
| Fe | 6ppm |
| Na | 22ppm |
| Cu | Do not detect |
(performance evaluation)
The chromium chloride solution that use obtains with embodiment 1-1～1-6 and comparative example 1-1, the large container of packing into constitutes chromate treating liquid, and drying is carried out in the test piece of dipping steel plate galvanized, carries out chromate treating then.Estimate the gloss intensity after handling.In following its result of table 9 expression.In table 9, ◎ represents that gloss is very good, and zero expression gloss is good, and * expression gloss is insufficient.
Table 9
| Chromate treating | |
| Embodiment 1-1 | ◎ |
| Embodiment 1-2 | ○ |
| Embodiment 1-3 | ◎ |
| Embodiment 1-4 | ○ |
| Embodiment 1-5 | ◎ |
| Embodiment 1-6 | ◎ |
| Comparative example 1-1 | × |
According to the result shown in the table 9 as can be known, if use the chromium chloride solution (the present invention's product) of embodiment, then the gloss that is produced by chromate treating is excellent.
And, for embodiment 1-4 and 1-5 and the chromium chloride solution that obtains of comparative example 1-1, estimate the easness that causes crystallization.In many lattice container of 50ml, add each sample about 40ml, add a cover in room temperature and negative environment below 0 ℃ and transfer postpone, have or not with the visual observations crystalline.With regard to crystalline has or not, even fine crystallization because the possibility of growing up as nuclear with it is arranged, is judged as crystallization.Table 10 ecbatic.
Table 10
By judging shown in the table 10, the solution that embodiment 1-4 and 1-5 obtains is not even observe crystallization in the following preservation of negative 0 degree yet.The solution relative therewith, that the comparative example 1-1 of the typical example of forming as the liquid of existing chromium chloride solution obtains is if crystallization is just observed near preservation 0 degree.
(embodiment 2-1)
In the glass reaction vessel of condenser is housed, add 60% chromic acid aqueous solution of 242.9g.Drop into 75% phosphoric acid of 121.5g water and 571.4g therein, fully stir, make the mixed aqueous solution of chromic acid and phosphoric acid.Separate therewith, in addition, add 75.2g water in advance in 98.5% ethylene glycol of 27.5g, dilution is 26% aqueous glycol solution, with adding this aqueous glycol solution in 3 hours.After this, continue 30 minutes slaking.The temperature of this moment is 108 ℃.After the slaking, check residual Cr
6+, add aqueous glycol solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.Shown in the Plessy's green aqueous solution that obtains composed as follows.
Table 11
| Cr(H 2PO 4) 3 | 50.4％ |
| Cr 6+ | Do not detect |
| TOC (to Cr) | 0.5％ |
| Oxalic acid (to Cr) | 0.1％ |
| Fe | 5ppm |
| Na | 20ppm |
| Cl | 10ppm |
| SO 4 | 45ppm |
(embodiment 2-2)
In the glass reaction vessel of condenser is housed, adds 387.3g water, drop into 122.8g chromium trioxide, fully stirring and dissolving again.Then, drop into 75% phosphoric acid of 320.0g, make the mixed aqueous solution of chromic acid and phosphoric acid.Separate therewith, in addition, add 177.1g water in advance in 99.5% methyl alcohol of 19.7g, dilution is 10% methanol aqueous solution, with adding this methanol aqueous solution in 3 hours.After this, continue 30 minutes slaking.The temperature of this moment is 108 ℃.After the slaking, check residual Cr
6+, add methanol aqueous solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.Shown in the Plessy's green aqueous solution that obtains composed as follows.
Table 12
| Cr(H 1.5PO 4) 2 | 30.3％ |
| Cr 6+ | Do not detect |
| TOC (to Cr) | 1.6％ |
| Oxalic acid (to Cr) | Do not detect |
| Fe | 6ppm |
| Na | 18ppm |
| Cl | 10ppm |
| SO 4 | 20ppm |
(comparative example 2-1)
The ethylene glycol that uses in replacing embodiment 2-1 and using the glucose, all the other and embodiment 2-1 similarly operate, and obtain the Plessy's green aqueous solution.Shown in the Plessy's green aqueous solution that obtains composed as follows.
Table 13
| Cr(H 2PO 4) 3 | 50.3％ |
| Cr 6+ | Do not detect |
| TOC (to Cr) | 3.9％ |
| Oxalic acid (to Cr) | 9.2％ |
| Fe | 4ppm |
| Na | 22ppm |
| Cl | 10ppm |
| SO 4 | 30ppm |
(performance evaluation)
The Plessy's green aqueous solution that use obtains with embodiment 2-1,2-2 and comparative example 2-1, the large container of packing into constitutes chromate treating liquid, and drying is carried out in the test piece of dipping steel plate galvanized, carries out chromate treating.Estimate the result of the gloss intensity after handling in following table 14 expression.In the table 14, zero expression gloss is good, and * expression gloss is insufficient.
Table 14
| Chromate treating | |
| Embodiment 2-1 | ○ |
| Embodiment 2-2 | ○ |
| Comparative example 2-1 | × |
By the result shown in the table 14 as can be known, if use the Plessy's green aqueous solution (the present invention's product) of embodiment, the gloss that produces by chromate treating is excellent.
(embodiment 3-1)
In the glass reaction vessel of condenser is housed, add 251.6g water, drop into the 168.6g chromium trioxide again, fully stirring and dissolving becomes 40% chromic acid aqueous solution.As reductive agent, use 18% the methanol aqueous solution that in 99.5% methyl alcohol of 27.0g, adds 119.2g water.In chromic acid aqueous solution, add this methanol aqueous solution with 1.22g/ minute speed, use pump of constant delivery type.This interpolation speed is to add the speed of 18% methanol aqueous solution of 146.2g in 2 hours.
Behind 12 minutes of beginning to add, separate 67.5% aqueous nitric acid that adds 470.6g in addition with 3.92g/ minute speed with methanol aqueous solution from methanol aqueous solution.The interpolation time of this interpolation speed and methanol aqueous solution is same, is to add the speed of aqueous nitric acid in 2 hours.The theoretical amount a of the nitric acid when methanol aqueous solution adds end and the ratio a/b of the theoretical amount b of methyl alcohol are 0.9.After methanol aqueous solution added end, the interpolation of aqueous nitric acid also finished after 12 minutes.After this, continue 30 minutes slaking.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add methanol aqueous solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.Can't see the generation of nitrous acid gas in the reaction.Shown in the chromium nitrate aqueous solution that obtains composed as follows.
Table 15
| Cr(NO 3) 3 | 40.5％ |
| Cr | 8.9％ |
| NO 3 | 31.66％ |
| NO 3/ Cr mol ratio | 3.00 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | Do not detect |
| TOC (to Cr) | 0.1％ |
| Fe | 4ppm |
| Na | 12ppm |
| Ca | 2ppm |
| Mg | Do not detect |
| Si | Do not detect |
| Al | Do not detect |
| Cu | Do not detect |
| Ni | Do not detect |
(embodiment 3-2)
In the glass reaction vessel of condenser is housed, add 60% chromic acid aqueous solution and the 140.0g water of 280.2g, fully stir, become 40% chromic acid aqueous solution.As reductive agent, use 20% the aqueous glycol solution that in 98.5% ethylene glycol of 31.7g, adds 121.9g water.In chromic acid aqueous solution, add this aqueous glycol solution with 1.28g/ minute speed, use pump of constant delivery type.This interpolation speed is to add the speed of 20% aqueous glycol solution of 153.6g in 2 hours.
Behind 12 minutes of beginning to add, separate 67.5% aqueous nitric acid that adds 470.6g in addition with 3.92g/ minute speed with aqueous glycol solution from aqueous glycol solution.The interpolation time of this interpolation speed and aqueous glycol solution is same, is to add the speed of aqueous nitric acid in 2 hours.The theoretical amount a of the nitric acid when aqueous glycol solution adds end and the ratio a/b of the theoretical amount b of ethylene glycol are 0.9.After aqueous glycol solution added end, the interpolation of aqueous nitric acid also finished after 12 minutes.After this, continue 30 minutes slaking.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add aqueous glycol solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.Can't see the generation of nitrous acid gas in the reaction.Shown in the chromium nitrate aqueous solution that obtains composed as follows.
Table 16
| Cr(NO 3) 3 | 40.6％ |
| Cr | 8.87％ |
| NO 3 | 31.62％ |
| NO 3/ Cr mol ratio | 2.99 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | 1.1％ |
| TOC (to Cr) | 0.2％ |
| Fe | 5ppm |
| Na | 16ppm |
| Ca | 2ppm |
| Mg | Do not detect |
| Si | Do not detect |
| Al | Do not detect |
| Cu | Do not detect |
| Ni | Do not detect |
(embodiment 3-3)
In the glass reactive tank of condenser is housed, add 60% chromic acid aqueous solution and the 35.0kg water of 70.0kg, fully stir, become 40% chromic acid aqueous solution.As reductive agent, use 18% the methanol aqueous solution that in 99.5% methyl alcohol of 6.8kg, adds 29.9kg water.In chromic acid aqueous solution, add this methanol aqueous solution with 306g/ minute speed, use pump of constant delivery type.This interpolation speed is to add the speed of 18% methanol aqueous solution of 36.7kg in 2 hours.
Behind 12 minutes of beginning to add, separate 67.5% aqueous nitric acid that adds 117.6kg in addition with 980g/ minute speed with methanol aqueous solution from methanol aqueous solution.The interpolation time of this interpolation speed and methanol aqueous solution is same, is to add the speed of aqueous nitric acid in 2 hours.The theoretical amount a of the nitric acid when methanol aqueous solution adds end and the ratio a/b of the theoretical amount b of methyl alcohol are 0.9.After methanol aqueous solution added end, the interpolation of aqueous nitric acid also finished after 12 minutes.After this, continue 30 minutes slaking.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add methanol aqueous solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.In the reaction, discharge the 50kg water of condensation, concentrate from condenser.Reaction finishes postcooling to normal temperature, drops into crystal seed, continues to stir diel.Separate the crystallization of separating out with separating centrifuge, reclaim the chromium nitrate crystallization of 25kg.The crystallization that obtains is confirmed to be Cr (NO in X-ray diffraction
3)
39H
2O.Shown in the chromium nitrate crystalline that obtains is composed as follows.
Table 17
| Cr(NO 3) 3·9H 2O | 98.9％ |
| Cr | 12.86％ |
| NO 3 | 46.15％ |
| NO 3/ Cr mol ratio | 3.01 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | Do not detect |
| TOC (to Cr) | 0.1％ |
| Fe | 30ppm |
| Na | 8ppm |
| Ca | 2ppm |
| Mg | Do not detect |
| Si | Do not detect |
| Al | Do not detect |
| Cu | Do not detect |
| Ni | Do not detect |
(embodiment 3-4)
In the glass reaction vessel of condenser is housed, add 60% liquid chromic acid and the 280.2g water of 280.2g, fully stir, become 30% chromic acid aqueous solution.As reductive agent, use 34% the aqueous glycol solution that in 98.5% ethylene glycol of 31.7g, adds 60.2g water.In chromic acid aqueous solution, add this aqueous glycol solution with 0.77g/ minute speed, use pump of constant delivery type.This interpolation speed is to add the speed of 34% ethylene glycol of 91.9g in 2 hours.
Behind 12 minutes of beginning to add, separate 67.5% nitric acid that adds 392.2g in addition with 3.27g/ minute speed with aqueous glycol solution from aqueous glycol solution.The interpolation time of this interpolation speed and aqueous glycol solution is same, is to add the speed of nitric acid in 2 hours.The theoretical amount a of the nitric acid when aqueous glycol solution adds end and the ratio a/b of the theoretical amount b of ethylene glycol are 0.9.After aqueous glycol solution added end, the interpolation of nitric acid also finished after 12 minutes.After this, continue 30 minutes slaking.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add aqueous glycol solution, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.Can't see in the reaction and produce nitrous acid gas.Shown in the chromium nitrate aqueous solution that obtains composed as follows.
Table 18
| Cr(OH) 0.5(NO 3) 2.5 | 36.5％ |
| Cr | 8.81％ |
| NO 3 | 26.37％ |
| NO 3/ Cr mol ratio | 2.51 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | 4.5％ |
| TOC (to Cr) | 1.0％ |
| Fe | 7ppm |
| Na | 15ppm |
| Ca | 4ppm |
| Mg | Do not detect |
| Si | Do not detect |
| Al | Do not detect |
| Cu | Do not detect |
| Ni | Do not detect |
(comparative example 3-1)
In the glass reaction vessel of condenser is housed, add 251.6g water, drop into the 168.6g chromium trioxide again, fully stirring and dissolving becomes 40% chromic acid aqueous solution.As reductive agent, use 26% the D/W that in 97% glucose of 39.0g, adds 107.2g water.In chromic acid aqueous solution, add this D/W with 1.22g/ minute speed, use pump of constant delivery type.This interpolation speed is to add the speed of 26% D/W of 146.2g in 2 hours.
Behind 12 minutes of beginning to add, separate 67.5% aqueous nitric acid that adds 470.6g in addition with 3.92g/ minute speed with D/W from D/W.The interpolation time of this interpolation speed and D/W is same, is to add the speed of aqueous nitric acid in 2 hours.The theoretical amount a of the nitric acid when D/W adds end and the ratio a/b of the theoretical amount b of glucose are 0.9.After D/W added end, the interpolation of aqueous nitric acid also finished after 12 minutes.After this, continue 30 minutes slaking.The temperature of this moment is 105 ℃.After the slaking, check residual Cr
6+, add D/W, continue slaking again.Confirm not have Cr with the diphenylcarbazone method
6+Colour developing after, finish as reaction.Can't see the generation of nitrous acid gas in the reaction.Shown in the chromium nitrate aqueous solution that obtains composed as follows.
Table 19
| Cr(NO 3) 3 | 40.4％ |
| Cr | 8.83％ |
| NO 3 | 31.58％ |
| NO 3/ Cr mol ratio | 3.00 |
| Cr 6+ | Do not detect |
| Oxalic acid (to Cr) | 9％ |
| TOC (to Cr) | 2.2％ |
| Fe | 5ppm |
| Na | 12ppm |
| Ca | 3ppm |
| Mg | Do not detect |
| Si | Do not detect |
| Al | Do not detect |
| Cu | Do not detect |
| Ni | Do not detect |
(performance evaluation)
Use is with embodiment 3-1,3-2 and 3-4 and the chromium nitrate aqueous solution that obtains of comparative example 3-1, and the large container of packing into constitutes chromate treating liquid, and drying is carried out in the test piece of dipping steel plate galvanized, carries out chromate treating.Estimate the gloss intensity after handling.In following its result of table 20 expression.In the table 20, ◎ represents that gloss is very good, and zero expression gloss is good, and * expression gloss is insufficient.
Table 20
| Chromate treating | |
| Embodiment 3-1 | ◎ |
| Embodiment 3-2 | ◎ |
| Comparative example 3-4 | ○ |
| Comparative example 3-1 | × |
By the result shown in the table 20 as can be known, if use the chromium nitrate aqueous solution (the present invention's product) of embodiment, the gloss that produces by chromate treating is excellent.
Utilizability on the industry
Aqueous solution of chromium salt of the present invention, oxalic acid content are micro-, process if use it to carry out metallic surface, just can obtain the goods of gloss excellence. In addition, manufacturing method according to the invention can advantageously be made the few aqueous solution of chromium salt of oxalic acid content industrial.
Claims (16)
1. metal finishing aqueous solution of chromium salt is characterized in that:
With respect to chromium, oxalic acid content is below the 8 weight %; With respect to chromium, all organic carbon is below the 4 weight %; Do not contain sexavalent chrome,
Described chromic salts is the basic chromic chloride of representing with composition formula Cr (OH) xCly, in the formula, and 0＜x ≦ 2,1 ≦ y＜3, x+y=3.
2. metal finishing aqueous solution of chromium salt as claimed in claim 1 is characterized in that: the proportion in the time of 20 ℃ is 1.35～1.44, and the mol ratio Cl/Cr of chlorine and chromium is more than 1, less than 3.
3. metal finishing aqueous solution of chromium salt as claimed in claim 1 is characterized in that: convert with Cr, concentration is 8.2～14 weight %.
4. metal finishing aqueous solution of chromium salt as claimed in claim 1 is characterized in that: do not contain not and Cr bonded free chlorion.
5. metal finishing aqueous solution of chromium salt is characterized in that:
With respect to chromium, oxalic acid content is below the 8 weight %; With respect to chromium, all organic carbon is below the 4 weight %; Do not contain sexavalent chrome,
Described chromic salts is with composition formula Cr (H
3-3/nPO
4)
nThe Plessy's green of expression, in the formula, n represents the number of 2 ≦ n ≦ 3.
6. metal finishing aqueous solution of chromium salt as claimed in claim 5 is characterized in that: the foreign metal ion in the aqueous solution is Na ≦ 30ppm, Fe ≦ 20ppm.
7. metal finishing aqueous solution of chromium salt as claimed in claim 5 is characterized in that: the impurity negatively charged ion in the aqueous solution is Cl ≦ 10ppm, SO
4≦ 100ppm.
8. metal finishing aqueous solution of chromium salt is characterized in that:
With respect to chromium, oxalic acid content is below the 8 weight %; With respect to chromium, all organic carbon is below the 4 weight %; Do not contain sexavalent chrome,
Described chromic salts is a chromium nitrate.
9. metal finishing aqueous solution of chromium salt as claimed in claim 8 is characterized in that:
As Cr (NO
3)
3Be scaled 40 weight %, the foreign metal ion in the aqueous solution is Na ≦ 30ppm, Fe ≦ 20ppm.
10. metal finishing aqueous solution of chromium salt as claimed in claim 8 is characterized in that: do not contain not and Cr bonded free nitrate ion.
11. make the method for the described metal finishing of claim 1, it is characterized in that with aqueous solution of chromium salt:
In chromic acid aqueous solution, as the fs of reaction, the organic reducing agent that interpolation is made up of monohydroxy-alcohol or dibasic alcohol, with the reduction in advance of a part of chromic acid, then, mix hydrochloric acid and this organic reducing agent, with respect to chromic acid, add more than 1 molar equivalent,, reaction is finished less than the hydrochloric acid of 3 molar equivalents.
12. method as claimed in claim 11 is characterized in that: monohydroxy-alcohol or dibasic alcohol are methyl alcohol, ethylene glycol or 1,3-propylene glycol.
13. make the method for the described metal finishing of claim 5, it is characterized in that with aqueous solution of chromium salt:
Mixed phosphate in chromic acid aqueous solution then, adds at least a organic reducing agent that is selected from monohydroxy-alcohol and the dibasic alcohol in advance, and reaction is carried out.
14. make the method for the described metal finishing of claim 8, it is characterized in that: in chromic acid aqueous solution, add nitric acid and organic reducing agent respectively and side by side with aqueous solution of chromium salt.
15. method as claimed in claim 14 is characterized in that:
Add nitric acid and organic reducing agent, make that chromic acid is converted to the needed nitric acid theoretical amount of chromium nitrate to be made as a, chromic acid is reduced the theoretical amount of needed organic reducing agent when being made as b, becomes the relation of a＜b.
16. method as claimed in claim 14 is characterized in that: organic reducing agent is monohydroxy-alcohol or dibasic alcohol.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP412589/2003 | 2003-12-10 | ||
| JP2003412589 | 2003-12-10 | ||
| JP132079/2004 | 2004-04-27 | ||
| JP142871/2004 | 2004-05-12 | ||
| JP259046/2004 | 2004-09-06 |
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| CN1886342A CN1886342A (en) | 2006-12-27 |
| CN100526221C true CN100526221C (en) | 2009-08-12 |
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| EP2322483A1 (en) * | 2008-09-05 | 2011-05-18 | Nippon Chemical Industrial Co., Ltd. | Chromium(iii) carbonate and process for production of same |
| CN105883920A (en) * | 2014-10-16 | 2016-08-24 | 山西国润制药有限公司 | Preparation method of chromium trichloride |
| EP3130325B1 (en) * | 2015-08-12 | 2018-11-14 | Ivoclar Vivadent AG | Agent for dentin and enamel conditioning |
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