CN1044448C - Medium temp. CO conversion catalyst and its preparing method - Google Patents

Abstract

The present invention relates to a medium temperature CO conversion catalyst and a preparation method thereof, which belongs to the technical field of catalysts containing metals or metallic oxides. The medium temperature CO conversion catalyst is prepared from ferrite deposited by electroplating waste containing chromium, necessary Fe2O3 and other components; the active phase of the medium temperature CO conversion catalyst is Fe3Cl4; when Fe<+3> in the position B is replaced by Cr<+3>, ferropicotite composite oxide with the structure is formed. With the preparation method of the present invention, wastes are changed into valuables; the preparation method is favorable to environmental improvement and can bring great economic benefit; the medium temperature CO conversion catalyst can be used for the industrial production of synthetic ammonia.

Description

Temperature carbon monoxide shift catalyst and manufacture method thereof

The invention belongs to the catalyst field that comprises metal or metal oxide, particularly belong to temperature carbon monoxide shift catalyst (hereinafter to be referred as the CO hts catalyst) field that utilizes electroplating wastewater of chromium to make, should be B01J 23/00 and C25D 21/18 by the IPC classification chart.

The CO hts catalyst is a kind of in the nine big class catalyst that use in the Ammonia Production, and is maximum a kind of of consumption.For example the yearly consumption of the CO hts catalyst of China reaches about 10,000 tons, and is costly.

Can make and produce the CO hts catalyst in many ways.But the CO hts catalyst that did not all use electroplating wastewater of chromium to make at home and abroad as far as we know.

The home and abroad generally adopts ferrite process to handle the waste water of chromium containing electroplating.The advantage of this method is simple, the small investment of technology, and is easy and simple to handle, effect is better, and can handle the waste water that high concentration contains chromium and other metal.But sediment is handled and is had any problem, and has problem of environmental pollution.

The objective of the invention is to overcome above-mentioned the deficiencies in the prior art, a kind of method that becomes the chromium containing electroplating sediment into the CO hts catalyst is provided, and a kind of CO hts catalyst of being made by the chromium containing electroplating sediment that contains the ammonification production requirement that meets is provided.

For realizing first purpose of the present invention, manufacture method of the present invention in turn includes the following steps:

A. be raw material with the electroplating wastewater of chromium, excessive copperas solution is added in the electroplating wastewater of chromium, and by adding alkali, heating, ventilation, stirring, make ferrite deposition wherein;

B. analyze CrO in the ferrite of gained deposition ₃, Fe ₂O ₃, MgO, CaO percentage by weight;

C. with CrO in the described catalyst that will make ₃, Fe ₂O ₃, MgO, CaO significant percentage be standard, ferrite is added not enough group component, and makes Fe wherein ₂O ₃Percentage by weight be 75-85%;

D. grind material, the granulation of sieving, oven dry, making particle moisture is 6-8%;

E. add 1% graphite (by particle weight), it is mixed with the granular iron oxysome;

F. use the tablet press machine compressing tablet;

G. roasting, cooling;

Most preferred embodiment according to manufacture method of the present invention:

1) said Fe ₂O ₃Percentage by weight be 80%;

2) said ferrite content is 20%.

For realizing second purpose of the present invention, temperature carbon monoxide shift catalyst of the present invention is to be that raw material is produced with the electroplating wastewater of chromium sediment, and its active phase structure is

Fe _A ³⁺(Fe _{1-3 δ} ²⁺Fe _{1+2 δ} ³⁺δ) _BO ₄Tri-iron tetroxide, work as Cr ³⁺The Fe that has replaced the B position ³⁺After, formed structure and be

Fe _A ³⁺(Fe _1-X ³⁺Fe ²⁺Cr _X ³⁺) _BO ₄The ferropicotite composite oxides.

Adopting the ferrite content of the product that preparation method of the present invention makes is 10-15%, and optimised quantity is 20%.

In order to be expressly understood essence of the present invention more, to describe the step of the inventive method below in detail, and describe CO hts catalyst of the present invention with reference to the accompanying drawings, wherein

Fig. 1 is an activity of such catalysts empirical curve of the present invention;

Fig. 2 is the Mossbauer spectral curve of catalyst of the present invention;

Fig. 3 is the X-ray diffraction diagram spectrum of catalyst of the present invention.

Main component in the electroplating wastewater of chromium is a ferrite.By analyzing as can be known, contain CrO in the ferrite ₃10-11% (by weight, down with), contain Fe ₂O ₃60-70%; Also have a spot of MgO and CaO.

Analyze by experiment as can be known, the CO hts catalyst is identical as composition contained in the chemical constituent in (B106, B109, B112 etc.) and the ferrite, and content and ferrite are very approaching.Be example just, wherein contain CrO with B106 type catalyst ₃12.4%, contains Fe ₂O ₃67.5%, contain MgO 4.1%, contain CaO 0.8%.See table 1. for details therefore, can utilize ferrite fully, the CO hts catalyst that promptly utilizes the chromium containing electroplating sediment to produce to meet the requirements is as long as add the ratio that the two differs.

Table 2 has provided the physical property and the catalytic activity of the catalyst and the B106 catalyst of different ferrite content.Data from table 2 as can be seen, ferritic content is that the catalyst of 10-50% is all close with the B106 catalyst performance, but the most suitable with 20%.

In order to find out the optimum formula of various compositions in the catalyst, ferrite to Xinsheng Switch Factory, Jinzhou and Shenyang Water Pump Factory has carried out component analysis (seeing Table 1) and has carried out burdening calculation, and the sample of 30 different proportionings tested, therefrom drawing 80% iron oxide and 20% ferrite is optimum formula.Table 3 has provided the test result for this optimum formula.The iron oxide that adds 75%-85% also can meet the demands basically.

Serve as to describe the step of making hts catalyst from electroplating wastewater of chromium in detail with preparation B106 hts catalyst below:

1, with the electroplating wastewater of chromium be raw material, excessive copperas solution is added in the chromate waste water that making hexavalent chrome reduction is trivalent chromium, its reaction equation is as follows:

Add alkali, heating, ventilation, stirring then, make the ferrite deposition.Ferrite is the oxide crystal that is spinel structure that has iron ion, oxonium ion, reaches other metal ion composition;

2, analyze CrO in the gained ferrite ₃, Fe ₂O ₃, MgO, CaO percentage by weight;

3, the chemical constituent in weight ratio that will obtain by step 2 and the B106 catalyst that for example will make is relatively found out the difference of the two, and ferrite is added not enough various group components, and make Fe wherein ₂O ₃Ratio is 75-85%, wherein with Fe ₂O ₃Ratio be 80% for best;

For example Jinzhou sample contains Fe ₂O ₃Be 71.29%, should supply 75-85%, and be best with 80%; Jinzhou sample contains CrO ₃11.04%.CrO according to the B106 catalyst ₃Ratio, then to 1 kilogram of ferrite should add 186.87 the gram CrO ₃

4, will supply 3Fe ₂O ₃, CrO ₃, MgO, CaO ferrite ground material 60 minutes, with 6-8 eye mesh screen choosing grain, oven dry, making particle moisture is 6-8%;

5, press the graphite of particle weight adding 1%, graphite mixes with the granular iron oxysome;

6, with tablet press machine (for example CZP-35 type tablet press machine) compressing tablet;

7, roasting is 1.5 hours, promptly obtains product after the cooling.

8, making the CO hts catalyst that ferrite content is 10-50% by known method, is best with 20% wherein.

To other CO hts catalyst except that B106, also use and above-mentioned identical step manufacturing.

The activity of such catalysts phase structure of making as stated above is

Fe _A ³⁺(Fe _{1-3 δ} ²⁺Fe _{1+2 δ} ³⁺δ) _BO ₄Tri-iron tetroxide work as Cr ³⁺The Fe that has replaced the B position ³⁺After, formed structure and be

Fe _A ³⁺〔Fe _1-X ³⁺Fe ²⁺Cr _X ³⁺〕 _BO ₄

The ferropicotite composite oxides, this is consistent with the conclusion of TOPSe.

In order to check with the produced catalyst of method of the present invention whether meet the requirement that ammonia synthesizing industry is produced, carry out activity experiment, Mossbauer analysis and the analysis of X-line diffraction spectrogram to it.

Fig. 1 represents the laboratory sample activity experiment curve that 102 factories carry out in Jilin with 20% ferrite proportioning.Active check is to carry out in the reactor of internal diameter 32mm, volume 30ml.Catalyst grain size is the 6-8 order, packing volume 30ml, unstripped gas proportioning CO: H ₂=1: 4, steam-to-gas ratio is 2: 1, during air speed 500 ^-1, detected temperatures is 400 ℃.At experimental session, measure once every day, and need there be the result of three continous-stables every tower sample interval one hour.Abscissa among Fig. 1 is represented the time, is unit with the sky; Ordinate is represented CO rate of change (%).Curve from Fig. 1 as can be seen, active higher during beginning, it is slower to descend within seven days, it is very fast to descend in seven to ten days, slower again after ten days, gradually steadily becomes a horizontal linear.After measured, specific area is 74.86 meters ²/ gram; Porosity is 38.60%.

Fig. 2 represents the Mossbauer study curve of hts catalyst.In the experiment, carry out mensuration under the room temperature, use with IAC-01 type Mossbauer spectrometer ⁵⁷CO (pd) source, intensity is 25m Curie, thickness of sample is 50mg/cm ³Speed is demarcated with a-Fe, and the Mossbauer parameter obtains by computer fitting.Abscissa among Fig. 2 is represented speed (mm/s); Ordinate is represented comparative counting (being relative intensity).Expressing six curve: a among Fig. 2 is Fe ₃O ₄B is r-Fe ₂O ₃C is B106, before the reduction; D is B106, after the reduction; E is a ferrite, before the reduction; F is a ferrite, after the reduction.Mossbauer parameter in the experiment is as shown in table 4.

As shown in Figure 2, the spectrum of unreduced two kinds of catalyst is r-Fe ₂O ₃Characteristic spectrum, middle δ ₃The bimodal of=0.38mm/s, Δ EQ=0.41MM/s is r-Fe ₂O ₃Little material super paramagnetic peak.Two cover spectral lines, middle super paramagnetic peak complete obiteration all appear in the reduction rear catalyst.Long-pending by B position and A plane than less than 2, can think that these two kinds of activity of such catalysts phase structures are that structure is

Fe _A ³⁺(Fe _{1-3 δ} ²⁺Fe _{1+2 δ} ³⁺δ) _BO ₄Tri-iron tetroxide.Cr ³⁺The Fe that has replaced the B position ³⁺After, formed structure and be

Fe _A ³⁺(Fe _1-X ³⁺Fe ²⁺Cr _X ³⁺) _BO ₄The brilliant composite oxides of siderochrome point.

The X-ray diffraction diagram of catalyst spectrum curve wherein before and after Fig. 3 represents to reduce.The same Fig. 2 of the implication of c, d, e, f.Abscissa is the angle of diffraction (degree); Ordinate is a relative intensity.Use Japan's 2028 type diffractometers of science in the experiment, copper target, nickel filter plate, wavelength 1.542 .As shown in Figure 2, unreduced two kinds of catalyst mainly contain Fe ₂O ₃, its Jing Gecanshuo ﹠amp;=8.491 Catalyst after the reduction is mainly Fe ₃O ₄, its Jing Gecanshuo ﹠amp;=8.495 The catalyst of this explanation contain ferrite has identical crystal structure with B106 type catalyst.

CO hts catalyst manufacture method of the present invention has following advantage:

1, fully utilizes electroplating wastewater of chromium, helped improving environment, reduced environmental pollution;

2, become the sediment discarded object into precious, bring tangible economic benefit for hts catalyst factory.For example, 1 ton of B106 catalyst of the comparable production of the catalyst that utilizes 1 ton of ferrite production to go out is saved 1000-1200 unit, and expense 18% reduces cost.If production capacity is 1000 tons/year, then can save 260,000 yuan every year;

3, technological process is simple, product strength is high, activity is good.

Table 1

Ferrite and B ₁₀₆The composition analysis of catalyst

	B 106	Ferrite
				A	B
		Fe 2O 3(％) CrO 3(％) CaO(％) MgO(％) CrO 3/Fe 2O 3(％)	67.5 12.4 0.8 4.1 15.6			70.8 10.5 1.6 1.0 14.8	70.4 10.1 1.3 0.3 14.4

Table 2

The catalyst and the B of different ferrite content ₁₀₆The physical property of catalyst and catalytic activity

	B 106	The contain ferrite catalyst
						10％	20％	30％	50％
		Active (%) bulk density (g/ml) intensity (Kg/cm 2) loss on ignition (%)	91.0	93.4	92.3％					92.6	89.8 1.5
1.6	1.5					1.5	1.5
			180	250	285			246	196
10	8.1					8.0	10.0			13.5

Table 3

The laboratory sample test data

The product specification certified products	HC-1141-78 B 106Finished product standard activity (%) intensity (Kg/cm 2) loss on ignition (%)		Different proportioning sample determination results
				90 150 ≤10	10％ 20％ 30％ 40％ 50％ 89.92 8.13 8.00 10.00 13.50 7.89
		High-quality product	Active (%) intensity (Kg/cm 2)			91 180	93.4 92.34 92.58 259 285 246
Bulk density (g/ml)				1.4-1.5	1.48 1.52 1.48
		Chemical composition (%)				Qualified

Table 4

The Mossbauer parameter

	HA HB δ A,Fe δ B,Fe (KO e) (KO e) (mm/s) (mm/s)
		B 106B before the c reduction 106E ferrite reduction back f Fe before the d ferrite reduction of reduction back 3O 4 a γ-Fe 2O 3b	491.8 0.42 479.2 458.6 0.35 0.68 489.0 0.39 484.7 462.1 0.34 0.70 504.9 483.8 0.34 490.7 0.40 0.77

Claims (5)

1, a kind of manufacture method of temperature carbon monoxide shift catalyst is characterized in that it in turn includes the following steps

(a) with the electroplating wastewater of chromium be raw material, excessive copperas solution is added in the chromate waste water, and, make ferrite deposition wherein by adding alkali, heating ventilation, stirring;

(b) CrO in the ferrite of analysis gained deposition ₃, Fe ₂O ₃, MgO, CaO percentage by weight;

(c) with the CrO in the described catalyst that will make ₃, Fe ₂O ₃, MgO, CaO percentage by weight be standard, described ferrite is added not enough group component, and makes Fe wherein ₂O ₃Percentage by weight be 75-85%;

(d) grind material, the granulation of sieving, oven dry, making particle moisture is 6-8%;

(e) add 1 weight % graphite, it is mixed with the granular iron oxysome;

(f) use the tablet press machine compressing tablet;

(g) roasting, cooling.

2, a kind of manufacture method as claimed in claim 1 is characterized in that wherein said Fe ₂O ₃Percentage by weight be 80%.

3, a kind of temperature carbon monoxide shift catalyst of making by the described method of claim 1-3 is characterized in that it is is that raw material is produced with the electroplating wastewater of chromium sediment, and its active phase structure is

Fe _A ³⁺(Fe _{1-3 δ} ²⁺Fe _{1+2 δ} ³⁺δ) _BO ₄Tri-iron tetroxide, work as Cr ³⁺The Fe that has replaced the B position ³⁺After formed structure and be

Fe _A ³⁺(Fe _1-X ³⁺Fe ²⁺Cr _X ³⁺) _BO ₄The ferropicotite composite oxides.

4, temperature carbon monoxide shift catalyst as claimed in claim 3, the ferrite content that it is characterized in that product is 10-50%.

5, temperature carbon monoxide shift catalyst as claimed in claim 3 is characterized in that wherein said ferrite content is 20%.

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