CN103466727A

CN103466727A - Method for reducing content of impurity ions introduced during preparation of oxides

Info

Publication number: CN103466727A
Application number: CN2012101870277A
Authority: CN
Inventors: 于杨; 陈海波; 仇冬; 王琼; 贺健; 毛春鹏; 殷惠琴; 曹建平
Original assignee: China Petroleum and Chemical Corp; Research Institute of Nanjing Chemical Industry Group Co Ltd
Current assignee: China Petroleum and Chemical Corp; Research Institute of Sinopec Nanjing Chemical Industry Co Ltd
Priority date: 2012-06-08
Filing date: 2012-06-08
Publication date: 2013-12-25

Abstract

The invention discloses a method for reducing the content of impurity ions introduced during preparation of oxides. The impurity ions comprise one or more of K<+>, Na<+>, SO4<2-> , X<-> (X=F, Cl, Br and I) and the like, and cannot be completely removed by water washing or in a subsequent roasting stage. The washing solvent in the method is an organic substance which has chemical polarity, and is low in boiling point and miscible with water, and is one or a mixture of methanol, ethanol, propanol, acetone and the like. The filter cake of an oxide precursor is subjected to at least one time or finite repeated times of water washing and then is further washed by the above solvent, so that finally the obtained oxides have substantially reduced impurity content.

Description

A kind of method that reduces the impurity ion content of introducing in oxides preparation process

Technical field

The present invention relates to a kind of method of introducing impurity ion content that reduces in oxides preparation process, the reduction of the impurity ion content that especially can't remove the water-soluble of residual after the routine washing, trace and in the follow-up roasting stage.The inventive method can be for the preparation field of the functional oxide material higher to purity requirement.

Background technology

In functional material, there is major part to belong to oxide compound, comprising single oxide and composite oxides, as catalytic material, luminescent material, stupalith etc.The performance of these materials is subject to the impact of foreign ion in material and content thereof to a certain extent, and wherein major part belongs to disadvantageous effect.For example, in catalyst preparation process, the use of precipitation agent and oxide compound precursor soluble salt inevitably can be introduced Na ⁺, K ⁺, F ^-, Cl ^-, Br ^-, SO ₄ ^2-deng the foreign ion that can't remove in the roasting stage.In precipitation process, these ions are mingled in throw out with physical adsorption and the water solubles, after limited number of time is washed at least one times, most of foreign ion is washed off, and in filter cake, minor amount of water dissolved impurity ion (content is at 500ppm ~ 2000ppm usually) can't further be washed significantly and reduce by routine by concentration difference.The existence of these ions can affect the physico-chemical property (specific surface area reduction, surface acid alkalescence change, adsorb and cover active sites etc.) of final catalyzer, and then affects its catalytic performance.Luminescent material mainly refers to high purity rare earth oxides (La ₂o ₃, Y ₂o ₃and Eu ₂o ₃deng) the various fluor made, and the existence of foreign ion will have a strong impact on the band gap width of luminophore, and then changed its excitation energy and luminous special energy.In addition, in stupalith, the existence of foreign ion can cause material melting point and lower hardness, wear resisting property and oxidation resistent susceptibility to descend.

Summary of the invention

The objective of the invention is to propose a kind of method of introducing impurity ion content in oxides preparation process that reduces.Use method of the present invention, can make in oxide compound precursor filter cake, can't wash the impurity ion content that reaches remarkable minimizing by routine and greatly reduce.

In the present invention, reducing the impurity ion content of introducing in oxides preparation process realizes by method as described below.Oxide compound precursor throw out filter cake is after the routine washing, the organism that re-uses polarity, lower boiling and dissolve each other with water (comprising one or more mixtures such as methyl alcohol, ethanol, propyl alcohol, acetone) is washed filter cake for solvent, the moisture of impure ion in filter cake is replaced with organic solvent, finally carry out suction filtration, drying, roasting and obtain the oxide compound that purity is higher.

Embodiment

Below with the laboratory specific embodiment, further illustrate the present invention:

embodiment 1

CuO-CeO ₂the preparation of composite oxides: the Cu (NO that measures respectively 1mol/L ₃) ₂ce (NO with 1mol/L ₃) ₃each 50mL of the aqueous solution is placed in the 500mL beaker and stirs, and then is added drop-wise to 1mol/L Na ₂cO ₃in the aqueous solution, also stir, endpoint pH is controlled at 7.0 ~ 9.0.Precipitation is carried out suction filtration after finishing, and the filter cake obtained carries out filtering and washing with 50 ℃ of distilled water, and each water consumption is 3 times of filter cake volume.Filter cake after washing is again by the further filtering and washing of methyl alcohol, and each measuring with alcohol is 1 times of filter cake volume.The filter cake that the different washing stages are obtained sample respectively and under 90 ℃ dry 4h, 350 ℃ of laggard row element analyses of lower roasting 4h (ICP technology), the results are shown in Table 1.

Table 1 oxide analysis result

Mode of washing/number of times	Washing/2	Washing/4	Washing/6	Washing/7	Washing/8	Organic solvent washing/1*	Organic solvent washing/2*	Organic solvent washing/3*
									Na content (ppm)	8200	2500	1080	560	540	330	250	190

*, after meaning to wash 8 times, continue with an organic solvent to be washed.

As can be seen from Table 1, continue to be washed to 8 times the CuO-CeO finally obtained for 7 times in the conventional washing of experience later ₂the content of Na in composite oxides reduces little, carries out filtering and washing and re-use methyl alcohol after washing 8 times, the CuO-CeO finally obtained ₂the content of Na in composite oxides reduces significantly and reduces.

embodiment 2

PdO-La ₂o ₃the preparation of composite oxides: the Pd (Cl) that measures 50g/L ₂hydrochloric acid soln 20mL and the La (NO of 1mol/L ₃) ₃solution 80mL is placed in the 500mL beaker and stirs, and then is added drop-wise to the K of 1mol/L ₂cO ₃in the aqueous solution, also stir, endpoint pH is controlled at 7 ~ 8.Carry out filtering and washing after precipitation finishes, except the washing temperature is that 60 ℃, organic solvent are used ethanol, other washing steps are identical with embodiment 1.Filter cake after washing is dry 3h under 110 ℃, and 650 ℃ of laggard row element analyses of lower roasting 3h, the results are shown in Table 2.

Table 2 oxide analysis result

Mode of washing/number of times	Washing/3	Washing/5	Washing/8	Washing/10	Washing/13	Organic solvent washing/3*
							K content (ppm)	1200	820	570	420	400	180
Cl content (ppm)	350	230	200	150	140	90

*, after meaning to wash 13 times, continue with an organic solvent to be washed.

As can be seen from Table 2, continue to be washed to 13 times the PdO-La finally obtained for 10 times in the conventional washing of experience later ₂o ₃k in composite oxides and the content of Cl reduce little, carry out filtering and washing and re-use ethanol after washing 13 times, the PdO-La finally obtained ₂o ₃two kinds of impurity ion content of K in composite oxides and Cl reduce greatly.

embodiment 3

The preparation of ZnO: the ZnSO that measures 1mol/L ₄solution 100mL is placed in the 500mL beaker, then drips the KHCO of 1mol/L ₃the aqueous solution also stirs terminal, and the pH value is controlled at 7 ~ 9.Carry out filtering and washing after precipitation finishes, except the washing temperature is 80 ℃, organic solvent use propyl alcohol-acetone (volume ratio is 1:1) mixed solvent, other washing steps are identical with embodiment 1.Filter cake after washing is dry 3h under 110 ℃, and 500 ℃ of laggard row element analyses of lower roasting 3h, the results are shown in Table 3.

Table 3 oxide analysis result

Mode of washing/number of times	Washing/2	Washing/4	Washing/6	Washing/8	Washing/10	Washing/12	Organic solvent washing/3*
								K content (ppm)	2200	1100	890	730	640	620	290
S content (ppm)	1400	1060	780	610	540	510	210

*, after meaning to wash 12 times, continue with an organic solvent to be washed.

As can be seen from Table 3, in the conventional washing of experience, continue for 10 times to be washed to 12 times later, K in the ZnO finally obtained and the content of S reduce little, carry out filtering and washing and re-use propyl alcohol-acetone mixed solution after washing 12 times, two kinds of impurity ion content of the K in the ZnO finally obtained and S reduce greatly.

Claims

1. the method for an impurity ion content that reduces to introduce in oxides preparation process, is characterized in that the oxide compound precursor, after the routine washing, re-uses polarity, lower boiling and with the organic solvent that water dissolves each other, filter cake washed.

2. method according to claim 1, is characterized in that described organic solvent comprises one or more mixtures of methyl alcohol, ethanol, propyl alcohol and acetone.

3. method according to claim 1, is characterized in that oxide compound comprises single oxide and composite oxides.

4. according to claim 1,2 or 3 described methods, it is characterized in that the oxide compound precursor obtains the target oxygen compound through washing, drying and calcining process, its detailed process is: the washing water temperature is 50 ℃ ~ 80 ℃, and organic solvent washing carries out at normal temperatures.

5. method according to claim 1, is characterized in that reducing the K that can't wash or can't remove in the follow-up roasting stage introduced in oxides preparation process ⁺, Na ⁺, SO ₄ ^2-, Cl ^-content.