ALUMINA SUPPORT, A PROCESS FOR PREPARING THE SUPPORT, A SILVER CATALYST PREPARED FROM THE SUPPORT, AND USE THEREOF
First Claim
1. An alumina support, comprising alpha-alumina as the main crystal phase of its backbone, and having a specific surface area of no higher than 3.0 m2/g, a pore volume ranging from 0.3 ml/g to 0.8 ml/g, and an alkaline earth metal content ranging from 0.05% to 2.0% by weight of the support,wherein the alumina support has such properties that treating the support with an aqueous oxalic acid solution having a concentration ranging from 0.4% to 2.0% by weight and having twice the weight of the support for 30 minutes produces a leach liquor having an aluminum content of no higher than 60 μ
- g/mL, a sodium content of no higher than 20 μ
g/mL, and a silicon content of no higher than 40 μ
g/mL.
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Abstract
An alumina support comprises alpha-alumina as the main crystal phase of its backbone, and having a specific surface area of no higher than 3.0 m2/g, a pore volume ranging from 0.3 ml/g to 0.8 ml/g, an alkaline earth metal content ranging from 0.05% to 2.0% by weight of the support, wherein the support has such properties that treating the support with an aqueous oxalic acid solution having a concentration ranging from 0.4% to 2.0% by weight and having twice the weight of the support for 30 minutes can produce a leach liquor having an aluminum content of no higher than 60 μg/mL, a sodium content of no higher than 20 μg/mL, and a silicon content of no higher than 40 μg/mL. Processes for preparing the alumina support, silver catalysts comprising the alumina support, and methods of preparing ethylene oxide by ethylene oxidation using the silver catalyst are also disclosed herein.
15 Citations
20 Claims
-
1. An alumina support, comprising alpha-alumina as the main crystal phase of its backbone, and having a specific surface area of no higher than 3.0 m2/g, a pore volume ranging from 0.3 ml/g to 0.8 ml/g, and an alkaline earth metal content ranging from 0.05% to 2.0% by weight of the support,
wherein the alumina support has such properties that treating the support with an aqueous oxalic acid solution having a concentration ranging from 0.4% to 2.0% by weight and having twice the weight of the support for 30 minutes produces a leach liquor having an aluminum content of no higher than 60 μ - g/mL, a sodium content of no higher than 20 μ
g/mL, and a silicon content of no higher than 40 μ
g/mL. - View Dependent Claims (2, 16, 17, 18, 19, 20)
- g/mL, a sodium content of no higher than 20 μ
-
3. A process for preparing an alumina support, comprising:
-
(a) mixing at least one alumina starting material, at least one alkaline earth metal salt, optionally at least one carbonaceous burnout material, optionally at least one fluoride, at least one binder and water to produce a mixture, wherein the alumina starting material comprises alpha-alumina trihydrate and pseudo-boehmite in a weight ratio of alpha-alumina trihydrate to pseudo-boehmite ranging from 0.5;
1 to 5;
1, andwherein based on the total weight of the alumina starting material, the alkaline earth metal salt is in an amount ranging from 0.05% to 3.0% by weight, calculated based on the alkaline earth metal, the carbonaceous burnout material is in an amount ranging from 0% to 30% by weight, the fluoride is in an amount ranging from 0% to 3% by weight, and the binder and water are in a total amount ranging from 10% to 40% by weight; (b) extruding the mixture obtained in step (a) to form shaped entities; (c) drying the shaped entities obtained in step (b) at a temperature ranging from 60°
C. to 200°
C.;(d) calcining the shaped entities obtained in step (c) at a temperature ranging from 1100°
C. to 1600°
C. to convert to a semi-finished alpha-alumina support;(e) treating the semi-finished alpha-alumina support obtained in step (d) with a thermally decomposable organic acid solution having a pH of no more than 2.5; (f) washing the treated support obtained in step (e) with water to produce a leach liquor having a pH of more than 5 and a water-washed product; and (g) heat-treating the water-washed product obtained in step (f) at a temperature ranging from 80°
C. to 1200°
C. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
Specification