Kaolin Microsphere NaY Zeolite Synthesis via Calcination
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Solution Overview
Problem
Existing methods for synthesizing high-content NaY molecular sieves using kaolin sprayed microspheres face challenges such as low crystallinity, high costs due to the need for super fine kaolin calcined materials, and poor attrition resistance, which affect the performance of catalytic cracking catalysts.
Innovation Solution
A method involving the addition of structural additives like starch, graphite powder, and carboxymethyl cellulose to kaolin clay, followed by pulping, spraying, calcination, and crystallization with directing agents, to produce kaolin microspheres with enhanced pore structure and increased NaY molecular sieve content, achieving higher crystallinity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If kaolin is calcined at high temperatures above 900°C to synthesize NaY molecular sieves, then the silicon to aluminum ratio increases, but crystallinity decreases to below 30%
Solution Approach 1:
The patent applies parameter changes by optimizing the calcination temperature range (900-1000°C) and duration (2-4 hours) to achieve the desired balance between silicon to aluminum ratio and crystallinity. By precisely controlling these thermal processing parameters, the method transforms kaolin into NaY molecular sieves with crystallinity reaching 40-50% while maintaining high silicon to aluminum ratio, resolving the contradiction between achieving high Si/Al ratio and maintaining crystallinity.
2Reliability
If super fine kaolin calcined materials are used to increase zeolite content, then crystallinity increases to above 40%, but manufacturing cost increases significantly
Solution Approach 1:
The patent employs ordinary kaolin clay as the raw material instead of expensive super fine kaolin calcined materials. By using readily available, low-cost kaolin and applying optimized calcination conditions (900-1000°C for 2-4 hours), the method achieves crystallinity of 40-50% without incurring high material costs, thus resolving the contradiction between achieving high crystallinity and controlling manufacturing cost.
Solution Approach 2:
The patent changes the processing parameters by implementing specific calcination temperature (900-1000°C) and time (2-4 hours) conditions that transform ordinary kaolin into high-crystallinity NaY molecular sieves. This parameter optimization eliminates the need for expensive pre-calcined super fine materials, achieving both high crystallinity and cost-effectiveness.
3Quantity of substance
If substantial amounts of kaolin calcined with low adhesive property are present in sprayed microspheres, then zeolite content increases, but attrition resistance deteriorates
Solution Approach 1:
The patent optimizes the calcination temperature (900-1000°C) and duration (2-4 hours) to achieve a balance between zeolite content and attrition resistance. By controlling these thermal parameters, the method produces NaY molecular sieves with sufficient crystallinity (40-50%) while maintaining the structural integrity of the microsphere, thus resolving the contradiction between achieving high zeolite content and maintaining attrition resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in high-content NaY molecular sieves with improved crystallinity and pore structure, leading to the production of high-performance catalytic cracking catalysts with enhanced resistance to heavy metals and hydrothermal stability.
Implementation Method 1
The microspheres undergo calcinations
Implementation Method 2
a portion of the microspheres are subsequently transformed into NaY molecular sieves in alkali system
Data Source
AI summary
A method for synthesizing high-content NaY molecular sieves with kaolin sprayed microspheres includes adding functional components and deionized water into kaolin so as to be pulped into a mixed slurry. The slurry is sprayed into microspheres. The microspheres are calcined at a temperature between 700 and 1,000° C. and mixed with a directing agent for crystallization. The resultant solid is filtrated and washed with water and then dried to obtain a final in-situ crystallized product with high content of molecular sieves.