Cellulose Pulp Dissolution via Alkaline Metal Hydroxide Slurry
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Solution Overview
Problem
Current methods for regenerating cellulose fibers often require expensive, toxic, or environmentally unfriendly chemicals and involve complex processes like derivatization, leading to high environmental costs and inefficiencies.
Innovation Solution
A method involving preparing an alkaline metal hydroxide solution at 4-10% concentration, mixing with cellulose pulp to form a slurry, heating, and dissolving in a cold alkaline solution without derivatization, reducing the need for substantive washing and neutralization steps, and using accelerators like manganese salts to improve process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If derivatization steps (e.g., xantification in viscose process) are used to dissolve cellulose, then dissolution efficiency improves, but environmental harm and process complexity increase
Solution Approach 1:
The invention changes the parameters of the alkaline solution (concentration, temperature, additives) to achieve effective cellulose dissolution without derivatization. Specifically, using 10-30% w/v NaOH at controlled temperatures with metal salts as additives modifies the dissolution parameters to work directly on native cellulose, eliminating the need for toxic derivatizing agents while maintaining high dissolution efficiency
Solution Approach 2:
The invention extracts and removes the harmful derivatization steps (xantification, carbon disulfide treatment) from the cellulose dissolution process. By taking out these toxic intermediate steps and replacing them with direct alkaline dissolution using enhanced NaOH solutions, the process achieves the same dissolution result without environmental harm
2Productivity
If derivatization steps are used to dissolve cellulose, then dissolution efficiency improves, but process complexity increases
Solution Approach 1:
The invention performs preliminary action by pre-treating the cellulose with the enhanced alkaline solution containing metal salts before the main dissolution step. This pre-treatment modifies the cellulose structure slightly to make it more receptive to direct dissolution, eliminating the need for multiple derivatization steps and simplifying the overall process sequence
Solution Approach 2:
The invention merges the pretreatment and dissolution steps into a single integrated process. By combining the alkaline treatment with metal salt additives that serve both as pretreatment agents and dissolution promoters, the process reduces the number of separate steps from multiple derivatization stages to a unified dissolution operation
3Object-affected harmful factors
If cold alkaline solution is used to dissolve cellulose, then environmental friendliness improves, but dissolution completeness worsens due to aggregate formation
Solution Approach 1:
The invention introduces metal salts (CaCl2, ZnCl2, FeCl3, etc.) as intermediary substances that facilitate the dissolution process in cold alkaline solutions. These metal salts act as mediators between the cellulose and the alkaline solution, preventing aggregate formation and ensuring complete dissolution while maintaining the environmentally friendly cold process conditions
Solution Approach 2:
The invention uses a composite alkaline solution system combining NaOH with metal salts. This composite solution leverages the synergistic effect of the strong base and metal ions to achieve complete cellulose dissolution at low temperatures, maintaining environmental friendliness while ensuring dissolution reliability
4Ease of operation
If acid hydrolysis is used as pretreatment to reduce polymer chain length, then cellulose accessibility improves, but additional washing and neutralization steps are required
Solution Approach 1:
The invention inverts the traditional approach by using alkaline treatment instead of acid hydrolysis for pretreatment. This reversal eliminates the need for subsequent neutralization steps, as the alkaline conditions are maintained throughout the dissolution process, reducing the number of process steps while achieving the same cellulose accessibility improvement
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
This method is more environmentally friendly, cost-effective, and eliminates the need for derivatization, providing a straightforward process for regenerating cellulose fibers with improved impregnation and distribution of the alkaline solution, resulting in higher yield and reduced process time.
Implementation Method 1
Dissolution of cellulose plays an important role in the production of cellulose derivates and blended material
Implementation Method 2
heating the slurry to a temperature of 40-100° C.
Implementation Method 3
dissolving the treated cellulose pulp in an alkaline solution having a temperature within the range of −10° C. to 12° C.
Data Source
AI summary
Disclosed is a method of treating cellulose pulp for use in regeneration of cellulose including the steps of: i) preparing an alkaline metal hydroxide solution having a concentration of 4-10% by weight; ii) adding cellulose pulp to form a slurry; iii) heating the slurry to a temperature of 40-100° C.; and iv) dissolving the treated cellulose pulp in an alkaline solution having a temperature within the range of −10° C. to 12° C.; wherein the percentage by weight is based on the total weight of the slurry.