Method for preparing 4a zeolite for detergent builder from high alumina coal gangue

Abstract

The invention discloses a method for preparing 4A zeolite used for washing assistant by using high-alumina coal gangue. The method is characterized by comprising the following steps: smashing the high-alumina coal gangue, then adding an activating agent for calcinations, then carrying out constant-pressure desilicication separation treatment to obtain a sodium silicate solution and desilicicationcoal ash, carrying out Bayer process treatment on the desilicication coal ash to obtain a sodium aluminate solution, and using the obtained sodium silicate solution and sodium aluminate solution to prepare the 4A zeolite. The method has the advantages that the high-alumina coal gangue is effectively utilized, the resource waste and environmental pollution problems caused by long-term stacking of high-alumina coal gangue are solved, resource utilization is performed on industrial wastes, and the production cost for preparing the 4A zeolite is reduced; only one sintering process is needed, the method is low in energy consumption and low in product cost, the sodium silicate solution is high in modulus and concentration, the production process is easy to control, the product quality is stable,the waste residue is low in yield, and desilicication is thorough; the industrial wastes are used for replacing monohydrallite as a raw material as soon as possible, so that environmental protectionis facilitated.

Description

Technical field: [0001] The invention relates to the field of industrial waste recycling, in particular to a method for preparing 4A zeolite for washing aids from high-alumina coal gangue. Background technique: [0002] 4A zeolite is a multi-purpose product, widely used in construction, chemistry, chemical industry and daily life, but the largest amount of 4A zeolite is used as a detergent builder. Different application fields have different performance requirements for 4A zeolite. For example, the adsorption capacity of 4A zeolite used in the chemical industry is the most important performance index, while the two most important indicators of 4A zeolite used as detergent builders are white Degree and calcium exchange capacity, the whiteness of 4A zeolite for washing is ≥96%, and the whiteness of superior products is >98%. [0003] At present, there are many ways to synthesize 4A zeolite. One is to use industrial pure aluminum hydroxide and liquid sodium hydroxide to rea...

AI Technical Summary

Problems solved by technology

However, the long-term stacking of high-alumina coal gangue will cause the following problems: 1. It will occupy a large amount of land resources, and a large amount of harmful elements will be released during the stacking process, causing environmental pollution, which does not meet the requirements of sustainable industrial development today; 2. High-alumina coal gangue contains a large amount of alumina and silicon oxide. If it is not recycled, the large amount of aluminum and silicon contained in it cannot be effectively utilized, resulting in a waste of resources.

However, the raw material of the Bayer process alumina production and dissolution process must be bauxite. The current bauxite in my country mainly depends on imports, and the cost is relatively high; It exists in the state of humus and asphalt, and the asphalt is insoluble in the alkali solution, and all of it is discharged with the red mud. The humus reacts with the alkali solution to form sodium humate and enters the sodium aluminate solution. The organic matter in the sodium aluminate solution is under the action of air. In the process of continuous oxidation, it gradually decomposes and transforms into a kind of simple organic matter and resinous substances such as sodium oxalate, so that the sodium aluminate solution prepared by the Bayer method presents a deep purple red color and has a low whiteness value. This sodium aluminate solution The whiteness value of the decomposed aluminum hydroxide product is generally around 80% to 90%.

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