High-pressure microwave digested quartz sand and method for preparing nano-amorphous silicon oxide

Abstract

The invention discloses high-pressure microwave digested quartz sand and a method for preparing nano-amorphous silicon oxide and relates to the technical field of treatment of the quartz sand. The method comprises comprehensive application of three technical measures of a high-pressure microwave hydrothermal technique, an effective liquid-phase forced mixing technique and a full-sealed material circulating technology, embodies field strengthening technical features of enhanced chemical reaction of a high-pressure microwave field and a high-pressure high-frequency impact flow field and green technical features of material cyclic utilization, and is an innovation of a wet process different from the traditional amorphous silicon oxide production technology. The method can be continuously operated, also can be intermittently operated, is short in process cycle, low in energy consumption, low in cost and high in additional value of a product, and is an optimal utilization approach with high efficiency and low consumption of wet process quartz sand tailings resources.

Description

technical field [0001] The invention relates to the technical field of quartz stone tailing treatment, in particular to a method for digesting quartz stone tailings with high-pressure microwaves and preparing nanometer amorphous silicon oxide. Background technique [0002] Quartz tailings are crystalline quartz with a crushed particle size of less than 0.125mm, SiO 2 The content is generally between 90% and 99%, and the impurity component is Al 2 o 3 and Fe 2 o 3 Mainly. In the glass industry, quartz sand with a particle size of less than 0.125 mm will corrode the refractory material after being put into the furnace, reduce the life of the furnace, affect the uniformity of the batch material, and also cause factors that are not conducive to glass production such as blocking the channel of the checker brick. Therefore, a large amount of quartz sand ≤ 0.125mm produced by quartz sand production enterprises cannot be used as raw materials for glass production, and is direct...

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Problems solved by technology

[0012] 1) It is difficult to control the microscopic mixing of materials during the reaction process. Stirring cannot provide the uniform reaction environment required for the precipitation reaction in a short time, and it is easy to cause local early nucleation, resulting in heterogeneous nucleation in the system, and the formation of amorphous silicon oxide. The particle size is difficult to reach the nanometer level, and the particle size distribution becomes wider;

[0013] 2) Inhomogeneous temperature distribution in the system caused by exothermic reaction and uneven convective heat transfer, which makes grain growth difficult to control and ultimately leads to poor reproducibility between product batches;

[0014] 3) With the discharge of waste gas and waste water, part of the heat energy cannot be used rationally, which is not conducive to energy saving and environmental protection;

[0015] 4) The cost of waste recycling and reuse is high, especially the sulfuric acid process with sodium silicate as raw material commonly used in China, which produces a large amount of sodium sulfate acidic wastewater

[0016] To sum up, the traditional method of preparing amorphous silicon oxide from crystalline quartz stone has many shortcomings such as long process flow, low conversion rate, high energy consumption, and easy to produce three wastes, etc., and the industrial production cost is too high

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