The preparation technology of precipitated silica (whose main component is silicon dioxide) is currently undergoing a critical transformation from "traditional and extensive" to "green, high-end, and refined." Based on the information I have reviewed, the current advancements in preparation technology mainly focus on three aspects: innovation in raw material sources, greening of the process, and purification and modification of high-end products.
The following is a detailed explanation of the advancements in precipitated silica preparation technology:
1. Breakthroughs in Raw Materials: From Ore to Biomass and Waste
Traditional precipitated silica is mainly produced by the reaction of water glass (sodium silicate) with acid, but current technologies are actively exploring more environmentally friendly and cost-effective silicon sources.
Biomass Method (Rice Husk Utilization):
This is a very promising technological path. It utilizes agricultural waste such as rice husks as a silicon source, preparing precipitated silica through steps such as carbonization and alkali dissolution. For example, Quecheng Co., Ltd. and the China Petroleum & Petrochemical Research Institute have developed relevant technologies.
Advantages: This method does not require the high-temperature melting of ore at 1500℃ used in traditional processes, significantly reducing energy consumption. Rice husks also produce steam as a byproduct during the conversion process, not only achieving resource utilization of waste but also significantly reducing the carbon footprint.
Industrial Waste Resource Utilization:
Utilizing fluorosilicic acid or fluorosilicate slag, byproducts of the fluorochemical industry, to prepare precipitated silica.
Advantages: This transforms fluorosilicate slag, which was originally solid waste or even hazardous material, into high-purity precipitated silica (with a specific surface area exceeding 300 m²/g), achieving "waste treatment with waste," and the process is simple and suitable for industrial production.

2. Greening and Intelligentization of the Process
To cope with increasingly stringent environmental policies (such as stricter wastewater COD emission limits), the production process is undergoing technological innovation.
MVR Evaporation Crystallization Technology:
In precipitated silica production, wastewater treatment is crucial. MVR (Mechanical Vapor Recompression) technology is becoming mainstream. It compresses and heats the steam in the wastewater for recycling, achieving zero wastewater discharge or a high recycling rate, and significantly reducing energy consumption.
Continuous Reaction Replacing Batch Production:
Traditional enterprises mostly use batch reactors, leading to large fluctuations in product batches. The current technological trend is towards the transformation to continuous and intelligent production lines.
Effect: Continuous reactions allow for more precise control of reaction conditions (such as pH and temperature), resulting in a more uniform particle size distribution of precipitated silica, better consistency in specific surface area, and more stable product performance.
Low Acid Consumption Process:
By optimizing the reaction pathway, the consumption of inorganic acids such as sulfuric acid is reduced (for example, from 1.35 tons/ton of product to 1.12 tons), thereby reducing the discharge of acidic wastewater.

3. High-End and Functional Preparation Technologies
With the growing demand from new energy vehicles and high-end manufacturing, ordinary precipitated silica can no longer meet market needs, and preparation technology is developing towards "high dispersion," "anti-yellowing," and "surface modification."
Wet Modification Technology (In-situ Modification):
This is key to increasing the added value of precipitated silica. In an aqueous suspension system, the surface properties are controlled by the reaction of the modifying agent with the hydroxyl groups on the surface of the precipitated silica.
Application: For example, in-situ modification using silane coupling agents or bio-based modifiers (such as polyethylene glycol) can significantly reduce the rolling resistance of tires, meeting the requirements of "green tires."
High Anti-Yellowing Technology:
To address the problem of high impurity content of iron and manganese in precipitated silica, a new impurity removal process has been developed. By adding a composite iron removal agent (such as sodium dithionite and EDTA) during the reaction stage, the insoluble trivalent iron is reduced and complexed, allowing it to be removed during the washing stage, thus solving the problem of easy yellowing of silicone rubber products.
Nanocomposite Structure Design:
Using a special preparation process, precipitated silica is combined with carbon materials to form a nano-silicon/carbon homogeneous structure. This material shows great potential in the field of lithium-ion battery silicon-carbon anodes (high initial Coulombic efficiency and long cycle life).