A method, product and application for preparing modified silica adsorbent by utilizing chlorosilane raffinate

Abstract

The invention discloses a method for preparing a modified silicon dioxide adsorbent from chlorsilane residual liquid. According to the method, a silane coupling agent is dropwise added into the chlorsilane residual liquid; stirring reaction is performed; the pH value of reaction mixed liquid is controlled to be in the range being 2 to 11 by an alkaline solution, so that silicon dioxide generatedthrough hydrolyzing chlorsilane residual liquid is modified into the modified silicon dioxide adsorbent with a hydrophobic function in site by the silane coupling agent. By the preparation process, the characteristic that the chlorsilane residual liquid takes self hydrolysis equilibrium reaction to generate silicon dioxide is skillfully utilized; the in-situ modification reaction of the silane coupling agent on the hydrolyzed silicon dioxide is combined; the hydrolysis equilibrium of the chlorsilane residual liquid is promoted to move in a direction of generating silicon dioxide, so that the chlorsilane residual liquid is fully converted into the modified silicon dioxide adsorbent; all reaction steps are mutually cooperated and promoted; the conversion efficiency of the chlorsilane residual liquid is effectively improved; the low-cost and high-value recovery and utilization on the chlorsilane residual liquid are really realized. In addition, the whole treatment process is simple and efficient; the energy is saved; the environment is protected; the industrial practical values are high.

Description

technical field [0001] The invention relates to the field of preparation of a new type of environmental material and recycling of industrial wastewater, in particular to a method, product and use of a modified silica adsorbent prepared from chlorosilane raffinate produced in the production process of photovoltaic cells. Background technique [0002] With the large-scale development and utilization of green energy and solar energy, the use of polysilicon as raw material for photovoltaic cells is becoming more and more extensive. The total output of polysilicon in China is increasing year by year, but the safety and environmental protection problems of chlorosilane raffinate, a by-product of polysilicon production, are becoming increasingly prominent. At present, most processes of domestic polysilicon production will produce a large number of by-products in the reaction process. Every 1t of polysilicon produced will generate about 10t of chlorosilane raffinate and 1-5t of hydro...

AI Technical Summary

Problems solved by technology

However, the silicon dioxide generated in this process is difficult to use due to its irregular shape and large particles, and it is generally treated as waste in landfill.

Moreover, the silica exchange capacity is small, the lattice defects in the skeleton are few, and it does not have redox property itself, which also limits its application in the field of wastewater adsorption treatment.

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