A kind of method that rice husk co-produces activated carbon and silicon compound fertilizer

Abstract

The invention discloses a method for co-production of activated carbon and silicon compound fertilizer by using rice hulls. The method comprises the steps of firstly mixing and impregnating the rice hulls and phosphoric acid; carrying out an activating reaction; cooling a product to a room temperature; hydrolyzing at the room temperature to recover phosphoric acid for cyclic utilization; hydrolyzing at a high temperature to recover a silicon-containing acid solution; washing filter residues with water to a neutral state; drying to obtain silicon-containing activated carbon; then mixing the silicon-containing activated carbon with a potassium hydroxide solution; sealing and heating; reacting at a constant temperature with stirring; cooling; filtering; separating filter residues from a silicon-containing alkali solution; washing the filter residues with water to the neutral state; drying to obtain terminal activated carbon containing a small amount of silicon; finally mixing the silicon-containing acid solution and the silicon-containing alkali solution; and adjusting a pH value to 8.5-9.5, thereby obtaining the silicon-containing compound fertilizer. The method takes advantages that phosphoric acid is low in an activating temperature and easy for recovery and potassium hydroxide is high in activity and strong in silicon-dissolving capacity, so that production cost is greatly reduced; product performances are improved and resources are utilized comprehensively. The method has no "three wastes" emission, and is an environment-friendly and clean production process route.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method for co-producing activated carbon and silicon compound fertilizer from rice husks. Background technique [0002] Rice husk is an important renewable biomass material with a wide range of sources and low price. It is of great economic and environmental significance to use rice husk to produce some functional materials. The composition of rice husk can be mainly divided into two parts: one part is a carbon-containing part composed of cellulose, hemicellulose, lignin, etc., and the other part is a silicon-containing part composed of silicon dioxide. There are many reports on the production of activated carbon or nano-silica materials from rice husks. However, the research on co-production of activated carbon and silicon compound fertilizer by using rice husk has not been reported yet. [0003] Activated carbon is an important porous material, which has a wide ra...

AI Technical Summary

Problems solved by technology

However, the development of the silicon fertilizer industry has the following problems: (1) High temperature processing of raw materials to produce silicon fertilizer, high processing temperature, complex production process, high energy consumption, correspondingly increased product costs

(2) directly pulverize slag and compound, the production process is simple, and the cost is low, but there is the shortcoming that effective silicon content is low; Simultaneously slag contains transition metal particles, easily pollutes paddy rice; (3) utilizes chemical synthesis raw materials such as water glass, It has the advantage of high effective silicon content, but it is expensive and difficult to promote

(4) Low production capacity, unable to meet market demand

Although there are many reports about silicon fertilizer in the literature, there is no report on the co-production of liquid silicon compound fertilizer by using the waste water produced in the process of producing activated carbon from rice husk