Method for modifying sawdust

A sawdust and modified technology, which is applied in the direction of climate sustainability, sustainable waste treatment, solid waste management, etc., can solve the problems that the strength and durability of sawdust cement-based composite materials cannot be improved, and the improvement effect is limited, so as to achieve the promotion of strength The effect of development, acceleration of cement hydration, and improvement of durability

Active Publication Date: 2021-03-19
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] Purpose of the invention: In view of the problem that the existing modified sawdust cannot improve the strength and durability of sawdust cement-based composite materials or the improvement effect is limited, the present invention provides a method for modifying sawdust, which coats calcium silicate hydrate on the surface of sawdust , the modified sawdust can effectively promote the strength development of sawdust cement-based composites and improve their durability

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Examples

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Embodiment 1

[0024] A method for modifying sawdust, comprising the steps of:

[0025] (1) Alkali treatment: Soak 250g of sawdust in 2500g of alkaline silicon source solution for 2 hours to obtain alkali-treated sawdust; wherein, the alkaline silicon source solution is an aqueous solution of sodium metasilicate pentahydrate, and the alkaline silicon source solution contains five The mass concentration of sodium metasilicate in water is 2%, and the temperature of the alkaline silicon source solution is 100°C;

[0026] (2) chemical co-precipitation reaction: while stirring step (1) gained alkali treatment sawdust, add the calcium acetate aqueous solution that molar concentration is 0.5mol / L (calcium ion) wherein, and control the calcium ion in the calcium source and The molar ratio of silicate ions in the alkali solution is 1:1, then continue to stir for 15 minutes, wash again, and vacuum-dry at 60°C to constant weight to obtain calcium silicate hydrate modified sawdust.

Embodiment 2

[0028] A method for modifying sawdust, comprising the steps of:

[0029] (1) Alkali treatment: Soak 250g of sawdust in 1250g of alkaline silicon source solution for 12h to obtain alkali-treated sawdust. The mass concentration of sodium metasilicate in water is 0.5%, and the temperature of the alkaline silicon source solution is 60°C;

[0030] (2) chemical co-precipitation reaction: while stirring step (1) gained alkali-treated sawdust, add the calcium acetate aqueous solution that molar concentration is 0.1mol / L (calcium ion) wherein, and control the calcium ion in the calcium source and The molar ratio of silicate ions in the alkali solution is 2:1, then continue to stir for 15 minutes, wash again, and vacuum-dry at 60°C to constant weight to obtain calcium silicate hydrate modified sawdust.

Embodiment 3

[0032] A method for modifying sawdust, comprising the steps of:

[0033] (1) Alkali treatment: Soak 250g of sawdust in 1800g of alkaline silicon source solution for 6 hours to obtain alkali-treated sawdust. The mass concentration of sodium metasilicate in water is 3%, and the temperature of the alkaline silicon source solution is 40°C;

[0034] (2) chemical co-precipitation reaction: while stirring step (1) gained alkali treatment sawdust, add the calcium acetate aqueous solution that molar concentration is 0.25mol / L (calcium ion) wherein, and control the calcium ion in the calcium source and The molar ratio of silicate ions in the alkali solution is 1.5:1, then continue to stir for 15 minutes, wash again, and vacuum-dry at 60°C to constant weight to obtain calcium silicate hydrate modified sawdust.

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Abstract

The invention discloses a method for modifying sawdust, which comprises the following steps: (1) soaking sawdust in an alkaline silicon source solution to obtain alkali-treated sawdust; and (2) addinga calcium source into the alkali-treated sawdust obtained in the step (1) while stirring, continuing to stir for reaction after the calcium source is added, and then washing and drying to obtain thehydrated calcium silicate modified sawdust. According to the modifying method, the surface of the sawdust is coated with hydrated calcium silicate with an early strength effect, the obtained hydratedcalcium silicate modified sawdust can provide nucleation sites for cement hydration, cement hydration is accelerated, and strength development of a sawdust cement based composite material is promoted;moreover, hydrated calcium silicate coated with the saw dust can reinforce an interface transition region of the saw dust and a cement matrix, so that the corrosion of an alkaline solution in the cement matrix to the saw dust is reduced while the strength of the saw dust cement based composite material is improved, and the durability of the saw dust cement based composite material is improved.

Description

technical field [0001] The invention relates to a method for modifying sawdust, which belongs to the technical field of building materials. Background technique [0002] As a common industrial by-product, sawdust is cheap and easy to obtain. It can be used in the technical field of building material production to improve the performance of the building material and reduce the production cost of the building material. For example, sawdust can be used in cement-based composite materials to reduce the weight of cement-based composite materials and improve the thermal insulation, sound absorption and sound insulation properties of cement-based composite materials. [0003] However, the main components of sawdust are cellulose, hemicellulose, lignin, and a small amount of fat, wax and other substances. These substances are easily degraded in alkaline solution. Ning and other substances will seriously hinder the hydration of cement, thereby delaying the strength development of c...

Claims

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Application Information

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IPC IPC(8): C04B20/10C04B18/26C04B20/02
CPCC04B20/1074C04B18/26C04B20/023Y02W30/91
Inventor 潘钢华周飞飞
Owner SOUTHEAST UNIV
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