JPS5836290A - Modification of regenerated pulp for filling cement from urban garbage - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the quality characteristics of recycled municipal waste pulp products used as cement fillers. That is, the present invention is based on the previously applied method (Japanese Patent Application No.
118269) and relates to recycled pulp which provides pulp cement boards with further improved qualities.

The amount of municipal waste discharged continues to increase year by year, and while the same level of disposal has been proposed, the development of municipal waste recycling technology as a resource-saving technology is an old-fashioned issue. In view of this, the present inventors conducted extensive research and devised a method for producing recycled pulp suitable for producing pulp cement boards using a relatively simple method. That is, paper-based separation groups obtained by sorting municipal waste using, for example, a semi-wet sorting device are disintegrated using a pulper, and relatively large residual mixed materials are removed from the resulting pulp slurry. After going through a rough sorting process, the remaining pulp is concentrated to obtain recycled pulp.

The present invention uses recycled pulp from this process and has improved its quality, more specifically, it is satisfied with its high strength, but by washing the pulp with simple chemicals, We have discovered that the dark affinity between cement and pulp can be improved beautifully.

In other words, recycled pulp separated from municipal waste has a relatively high zeta potential, with normal pulp having a zeta potential of -80 to -20 mV.
Although it can be seen from the level, this is about -10 mV, which means that the monodispersity is slightly lower than that of ordinary pulp, making it less likely to form flocs, and that it has a slightly lower affinity with cationic cement components. I understand. Therefore, various methods have been tried to negatively charge the recycled pulp, and as an economically advantageous method, washing with a caustic alkaline solution or treating with an oxidizing chlorine compound has been found.
It is our wish that the properties and therefore the strength properties of the pulp cement board obtained are significantly improved.

Here, the caustic alkaline solution is an aqueous solution of an alkali metal hydroxide or an alkaline earth metal hydroxide. Generally, a caustic soda aqueous solution is used from an economic point of view. The amount of caustic used ranges from 0.1% to 20% by weight relative to the regeneration valve, especially for I
The chlorine compound having an oxidizing effect, which preferably has a N content of 10%, includes chlorine, chlorine dioxide, hypochlorite, and the like. Similarly to the case of caustic alkali, the weight ratio is in the range of 0.1 to 20%, particularly preferably in the range of 0.1 to 10%, based on the weight of the regenerated bulb. Although the temperature during the treatment is above normal, there is no need to perform the treatment under particular heating conditions. There is no problem even if the treatment of both compounds is used in combination.The regenerated valve subjected to such treatment can be used after being washed with water, or it can be thoroughly dehydrated and filled into cement as it is. By this treatment, the zeta potential of the regenerated bulb is reduced to the level of a normal bulb, and not only the dispersibility is improved, but also the cement affinity is improved. Therefore, the strength of the obtained pulp cement board is improved.

Examples will be described below, but the present invention is not limited thereto.

Implementation H1 Municipal waste (Kanazawa area, Yokohama City) was separated using a semi-wet selective crushing sorter, and the paper-containing extract was fed into a pulper to disintegrate the paper, and the resulting pulp slurry was A regenerated valve was manufactured by using a stage vibrating screen, a vertical shaper, a pressure screen, and then a heat exchanger machine to remove coarse foreign matter. This is a liquid containing about 2,696 recycled nozzles, and as components other than recycled pulp, it contains fine particles that are large enough to pass through a Sa & screen made of a perforated plate with numerous small holes with a pore diameter of 8. ,
In addition, the pulp and appearance contained about 1.2% of screen residue of 0.2%, such as plastics with similar specific gravity, Ai, Fiber #III, and aluminum foil. A 10% caustic soda solution was added to the water suspension (8% once in the valve) of this regeneration valve. The amount of caustic soda added to pulp is 1%
Met. This material was stirred at room temperature for 80 minutes, dehydrated, and washed with water. The concentration of the resulting mixture of 18% by weight of the caustic soda-treated recycled pulp, 52% by weight of ordinary Portland cement, 6% by weight of chrysotile stone wire, and 80% by weight of serpentinite powder was approximately 20%. Add water so that the water becomes uniform, mix uniformly in a disintegrator (101 volumes), and transfer the resulting suspension to a square sheet machine (26x25c).
After forming it into a plate shape using IL), it was further pressurized and dehydrated using a hydraulic hand press until the bulk specific gravity reached 1.1 sickles. The strength of the recycled municipal waste pulp reinforced with caustic soda treatment obtained in this way was s 180 "I / cd. Similarly,
Although it was not treated at all, it was 994/c11.

Example 2 According to Example 1, a sodium hypochlorite aqueous solution was used instead of caustic soda. In other words, the water suspension of the regeneration valve (
A hypochlorous acid solution with an available chlorine content of 1096 was added (once the bulb was 8%). At this time, the amount of available chlorine added to the regeneration valve was 1%. After stirring the kernels for 80 minutes, they were centrifugally dehydrated to a moisture content of 7G%.

The thus obtained sodium hypochlorite-treated regenerated pulp was uniformly mixed in a disintegrator (1ON8) with the formulation shown in Example 1.
m 8! Water was added thereto so that each sample of this suspension solution had a volume of 896, and the mixture was stirred for 80 minutes as long as the sample did not settle. This suspension was molded into a square sheet machine and pressed into a plate in the same manner as in Example 1. The thus obtained municipal waste recycling valve reinforced cement was heated at room temperature for 21 days (
After curing at 25±2° C.), the product was dried with hot air in the same manner as in Example 1. Bending strength of the object (distance between fulcrums,
The test piece width was the same as in Example 1) and was 199 QAi. Similarly, the sample not treated at all was 1204/d.

Claims (1)

[Claims] A method for reforming paper-containing extracts obtained by sorting municipal waste.