Waste newsprint enzymatic deinking (medium)

2 Results and discussion 2.1 Enzymatic deinking laboratory results Before the industrial production test, the enzymatic deinking experiment was first carried out using the solid cellulase-produced bulk cellulase preparation. Enzymatic deinking conditions were: 45°C, pH 5.0, 0.4 IU/g, deinking agent 0.5%, 30 min. H2O2 bleaching conditions: Na2SiO35%, NaOH 1.5%, H2O21.5%, 70°C, 30 min.
Figure 1 is a comparison of the whiteness of the enzyme-treated deinked pulp after bleaching with H2O2.

Fig.1 Comparison of brightness of enzymatic deinked pulp after bleaching with H2O2 and corresponding control pulp

It can be seen that the whiteness of the enzymatic deinked pulp can be increased by 2% to 5% compared to the control pulp, which verifies the deinking effect of the previously prepared cellulase preparation in the laboratory.
On this basis, a 100% enzymatic deinking paste was used on the dynamic former to make high-quality newsprint at a speed of 1100 m/min. And compared with newsprint paper made from chemical deinked pulp under the same conditions. The performance indicators are shown in Table 1.
It can be seen from the table that the optical and physical properties of the enzymatic deinking newsprint exceed the national newsprint standards such as B. At the same H2O2 dosage, the whiteness of the enzymatic deinked pulp was 7.0% higher than that of the chemical deinked pulp. At the same beating degree, the split length of deinked pulp is similar, but the tearing index of enzymatic mechanical deinking pulp is slightly lower.
2.2 Enzymatic deinking of industrial production tests Based on the above experiments, an enzymatic deinking production test was conducted on a waste paper deinking line. And on the 1760mm paper machine successfully made qualified newsprint.
The following figure shows the equipment flow for this production test.
Equipment flow of enzymatic deinking industrial production test (to be continued)