Production test of applying starch into the hottes

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Application of starch in recycled pulp production test

key words: paper; Recycled paper; Internal sizing; Starch

at present, the paper produced by our factory has problems such as hair and powder loss, inaccurate overprinting, etc. 90% of the raw materials used are secondary or tertiary fibers. In the process of paper machine forming, if some chemical additives are not added, the products are difficult to meet the requirements of color printing. In view of the following reasons:

(1) our factory does not have the conditions for surface sizing and soft calendering finishing of paper

(2) our factory uses deep underground well water with a water temperature of about 50 ℃, which is very unfavorable for rosin sizing. So far, no rosin sizing and methods suitable for this condition have been found

(3) the wet strength agent must be fully matured before it works, and adding wet strength agent is not suitable for the production conditions of our factory

in this case, it is proposed to choose the sizing agent in starch pulp. First of all, we should know the following information in detail. The laboratory conducted a small test and screened out Tianjin Light Industry Institute starch and Y starch. The suitable addition conditions of auxiliary materials are as follows: the amount of starch is 1%, the amount of talc is not more than 2%, and the amount of aluminum sulfate is 2%. The addition order of starch and aluminum sulfate has little effect on the paper. A pilot test was carried out on the basis of a small test

1 starch preparation and sizing

1.1 starch sizing process (Figure 1 is omitted)

1.2 starch modified raw material ratio (Tianjin Light Institute formula)

100 parts of raw starch

4 ~ 6 parts of anhydrous sodium sulfate

4 ~ 5 parts of sodium hydroxide

8 parts of modifier

a certain amount of water to make its concentration 30%

1.3 sizing process conditions

size ratio: 100% deinked pulp; Rubber: 1% modified starch, adjusted according to the operating conditions; Filler: 2% - 4% aluminum sulfate, root force value display device and record to judge whether the material (or finished product) is qualified and reaches the predetermined performance index. Adjust according to the product quality, 2% talc powder

2 the product quality test results before and after sizing and the use of the CNAs accreditation certificate issued by the National Accreditation Commission for conformity assessment of China, the only and most authoritative laboratory accreditation institution in China, have been obtained by the pilot product shijinmin laboratory.

2.1 the test results of products before and after sizing

Table 1 shows the physical performance indicators of our factory's paper before and after sizing

Table 1 before sizing Post paper index test results

whiteness% smoothness s

forward/reverse fracture length m tear index

Mn · m2/g opacity% wax stick ash% applied and designed to force it to flow through the continuous fiber glue before

51.5 ~ 54.4

52.4 ~ 54.349 ~ 66/45 ~ 61

45 ~ 59/44 ~ 553840 ~ 3930

3545 ~ 39005.11 ~ 5.22


5.01 ~ 5.1194.2 ~ 95.5

94.8 ~ 95.65, 6

5, 63.60 ~ 4.36

4.73 ~ 5.51 note (1) the above data refers to the variation range of 3 days before sizing and the fluctuation range of 5 days for sizing paper

note: (2) the large fluctuation range of the breaking length of sizing paper is caused by the change of raw materials during the pilot test

at the beginning of the test, the raw materials changed to varying degrees every day, the amount of starch added was unstable, and the whole system of the paper machine was unbalanced, resulting in low indicators. Later, all aspects tended to be stable, and the process was fine tuned, and the product quality was gradually improved. The appearance of the sizing paper is good, the difference between two sides is significantly reduced, and the feel is fine and smooth

2.2 white water test before and after sizing

the test results show that the concentration of white water after sizing is significantly reduced, indicating that this starch has a good retention effect

2.3 trial of pilot products

the pilot products after sizing are used centrally on a printing machine in the newspaper printing plant, and a total of more than 80000 copies are printed from the beginning to the end. There is no obvious difference in quality between the first and last prints, and there are no printing obstacles such as broken ends and pleats in the printing operation

2.4 environmental protection detection

it can be seen from the paper making clarifier and the general discharge outlet of the workshop that the suspended solids and COD are significantly reduced after adding glue, and the suspended solids and COD at the outlet of the air flotation tank are also reduced, indicating that adding glue is conducive to wastewater treatment and reduce environmental pollution

3 economic benefit analysis


raw material cost per ton of amphoteric starch: 4517 yuan

8 kg of amphoteric starch per ton of paper, cost: 8 × 4.517=36.136 yuan

starch cost per ton of paper (including water, electricity, steam and labor costs): 12.81 yuan

total cost per ton of paper:

36.136+12.81=48.95 yuan


deinked pulp: 3400 yuan/ton, pulp consumption: 1080 kg/ton of paper

saved pulp: 2.7% (including: ash retention increased by 1.5%, starch retention by 0.6%, fine fiber retention).Increase by 0.6%)

pulp saving per ton of paper:

1080 × 2.7%=29.16 kg

cost reduction per ton of paper:

29.16 × 3.4=99.144 yuan

net increase benefit per ton of paper:

99 95=50.194 yuan

in this test, through continuous adjustment of the process, we finally overcome the production obstacles of gluing wool cloth in the past. After 5 days of continuous test, we produced batch products, which proved that it is feasible to apply starch in the pulp under the production conditions of our factory, and it has better economic and environmental benefits

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