Date of Award

4-1995

Degree Name

Bachelor of Science

Department

Paper Science and Engineering

Abstract

Recycling of various paper wastes is becoming very popular. These wastes can include newsprint, mixed paper, office paper, and old corrugated container. This thesis experiment evaluated old newspapers. Newspapers contain inks which require mechanical action to break them into particles small enough for flotation or screening deinking. The mechanical action was produced by the Shinhama kneader. The objective of this experiment is to analyze the effect of the Shinhama on ink particle sizes, and fiber degradation. The variables for the operation of the Shinhama included varying the power loading of the machine, and the pH of the stock. The power loadings used were 15 amps and 18 amps, and the pHs were 7.51 and 10.17. Old newspapers were pulped to obtain the ink particles which were evaluated with the image analyzer. This pulp was slurried in the hydrapulper and run through the Shinhama high consistency kneader. Fiber degradation was measured by producing TAPPI beater curves, running Kajaani fiber length analysis, and testing the strength properties of tear, tensile, and zero span tensile, before and after each run through the Shinhama. A pulp sample was obtained and tested every time an operating variable was changed. The following conclusions can be drawn from the analysis of the obtained results: the pH of the stock is irrelevant to the performance of the kneader, the kneader operates best at a medium power loading, the Shinhama is very effective in breaking up ink particles for effective removal with flotation, fiber length reduction through the kneader was 17.1%, at the 7.51 pH level ink particle sizes were reduced 79%, and ink particle sizes were reduced 57.1% for the 10.17 pH level. Based on this experiment, the Shinhama can be effectively used as a new method for deinking waste papers.

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