Pilot Deinking Treatment of Mixed Office Waste Using a Standpipe Flotation Facility

廢紙回收項目中混合辦公室廢紙因脫墨較為困難，一般利用率偏低。本研究結合離心淨漿、大氣泡與微氣泡（溶氣浮選）功能以及先驅廠規模之特點，設計立管式脫墨浮選槽，進行混合辦公室廢紙之脫墨等試驗。廢紙於實驗室先行燒杯規模之脫墨試驗，第一階段僅添加傳統脫墨劑，未使用十八醇與酵素等製劑。結果顯示廢紙抄製手抄紙之污點面積近4000平方公厘m^(-2)；脫墨處理可降低污點數至760平方公厘m^(-2)以下，最佳總脫墨效率為93%；舊報紙的脫墨則甚為潔淨，無顯著墨斑殘留。回收混合辦公廢紙於散漿後調整濃度以立管式浮選脫墨處理施以兩種循環速率及兩種氣泡之空氣流量。結果顯示未浮選漿之墨斑面積為2377平方公厘m^(-2)。水力停留時間相當循環三次後之手抄紙墨斑面積則減為79平方公厘m^(-2)以下，最佳者僅28平方公厘m^(-2)，相當於98.8%之總脫墨效率；正式試驗採不同批混合辦公廢紙進行2^4階乘散漿試驗後立管浮選脫墨。未處理漿約含10,800平方公厘m^(-2)墨點；浮選後最佳結果僅含251平方公厘m^(-2)之墨點，相當於97.7%之總脫墨效率；散漿溫度與濃度為主要影響效應。本法實用化之前景大有可為。

關鍵字

浮選脫墨；混合辦公室廢紙；立管；污點數；脫墨率

並列摘要

Mixed office waste (MOW) is one of the least effectively recycled items among recyclable paper products due to difficulty in deinking laser-printed and xerographic paper, and the mixing of white and colored sheets. We combined the effects of centri-cleaning, and macro- and micro-air bubble flotation (DAF) capabilities and built a pilot-scale standpipe-type treatment unit to conduct deinking tests. Wastepaper was first deinked in our lab using a blender for disintegration and then bubble aeration for flotation in beakers. The results indicated that without treatment, hand sheets of recycled MOW had a speck area of ca. 4000mm^2 m^(-2), while with the addition of only commonly used deinking chemicals, the ink speck could be reduced to less than 760mm^2 m^(-2); the best result achieved was a 93% overall removal rate. In the preliminary pilot-scale deinking test, the deinking chemicals were added during repulping of the MOW wastepaper. After consistency adjustment, the ensuing flotation deinking was carried out using a standpipe unit. The results after a hydraulic retention time equivalent to 3 recirculations reduced the ink speck area from 2377mm^2 m^(-2)to＜79mm^2 m^(-2) with the best result being 28mm^2 m^(-2); an overall removal rate of 98.8% was achieved. In the formal test series, the MOW was first disintegrated using a high-consistency pulper at 2 levelseach of consistency, temperature, NaOH, and surfactant dosages. Then after dilution, each treated batch was deinked in the standpipe flotation unit using the optimal pulp flow and aeration rates for a treatment time equivalent to 3 recirculations. Handsheets from untreated wastepaper contained ca.10,800mm^2 m^(-2) ink specks, and after flotation treatment, the speck count was markedly reduced, with the best result of only 252 mm^2 m^(-2) which equals an overall deinking efficiency of 97.7%. The temperature and consistency during repulping were shown to be the most influential operational parameters. Practical application of this deinking technology to the production line appeared very promising.

並列關鍵字

flotation deinking ； mixed office waste paper MOW ； standpipe ； dirt count ； deinking rate

國際替代計量

Pilot Deinking Treatment of Mixed Office Waste Using a Standpipe Flotation Facility

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