Pulp whiteness

　The whiteness of pulp is higher, the better whitening effect whitening agent. Only in the high brightness in the use of whitening agent is more economic and reasonable.For example, white pulp in 70% / SO or less, white degree is lower, the worse thewhitening effect. Brightener dosage is same, whiteness value is very small. When thepulp whiteness in the 80%ISO is easily whitening, using 4 ~ 6kg / t paper liquidwhitener NT a 3 NT or 3 B brightness can reach 9o% ~ 95%ISO. If the restriction ofpulping and bleaching conditions of process and equipment, pulp brightness can onlybelow 75%ISO, recommend the use of NT 8, but must make the pH more than 7, in order to have the ideal whitening effect. If the deinking recycled paper, taking part in the wastepaper has used whitening agent, by adding common whitening agent toimprove the whiteness of the paper product is difficult, can try to choose specialwhitening agent F1Nw, because the price is more expensive, the careful selection ofNT 3, a B type is optional products.

Since the agent.

　In the process, some pulp whiteness conditions, amount of oven dry pulp bleaching agent is very important. First, along with the increase of whitening agent dosage,rapidly improve the whiteness, and reached a peak. After the peak with the whitening agent dosage increases, the peak brightness changes very little, or even decline.

When the brightener dosage increased from 0 to 0.4%, the whiteness increased linearly; but when the content was increased from 0.4% to 0.8%, whiteness valueincrease is very small. The whitening agent cost will increase by 1 times! Production of brightening agent dosage reaches 12 ~ 16KG / t paper whiteness, but still little change, this is the truth. More than the peak amount, plus whitening agent, to improve the whiteness of no significance. Of course, in a machine, special paper,special technology condition, how much is the whitening agent reached the peak ofwhiteness, or what would be a reasonable amount of economic whitening agent, thefactory is not the same, to do some research work. We recommend economicamount, NT - 3, NT - 3 B is generally 4 ~ 8kg / t paper, NT 8 is generally 3 ~ 6kg / T paper.

The value of pH and alum dosage

　Generally speaking, the whitening agent in pH7.0 ~ 9, can obtain better whitening effect, especially NT 8, recommend the use of above pH6.5, such as pH value below 6.5, recommend the use of NT 3, NT 8 to two because of a sulfonic acid type,although the whitening strength than NT 3 high, but the acid poor. Add the alum inpapermaking system has a certain impact on the whitening effect, first with the addition of alum, system of pH decreased; the second alum dosage increased,electropositive enhancement, enhanced disturbance of the whitening agent; third is the iron alum contains more, and brightener for patience iron, copper ion.