Recovering process for white water of paper making by stewing type precipitation method

Abstract

The invention discloses a technique for recycling paper-making white water by adopting a keeping-stand type precipitation method. The white water generated in the paper-making process is introduced into one or more than one sedimentation tank to keep stand to the extent that the turbidity degree of a clear solution is less than 40ppm, the clear solution can be educed to use, and the deposited matter is collected. The technique has the advantages that: 1. the investment is less than that of the familiar method; 2. the water is recycled in the paper-making process; moreover, the clear solution can be taken as the water for washing a mesh and a blanket because the clear solution can satisfy the high requirement of water in the paper-making process, the water consumption per ton of paper is reduced to less than 2 tons from 135 tons; 3. the raw materials such as fine fibers filtered in the paper-making process is recycled and is not discharged, the grout consumption per ton of paper is reduced to 1.04 tons from 1.12 tons, thereby realizing the zero emission and the clean production in the production process.

Description

technical field [0001] The invention relates to a recycling process of industrial waste water, in particular to a process for treating white water in papermaking industry. Background technique [0002] At present, the known papermaking industry mainly treats papermaking white water by air flotation, and also uses sedimentation to treat white water, but it is a flow type. The former is to use air bubbles to adhere to the suspended solids in the liquid, making them float to the liquid surface and then discharged to achieve the purpose of solid-liquid separation; the latter is to separate solid substances from the liquid according to the principle of gravity (see "Paper Machine White Water Recovery Technology" ). These two methods have problems such as large investment, many influencing factors, and difficult control. For example, the quality of dissolved air water by air flotation method is affected by the preparation method of dissolved air water; the pressure and temperatu...

AI Technical Summary

Problems solved by technology

That is to say, a slight change in the water flow speed will affect the sedimentation effect, and the separation of the sediment is carried out under dynamic conditions while the sedimentation is in progress, so it is easy to affect the water flow speed and the balance of the system

Moreover, the concentration of the sediment (mainly fine fibers) separated by this method varies greatly, which also has a certain impact on recycling.

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