A coagulant addition control method for slime water clarification

Abstract

An adding control method for flocculants used for clarifying coal slime water comprises steps as follows: feed of a coal slime water clarifying system is taken for a sedimentation test, and the water quality is adjusted by independently adding or selectively adding sodion, potassium ion, calcium ion and magnesium ion flocculants in a combined manner; and when the coal slime water clarifying effect meets indexes of a certain sedimentation speed, supernatant turbidity and the like, the content of sodions, potassium ions, calcium ions and magnesium ions in the coal slime water is measured, the sum of content of positive ions represents the strength of critical positive ions of the coal slime water, the initial positive ion strength of the feed of the coal slime water clarifying system is measured online, the adding quantity of required positive ions is calculated when the initial positive ion strength is lower than the strength of critical positive ions, and a corresponding quantity of flocculants is accurately added. As for sedimentation clarifying of the coal slime water of a coal preparation plant, accurate and reasonable water quality control indexes are selected, the flocculant adding amount is quantitated, and the clarifying efficiency of the coal slime water of the coal preparation plant is effectively improved. The method is simple and easy to realize, the use amount of flocculants is reduced, and economic and social benefits are remarkable.

Description

technical field [0001] The invention relates to a coagulant addition control method for coal slime water clarification, especially suitable for accurate control of coagulant addition for coal slime water clarification that is difficult to settle in a coal preparation plant, and is also suitable for controlling the amount of coagulant used in the clarification treatment of other mineral processing wastewater . Background technique [0002] Coal sorting is a water-intensive process, and it takes about 3m3 to wash one ton of coal 3 Water, which contains a large number of negatively charged fine particles, has the properties of suspension and colloid. In order to ensure the production of each link of the coal preparation plant and realize the closed cycle of washing water, the slime water needs to be settled and clarified. The traditional method of coal slime water treatment is to use the method of adding coagulant and flocculant to strengthen the settlement of fine particle sl...

AI Technical Summary

Problems solved by technology

However, the selection of calcium hardness and water hardness mainly considers the agglomeration of calcium ions, magnesium ions and the sum of the two in coal slime water to fine particles, ignoring the agglomeration of monovalent ions such as sodium ions and potassium ions in the water body. Sodium and potassium ions also have a certain contribution to the coagulation of fine particles, which cannot be ignored; the conductivity in the water body cannot be directly calculated to control the amount of coagulant added, and various anions and cations in the water body all contribute to the conductivity. The unavoidable ions in L water body are taken as an example. The conductivity contributed by sodium ions is 2.13S / cm, that of potassium ions is 1.84S / cm, that of calcium ions is 2.60S / cm, that of magnesium ions is 3.82S / cm, and that of chloride ions is 2.14S / cm. cm, sulfate is 1.54S / cm, and carbonate is 2.82S / cm. The accuracy of controlling the amount of coagulant added through conductivity still needs to be improved

If the selected water quality index is not accurate enough, the amount of coagulant added is not accurate, and it is easy to use insufficient or excessive amount. If the amount of coagulant is insufficient, it will be difficult to achieve the clarification effect. Excessive coagulant will affect the separation index of the flotation process. High salt ion concentration Even aggravating the electrochemical corrosion of coal preparation equipment will directly affect the economic, environmental and social benefits of the coal preparation plant