Process and equipment for recycling filter pressing waste water in production of nano activated calcium carbonate

Abstract

The invention discloses a process and equipment for recycling filter pressing waste water in production of nano activated calcium carbonate. The process and the equipment provided by the invention are capable of completely purifying filter pressing waste water in production of nano activated calcium carbonate so that the filter pressing waste water can be up to the standard of water used for the production of nano activated calcium carbonate; and therefore, recycling is realized. The process provided by the invention comprises the following steps of: slowly adding an organic flocculant to a burdening tank with clear water and stirring quickly to obtain an emulsion solution; diluting the obtained emulsion solution by using water until the concentration of the solution is 0.1-0.5%; activating carbonate sinter in an activation tank in the activation process of nano activated calcium carbonate, then introducing the diluted solution into the activation tank and then continuously and quickly stirring for 10-15 min; carrying out diaphragm filter pressing on the slurry which is quickly stirred for 10-15min; discharging filtrate into a production settling basin; adding an inorganic regulator to regulate the pH to 7-9; cyclically using the overflowing clear water in the production of nano activated calcium carbonate; and simultaneously, generating a little precipitate.

Description

technical field [0001] The invention relates to the industrial production and preparation of nano active calcium carbonate in the field of inorganic powder preparation. Background technique [0002] At present, most nano-calcium carbonate and light calcium carbonate production enterprises use groundwater, and almost all of the discharged wastewater is absorbed by the surface, directly polluting groundwater, forming a vicious circle; and the existing production still has a large amount of supplementary water (especially for digestion Water use), low recycling rate and other issues, have an adverse impact on the production operation and production costs of enterprises. According to statistics, the average water consumption of 60 nanometer and light calcium carbonate enterprises in 2007 was more than 10 tons per ton of calcium carbonate products. The water consumption is reduced to about half (5 tons). [0003] There are two main reasons why the filter press wastewater in the...

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Problems solved by technology

[0003] There are two main reasons why the filter press wastewater in the production of nano-calcium carbonate cannot be directly re-used in the production process. The filtrate of ultra-fine particles cannot be directly used in the front-end production; the second is that the water-soluble agents such as bleaching agent, crystal form directing agent and surface treatment agent added to the calcium hydroxide fine slurry will eventually enter the filtrate. If the filtrate does not remove impurities and Ions that are harmful to production will affect the crystal form and product quality of nano-calcium carbonate, so it cannot be used in the digestion section with the most water consumption (accounting for more than 90% of the total water consumption)

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