Questions about the moisture content of electroplating sludge after filtration?

Sludge generally includes adsorbed water, interstitial water, capillary water, and internal water. Generally speaking, in addition to selecting an appropriate dewatering process, sludge also needs to be pre-treated before dewatering. Since I am not aware of the specific conditions of sludge in this industry, I can only give general suggestions. I’m not sure whether your company employs methods such as concentration or chemical treatment; however, in my opinion, a moisture content of 70% is quite good. Hehe, just my humble opinion! ! !

The forms of water present in sludge include interstitial water and free water within the particle gaps; about 70% of this water can be separated through gravitational sedimentation (concentration and compaction)； Capillary water is the water surrounding highly dense fine sludge particles; it is formed due to capillary action and accounts for about 20%. This water can be separated by applying external forces such as centrifugal force or negative pressure, which break down the effects of surface tension and cohesion at the capillary surfaces ； There is water adsorbed on the particle surface and bound within it, accounting for about 10%. Surface adsorbed water is the moisture attached to the surface of sludge particles; it has a strong adhesive effect and is commonly found on the surfaces of colloidal particles, biological sludge, and other solids. Coagulation methods are used to cause these colloidal particles to flocculate together, thereby removing the water adhering to their surfaces ； Internal bound water is the water bound within sludge particles, such as the water inside cells in biological sludge, or the crystalline water associated with metal compounds in inorganic sludge; it can be removed through biological separation or thermal methods. Generally, when the moisture content is above 85%, the sludge is in a fluid state ； It is in a plastic state when it is between 65% and 85% ； It is in a solid state when below 60%. Under normal circumstances, the moisture content of sludge after dewatering is around 75%; a moisture content of 70% in your case is already quite good.

The crystal water carried by metal compounds in inorganic sludge might be the cause of this problem

Due to the presence of pore water, capillary water, bound water, etc., the moisture content of sludge in plate and frame filtration is generally between 70% and 80%; achieving 70% is already quite good. Only new filter fabrics can achieve such a level, and after being used for some time, the moisture content may be even higher.