Electroplating and polishing
Treatment of waste waters containing heavy metals, contaminants or excess turbidity
Removal of metal ions and organic compounds dissolved or suspended in water.
- Clay has been used as a low cost adsorbent to assist with cost effective removal of metals and organic compounds from wastewaters.
- The calcium bentonite clays have a high capacity to bind metal ions dissolved in solution. This adsorption, the binding of chemicals to clay surfaces, is a rapid process and the binding is strong.
- Once these metals are bound to the clay they can be rapidly separated from water by removing the clay.
- The clay can then be flocculated by adding special flocculating chemicals; these cause the clay to form large aggregates that can be easily removed form water.
- Metal ions including copper, zinc, lead, mercury and cadmium bind strongly to the charged surfaces of the clay and can be removed from the water as metal/clay complex.
- Similar process occurs with a range of organic chemicals, which also bind strongly onto the clay surface. These include industrial dyes, solvents, herbicides, pesticides and other toxins.
The process of clay binding to the chemicals and then being separated from water by removing the clay is illustrated below.
See photos, can also have a short video of the dye clay removal process
Treatment of waste waters from mechanical maintenance activities
Removal of suspended and emulsified oils and fats from wastewaters
Waste water from many industries and can contain emulsified or dispersed fats, oils, grease, fuels or other hydrocarbons. These oils and fats need to be removed prior to discharge or reuse of wastewaters. The high-grade calcium bentonite clays have an affinity for fats and hydrocarbons, when fats and oils are bound to the clay they can be rapidly separated from water.
- Clay treatment processes for dispersed or emulsified fats, oils and hydrocarbons utilise the affinity of clays for these oils and fats and modern chemistry and engineering to separate the clay/oil complex from water.
- The clays are processed and refined but are still GRAS status. So where tallow and oil can be reused in stock feeds or other applications, the use of clay and suitable additives means that recovered products will be safe for reuse.
- For other applications where feed grade components are not required different additives can be used.
Photograph oil/water separation, engine oil, black
