News
An effective solution to the water softener hardness
Water hardness refers to the initial calcium and magnesium ions precipitate soap capacity. Total hardness of water refers to water calcium and magnesium ions in the total concentration, including the carbonate hardness (ie by heating can be precipitated as calcium carbonate and magnesium ions, is also known as temporary hardness) and non-carbonate hardness (i.e. not precipitated after heating the part of calcium and magnesium ions, also known as permanent hardness).
Some metal cations in water, together with a number of anions in the water is heated in the process, was concentrated by evaporation, easy to form scale, attached to the heating surface and affecting the thermal conductivity, the water we put the total concentration of these metal ions is called the water hardness.
If the natural water the most common metal ions are calcium ions (Ca2 +) and magnesium (Mg2 +), which with anions such as carbonate ion (CO32-), bicarbonate ion (HCO3-), sulfate ion (SO42 -), chloride (CL-), and nitrate ion (NO3-), etc. combine to form calcium and magnesium carbonates, bicarbonates, sulfates, chlorides and nitrates, such as hardness. In water of iron, manganese, and other metal ions will form Dou hardness, but since they are rarely in natural water content, can be negligible. So it is usually put Ca2 +, Mg2 + concentration as the total water hardness. Water Hardness great impact on the boiler water, therefore, should be based on a variety of different parameters of water quality requirements for boiler water softening or desalination process.
Water hardness and carbonate hardness is divided into two kinds of non-carbonate hardness.
Carbonate hardness: is mainly calcium and magnesium bicarbonate [Ca (HCO3) 2, Mg (HCO3) 2] formed hardness, a small amount of carbonate hardness. After bicarbonate hardness decomposed by heat into a precipitate removed from the water, sometimes referred to as temporary hardness.
Non-carbonate hardness: mainly by magnesium sulfate, chloride and nitrate salts formed hardness. Such hardness can not be removed by heat decomposition, it is also known as permanent hardness, such as CaSO4, MgSO4, CaCL2, MgCL2, Ca (NO3) 2, Mg (NO3) 2 and so on.
Carbonate hardness and non-carbonate hardness and total hardness known; Ca2 + content of the water is called calcium hardness; Mg2 + content in water is called magnesium hardness; when the water total hardness less than the total alkalinity, they are poor, referred to as negative stiffness.
How to test the hardness of water?
In a water sample by adding pH = 10.0 ammonia buffer solution and a little chrome black T indicator solution was red; standard solution titration with EDTA, EDTA first with the free Ca2 + ligand, and then with Mg2 + ligand; in measuring point, EDTA is deprived from MgIn-Mg2 +, so that the free indicator out of solution color from red to blue-, is the end.
When water samples Mg2 + rare, because CaIn-than MgIn-sensitive chromogenic much worse, often not sharp end. In order to improve the sensitivity finish discoloration, EDTA standard solution in an appropriate amount of Mg2 + (EDTA calibration in before adding, so as not to affect the EDTA titration and measured quantitative relationship between ions), or by adding a certain amount of buffer solution The Mg-EDTA salts.
Total hardness of water by EDTA standard solution concentration cEDTA and consumption volume V1 (ml) to calculate. As CaO, in units of mg / L.
Precautions
Determination of total hardness was adjusted with ammonia buffer pH.
Note that adding a masking agent masking interfering ions, masking agents to join in the indicator before.
Determination of total hardness near the end when it drops more slowly shake.
If the water temperature is too low when measured in water samples should be heated to 30 ~ 40 º C and then measured.
America live softener to effectively remove lead and dirt rust stains, reducing calcium and magnesium ions, comprehensive family life with softening; may meet the family bath, laundry, water heaters and other negative providing quality water, reducing the amount of household cleaners and clothing damage, improve water heaters equipment efficiency, excellent cosmetic results.