Patent ID: 8007560

Claim:
A method for alkali soil amelioration by using FGD byproduct (lime or limestone/gypsum process) from thermal power plants and facilities, comprising applying said FGD byproduct from thermal power plants and facilities into the alkali soil to be ameliorated, wherein the amount of the FGD byproduct from thermal power plants and facilities is determined by measuring the contents of CO 3 2− , HCO 3 − , SO 4 2− , Cl − , Ca 2+ , Mg 2+ , K + , and Na + in the alkali soil, and the contents of the exchangeable cations of K, Na, Ca, Mg, to determine the mole amounts of Na 2 CO 3 , NaHCO 3 , Mg(HCO 3 ) 2 , exchangeable sodium ion, and exchangeable magnesium ion per kilograms of the alkali soil; wherein the theoretical application amount of the FGD byproduct from thermal power plants and facilities applied per kilograms of the alkali soil is determined by the following formula (1), M =( 1/2 M 1 +M 2 +M 3 +M 4 +M 5 )× Mn /(C×1000) (1) wherein: M represents the theoretical application amount of the FGD byproduct from thermal power plants and facilities, kilograms; C represents the percent content by weight of the calcium sulfate in the FGD byproduct from thermal power plants and facilities; Mn represents the molecular weight of the calcium sulfate; M 1 represents the molar amount of the exchangeable sodium in the alkali soil, M 2 represents the molar amount of the exchangeable magnesium ion in the alkali soil, M 3 represents the molar amount of Mg(HCO 3 ) 2 in the alkali soil, M 4 represents the molar amount of Na 2 CO 3 in the alkali soil, and M 5 represents the molar amount of NaHCO 3 in the alkali soil, wherein the actual application amount of the FGD byproduct from thermal power plants and facilities is 110% to 150% of the theoretical application amount , and wherein the relationship between the application amount of the FGD byproduct and the alkalization degree of the alkali soil is as follows: the application amount of the FGD byproduct is 18,000-22,500 kilograms per hectare for the alkali soil being slightly alkalized having an alkalization degree of 10 to 20%, the application amount of the FGD byproduct is greater than 22,500 up to 30,000 kilograms per hectare for the alkali soil being moderately alkalized having an alkalization degree of greater than 20 up to 30%, and the application amount of the FGD byproduct is greater than 30,000 up to 75,000 kilograms per hectare for the alkali soil being heavily alkalized having an alkalization degree of above 30%.