Coagulating agent of plant origin for water treatment

A coagulating agent characterised by a metal-free content and an active material content of 28 to 32% by weight obtained from the polymerisation of an Acacia mearnsii extract, an amino compound and an aldehyde, wherein the addition of Acacia mearnsii extract over the dilution of the amino compound in water is carried out until an Acacia mearnsii extract:amino compound weight ratio that ranges between 3:1 and 2.5:1 is achieved, and where the addition of aldehyde is carried out until an aldehyde:initial amino compound weight ratio that ranges between 1.5:1 and 1:1 is reached, characterized in that the coagulating agent is obtained following the next stages:

• (i) dilution of an amino compound in water at a temperature that ranges between 20° C. and 30° C.;
• (ii) addition of Acacia mearnsii extract until an Acacia mearnsii extract:amino compound weight ratio ranges between 3:1 and 2.5:1;
• (iii) heating of the mixture from stage (ii) to a temperature that ranges between 2° and 40° C.;
• (iv) addition of aldehyde until an aldehyde:initial amino compound weight ratio that ranges between 1.5:1 and 1:1 is achieved;
• (v) stirring of the mixture from stage (iv) at a temperature that ranges between 4° and 50° C. for a period of between 30 and 60 minutes;
• (vi) adjustment of the pH of the previous mixture to values that ranges between 1.5 and 1.7;
• (vii) stirring of the mixture from stage (vi) at a temperature that ranges between 45 and 55° C. for a period of between 50 and 70 minutes;
• and
• (viii) cooling of the mixture from stage (vii) to a temperature of 25 to 40° C.;
• wherein the amino compound is selected from monoethanolamine, methylamine, and dimethylamine, or combinations thereof, and the aldehyde is selected from formaldehyde and acetaldehyde.