The invention relates to a method for preparing
potassium fluoborate with the co-product of white
carbon black and
sodium fluosilicate, which takes hydrofluosilicic acid,
boric acid, industrial salt and
potassium chloride as main raw materials and particularly comprises the steps as follows: (1) the hydrofluosilicic acid is firstly added into a leaching tank which is then preheated to 60 DEG C to 100 DEG C and then opened for carrying out stirring, theoretical quantity of
boric acid is added into the hydrofluosilicic acid, then the leaching tank is obturated and reaction is carried out continuously for 2.0 hours to 6.0 hours, and leaching is carried out at the constant temperature of 60 DEG C to 100 DEC G; (2) qualified
fluoboric acid solution after being leached is filtered, the white
carbon black is dried after progressive concentration and washing by levels of water to produce the white
carbon black; (3) the filtrate obtained and a first
lotion are added with the industrial salt for purifying and disiliconization, then theoretical quantity of industrial salt is added for carrying out reaction for 10 minutes to 30 minutes to prepare
sodium fluosilicate
slurry; (4) the
sodium fluosilicate
slurry prepared is filtered, washed and dried to obtain
sodium fluosilicate products, and the filtrate obtained is used for synthetizing the
potassium fluoborate; (5) theoretical quantity of potassium
chloride is added into the filtrate obtained in step (4) for carrying out reaction for 10 minutes to 30 minutes; (6) after the reaction in step (5) completes,
filtration is carried out, an ointment is washed by primary water and dried to obtain the potassium fluoborate.