CS232802B1 - Waste disposal method using cementation powder - Google Patents

Abstract

The purpose of the invention is to solve the problem of disposal of waste cement powders from engineering operations by using them in the production of barium salts. The stated purpose is achieved by treating the waste with a mixture of barite and coke at a temperature of 1150 to 1350 CC for 2 to 4 hours, the waste constituting a maximum of 12% by weight, based on barite. The reaction mixture is then treated with an appropriate acid to obtain a barium salt solution, which is separated from the insoluble residue.

Description

The present invention relates to a novel process for the disposal of waste after the use of cementing powders containing toxic barium carbonate by utilizing said waste in the production of barium salts.

Up to now, the waste has been disposed of after the use of cementing powders by converting barium carbonate with hydrochloric acid to barium chloride and its detoxification with sulfuric acid to non-toxic barium sulfate. The disadvantages of this method are the demands on safety of work (work with acids) and highly corrosive environment; the procedure is imperfect, since the amount of free acid that remains in the waste must be neutralized before being transported to the landfill.

Furthermore, it has been proposed to sterilize said ¹ waste with soluble waste sulphates. The disadvantage of this method is the need for chemicals, manpower and landfill.

Finally, according to MS. U.S. Patent No. 193,756 converts barium carbonate to hydrochloric acid into barium chloride and green vitriol to nontoxic barium sulphate. After alkalization and concentration with a combustible substance, the mixture is added to the combustion system. The advantage of this process is that no landfill is required; its disadvantage is the demand for chemicals, manpower and fuel system load.

The above drawbacks are overcome by the proposed process according to the invention, which is based on the disposal of waste in the production of barium salts. The waste is added to the mixture of barite and coke in an amount of max. 12% by weight, based on barite. At the same time, the required amount of coke is reduced. The newly formed batch is subjected to a rotary kiln temperature of 1150 to 1350 ° C for 2 to 4 hours. A melt of barium sulfide, barium carbonate and ash is formed. The melt is further reacted with water according to the equation

BaS + 2 H 2 O = Ba (OH) ₂ + BafSH 3.

Barium compounds which do not dissolve in water or only partially, such as barium carbonate obtained from waste, are converted into solution by reaction with hydrochloric acid. The resulting barium bisulfide and barium chloride intermediates are used to produce barium salts. The remaining sludge is deposited in a landfill site after detoxification.

The proposed procedure destroys waste without the need for labor, chemicals, process equipment and landfill. At the same time, it increases the amount of barium salts produced while saving coke.

Example

The plant produces 10 tons of waste per year. The waste is gradually stored so that it is not mixed with other materials and is transported to the processor after the transport volume has accumulated. In the classic production of barium salts, the processor proceeds as follows: the charge is 4 parts barite and 1 part coke. 4 parts of barium salts are available for further production, i.e. 100% barite and 25% coke were used per unit amount. A batch of 80 parts barite, 15 parts coke and 10 parts waste was used in the process of the invention. 81 parts of barium salts were formed, i.e. 98.77 percent barite and 18.52% coke were used per unit amount of usable barium salt produced. The raw material intensity of barite decreased by 1.23 ° / o and coke by 6.48 ° / o. The effect of adding waste to the raw materials resulted in an increase in the yield of soluble barium acids by 1.23%.

The invention can be used in any plant producing cementitious powders on the one hand and barium salt manufacturers on the other.

Claims (1)

subject in Waste disposal method after use of a cementing powder, characterized in that the waste is treated with a mixture of barite and coke at a temperature of 1150 to 1350 ° C for 2 to 4 hours, the waste being at most 12 ° / o Y N A L E Z The weight, based on barite and the reaction mixture, is then treated with the appropriate acid to obtain a barium salt solution which is separated from the undissolved residue.