CS253478B1 - Method of heavy metals removal and radioactive liquid wastes desactivaction - Google Patents

Abstract

Method of removing heavy metals and deactivating radioactive liquid wastes, for example wastewater, solutions and uranium industry, cleaning and neutralization, the essence of which lies in that it is added to the liquid waste carbide lime with concentration - active calcium oxide 0.1 to 30 wt% in quantities of 0.001 to 500 kg per m of liquid recovery. The solid phase formed was formed separated from the liquid phase by conventional Approaches.

Description

The present invention relates to a process for the removal and purification and neutralization of heavy metals and the removal of radioactive liquid wastes such as waste waters, solutions and suspensions of the uranium industry.

Lime is often used to neutralize and purify wastewater, solutions and suspensions of the uranium industry, in particular mine waters, acidic saline solutions that are lost during underground leaching of uranium ores and precipitated scrap. In addition, these lime must be quenched prior to use and converted to calcium hydroxide, which is the chemical's own purifying and neutralizing agent. The ballast substances contained in the lime grades of the lower quality classes make it difficult to extinguish and dispense into the purified water, solutions or suspensions, and in addition increase the amount of sludge produced by these processes. Waste water, uranium industry solutions and suspensions contain, in addition to heavy metals, a number of radionuclides, to which calcium hydroxide, prepared conventionally from conventional lime, is ineffective in most cases in purification or neutralization.

In the production of acetylene, large amounts of so-called carbide lime are generally omitted, for which use has not yet been found, in particular for the content of coke, carbon black, ferrosilicon, acetylene and some other substances. Carbide lime, which is lost during the production of acetylene, is usually deposited in sludges and thus significantly reduces the environmental value.

The above mentioned drawbacks are largely eliminated by the process for removing heavy metals and radioactive liquid waste in accordance with the invention, which comprises adding to the liquid waste carbide lime having an active calcium oxide concentration of 0.1 to 30% by weight in an amount of 0.001 to 30% by weight.

253 478

- 2 500 kg per n? liquid waste. The resulting solid phase is separated from the liquid phase by conventional methods.

Using carbide lime to remove heavy metals and

Desactivation in wastewater treatment, uranium industry solutions and suspensions by the method of the present invention can fully replace commonly used lime, while carbide lime has numerous advantages over them, such as higher reactivity, more favorable granulometric composition, higher quality of calcium oxide and oxide content. magnesium, which is at the level of lime of higher quality classes, which is not available in large quantities. «

It is also advantageous that adsorption of radionuclides occurs on the carbon black and coke present in carbide lime and at the same time the heavy metal content of the treated waters and solutions is significantly reduced due to the small amounts of sulfides, arsine and phosphine. eliminates bivalent form in the precipitation and neutralization of uranium wastewater, solutions and suspensions, resulting in a higher quality of purified waters and solutions, a reduction in the specific consumption of calcium oxide for purification and neutralization, and smaller sludge volumes with a higher dry matter content.

The carbide lime discharged in the production of acetylene has approximately the following composition, which is expressed in% by weight on a dry weight basis.

Ca (OH) ₂ + Mg (OH) ₂ CaCO ₃ + MgCO ₃ 80 - 85% Si0 ₂ up to 2% especially A1 ₂ O ₃ and Pe ₂ 0 ₃ up to 2% sulfides up to 0,3% coke and ferrosilicium up to 0,5% insoluble in HCl up to 1,5%

The dry matter content of the carbide lime slurry varies from 10 to 55% by weight, depending on the process for producing acetylene and the method and time of depositing the carbide lime in the sludges.

The carbide lime dry matter contains the following organic substances in an amount by weight:

extractable by carbon tetrachloride up to 5.10 “^%

253 478 oil content up to 3 · 10 ”^% arsenic and phosphine traces

Example

In the precipitation of acidic saline solutions of the Strážek block deposits with lime milk with a concentration of 100 g / l of calcium oxide prepared from lime ground finely ground and carbide lime, the results shown in the attached table are achieved.

253 478

Ί§> o ί * CM

N LA and* O O vo O O • O τ— in- O CM ▼ - PS in- P II '«0 >> w p O 'Φ • d ► O 'rl • d PS • H Φ • P in > « Fri LA r ~ IN" 'CD aJ · » •in Tm O O LA O O WHAT O ▼ - \ J O ▼ PS IN" P '<0

la o co co t—

-vfCM in

CM

Z • sf

IA LA LA LA CM T— O O O T * CM * •to "to · » "to O O O O O O 7 7 IN 7

ia la la o o

CM

LA ό

PS> ra

N

S>

O

PS pi 'cd

CA

CM LA

CA

CA

CA la vo o b o o CM CA co

LA · * <ΓΑ About CM

T '' d CM M o o o o o o

7 7 7 7 7

CM (A CM

About X »LA V CA

VO LA CO CO IA CM t- O VO O OJ -1- 0 0 0 0 0 v

r-tA V CM

CA VO ·, •IN LA Ο- CA νο xř

o ná

Ή

Fri

. G

co • d • rl

Fh

and)

O1 o

PS

Pi 'cd

CA

IA <4 ” · * "to O O * - o O CM CA r * WHAT

<A bCO approx

’Φ IA · * LA O $ LA O r ~ •in CM •IN LA 00 · * CA •in r— ' the CM T— O O O O O -4- b- 7 the <4 IN 7 7 7 7 O CA CA

M

WITH

O

S>

G

Λ)

O • P

N

O

P

CA bIA

LA o

CO <7 \ CM vo

IN CA CA CM CM VO r— vo r— LA CA •to "to •to •to · » •to CM v- CA CM LA > 4 · O LA O O in- O O O CM LA b- O O r— 0- <4 · O O 4 · νθ τ— T—

ι — I

I

Η r-l i — t H i — 1 H r — 1

I-I-I-I (-I-R-I) -I-H-I-N

O r — I CO 'co PS r — I o

- «4 · o

what

CM w

+ + φ + cm cvi (* <CM cd ω.. p o g K g

Qj + S W i

CM 4 4 · O CO • P HO r-l

P ++

NfA CM I O Η Pm pS <a {f2i +

CM

O +

CM + + CA CM Pi 'd P £> CO O O P +

CM

• • CQ IQ & & O O • • > > »D »D P Pi O She knows. O d Pi

Claims (1)

OBJECT OF THE INVENTION 253 478 Process for removing heavy metals and for deactivating, for the purification and neutralization of radioactive liquid wastes, for example waste water, solutions and suspensions of the uranium industry, characterized in that carbide lime having an active calcium oxide concentration of 0.1 to 30% by weight is added to the liquid waste. 0.001 to 500 kg / m &lt; 3 &gt; of liquid waste and the resulting solid phase is separated from the liquid phase.