DD151634B1 - CIRCUIT ARRANGEMENT FOR SLOW LINEAR RUNNING SPEED-CONTROLLED TAILGATE ENGINES - Google Patents

Description

Process for the recovery of gold from gold porcelain breakage

Field of application of the invention;

The invention relates to a method for the recovery of gold from gold porcelain fracture. The field of application of the invention also extends to the processing of all gold, non-metallic substances, e.g. Glass, plastic, paper, leather.

Bek ate technical solutions

Gold porcelain fracture has hitherto been processed exclusively by an enrichment process in the lead furnace. However, this method of processing has the following disadvantages:

- Porcelain has an unfavorable composition for the shaft of the process. So that the slag formers SiO ₂₁ Al ₂ CU and MgG / CaO are completely clogged and the gold can accumulate as quantitatively as possible in the metallic lead, correction additives in the form of sand, scale and lime are necessary in such an amount that three times of slag is formed. Daduruh the leaching losses increase for both the precious metals as well as for the non-ferrous metals in the process.

- The melting range of porcelain is compared to the melting temperature of the shaft furnace very high, so that a true integration of the porcelain is ensured in the melt only by maintaining the correct Cchlackenzusammensetzung by exact dosage of the correction additives.

If porcelain breakage remains unchanged in the kiln crucible, it is likely that the stitches or the passage to the forerun will clog up.

The disadvantages of the thermal processing of gold porcelain fracture are so gxavierend that was partially dispensed with a workup of the resulting gold porcelain breakage.

Zisl of the invention is a simple, economical process that allows the quantitative recovery of gold independently of other metallurgical processes.

VJ esen the invention

The invention is based Ai gabe to provide a method for processing gold porcelain fracture by a wet chemical process.

According to the invention the object is achieved in that the gold-containing material is treated with an aqueous solution of thiourea substance, an oxidation potential of 270-30 niV, measured Pt against calomel electrode, is set with the addition of an oxidizing agent, the gold in the form of Complex compounds is brought into solution and is recovered by cementation and / or absorption on an ion exchanger.

A preferred embodiment of the invention provides that the solid Ausfjangsmaterial with an aqueous solution of thiourea, the

0.1 mol / l thiourea 0, 0% mol / l Fe-III-d sulfate 0.05 mol / l sulfuric acid

contains, where the gold dissolves in complex form according to the following equation:

2Au + Fe ₂ (SO ₄₎ + 4SC (NH) _{2) 2} -. = "(Au / SO (NH _{2) 2/2) 2} S0 ₄ + 2FeSO ^

The freshly prepared solution looks reddish and has a. electrochemical potential of 310 mV. In order to promote the dissolution of gold as complex compound of the thiourea, which is ThioharnstoffIb ^- solution an oxidant, preferably Fe-III-sulphate is added. According to a further feature of the invention, the effectiveness of the solution is obtained by constant Na o ^h se- zen of oxidizing agent, this refreshment is determined by measuring the oxidation potential in the solution, ie the effectiveness of the solution and thus the required leaching time can be Determine via the potential measurement and adjust afterwards.

The amount of oxidizing agent should be such that a potential of 270-300 mV is established.

The effectiveness of the solution decreases with time, because not; only for the dissolution of the gold, but partly for the oxidation of sulfur from the thiourea to elemental sulfur, part of the oxidizing agent is consumed;

S ² ~ + 2Fe ^ "S + 2? E ²⁺

As the potential decreases, the time required to detach a given amount of gold increases.

The dissolution process is by heating - preferably to 30 35 ⁰ O - and moving the liquor - preferably by introducing air - accelerated. Named temperature increase brings a shortening of the. Solve required time by 2 to 3 times.

The gold is in dissolved form as a complex compound (Au / SO (NK ₂ ) ₂ 7 ₂ ) 2 ^S0 4 ^{and can be} recovered ^{in the} next step both by cementation with metallic zinc and by absorption on a strongly acidic cation exchanger, preferably Wofatit KPS become.

The cementation of the gold from the liquor is expediently carried out with bar zinc, since with the use of zinc dust next to the cementation still a strong Lösereaktion the zinc with the sulfuric acid present under vigorous evolution of hydrogen expires until the liquor is neutral. Besides, has bars

Zink the further advantage that the unused rods can be mechanically removed from the solution and used for subsequent cementation.

The exchanger is used in the H ¹ -form. After filtration to separate off sulfur and porcelain fragments, the solution can be used without any pretreatment.The exchanger is expediently used in the two-column process.The process is checked for gold by known analytical methods and the resin is replaced when exhausted. * Obtained by ashing of the loaded resin to get the ballistic gold »

The thiourea solution is recycled. The invention will be explained in more detail by the following example;

Embodiment j

In 30 liters of an aqueous solution containing 0.1 mol of thiourea, 0.01 mol of Fe ₂ (SO ₃ ) ₃ and 0.05 mol of H ₂ SO ₄ per liter, 33 »5 kg porcelain gold fracture in a Plejtefaß at room temperature in 3 batches leached one after the other. While introducing air, the solution was constantly agitated. The freshly prepared solution had an oxidation potential of 280 mV, which was maintained during the leaching by continuous addition of a total of 15 g Fe ^ ⁺ in a range of 270 - 3OO mV. As a result, the effectiveness of the solution remained almost constant. The leaching of a batch of gold porcelain break lasts 75 - 90 minutes.

The L _a UGE contained> 5J8 mg Au / 1 and 1.2 g Fe / 1 after the throughput of 33 »5 kg Porcelain Gold breakage. There had been 8.2 g of sulfur, which can be discarded without hesitation; it contained only 0.006% Au. The leached porcelain was washed with water to keep the leaching losses low.

The clear gold-containing solution was mixed at a flow rate

-1 -2 before about 1 1. H . cm over 2 columns each with 1 1 Wofatit EPS in H 'form given. After the flow rate of 30 1 solution, the capacity of the exchanger was not exhausted by far "The effluent solution containing a gold content of 0.3 - hctte 0.5 mg / 1, the leaching runs in front again.

Claims (4)

Erfindungsanspruoh 1, A process for Mickgewinnung gold from gold porcelain, wherein the gold-containing material is treated with the addition of oxidizing agent, preferably ferric compounds, with an aqueous solution of uliourea, brought the gold in the form of complex compounds in solution and by absorption on an ion exchanger is recovered, characterized in that the effectiveness of the thiourea solution and thus the amount of oxidizing agent required over the oxidation potential of the solution measured and to a potential of 270 - 300 mV, measured Pt- against calomel electrode, adjusted and the gold by absorption on a strongly acidic cation exchanger is recovered » 2. Method according to item 1, characterized that the aqueous starting solution 0.01 - 1 mol / l SC (NHg) ₂ 0.01 - 1 mol / l Fe-III sulfate 0.01-2 mol / l H ₂ SO ₄ contains, wherein the oxidizing agent of the solution is added immediately before or during the leaching process. 3 * The method of item 1 and 2, dadurch.gekennz eichnet that the aqueous solution to 30 - 35 ⁰ C. and is moved by introducing air. 4 · Method according to item 1, characterized gekennzeic hnet. that the cation is therefore ashed for the extraction of the gold.