FI65811C - FREEZING REQUIREMENTS FOR HOMOGRAPHIC INSPECTION PRODUCTS WITH NICKEL HEALTH SULFID - Google Patents

Description

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Pfetmt-och ragtaentyralMtt ^ AmMmpJKkM * l 30.03.84 (32) (33) (31) ΡΥΥ * «* Υ« moOww- * | lrt prtortut 26.12.74 USA (US) 536384 (71) AMAX Inc., 1270 Avenue of the Americas, New York, New York 10020, USA (72) Donald 0. Buker, Denver, Colorado, Richard A. Ronzio, Golden,

The present invention relates to a process for the preparation of a homogeneous feed product from nickel-containing sulfide metals. Extraction at atmospheric pressure means extraction in a hot acid solution at atmospheric pressure as opposed to extraction at high pressure.

Methods have been proposed for the selective extraction of nickel from nickel-containing sulphide-metal rocks, for example nickel sulphide and nickel-copper sulphide metal rocks.

For example, U.S. Patent 940,292 (issued November 16, 1909) discloses a method for selectively extracting nickel from a nickel-copper metal rock containing 40% nickel, 40% copper, and the remainder predominantly sulfur. The metal rock is ground and mixed with a hydrochloric acid solution at 83 ° C. According to the patent, a significant part of the nickel is selectively dissolved from the meta rock, with copper remaining in the residue.

The nickel-copper metal 11 of U.S. Patent 967,072 (August 9, 1910) is extracted with hot sulfuric acid to selectively dissolve nickel. The process is based on the in situ formation of H 2 Sin to prevent the dissolution of copper from the metal scale.

U.S. Patent 1,756,092 (April 29, 1930) describes a method for the selective extraction of nickel from nickel-copper sulfide metal rock. To accelerate the dissolution of nickel in acid 6581 1, the metal rock is melted and then rapidly cooled by granulation in water. The extraction is carried out in sulfuric acid at atmospheric pressure and at a temperature of 80 to 100 ° C.

U.S. Patents 2,223,239 (November 16, 1940), 2,239,626 (April 22, 1941) and 2,753,259 (July 2, 1956) disclose the selective extraction of nickel from nickel-copper with acid, for example HCl or H ^ SO ^ tllä. The patents emphasize the importance of using metal rock with a stoichiometrically lower sulfur content than the amount of all metals present. The lower the amount of combined sulfur, the higher the amount of nickel recovered by extraction.

However, the problem with atmospheric pressure extraction of nickel-containing metal rock is that the extraction properties of the metal rock tend to vary from alloy to alloy, whether in the cast or conventionally granulated state. Such properties are usually reflected in long extraction times, which adversely affect the economics of the process. There would be a need to provide a pre-treatment method independent of previous steps of a metal rock to ensure a uniform product with substantially uniform extraction properties, especially in terms of shorter extraction times and higher extraction efficiencies.

It is an object of the present invention to provide a nickel-containing sulphide metal rock in a form in which most of the nickel is economically selectively extractable in hot acid at atmospheric pressure. Another object is to provide a method for producing a nickel-containing metal rock with improved extraction properties, in which a plurality of metal stones of different origins are mixed together with or without the addition of scrap metal such as nickel, cobalt or copper-containing scrap metal and alloys containing these metals.

According to the invention, there is provided a process for the preparation of sulphide metallic stones for acid extraction at atmospheric pressure, for example for the preparation of nickel-containing sulphide metallic stones. The process mixes several different grades of nickel-containing sulfide metal stones to give a composition of 30 to 75% by weight of nickel (e.g. 40 to 70% by weight), up to 50% copper (e.g.

2 to 40%), up to 10% Co, k to 25% sulfur (eg 5 ”20%) and up to 5% iron, in which case the total amount of nickel, copper and sulfur is at least 90% by weight of the metal stone, whereby the sulfur content of the metal stone is less than that required to stoichiometrically coalesce with the metals therein, but does not exceed the amount required to coalesce with nickel N i ^^ 2-ks i, a melt bath of molten metal 1 having the above properties is formed at a temperature of at least 100 ° C higher than the flow-solidity temperature of the composition, lowering the temperature to a granulation temperature in the range of 50 ° C above - 100 ° C below said flow-solidity temperature, granulating said metal rock in the presence of said coolant, cooling it in a cooling liquid temperature range and then finely grinding said granulated metal stone so that at least 50 & passes through a sieve with a free mesh size of 0.05 3 mm.

Experiments have shown, as mentioned above, the preconception 1 IyI Ia and the prepared metal I to knife have excellent properties compared to metal stones of the same composition, either in the cast state or in the conventionally prepared granulated state. The production of metal rocks in the cast state usually involves the slow cooling of a large molten mass of nickel-containing sulfide, which usually results in a segregated structure. Such metal rocks in the finely ground state do not behave uniformly at atmospheric pressure during extraction, because such metal rocks usually have different melting and cooling stages. Conventionally granulated metal stones are those metal stones which have been granulated by casting said metal stone at a temperature substantially above the flow-solidity temperature of said metal stone, i.e. above 100 ° C above said flow-solidity temperature.

Although conventionally granulated metal stones have better extraction properties in the finely ground state than cast metal stones, such metal stones vary in properties from one batch or composition to another and do not always provide uniform extraction results.

Time is an important economic factor in atmospheric pressure extraction. Thus, by shortening the extraction time in the selective leaching of nickel from the metal rock, the remaining residue can thus be treated much more quickly under high pressure to extract the remaining valuable metals such as nickel and copper.

According to the invention, it has been found that uniform and considerably improved extraction results can be obtained by controlling the granulation temperature in a range not exceeding 50 ° C above the flow-solidity temperature of the metal rock composition and extending at 100 ° C below said flow-solidity temperature. , where the molten metal rock can be easily cast and granulated in a cooling medium, e.g. water, water jet, cooling gas, etc.

The thermal properties of a particular metal rock composition are determined by heating the metal rock to a preheated temperature above its solidity-flow temperature and then allowing it to cool slowly through the solidity-flow temperature range of 11 0581 1 to cool the metal at a temperature of one or more thermal barriers.

Once a thermal barrier to solidity temperature has been determined for a particular metal rock composition, this temperature is then utilized to determine the correct granulation temperature as defined below.

As discussed above, the metal rock grades of the various prior steps can be treated to provide a finely ground metal rock having the desired dissolution rate in hot sulfuric acid. The amount of nickel present in the total amount of nickel available for extraction depends on the composition of the metal rock. For example, the lower the amount of sulfur in the metal rock, the greater the amount of nickel available to be extracted (usually in the form of finely dispersed metallic nickel) and the compound in which the nickel is fused as NiS is not readily soluble in acid during the period in question.

To illustrate the above, analyzes of different grades of metal stones are shown in both the cast state and the granulated state (invention) in the following table.

Table 1 | Metal 1 rock type Element - * _ Available from nickel * metal rock I Ni Cu S Fe total nickel x IA (casting) AO, 0 39 »6 l6, A 0.23 6l | 2A (granulated) AO, 8: 38, 8 16.6 0, A3! 61 i; »'(Invention) \' i HB (in casting) · 68.0 3» A »21.0 I 3, ^ * 50» | 2B (Built)! 68.0 6.8 | 18.6 * 2.88 50 ((invention): 1C (granulated) j 51.6 j 38, A; 5.0 j 1.8A 92xx | (low S) ''> jj 2C (granulated)! 52, 0 | 38.8 j 5, A 1, 28 95 j (low S) jj

(invention) _j___J

5,65811 x - Estimated from Ni-Cu-S triangular diagram xx - Obtained granulated from Outokumpu in Finland

In the table, the metal stones IA and IB are in the cast state, while the metal stone 1C is conventionally in the granulated state.

The above-mentioned metal stones were then converted into granulated metal stones according to the invention, namely 2A, 2B and 2C.

In the case of metal rock IA, the charge was prepared by mixing with the received metal rock such substances as nickel powder, copper granules and elemental sulfur in percentages corresponding to the original composition of metal rock IA. The charge was melted in a 15 KW induction furnace and the melt was raised to 1371 ° C. The immersion thermocouple was immersed in a molten bath and the heating was stopped. A cooling curve was obtained which gave a resting point at a flow-solidity temperature of 960 ° C.

Using the resting temperature as a guide, the above charge was reheated substantially above the flow-solidity temperature of 1371 ° C and then dropped into a preheated clay-graphite crucible (preheated to 1093 ° C) and allowed to cool to the desired granulation temperature. is an opening or diameter of about 0.6 mm in which the pool was placed in a granulation device with a rotating plate to which carbon blades are radially attached. A perforated copper ring is placed in a device surrounding a casting basin through which water is sprayed when a stream of molten metal rock is fed at its own weight at 982 ° C to impinge on the surface of the rotating plate for deflection by carbon vanes. The temperature of the metal rock during the casting step is essentially the same as the flow-solidity temperature or slightly, for example 20-5 (Pc above it). from which they are assembled.

After granulation, the product is ground so that 50¾ of it remains on the 64 nm sieve and 75% of the finely ground product passes through a 94 gm sieve.

The metal stone 2B was prepared by granulating the metal stone IB, and the metal stone 2C was prepared by granulating the metal stone 1C, after which the granulated metal stones were ground as described above.

After the preparation of the finely ground metal stones according to the invention, each metal stone was subjected to an extraction program using an extraction solution containing 22 g per liter (g / l) of CuXX ions and 46 g / l of H 2 SO 4. The presence of copper ions in the solution 6,658,111 corresponds to the recycling of spent electrolyte from copper electrolyte cells, as explained below. Each test batch was introduced into 450 ml of a solution in which air was effectively bubbled at 520 ml / min and the solution was stirred at 420 rpm while maintaining the temperature at 75 ° C. The acid containing the above-mentioned acid has an initial acid pH of less than 0.5 and generally a pH of about 0.3.

According to the invention, the granulated metal rock is comparable to the corresponding received metal rock obtained by extracting the corresponding metal stones under the above-mentioned conditions until the heavy solution reaches a pH of 5.3, said pH being taken to indicate complete dissolution for practical purposes. The time after which the pH is 5.3 is used to compare the properties of different metal stones.

The results obtained by extracting 164 g of each metal rock IA and 2A in a 450 mm solution (about 271 wt-fc solids) are shown in the following table.

Table 2

Metal 1stone type Melting point ° C Granulation ° C Time min. that CuXX g / J% Ni extraction pH is 5.3 IA Casting 83 0.001 18.1 2A 1371 982 65 0.001 26j After extraction of I64g, the solution reached pH 5.3 much faster with granulated metal 1 stone than with cast metal 1 rock. and much higher amounts of soluble nickel were obtained. In both experiments, copper was cemented to a very low level of 0.001 g / l, 1 ppm, due to the free nickel in the solution-free metal brick.

However, when less than 91g of the same metal 1 age samples were extracted with the same amount of solvent (i.e., at a lower lower density), about 80¾ of the available nickel was extracted, whereby the granulated metal rock 2A was extracted 25 minutes faster than the cast metal rock IA. Virtually all of the copper was cemented by the nickel free of the leach solution in both metal stones, as shown in Table 3 ·

Table 3

Metal 1 type of rock Melting point ° C Granulation ° C Time min. To Cuxxg / 1% Ni extraction pH is 5.3 IA Casting 145 0.002 47.6 2A 1371 982 120 0.002 47.3 6581 1

Similar tests were performed on metal stones IB and 2B. The results are shown in the following table.

Table **

Metal stone type Melting point ° C Granulation ° C Time min. To CuXX g / 1? The pH of the extract is 5.3 IB Valuna> 250 7.20 25.9 2B 1371 982 110 0.001 ** 1.1

The extraction of the granulated metal rock 2B was completed after 110 minutes. About * ♦ 1? was extracted, corresponding to about 80% of the available 1-soluble nickel. Virtually all of the copper was discarded from the solution. On the other hand, the cast metal had been extracted very sparingly, so that after 250 minutes only 25.9¾ had dissolved. Solution IB still contained a relatively large amount of copper (7.2 g / l).

Experiments have shown that the temperature of the granules has an effect on the extraction activity of the substance. For example, metal rock 2A granulated at 1260 ° C to 1371 ° C tended to be less reactive than metal rock granulated at approximately 982 ° C.

The low sulfur metal scale 1C charge was melted at 1371 ° C and then granulated at 1150 ° C and 1260 ° C, respectively. The cooling curve showed that the flow-solidity temperature of this metal stone was about 1180 ° C. Thus, the second granulation temperature of 1150 ° C was 30 ° C below the flow-solidity temperature, while 1260 ° C was 85 ° C above this temperature.

An extraction program comprising 88 g of two differently ** in 50 ml (16¾ by weight of solid) a solution of the above-mentioned granulated metal rock gave the following results.

Table 5

Melting point ° C Granulation ° C Time min. To CuXX g / 1 Extracted Ni-? The pH is 5.3 1371 1260 185 0.001 38.3 1371 11 * »9 165 0.001 37, * ♦

As can be seen, although essentially the same amount of nickel dissolved, at 1150 ° C, the granulated limestone was more active in reaching a pH of 5.3 in 20 minutes faster. In other words, the extraction at atmospheric pressure takes place more quickly with the granulated metal rock according to the invention.

When ** 9 g of the same metal rock was extracted in the same manner with the same amount of solution as in Table 5, the following results were obtained.

8 6581 1

Table 6 O O) Οζ

Mp C Granulation C Total Final pH Cu g / l Extracted Ni-¾ extraction time 1371 1260 460 4.5 4.0 49.2 1371 1149 380 4.5 1.7 51.8

Much faster extraction was achieved at 1150 ° C with the granulated material compared to the granulation temperature of 1260 ° C. As can be seen, the metal rock cooled at 1150 ° C was extracted 80 minutes faster and more copper was discarded from the solution.

The extraction at atmospheric pressure is carried out at a time when the pH rises substantially above 4, e.g. to 4.5 and above, suitably at least to 5.

It is noted that the nickel-containing metal 1 grains granulated according to the invention produce a very fine-grained structure which is almost uniform when examined optically. In contrast, cast metal stone contains much larger granules in the separation steps. In the cast metal 1 primrose, the contact area at different stages is greatly reduced and as a result, the rate of gal but is-type reactions, due to the presence of free nickel during extraction, is also reduced.

The granulation temperature 1a has a beneficial effect on the extraction time. As indicated above, the temperature may be from 50 ° C above the solidity-fluidity temperature to 100 ° C below this temperature, the granulation temperature being suitably below the fluidity-solidity temperature, for example 15-75 ° C below this temperature.

Generally speaking, in metal 1 ethers with the same Ni: Cu weight ratio, the flow-solidity temperature increases as the sulfur content decreases. For example, in the case of a low-sulfur metal rock 1C (51.6¾ Ni, 38.4¾ Cu, 5¾ S, and 1.84 ¾ Fe), the flow-solidity temperature is 1200 ° C as determined from the Ni-Cu-S diagram. The experimental cooling curve gave a temperature of about 1203 ° C. The above-mentioned metal rock corresponds to the metal stones shown in Tables 5 and 8.

As discussed above, the granulation treatment of the invention is important to provide a feed product with increased extraction rates. This is important because it is able to provide a unit operation in which several processes can be equated to recover nickel, cobalt and copper, among others, such precious metals.

The granulation treatment can form the first step of the process. After granulation, the metal rock is finely ground to obtain a finely divided feed product of which at least 50¾ passes through a 94 μm sieve. · The metal rock may be a mixture of conventionally prepared metal rock compositions to which scrap metal (e.g. Ni, Co, Cu, etc.) may be optionally added together. with nysrik.

A typical granular metal 1 to knife has the following composition: 50.5¾ Ni, 28, U Cu, 0.6¾ Co, 2% Fe and 18.8¾ S.

In short, a typical unit operation involves placing a granulated metal rock in a finely ground state for extraction with acid at a temperature of 65 "to 85 ° C, while the extraction solution is highly gasified. Generally speaking, the density of the pulp may be 10-40¾ solids. The acid extraction solution is suitably electrolyte. recycled from the copper electrolyte process, which recycling is carried out later in the process, for example, an electrolyte containing 55 g / l Ni, 20 g / l Cu, 0.85 g / l Co, 122 g / l SO 2 ions and A 3 g / l Η 2 $ 0 ^.

Broadly speaking, the electrolyte used may contain up to 75 g / l of nickel, which is combined as sulphate, 5 ~ 30 g / l of copper Jd <a is combined as sulphate and 20-100 g / l of free sulfuric acid.

Copper is removed from the solution by hydrolysis and / or cementation during extraction at atmospheric pressure, and the resulting nickel-rich solution is treated to remove iron and then sent to nickel and cobalt for art. Methods for taking art of nickel and cobalt are well known and will not be explained in this specification.

After extraction at atmospheric pressure, the residue is filtered, washed and slurried with acid 1 to remove most of its iron. At this point, the residue may contain 28¾ Ni, ^ 8¾ Cu, 0.8¾ Co, 2, k% Fe and 22¾ S. After washing, the residue is slurried (e.g. 20-50¾ solids) and high pressure extraction is performed in an acid solution of about 2.6-3 .0 bar at an overpressure temperature of 177 - 20k ° C. This results in a heavy broth which, after filtration, becomes a feed solution for the separation of copper by electrolysis and which, after acidification and dilution, contains l »0-50g / l Ni, 40-50g / l Cu and 100g / l of free sulfuric acid.

The above solution is sent for copper electrolysis, the spent solution is recycled for extraction under atmospheric pressure and contains 55 g / l Ni, 20 g / l Cu, 0.85 g / l Co, 122 g / l SO 2 ions and * 3 g / l H 2 SO 4.

One important advantage in the production of the desired feed metal is by mixing together metal stones of different qualities and phases using scrap metal (Ni, Co,

Cu, mixtures thereof, etc.) with or without them, is that the feed product is obtained after granulation, which is independent of the previous stage of the mixed substances. Examples of mixed mixtures used to prepare the granulated feedstock of the invention include the following.

6581 1 10

Table 7

Substance Mixture _ Composition__ Other, X

weight% Ni% Cu I S% Fe IA 45 40 39.6 16.4 0.23 3.8 1B 45 68 3.4 21.0 3.40 3.2

Cu-romu 10 - 100.0 "

Seos- I

composition 100 48.6 29.5 16.9 1.6 3.4

Table 8

Substance Mixture _ Composition_ Other,% by weight% Ni% Cu | IS% Fe IB 30 68.0 3.4 j 21.0 3.4 4.2 1C 40 51.6 38.4 5.0 1.8 3.2 ----! ---

Mone1 - i romu 13 67.0 30.0 - 1.5 1.5 Mn

Cu-romu 10 100.0

Sulfur 7 - - 100.0

Mixture composition 100 49.8 30.3 15.3 1.9 2.7

As will be appreciated, any desired mixture can be prepared if the final mixture is melted and granulated according to the invention. Although cobalt is not mentioned in Tables 7 and 8, it is clear that it is present in small amounts in most nickel-containing sulfide metals. Of course, cobalt scrap can be used as a matel or mixtures to prepare mixed compositions in which the amount of cobalt can be 10% or more.

Claims (2)

A process for producing a homogeneous feed product from various grades of nickel-containing sulphide metal stones, which grades are characterized by non-homogeneous extraction properties when extracted at atmospheric pressure in a hot solution containing free sulfuric acid, characterized by mixing several different grades of nickel-containing sulphide the grades have been chosen to give an average composition of 30 to 75% by weight; nickel, up to $ 50 by weight of copper, up to 10% by weight of cobalt, A - up to 25% by weight of sulfur and up to $ 5 by weight of iron, with a total nickel, cobalt, copper and sulfur content of at least 90 % by weight of the blended composition, and wherein the amount of sulfur in the blended composition is less than the amount required to stoichiometrically coalesce with the metabase present, but does not substantially exceed the amount required to coalesce with nickel; forming a melt bath from the thus mixed metal rock composition at a temperature at least 100 ° C higher than the flow-solidity temperature of the mixed metal rock composition; lowering the temperature of the molten metal rock to a granulation temperature in the range of 50 ° C above 100 ° C to below the flow-solidity temperature; granulating the metal rock and cooling it in the presence of a coolant from a granulation temperature in the granulation temperature range; and then comminuting the granulated metal stone so that at least 50% passes through a screen having a free mesh size of 0.053 true. Process according to Claim 1, characterized in that the mixed composition obtained from metal of different qualities contains ** 0 to 70% nickel, 1 I 6581 1 Patent claims 2. AO% copper and 5 "20% sulfur, and that the granulation temperature is in the range of 15 to 75 ° C below the flow-solidity temperature.