Part Manufacturing Process Improvements Housing

Contents

Task

Contents

Introduction

1. Literary review

1.1. Prevalence of gold in nature

1.2. Application of gold in science and technology

1.3. Physicochemical properties of gold

1.4. General information about sorption

1.5. Ion exchange mechanism

1.6. Methods of extracting and concentrating noble

metals

1.7. Preparation of metal sulfides

1.8. Principle of sorption on inorganic sorbents

1.9. Series Rule

1.10. Practical meaning of a series rule

1.11. Goals and objectives of thesis

2. Experimental part

2.1. Reagents used

2.2. Preparation of solutions

2.3. Method of sorbent production

2.4. Gold quantification by potentiometric titration

2.5. Description of the experiment

2.6. Calculation of kinetic constraints

2.7. Calculation of thermodynamics of sorption process

3. Enlarged Design

3.1. Description of the proposed process diagram

3.2. Material calculation of the main unit

3.3. Calculation of periodic ion exchange column

3.4. Mechanical calculation of the main unit

3.5. Hydraulic calculation

3.6. Preparation of functional diagram of automation

4. Occupational safety

4.1. Analysis of hazards and hazards

4.2. Chemical Toxic Poisoning Safety Measures

4.3. Electrical safety

4.4. Measures to protect against mechanical injury

4.5. Noise and vibration protection measures

4.6. Measures to ensure sanitary standards for natural and artificial lighting

4.7. Water supply

4.8. Sewerage system

4.9. Production ventilation

4.10. Fire safety

4.11. Conclusion

5. Economic part

5.1. Production Planning

5.2. Production capacity calculation

5.3. Organization of labour and wages

5.4. Calculation of the number of main workers, employees, ITR and MOS

5.5. Calculation of the number of duty personnel

5.6. Calculation of the annual salary fund of the main workers

5.7. Calculation of the supplementary wage fund

5.8. Calculation of the salary fund of auxiliary workers

5.9. Calculation of the salary fund of ITR, employees and MOS

5.10. Capital Cost Calculation

5.11. Development of costing and cost of production

5.12. Conclusion

Conclusions

Аnnotation

List of literature used

Introduction

Noble metals (Au, Ag, Pt, Os, Yr, Pd, Rh, Ru) have unique properties based on catalytic activity, high melting point and corrosion resistance. This determines the widespread use of noble metals in various industries: in the automotive, chemical, electronic industries and others. Increasing global demand and consistently high prices for precious metals make them the most promising minerals and require further research and research in order to identify new ore phenomena and develop methods of extraction and concentration.

At the same time, the development of selective extraction and sorption methods for the extraction of noble metals from secondary raw materials, both from acidic and alkaline solutions obtained during the processing of electronic waste, spent fuel from nuclear power plants and the treatment of waste water from industrial enterprises, is now of great importance.

Among various types of sorbents, inorganic and complexing sorbents are most often used to extract and concentrate noble metals; ion exchange resins, coal, modified polymer materials and other supports are also used.

Of the inorganic sorbents, sulfides of a number of metals have found the greatest use in the extraction and concentration of noble metals. Sulfide sorbents exhibit selectivity to cations forming insoluble sulfides. The main exchange reaction is the reaction of replacing the sulfide cation with the corresponding ion from the solution. In the aqueous medium, the reaction proceeds at a high rate. The very small solubility of noble metal sulfides, their ability to be isolated in strong acidic media allows the noble metals to be selectively extracted and concentrated.

Metal sulfides used as sorbents, in most cases, are prepared by chemical deposition on various substrates (glass, cellulose, polyethylene terephthalate, gelatin, etc.), which leads to the formation of thin microcrystalline films. However, in these thin film systems, ion exchange processes due to the difficult diffusion of sorbate into the crystal array are relatively slow. This drawback can be largely overcome by using polymer sorbents in the form of so-called "filled" sorption materials rather than microcrystalline films as the sorbent. They are a neutral polymer composite material within which a finely dispersed filler sorbent (difficult to dissolve sulfide) is firmly retained, allowing the formation of granules of any shape therefrom.

One promising polymer for constructing such "filled" sorption materials is agar. Agar is a polysaccharide formed by long chain molecules connected to each other by a limited number of transverse bonds. As a result, after the introduction of the filler, a large number of crystalline metallosulfide blocks are formed that are capable of receiving and fixing molecules or ions of the sorbed substance. In addition, agar as a microporous substance has a very well-developed surface. Therefore, when it is contacted with an aqueous solution of a noble metal, it is ensured that both the solvent and the subsequently dissolved substance in it penetrates into its array. In addition, agar globules have sufficient resistance to physical and mechanical effects and temperatures of solutions in contact with them up to 100 0C, as well as to the action of alkaline and slightly acidic solutions.

The purpose of the work is to develop a method of producing an agar-based sorbent containing some metal sulfides and to identify the possibilities of these sorption systems as sorbents of gold (III) ions.

1. Literary review

1.1. Prevalence of gold in nature

The earth's crust contains gold 20 times less than silver, and 200 times less than mercury. The uneven distribution of gold in various parts of the earth's crust makes it difficult to study its geochemical features. The seas and oceans contain about 10 billion tons of gold. About the same amount of gold is contained in river and groundwater.

Increased gold content is found in the waters of springs and rivers flowing in gold-bearing regions. In nature, gold is mainly in its native form and is a mineral that is a solid solution of silver in gold containing up to 43% Ag, with impurities of copper, iron, lead, less often bismuth, mercury, platinum, manganese and other elements. In addition, gold is found in the form of natural amalgam, as well as chemical compounds - solenides and tellurides. In terms of particle size, native gold is divided into finely dispersed (1-5 microns), pulverized (5-50 microns), fine (0.05-2 mm) and large (more than 2 mm). Particles weighing more than 5 g belong to nuggets. The largest nuggets are the Holterman Plate (285 kg) and the Coveted Stranger (71 kg) found in Australia. Finds of nuggets are known in many areas of the Urals, Siberia, Yakutia and Kolyma. Native gold is concentrated in hydrothermal deposits.

Gold deposits are divided into native and crumbling. Gold deposits were formed in different geological eras at different depths - from tens of meters to 4-5 km from the surface of the earth. The indigenous deposits are represented by veins, systems of veins, deposits and zones of live-in ores with a length of tens to thousands of meters. For a long period of history, the land of the mountain was destroyed and the water carried away everything that did not dissolve in the rivers. At the same time, heavy minerals separated from the lungs and accumulated in places where the flow rate was small. So placer deposits with a concentration of relatively large gold were formed. As a rule, industrial placers are formed relatively close to the indigenous deposits. A certain part of microscopic gold particles remains in placers, however, due to the impossibility of its extraction, it is not of practical importance. Some microscopic and colloidal gold particles are carried away by aquatic sources into the seas, oceans and lakes, where it is scattered in the form of thin suspensions or is in silty sediments. Thus, as a result of erosion processes, most of the gold is irretrievably lost. [1]

1.2. Application of gold in science and technology

For thousands of years, gold has been used for the production of jewelry and coins, and the use of gold for dental prosthetics is known to the ancient Egyptians. The use of gold in the glass industry has been known since the end of the XVII century. gold foil, and later electroplating with gold was widely used to gild the domes of church churches. Only the last 40-45 years can be attributed to the period of purely technical use of gold. Gold has a unique complex of properties that does not have any other metal. It has the highest resistance to aggressive media, in terms of electro-and thermal conductivity it is inferior only to silver and copper, the gold core has a large neutron capture section, gold's ability to reflect infrared rays is close to 100%, in alloys it has catalytic properties. Gold is very technological, ultra-thin foil and micron wire are easily made from it. Gold coatings are easily applied to metals and ceramics. Gold is soldered well and welded under pressure. Such a set of useful properties led to the widespread use of gold in the most important modern industries of technology: electronics, communications technology, space and aviation technology, chemistry.

It should be noted that 90% gold is used as coatings in electronics. Electronics and related engineering industries are the main consumers of gold in technology. In this field, gold is widely used for connection of integrated circuits by pressure welding or ultrasonic welding, contacts of plug connectors, as thin wire conductors, for soldering elements of transistors and other purposes. In the latter case, it is especially important that gold forms light-melting eutectics with indium, gallium, silicon and other elements that have conductivity of a certain type. In addition to technological improvements in electronics, palladium, tin coatings, tin alloys with lead and an alloy of 65% Sn + 35% Ni with a gold sublayer began to be used instead of gold for a number of parts and assemblies. Tin alloy with nickel has high wear resistance, corrosion resistance, acceptable value of contact resistance and electrical conductivity. Despite the fact that at present the consumption of gold in electronics is constantly increasing, it is believed that it could be 30% higher if it were not for measures aimed at saving gold.

In microelectronics, gold-based pastes with different electrical resistance are widely used. The wide use of gold and its alloys for contacts of low-current equipment is due to its high electrical and corrosive properties. Silver, platinum and their alloys, when used as micro-current switching contacts at micro-stresses, give much worse results. Silver quickly dims in an atmosphere contaminated with hydrogen sulfide, and platinum polymerizes organic compounds. Gold is free from these disadvantages, and contacts made from its alloys provide high reliability and long service life. Gold solders with low steam pressure are used for soldering vacuum tight joints of electronic lamp parts, as well as for soldering units in the aerospace industry.

Gold alloys with cobalt or chromium are used for temperature control and especially for low temperature measurements. In the chemical industry, gold is mainly used for cladding steel pipes designed to transport aggressive substances.

Gold alloys are used in the production of watch cases and feathers for pens. In medicine, not only denture gold alloys are used, but also medical preparations containing gold salts for various purposes, for example, in the treatment of tuberculosis. Radioactive gold is used in treatment of malignant tumors. In scientific research, gold is used to capture slow neutrons. With the help of radioactive gold isotopes, diffusion processes in metals and alloys are studied.

Gold is used to metallize the windows of buildings. During the hot summer months, a significant amount of infrared radiation passes through the window windows of buildings. Under these circumstances, the thin film (0.13 μm) reflects infrared radiation and becomes much cooler in the room. If current is passed through such a glass, it will acquire fog properties. Gold-coated inspection windows of ships, electric locomotives, etc. are effective at any time of the year. [2]

1.3. Physicochemical properties of gold

Gold is a gravitational, forged metal of a specific yellow color. Gold is the chemical element of group I, the 2nd subgroup of the periodic system of elements of D. I. Mendeleev with sequence number 79. The physical properties of gold are as follows: atomic mass 196.967; density 1932 g/cm3; melting point 1063 ° C; boiling point 2947 ° C; specific heat capacity 130 J/( kg. ° С); elongation of 3050%.

As can be seen from these data, gold is a heavy metal that has a large relative elongation when forged. Gold can be rolled but or forged into sheets about 0.00008 mm thick, which are shone in bluish green. High gold density is important for the processes of gravitational enrichment of gold-bearing ores and placers, since all other ore rocks and minerals have a much lower density.

Despite the fact that gold in the periodic system of D. I. Mendeleev is in the same group as silver and copper, its chemical properties are much closer to the chemical properties of platinum group metals. The electrode potential of the Au - Au (111) pair is - 1.5 V. Due to this high value, diluted and concentrated HCI, HNO, HSO do not act on gold. However, in HCI, it dissolves in the presence of oxidants such as magnesium dioxide, iron chloride and copper, as well as under high pressure and at high temperature in the presence of oxygen. Gold is also readily soluble in a mixture of HCI and HNO (royal vodka). Chemically, gold is a inactive metal. In air, it does not change, even with strong heating. Gold is readily soluble in chlorine water and in aerated solutions of alkali metal cyanides. Mercury also dissolves gold, forming an amalgam, which at a content of more than 15% gold becomes solid. Two rows of gold compounds are known, corresponding to oxidation states + 1 and + 3. So, gold forms two oxides - gold oxide (I), or gold oxide, AuO and gold oxide (III), or gold oxide, AuO. Compounds in which gold has an oxidation state of + 3 are more stable. Gold compounds are easily reduced to metal. The reducing agents can be hydrogen under high pressure, many metals in the range of stresses up to gold, hydrogen peroxide, two tin chloride, iron sulphate, titanium trichloride, lead oxide, manganese dioxide, alkali and alkaline earth metal peroxides. Various organic substances are also used to reduce gold: formic and oxalic acids, hydroquinone, hydrazine, methol, acetylene, etc. Gold is characterized by the ability to form complexes with oxygen and sulfur-containing ligands, ammonia and amines, due to the high energy of the formation of corresponding ions. Most often, compounds of monovalent and trivalent gold are found. Often they are considered as complex molecules consisting of an equal number of atoms Au (I) and Au (III). Trivalent gold is a very strong oxidizing agent, it forms many stable compounds. Gold is combined with chlorine, fluorine, iodine, oxygen, sulfur, tellurium and selenium. [3]

1.4. General information about sorption

By sorption we mean the process of absorption of one or more components from a solution by a solid substance - a sorbent. The substance to be absorbed is called sorbate or sorbent.

Sorption processes (like other mass transfer processes) are selective and usually reversible. Due to their reversibility, it becomes possible to separate absorbed substances from the sorbent, or to conduct a desorption process.

Sorption is mainly used at low concentrations of the absorbed substance in the starting mixture, when it is necessary to achieve almost complete recovery of the sorbent. Where the concentration of the absorbed substance in the starting mixture is high, it is generally more advantageous to use absorption.

The importance of sorption processes has increased greatly recently due to the increased need for high purity substances.

Distinguish between physical and chemical sorption. Physical sorption is due to the mutual attraction of sorbate and sorbent molecules under the influence of VanderWaals forces and is not accompanied by the chemical interaction of the sorbed substance with the absorber. Chemical sorption, or chemisorption, results in a chemical reaction between the molecules of the absorbed substance and the surface molecules of the scavenger.

As sorbents, porous solids with a large specific surface area, usually referred to as a unit mass of the substance, are used.

In industry, the absorber is mainly activated coals and mineral sorbents (silica gel, zeolites, etc.), and for the extraction and concentration of noble metals, synthetic ion exchange resins (ionites) are mainly used.

Ionites. These sorbents are both natural and synthetic inorganic and organic substances. Natural ionites include zeolites, clay minerals, fossil coals, etc. Synthetic ionites are fused zeolites and molecular sieves (zeolites with a regular crystal structure), ion exchange resins, activated minerals and organic substances, etc.

Ion exchange technology for extraction and concentration of noble metals from ores and concentrates is based on the use of ion exchange resins.

Ionites are practically insoluble in water, as well as in conventional solvents, and have mobile ions capable of exchanging for an equivalent amount of ions (with the same sign) from the electrolyte solution with which the absorber contacts.

Ionites containing acidic active groups and exchanging mobile anions with the electrolyte solution are called anionites, and ionites containing basic active groups and exchanging mobile cations are called cationites. There are also amphoteric ionites capable of cationic and anionic exchange at the same time.

Many natural compounds and chemicals produced artificially have ion-exchange properties. However, in practical terms, the first place among them is occupied by ionites obtained from synthetic polymers - ion exchange resins. They are solid insoluble three-dimensional polymers.

Insolubility and chemical resistance of synthetic ionites is ensured by the choice of starting insoluble materials for synthesis, when using ionites in pulp processes they should have a high

mechanical strength against abrasion and impact loads. Increased mechanical strength of ionites is achieved by addition of an increased amount of binding substance - divinylbenzene (DVB) to the resin matrix. The percentage of DVB is called the "crosslinking percentage." Anionites used in production processes contain 812% DVB.

Ionites are released in the form of grains of regular spherical shape. Depending on the conditions of synthesis, the type and purpose of the ionite grains, they can have different dimensions in the cross-section - from 0.2 to 1.2 mm.

Ion exchange resins have a large exchange capacity, selectivity to individual nones, chemical resistance and mechanical strength. Therefore, now they are the most common ionites, which have practically displaced other types of ionites in industrial conditions.

Ionites containing only one type of active groups are called monofunctional, with several types of active groups - polyfunctional. The monofunctional ionite is a strongly basic anionite of the "AM" brand, which contains only one type of functional group - a strongly basic quaternary ammonium base - S [N] * -

By changing the composition of the active groups in the synthesis of ion exchange resins, ionites with very diverse properties can be obtained.

Polyfunctional anionite is AM2B anionite used in gold sorption technology. [4]

1.5. Ion exchange mechanism

If we denote the ion exchanging letters A and B, then the ion exchange reaction in general form can be written as follows:

R-[A+B] ↔ R-[B+A]

The most simplified model of ion exchange resin is ionite in the form of a sponge, in the pores of which counterions float. When such a sponge is immersed in the solution, counterions can leave its pores and pass into the solution. In order to maintain electroneutrality in the sponge, an equivalent amount of other ions from the solution must enter the ionite.

There are a large number of theories and hypotheses that explain the mechanism of ion exchange, but none of them at present can satisfactorily describe the entire variety of phenomena occurring in ion exchange processes. However, the basic ion exchange provisions have already been well developed.

According to modern ideas, ion exchange reactions occur due to the difference in the chemical potentials of exchanging ions in the ionite phase and in the electrolyte solution. Since counterion A has a high concentration in the ionite phase, when the ionite contacts the electrolyte solution, it tries to diffuse into the solution, where its concentration is insignificant. Thus, the electroneutrality of the ionite is disturbed, and the ionite receives an additional charge. In order to return to the original position of electroneutrality and compensate for the resulting charge, the ionite is forced to absorb from the solution an equivalent amount of ions of the same sign that must occupy the active groups released by the counterions released from the ionite. Due to the absorption of ions from the solution, the ionite again becomes electroneutral.

Thus, the diffusion of counterions from the resin into the solution and vice versa is limited by the condition that the ionite maintains electroneutrality; compensation of electric charge of fixed ions at transition of ions A from ionite to solution is performed by replacement of ions A in ionite with equivalent number of ions in from solution. In other words, ions in the ionite-solution system are affected, on the one hand, by a concentration gradient that causes diffusion, and on the other hand, by electrostatic forces that counteract ion diffusion.

The ion redistribution process proceeds until dynamic equilibrium is established, at which for each mobile ion the electric field effect is balanced by diffusion flow. In the case of ion exchange equilibrium, the amount of counterions passing from the resin phase to the solution is equivalent to the amount of ions of the same sign but of a different grade passing from the solution to the resin phase. [5]