Discharge elimination of chromium metal and chromium salts production process of environmental pollution and waste obtained during utilization of it. Chromium is added to the iron ore of chromium soda ash, dolomite, limestone calcination temperature 1100 ~ 1200 ℃, the residue was leached with water, sodium chromate. About 3 to 5 tons of chromium slag is produced per 1 t of chromate produced.
Ingredients The chemical composition of chromium residue is shown in the table below.
Chromium mainly composed of well-mineral periclase (MgO), dicalcium silicate (β-2CaO • SiO 2) , iron calcium aluminate (4CaO • Al 2 O 3 • Fe 2 O 3), calcium chromite ( α–Ca(CrO 2 ) 2 ), chrome spinel ((Mg•Fe)(CrO 2 ) 2 ), sodium chromate tetrahydrate (4Na 2 CrO 4 •4H 2 O), and the like. Among them, a large part of the composition of the phase resembling cement, so the chromium slag is also hydraulic, and agglomerates in the air.
Hazard The main poison in the chromium residue is water-soluble sodium chromate tetrahydrate. Sodium chromate is a strong oxidant and is highly toxic. The chromium slag stack not only occupies the land, but also the fine particles fly with the wind to cause air pollution; the chromium slag is stacked in the open air and is immersed in rain and snow. The hexavalent chromium contained in the slag is dissolved and infiltrated into the groundwater or into the rivers and lakes, polluting the environment. The chromium slag yard of a certain iron alloy plant in China has not taken corresponding anti-seepage measures, causing the groundwater hexavalent chromium ion content to soar to 150-180mg/L, which is thousands of times higher than the drinking water standard, forming serious pollution pollution and downstream pollution. The scope has been increased to 15 to 20 km 2 . The domestic water consumption of several villages in the polluted areas depends on the introduction of tap water from outside or the supply of water by vehicles; various crops are also polluted to varying degrees. Aerosols of hexavalent chromium, chromium compounds and chromium compounds can harm human and animal health in many forms. Therefore, the storage yard of chromium slag must be paved with anti-seepage and additional hoods.
Handling and Utilization The way to prevent chromium slag contamination is to detoxify. Hexavalent chromium can be reduced under acidic conditions with a reducing agent, or under alkaline conditions with alkali metal sulfides or hydrosulfides, or at high temperatures and anoxic conditions in the presence of sulfur, carbon and carbide. It is a less toxic trivalent chromium. There are six main aspects of the use of chromium slag.
1. Making sintered bricks. The chromium slag is dried and pulverized, and the ingredients are mixed according to the ratio of 40% of chromium slag powder and 60% of clay , and are billed and baked. In high temperature and strong reducing environment, hexavalent chromium is reduced to trivalent chromium which is insoluble in water, eliminating highly toxic, and bricks can meet construction requirements.
2. Manufacturing cement. Using chromium slag, limestone, clay and other raw materials in accordance with ordinary Portland cement, cement clinker can be fired to make cement. The chromium residue after carbon reduction is the same as the blast furnace slag, the converter steel slag and the Portland cement clinker. Adding about 5% of gypsum can also produce less clinker steel slag cement.
3. Production of chromium slag cast stone. Mix 30% chromium slag, 25% silica sand (including SiO 2 >95%), 45% flue ash, 3% to 5% iron oxide scale (rolled steel skin), pulverize, and melt in a 1500 ° C tank kiln at 1300 ° C Under the casting, crystallization, annealing and slow cooling is the finished product, the simulated diabase stone composition is an excellent acid and corrosion resistant material.
4, the production of calcium and magnesium phosphate fertilizer instead of serpentine. The main components of serpentine are MgO and SiO 2 , which can be replaced by chromium slag. First pelletizing chromium slag, anthracite by: Phosphate: Chromium: silica = 37.5: 50:35:15 (weight ratio) is the ratio of ingredients was charged in a blast furnace, melt reaction at 1600 deg.] C, quenched by water quenching Cold, drain separation, drying in the drum, the ball mill smashed to get the finished product.
5. Replace dolomite and limestone for ironmaking flux. The content of CaO and MgO in the chromium slag is similar to that in the dolomite and limestone used in iron making, and can replace the dolomite and limestone iron making. Refining 1t pig iron consumes 600kg of chromium slag, hexavalent chromium can be completely reduced and detoxified thoroughly, and the chromium content of pig iron rises, hardness, wear resistance and corrosion resistance are improved.
6. Instead of chromite ore as a glass colorant. Chromium ore fines are commonly used as colorants in the manufacture of green glass, mainly by utilizing the optical properties of trivalent chromium ions in glass. The chromium slag contains a part of unreacted chrome ore and hexavalent chromium. The high temperature is favorable for the conversion of hexavalent chromium to trivalent chromium, completely detoxification, and the obtained product has bright green color. The chromium slag addition amount is preferably 3% to 5%.
In addition, the water-quenched chromium residue can also be used as a cement mixed material, a mineral wool raw material, a heat-resistant cementing material, a molten cement raw material, and the like. Since chromium slag is toxic and difficult to transport, its use is limited.
1.Welding materials
In Welding, substances called filler materials or consumables are used. As the name implies, these substances provide filler or a body of molten materials that provides a strong bond to be formed between the base metals used. Most welding processes will also require some form of shielding to protect both the main components and filler from being oxidized during the process.
The type of welding materials used during welding depends on the nature of the job intended. Electrodes draw the necessary energy in order to perform welding applications. Luoyang Golden Egret Company has any kind of welding materials include CTC Welding Rod /rope, SCTC welding rod/rope, TC electronic welding rod, Ni-based welding rod, flux-cored Welding Wires, solid welding wires and etc.
Welding can be applied in different kinds of industries such as building and construction, oil and gas, marine, power generation, steel, mine tools, automobile, transportation and etc.
2. Welding rod
1)Cast tungsten carbide based tubular rod
The hard phase of the rod is cast tungsten carbide which leads to higher hardness and better wear-resistance.
Wear resistance: the wear resistance is 6-7 times better than others. Tested by ASTM G65
Mainly used for Mining machinery, Geological tools, Petroleum drilling tools etc, by Oxy-Acetylene with weak carburizing flame.
Product recommendation:
GT1103 (CTC, 60-80 mesh),
GT1103-1(CTC, 20-30 um),
GT1103-2(CTC, 40-60 um)
2)The hard phase of tube rod is carbide pellets which leads to higher impact resistance and better wear resistance than CTC cloase rod.
Wear resistance: the wear resistance is 6-7 times better than others. Tested by ASTM G65 wear test.
Mainly used for mining machinery. Geological tools etc; by Oxy-acetylene with weak carburizing flame.
Product recommendation:
GT2102 (Cemented carbide grit, 30-60mesh)
GT2102-2(Cemented carbide grit, 30-40mesh)
GT2102-3(Cemented carbide grit, 40-60mesh)
3)Tube rod is composited by Cemented carbide pellets, Spherical CTC and CTC. The layer has higher impact resistance, better wear resistance and good fluidity than other rods.
Wear resistance: the wear resistance is 6-7 times better than others. Tested by ASTM G65.
Mainly used for oil method drill bits, such as Tri-cone bit, Steel tooth bit, PDC bit, etc. By Oxy-Acetylene with weak carburizing flame.
Product recommendation:
GT3302 (carbide pellets, 20-40mesh)
GT3302-1(carbide pellets, 14-40um)
4)The hard phase of the rod is monocrystal WC, the welding layer has a higher wear resistance and better impact resistance.
The wear resistance is 6-7 times better than others, tested by ASTM G65 method.
Mainly used for the repair and strength for oil drills bits, such as PDC bit diameter holding by Oxy-Acetylene with weak carburizing flame.
Product recommendation:
GT4104 (Monocrystal WC, 80-200mesh)
3. Welding Rope
Made form mixture of CTC and self-fluxing nickel alloy covering on nickel wire. The CTC is in spherical or irregular with good wear resistance; the nickel alloy is in spherical or nearly spherical shape with good wettability and erosion resistance and better corrosion resistance than tubular rod.
Recommend to use Petroleum drilling tools, Concrete mixing blade, Mud pump, Coal sluice, Coal drill pipe, Tunnel drilling machinery etc.
By Oxy-Acetylene Welding with weak carburizing flame.
Product recommendation:
GS110450N (CTC, 4mm, HRC 47-55)
GS110550N (CTC, 5mm, HRC 47-55)
GS110650N (CTC, 6mm, HRC 47-55)
4. Welding Bar
The rod is sintered by CTC and Ni-based powders. The CTC(Cast Tungsten Carbide) is in irregular or spherical shape with better wear resistance and the nickel alloy is in spherical or nearly spherical shape and has good wettability with cast tungsten carbide. The cladding layer has a higher impact resistance and better wear resistance.
Its wear resistance and corrosion resistance is between tube rod and flexible rope.
Mainly used on the Steel PDC bit, Concrete mixer blade, Mud pump, Miner chute, Miner drill stem and Mechanical parts of Tunnel rock drill machine etc.
Welded by Oxy-Acetylene with weak carburizing flame.
Product recommendation:
GD4025253-3(CTC, SCTC, 4*600/6*600)
GD4030303-3(CTC, SCTC, 4*600/6*600)
5. Welding wire
Intensified molybdenum titanium vanadium composite chromium carbide welding wire can improve layer`s bonding strength and tenacity. This wire can use for multilayer welding which has no peel off, and it can maintain good wear resistance under certain impact working condition.
Product recommendation:GSQD671Mo-4(1.6mm)
Medium carbon and high chromium wear resistance welding wire has a higher hardness, stronger wear resistance, and excellent toughness by adding a certain amount of molybdenum alloys and boride. It has a better impact resistance and strip resistance than high chromium cast iron type materials
Product recommendation: GSQD621Mo-4(1.6mm)
With high sphericity & excellent alloy organization, cemented carbide pellet is mainly used in welding, as an adding material of PTA Powder , tubular welding rod, to improve the wear resistance of the workpieces greatly.
Product recommendation: GQ06
Cemented carbide grit with different percent of cobalt has good abrasive resistance and is widely used for making grinding, polishing and cutting tools.
Product recommendation: GS08A
Weld Materials,Tubular Welding Rod,Welding Electrodes,Stainless Steel Welding Rod
Luoyang Golden Egret Geotools Co., Ltd , https://www.xtcthermalspray.com